Programs & Examples On #Opos

OLE for Retail POS. An architecture for Win32-based POS device access.

How to install JDK 11 under Ubuntu?

I created a Bash script that basically automates the manual installation described in the linked similar question. It requires the tar.gz file as well as its SHA256 sum value. You can find out more info and download the script from my GitHub project page. It is provided under MIT license.

Support for the experimental syntax 'classProperties' isn't currently enabled

For ejected create-react-app projects

I just solved my case adding the following lines to my webpack.config.js:

  presets: [
    [
      require.resolve('babel-preset-react-app/dependencies'),
      { helpers: true },
    ],
    /* INSERT START */
    require.resolve('@babel/preset-env'),
    require.resolve('@babel/preset-react'),
      {
      'plugins': ['@babel/plugin-proposal-class-properties']
    } 
    /* INSERTED END */
  ],

com.apple.WebKit.WebContent drops 113 error: Could not find specified service

Perhaps the below method could be the cause if you've set it to

func webView(_ webView: WebView!,decidePolicyForNavigationAction actionInformation: [AnyHashable : Any]!, request: URLRequest!, frame: WebFrame!, decisionListener listener: WebPolicyDecisionListener!) 

ends with

decisionHandler(.cancel)

for the default navigationAction.request.url

Hope it works!

Cannot connect to the Docker daemon on macOS

You should execute script for install docker and launch it from command line:

brew install --cask docker
sudo -H pip3 install --upgrade pip3
open -a Docker
docker-compose ... 

after that docker-compose should work

Remove all items from a FormArray in Angular

While loop will take long time to delete all items if array has 100's of items. You can empty both controls and value properties of FormArray like below.

clearFormArray = (formArray: FormArray) => { formArray.controls = []; formArray.setValue([]); }

How to import an Excel file into SQL Server?

You can also use OPENROWSET to import excel file in sql server.

SELECT * INTO Your_Table FROM OPENROWSET('Microsoft.ACE.OLEDB.12.0',
                        'Excel 12.0;Database=C:\temp\MySpreadsheet.xlsx',
                        'SELECT * FROM [Data$]')

What are the new features in C++17?

Language features:

Templates and Generic Code

Lambda

Attributes

Syntax cleanup

Cleaner multi-return and flow control

  • Structured bindings

    • Basically, first-class std::tie with auto
    • Example:
      • const auto [it, inserted] = map.insert( {"foo", bar} );
      • Creates variables it and inserted with deduced type from the pair that map::insert returns.
    • Works with tuple/pair-likes & std::arrays and relatively flat structs
    • Actually named structured bindings in standard
  • if (init; condition) and switch (init; condition)

    • if (const auto [it, inserted] = map.insert( {"foo", bar} ); inserted)
    • Extends the if(decl) to cases where decl isn't convertible-to-bool sensibly.
  • Generalizing range-based for loops

    • Appears to be mostly support for sentinels, or end iterators that are not the same type as begin iterators, which helps with null-terminated loops and the like.
  • if constexpr

    • Much requested feature to simplify almost-generic code.

Misc

Library additions:

Data types

Invoke stuff

File System TS v1

New algorithms

  • for_each_n

  • reduce

  • transform_reduce

  • exclusive_scan

  • inclusive_scan

  • transform_exclusive_scan

  • transform_inclusive_scan

  • Added for threading purposes, exposed even if you aren't using them threaded

Threading

(parts of) Library Fundamentals TS v1 not covered above or below

Container Improvements

Smart pointer changes

Other std datatype improvements:

Misc

Traits

Deprecated

Isocpp.org has has an independent list of changes since C++14; it has been partly pillaged.

Naturally TS work continues in parallel, so there are some TS that are not-quite-ripe that will have to wait for the next iteration. The target for the next iteration is C++20 as previously planned, not C++19 as some rumors implied. C++1O has been avoided.

Initial list taken from this reddit post and this reddit post, with links added via googling or from the above isocpp.org page.

Additional entries pillaged from SD-6 feature-test list.

clang's feature list and library feature list are next to be pillaged. This doesn't seem to be reliable, as it is C++1z, not C++17.

these slides had some features missing elsewhere.

While "what was removed" was not asked, here is a short list of a few things ((mostly?) previous deprecated) that are removed in C++17 from C++:

Removed:

There were rewordings. I am unsure if these have any impact on code, or if they are just cleanups in the standard:

Papers not yet integrated into above:

  • P0505R0 (constexpr chrono)

  • P0418R2 (atomic tweaks)

  • P0512R0 (template argument deduction tweaks)

  • P0490R0 (structured binding tweaks)

  • P0513R0 (changes to std::hash)

  • P0502R0 (parallel exceptions)

  • P0509R1 (updating restrictions on exception handling)

  • P0012R1 (make exception specifications be part of the type system)

  • P0510R0 (restrictions on variants)

  • P0504R0 (tags for optional/variant/any)

  • P0497R0 (shared ptr tweaks)

  • P0508R0 (structured bindings node handles)

  • P0521R0 (shared pointer use count and unique changes?)

Spec changes:

Further reference:

org.springframework.web.client.HttpClientErrorException: 400 Bad Request

This is what worked for me. Issue is earlier I didn't set Content Type(header) when I used exchange method.

MultiValueMap<String, String> map = new LinkedMultiValueMap<String, String>();
map.add("param1", "123");
map.add("param2", "456");
map.add("param3", "789");
map.add("param4", "123");
map.add("param5", "456");

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

final HttpEntity<MultiValueMap<String, String>> entity = new HttpEntity<MultiValueMap<String, String>>(map ,
        headers);
JSONObject jsonObject = null;

try {
    RestTemplate restTemplate = new RestTemplate();
    ResponseEntity<String> responseEntity = restTemplate.exchange(
            "https://url", HttpMethod.POST, entity,
            String.class);

    if (responseEntity.getStatusCode() == HttpStatus.CREATED) {
        try {
            jsonObject = new JSONObject(responseEntity.getBody());
        } catch (JSONException e) {
            throw new RuntimeException("JSONException occurred");
        }
    }
  } catch (final HttpClientErrorException httpClientErrorException) {
        throw new ExternalCallBadRequestException();
  } catch (HttpServerErrorException httpServerErrorException) {
        throw new ExternalCallServerErrorException(httpServerErrorException);
  } catch (Exception exception) {
        throw new ExternalCallServerErrorException(exception);
    } 

ExternalCallBadRequestException and ExternalCallServerErrorException are the custom exceptions here.

Note: Remember HttpClientErrorException is thrown when a 4xx error is received. So if the request you send is wrong either setting header or sending wrong data, you could receive this exception.

Launch an event when checking a checkbox in Angular2

You can use ngModel like

<input type="checkbox" [ngModel]="checkboxValue" (ngModelChange)="addProp($event)" data-md-icheck/>

To update the checkbox state by updating the property checkboxValue in your code and when the checkbox is changed by the user addProp() is called.

How can I conditionally import an ES6 module?

No, you can't!

However, having bumped into that issue should make you rethink on how you organize your code.

Before ES6 modules, we had CommonJS modules which used the require() syntax. These modules were "dynamic", meaning that we could import new modules based on conditions in our code. - source: https://bitsofco.de/what-is-tree-shaking/

I guess one of the reasons they dropped that support on ES6 onward is the fact that compiling it would be very difficult or impossible.

Can't push image to Amazon ECR - fails with "no basic auth credentials"

Just adding to this as in case someone out there is suffering from never Reading The F Manual like me
I followed all the suggested steps from above such as

aws ecr get-login-password --region eu-west-1 | docker login --username AWS --password-stdin 123456789.dkr.ecr.eu-west-1.amazonaws.com

And always got the no basic auth credentials
I had created a registry named

123456789.dkr.ecr.eu-west-1.amazonaws.com/my.registry.com/namespace 

and was trying to push an image called alpine:latest

123456789.dkr.ecr.eu-west-1.amazonaws.com/my.registry.com/namespace/alpine:latest
2c6e8b76de: Preparing
9d4cb0c1e9: Preparing
1ca55f6ab4: Preparing
b6fd41c05e: Waiting
ad44a79b33: Waiting
2ce3c1888d: Waiting
no basic auth credentials   

Silly mistake on my behalf as I must create a registry in ecr using the full container path.
I created a new registry using the full container path, not ending on the namespace

123456789.dkr.ecr.eu-west-1.amazonaws.com/my.registry.com/namespace/alpine

and low and behold pushing to

123456789.dkr.ecr.eu-west-1.amazonaws.com/my.registry.com/namespace/alpine:latest 
The push refers to repository [123456789.dkr.ecr.eu-west-1.amazonaws.com/my.registry.com/namespace/alpine]
0c8667b5b: Pushed
730460948: Pushed
1.0: digest: sha256:e1f814f3818efea45267ebfb4918088a26a18c size: 7

works just fine

Setting up and using Meld as your git difftool and mergetool

How do I set up and use Meld as my git difftool?

git difftool displays the diff using a GUI diff program (i.e. Meld) instead of displaying the diff output in your terminal.

Although you can set the GUI program on the command line using -t <tool> / --tool=<tool> it makes more sense to configure it in your .gitconfig file. [Note: See the sections about escaping quotes and Windows paths at the bottom.]

# Add the following to your .gitconfig file.
[diff]
    tool = meld
[difftool]
    prompt = false
[difftool "meld"]
    cmd = meld "$LOCAL" "$REMOTE"

[Note: These settings will not alter the behaviour of git diff which will continue to function as usual.]

You use git difftool in exactly the same way as you use git diff. e.g.

git difftool <COMMIT_HASH> file_name
git difftool <BRANCH_NAME> file_name
git difftool <COMMIT_HASH_1> <COMMIT_HASH_2> file_name

If properly configured a Meld window will open displaying the diff using a GUI interface.

The order of the Meld GUI window panes can be controlled by the order of $LOCAL and $REMOTE in cmd, that is to say which file is shown in the left pane and which in the right pane. If you want them the other way around simply swap them around like this:

    cmd = meld "$REMOTE" "$LOCAL"

Finally the prompt = false line simply stops git from prompting you as to whether you want to launch Meld or not, by default git will issue a prompt.


How do I set up and use Meld as my git mergetool?

git mergetool allows you to use a GUI merge program (i.e. Meld) to resolve the merge conflicts that have occurred during a merge.

Like difftool you can set the GUI program on the command line using -t <tool> / --tool=<tool> but, as before, it makes more sense to configure it in your .gitconfig file. [Note: See the sections about escaping quotes and Windows paths at the bottom.]

# Add the following to your .gitconfig file.
[merge]
    tool = meld
[mergetool "meld"]
    # Choose one of these 2 lines (not both!) explained below.
    cmd = meld "$LOCAL" "$MERGED" "$REMOTE" --output "$MERGED"
    cmd = meld "$LOCAL" "$BASE" "$REMOTE" --output "$MERGED"

You do NOT use git mergetool to perform an actual merge. Before using git mergetool you perform a merge in the usual way with git. e.g.

git checkout master
git merge branch_name

If there is a merge conflict git will display something like this:

$ git merge branch_name
Auto-merging file_name
CONFLICT (content): Merge conflict in file_name
Automatic merge failed; fix conflicts and then commit the result.

At this point file_name will contain the partially merged file with the merge conflict information (that's the file with all the >>>>>>> and <<<<<<< entries in it).

Mergetool can now be used to resolve the merge conflicts. You start it very easily with:

git mergetool

If properly configured a Meld window will open displaying 3 files. Each file will be contained in a separate pane of its GUI interface.

In the example .gitconfig entry above, 2 lines are suggested as the [mergetool "meld"] cmd line. In fact there are all kinds of ways for advanced users to configure the cmd line, but that is beyond the scope of this answer.

This answer has 2 alternative cmd lines which, between them, will cater for most users, and will be a good starting point for advanced users who wish to take the tool to the next level of complexity.

Firstly here is what the parameters mean:

  • $LOCAL is the file in the current branch (e.g. master).
  • $REMOTE is the file in the branch being merged (e.g. branch_name).
  • $MERGED is the partially merged file with the merge conflict information in it.
  • $BASE is the shared commit ancestor of $LOCAL and $REMOTE, this is to say the file as it was when the branch containing $REMOTE was originally created.

I suggest you use either:

[mergetool "meld"]
    cmd = meld "$LOCAL" "$MERGED" "$REMOTE" --output "$MERGED"

or:

[mergetool "meld"]
    cmd = meld "$LOCAL" "$BASE" "$REMOTE" --output "$MERGED"
    # See 'Note On Output File' which explains --output "$MERGED".

The choice is whether to use $MERGED or $BASE in between $LOCAL and $REMOTE.

Either way Meld will display 3 panes with $LOCAL and $REMOTE in the left and right panes and either $MERGED or $BASE in the middle pane.

In BOTH cases the middle pane is the file that you should edit to resolve the merge conflicts. The difference is just in which starting edit position you'd prefer; $MERGED for the file which contains the partially merged file with the merge conflict information or $BASE for the shared commit ancestor of $LOCAL and $REMOTE. [Since both cmd lines can be useful I keep them both in my .gitconfig file. Most of the time I use the $MERGED line and the $BASE line is commented out, but the commenting out can be swapped over if I want to use the $BASE line instead.]

Note On Output File: Do not worry that --output "$MERGED" is used in cmd regardless of whether $MERGED or $BASE was used earlier in the cmd line. The --output option simply tells Meld what filename git wants the conflict resolution file to be saved in. Meld will save your conflict edits in that file regardless of whether you use $MERGED or $BASE as your starting edit point.

After editing the middle pane to resolve the merge conflicts, just save the file and close the Meld window. Git will do the update automatically and the file in the current branch (e.g. master) will now contain whatever you ended up with in the middle pane.

git will have made a backup of the partially merged file with the merge conflict information in it by appending .orig to the original filename. e.g. file_name.orig. After checking that you are happy with the merge and running any tests you may wish to do, the .orig file can be deleted.

At this point you can now do a commit to commit the changes.

If, while you are editing the merge conflicts in Meld, you wish to abandon the use of Meld, then quit Meld without saving the merge resolution file in the middle pane. git will respond with the message file_name seems unchanged and then ask Was the merge successful? [y/n], if you answer n then the merge conflict resolution will be aborted and the file will remain unchanged. Note that if you have saved the file in Meld at any point then you will not receive the warning and prompt from git. [Of course you can just delete the file and replace it with the backup .orig file that git made for you.]

If you have more than 1 file with merge conflicts then git will open a new Meld window for each, one after another until they are all done. They won't all be opened at the same time, but when you finish editing the conflicts in one, and close Meld, git will then open the next one, and so on until all the merge conflicts have been resolved.

It would be sensible to create a dummy project to test the use of git mergetool before using it on a live project. Be sure to use a filename containing a space in your test, in case your OS requires you to escape the quotes in the cmd line, see below.


Escaping quote characters

Some operating systems may need to have the quotes in cmd escaped. Less experienced users should remember that config command lines should be tested with filenames that include spaces, and if the cmd lines don't work with the filenames that include spaces then try escaping the quotes. e.g.

cmd = meld \"$LOCAL\" \"$REMOTE\"

In some cases more complex quote escaping may be needed. The 1st of the Windows path links below contains an example of triple-escaping each quote. It's a bore but sometimes necessary. e.g.

cmd = meld \\\"$LOCAL\\\" \\\"$REMOTE\\\"

Windows paths

Windows users will probably need extra configuration added to the Meld cmd lines. They may need to use the full path to meldc, which is designed to be called on Windows from the command line, or they may need or want to use a wrapper. They should read the StackOverflow pages linked below which are about setting the correct Meld cmd line for Windows. Since I am a Linux user I am unable to test the various Windows cmd lines and have no further information on the subject other than to recommend using my examples with the addition of a full path to Meld or meldc, or adding the Meld program folder to your path.

Ignoring trailing whitespace with Meld

Meld has a number of preferences that can be configured in the GUI.

In the preferences Text Filters tab there are several useful filters to ignore things like comments when performing a diff. Although there are filters to ignore All whitespace and Leading whitespace, there is no ignore Trailing whitespace filter (this has been suggested as an addition in the Meld mailing list but is not available in my version).

Ignoring trailing whitespace is often very useful, especially when collaborating, and can be manually added easily with a simple regular expression in the Meld preferences Text Filters tab.

# Use either of these regexes depending on how comprehensive you want it to be.
[ \t]*$
[ \t\r\f\v]*$

I hope this helps everyone.

Make view 80% width of parent in React Native

You can also try react-native-extended-stylesheet that supports percentage for single-orientation apps:

import EStyleSheet from 'react-native-extended-stylesheet';

const styles = EStyleSheet.create({
  column: {
    width: '80%',
    height: '50%',
    marginLeft: '10%'
  }
});

HikariCP - connection is not available

From stack trace:

HikariPool: Timeout failure pool HikariPool-0 stats (total=20, active=20, idle=0, waiting=0) Means pool reached maximum connections limit set in configuration.

The next line: HikariPool-0 - Connection is not available, request timed out after 30000ms. Means pool waited 30000ms for free connection but your application not returned any connection meanwhile.

Mostly it is connection leak (connection is not closed after borrowing from pool), set leakDetectionThreshold to the maximum value that you expect SQL query would take to execute.

otherwise, your maximum connections 'at a time' requirement is higher than 20 !

In CSS Flexbox, why are there no "justify-items" and "justify-self" properties?

I know this doesn't use flexbox, but for the simple use-case of three items (one at left, one at center, one at right), this can be accomplished easily using display: grid on the parent, grid-area: 1/1/1/1; on the children, and justify-self for positioning of those children.

_x000D_
_x000D_
<div style="border: 1px solid red; display: grid; width: 100px; height: 25px;">_x000D_
  <div style="border: 1px solid blue; width: 25px; grid-area: 1/1/1/1; justify-self: left;"></div>_x000D_
  <div style="border: 1px solid blue; width: 25px; grid-area: 1/1/1/1; justify-self: center;"></div>_x000D_
  <div style="border: 1px solid blue; width: 25px; grid-area: 1/1/1/1; justify-self: right;"></div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

ConnectivityManager getNetworkInfo(int) deprecated

connectivityManager.getActiveNetwork() is not found in below android M (API 28). networkInfo.getState() is deprecated above android L.

So, final answer is:

public static boolean isConnectingToInternet(Context mContext) {
    if (mContext == null) return false;

    ConnectivityManager connectivityManager = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivityManager != null) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            final Network network = connectivityManager.getActiveNetwork();
            if (network != null) {
                final NetworkCapabilities nc = connectivityManager.getNetworkCapabilities(network);

                return (nc.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) ||
                        nc.hasTransport(NetworkCapabilities.TRANSPORT_WIFI));
            }
        } else {
            NetworkInfo[] networkInfos = connectivityManager.getAllNetworkInfo();
            for (NetworkInfo tempNetworkInfo : networkInfos) {
                if (tempNetworkInfo.isConnected()) {
                    return true;
                }
            }
        }
    }
    return false;
}

How to send a POST request with BODY in swift

If you are using Alamofire v4.0+ then the accepted answer would look like this:

let parameters: [String: Any] = [
    "IdQuiz" : 102,
    "IdUser" : "iosclient",
    "User" : "iosclient",
    "List": [
        [
            "IdQuestion" : 5,
            "IdProposition": 2,
            "Time" : 32
        ],
        [
            "IdQuestion" : 4,
            "IdProposition": 3,
            "Time" : 9
        ]
    ]
]

Alamofire.request("http://myserver.com", method: .post, parameters: parameters, encoding: JSONEncoding.default)
    .responseJSON { response in
        print(response)
    }

How to make HTTP Post request with JSON body in Swift

import UIKit

class ViewController: UIViewController {

    var getdata = NSMutableData()
    @IBOutlet weak var password_txt: UITextField!
    @IBOutlet weak var mobile_txt: UITextField!
    @IBOutlet weak var email_txt: UITextField!
    @IBOutlet weak var name_txt: UITextField!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.

    }
    @IBAction func RegAction(_ sender: UIButton) {
        let url = URL(string: "https//.....")
        var requrl = URLRequest(url: url!)
        requrl.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "content_type")
        requrl.httpMethod = "post"
        let postString = "name=\(name_txt.text!)&email=\(email_txt.text!)&mobile=\(mobile_txt.text!)&password=\(password_txt.text!)"
        print("poststring-->>",postString)
        requrl.httpBody = postString.data(using: .utf8)
        let task = URLSession.shared.dataTask(with: requrl){(data,response,error) in
            let mydata = data
            do{
                print("mydata",mydata!)
                do{
                    self.getdata.append(mydata!)
                    let jsondata = try JSONSerialization.jsonObject(with: self.getdata as Data, options: [])
                    print("jsondata-->",jsondata)
                }
            }
            catch
            {
                print("error-->",error.localizedDescription)
            }
        };
        task.resume()

    }
}
`GET METHOD`
import UIKit

class ViewController: UIViewController,UITableViewDelegate,UITableViewDataSource {
    var dataarray = [[String: Any]]()
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return dataarray.count
    }
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 450.0
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell
        let  item = dataarray[indexPath.row]

        cell.name_txt.text = item["name"]as? String ?? ""
        cell.pname_txt.text = item["realname"]as? String ?? ""
        cell.team_txt.text = item["team"]as? String ?? ""
        cell.firstapp_txt.text = item["firstappearance"]as? String ?? ""
        cell.Createdby_txt.text = item["createdby"]as? String ?? ""
        cell.Publisher_txt.text = item["publisher"]as? String ?? ""

        if item["imageurl"]as? String ?? "" != ""{
            let url = URL(string: item["imageurl"]as? String ?? "")
            if url != nil{
                let data = try? Data(contentsOf: url!) //make sure your image in this url does exist, otherwise unwrap in a if let check / try-catch
                cell.imgvw.image = UIImage(data: data!)
            }
        }
        return cell
     }


    @IBOutlet weak var apiTable: UITableView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }
    override func viewWillAppear(_ animated: Bool) {
        guard let url = URL(string: "https://www.simplifiedcoding.net/demos/marvel/")
            else {return}
        let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
            guard let dataResponse = data,
                error == nil else {
                    print(error?.localizedDescription ?? "Response Error")
                    return }
            do{
                //here dataResponse received from a network request
                let jsonResponse = try JSONSerialization.jsonObject(with:
                    dataResponse, options: []) as? [[String:Any]] ?? [[:]]
                print("jsonResponse---->",jsonResponse) //Response result

                self.dataarray = jsonResponse
                DispatchQueue.main.async {



                    self.apiTable.reloadData()
                }
            } catch let parsingError {
                print("Error", parsingError)
            }
        }
        task.resume()
    }

}

RecyclerView and java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder in Samsung devices

Thanks to @Bolling idea I have implement to support to avoid any nullable from List

public void setList(ArrayList<ThisIsAdapterListObject> _newList) {
    //get the current items
    if (ThisIsAdapterList != null) {
        int currentSize = ThisIsAdapterList.size();
        ThisIsAdapterList.clear();
        //tell the recycler view that all the old items are gone
        notifyItemRangeRemoved(0, currentSize);
    }

    if (_newList != null) {
        if (ThisIsAdapterList == null) {
            ThisIsAdapterList = new ArrayList<ThisIsAdapterListObject>();
        }
        ThisIsAdapterList.addAll(_newList);
        //tell the recycler view how many new items we added
        notifyItemRangeInserted(0, _newList.size());
    }
}

Docker Compose wait for container X before starting Y

Natively that is not possible, yet. See also this feature request.

So far you need to do that in your containers CMD to wait until all required services are there.

In the Dockerfiles CMD you could refer to your own start script that wraps starting up your container service. Before you start it, you wait for a depending one like:

Dockerfile

FROM python:2-onbuild
RUN ["pip", "install", "pika"]
ADD start.sh /start.sh
CMD ["/start.sh"]

start.sh

#!/bin/bash
while ! nc -z rabbitmq 5672; do sleep 3; done
python rabbit.py

Probably you need to install netcat in your Dockerfile as well. I do not know what is pre-installed on the python image.

There are a few tools out there that provide easy to use waiting logic, for simple tcp port checks:

For more complex waits:

RecyclerView - How to smooth scroll to top of item on a certain position?

You can reverse your list by list.reverse() and finaly call RecylerView.scrollToPosition(0)

    list.reverse()
    layout = LinearLayoutManager(this,LinearLayoutManager.VERTICAL,true)  
    RecylerView.scrollToPosition(0)

Android changing Floating Action Button color

mFab.setBackgroundTintList(ColorStateList.valueOf(ContextCompat.getColor(mContext,R.color.mColor)));

What is the difference between utf8mb4 and utf8 charsets in MySQL?

UTF-8 is a variable-length encoding. In the case of UTF-8, this means that storing one code point requires one to four bytes. However, MySQL's encoding called "utf8" (alias of "utf8mb3") only stores a maximum of three bytes per code point.

So the character set "utf8"/"utf8mb3" cannot store all Unicode code points: it only supports the range 0x000 to 0xFFFF, which is called the "Basic Multilingual Plane". See also Comparison of Unicode encodings.

This is what (a previous version of the same page at) the MySQL documentation has to say about it:

The character set named utf8[/utf8mb3] uses a maximum of three bytes per character and contains only BMP characters. As of MySQL 5.5.3, the utf8mb4 character set uses a maximum of four bytes per character supports supplemental characters:

  • For a BMP character, utf8[/utf8mb3] and utf8mb4 have identical storage characteristics: same code values, same encoding, same length.

  • For a supplementary character, utf8[/utf8mb3] cannot store the character at all, while utf8mb4 requires four bytes to store it. Since utf8[/utf8mb3] cannot store the character at all, you do not have any supplementary characters in utf8[/utf8mb3] columns and you need not worry about converting characters or losing data when upgrading utf8[/utf8mb3] data from older versions of MySQL.

So if you want your column to support storing characters lying outside the BMP (and you usually want to), such as emoji, use "utf8mb4". See also What are the most common non-BMP Unicode characters in actual use?.

Remove all items from RecyclerView

setAdapter(null);

Useful if RecycleView have different views type

React / JSX Dynamic Component Name

<MyComponent /> compiles to React.createElement(MyComponent, {}), which expects a string (HTML tag) or a function (ReactClass) as first parameter.

You could just store your component class in a variable with a name that starts with an uppercase letter. See HTML tags vs React Components.

var MyComponent = Components[type + "Component"];
return <MyComponent />;

compiles to

var MyComponent = Components[type + "Component"];
return React.createElement(MyComponent, {});

AngularJS: No "Access-Control-Allow-Origin" header is present on the requested resource

This is a server side issue. You don't need to add any headers in angular for cors. You need to add header on the server side:

Access-Control-Allow-Headers: Content-Type
Access-Control-Allow-Methods: GET, POST, OPTIONS
Access-Control-Allow-Origin: *

First two answers here: How to enable CORS in AngularJs

iFrame onload JavaScript event

Update

As of jQuery 3.0, the new syntax is just .on:

see this answer here and the code:

$('iframe').on('load', function() {
    // do stuff 
});

Refreshing data in RecyclerView and keeping its scroll position

Yes you can resolve this issue by making the adapter constructor only one time, I am explaining the coding part here :

if (appointmentListAdapter == null) {
        appointmentListAdapter = new AppointmentListAdapter(AppointmentsActivity.this);
        appointmentListAdapter.addAppointmentListData(appointmentList);
        appointmentListAdapter.setOnStatusChangeListener(onStatusChangeListener);
        appointmentRecyclerView.setAdapter(appointmentListAdapter);

    } else {
        appointmentListAdapter.addAppointmentListData(appointmentList);
        appointmentListAdapter.notifyDataSetChanged();
    }

Now you can see I have checked the adapter is null or not and only initialize when it is null.

If adapter is not null then I am assured that I have initialized my adapter at least one time.

So I will just add list to adapter and call notifydatasetchanged.

RecyclerView always holds the last position scrolled, therefore you don't have to store last position, just call notifydatasetchanged, recycler view always refresh data without going to top.

Thanks Happy Coding

Use Excel VBA to click on a button in Internet Explorer, when the button has no "name" associated

With the kind help from Tim Williams, I finally figured out the last détails that were missing. Here's the final code below.

Private Sub Open_multiple_sub_pages_from_main_page()


Dim i As Long
Dim IE As Object
Dim Doc As Object
Dim objElement As Object
Dim objCollection As Object
Dim buttonCollection As Object
Dim valeur_heure As Object


' Create InternetExplorer Object
Set IE = CreateObject("InternetExplorer.Application")
' You can uncoment Next line To see form results
IE.Visible = True

' Send the form data To URL As POST binary request
IE.navigate "http://webpage.com/"

' Wait while IE loading...
While IE.Busy
        DoEvents
Wend


Set objCollection = IE.Document.getElementsByTagName("input")

i = 0
While i < objCollection.Length
    If objCollection(i).Name = "txtUserName" Then
        ' Set text for search
        objCollection(i).Value = "1234"
    End If
    If objCollection(i).Name = "txtPwd" Then
        ' Set text for search
        objCollection(i).Value = "password"
    End If

    If objCollection(i).Type = "submit" And objCollection(i).Name = "btnSubmit" Then ' submit button if found and set
        Set objElement = objCollection(i)
    End If
    i = i + 1
Wend
objElement.Click    ' click button to load page

' Wait while IE re-loading...
While IE.Busy
        DoEvents
Wend

' Show IE
IE.Visible = True
Set Doc = IE.Document

Dim links, link

Dim j As Integer                                                                    'variable to count items
j = 0
Set links = IE.Document.getElementById("dgTime").getElementsByTagName("a")
n = links.Length
While j <= n                                    'loop to go thru all "a" item so it loads next page
    links(j).Click
    While IE.Busy
        DoEvents
    Wend
    '-------------Do stuff here:  copy field value and paste in excel sheet.  Will post another question for this------------------------
    IE.Document.getElementById("DetailToolbar1_lnkBtnSave").Click              'save
    Do While IE.Busy
        Application.Wait DateAdd("s", 1, Now)                                   'wait
    Loop
    IE.Document.getElementById("DetailToolbar1_lnkBtnCancel").Click            'close
    Do While IE.Busy
        Application.Wait DateAdd("s", 1, Now)                                   'wait
    Loop
    Set links = IE.Document.getElementById("dgTime").getElementsByTagName("a")
    j = j + 2
Wend    
End Sub

java.lang.NoClassDefFoundError: org/json/JSONObject

Add json jar to your classpath

or use java -classpath json.jar ClassName

refer this

Multipart File Upload Using Spring Rest Template + Spring Web MVC

A correct file upload would like this:

HTTP header:

Content-Type: multipart/form-data; boundary=ABCDEFGHIJKLMNOPQ

Http body:

--ABCDEFGHIJKLMNOPQ

Content-Disposition: form-data; name="file"; filename="my.txt"

Content-Type: application/octet-stream

Content-Length: ...

<...file data in base 64...>

--ABCDEFGHIJKLMNOPQ--

and code is like this:

public void uploadFile(File file) {
        try {
            RestTemplate restTemplate = new RestTemplate();
            String url = "http://localhost:8080/file/user/upload";
            HttpMethod requestMethod = HttpMethod.POST;

            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.MULTIPART_FORM_DATA);


            MultiValueMap<String, String> fileMap = new LinkedMultiValueMap<>();
            ContentDisposition contentDisposition = ContentDisposition
                    .builder("form-data")
                    .name("file")
                    .filename(file.getName())
                    .build();

            fileMap.add(HttpHeaders.CONTENT_DISPOSITION, contentDisposition.toString());
            HttpEntity<byte[]> fileEntity = new HttpEntity<>(Files.readAllBytes(file.toPath()), fileMap);

            MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
            body.add("file", fileEntity);

            HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers);

            ResponseEntity<String> response = restTemplate.exchange(url, requestMethod, requestEntity, String.class);

            System.out.println("file upload status code: " + response.getStatusCode());

        } catch (IOException e) {
            e.printStackTrace();
        }

}

How to scroll to the bottom of a RecyclerView? scrollToPosition doesn't work

I know its late to answer here, still if anybody want to know solution is below

conversationView.smoothScrollToPosition(conversationView.getAdapter().getItemCount() - 1);

how to fix Cannot call sendRedirect() after the response has been committed?

you have already forwarded the response in catch block:

RequestDispatcher dd = request.getRequestDispatcher("error.jsp");

dd.forward(request, response);

so, you can not again call the :

response.sendRedirect("usertaskpage.jsp");

because it is already forwarded (committed).

So what you can do is: keep a string to assign where you need to forward the response.

    String page = "";
    try {

    } catch (Exception e) {
      page = "error.jsp";
    } finally {
      page = "usertaskpage.jsp";
    }

RequestDispatcher dd=request.getRequestDispatcher(page);
dd.forward(request, response);

getting error HTTP Status 405 - HTTP method GET is not supported by this URL but not used `get` ever?

Override service method like this:

protected void service(HttpServletRequest request, HttpServletResponse   response) throws ServletException, IOException {
        doPost(request, response);
}

And Voila!

Why does pycharm propose to change method to static

Since you didn't refer to self in the bar method body, PyCharm is asking if you might have wanted to make bar static. In other programming languages, like Java, there are obvious reasons for declaring a static method. In Python, the only real benefit to a static method (AFIK) is being able to call it without an instance of the class. However, if that's your only reason, you're probably better off going with a top-level function - as note here.

In short, I'm not one hundred percent sure why it's there. I'm guessing they'll probably remove it in an upcoming release.

AngularJS : Factory and Service?

Factory and Service is a just wrapper of a provider.

Factory

Factory can return anything which can be a class(constructor function), instance of class, string, number or boolean. If you return a constructor function, you can instantiate in your controller.

 myApp.factory('myFactory', function () {

  // any logic here..

  // Return any thing. Here it is object
  return {
    name: 'Joe'
  }
}

Service

Service does not need to return anything. But you have to assign everything in this variable. Because service will create instance by default and use that as a base object.

myApp.service('myService', function () {

  // any logic here..

  this.name = 'Joe';
}

Actual angularjs code behind the service

function service(name, constructor) {
    return factory(name, ['$injector', function($injector) {
        return $injector.instantiate(constructor);
    }]);
}

It just a wrapper around the factory. If you return something from service, then it will behave like Factory.

IMPORTANT: The return result from Factory and Service will be cache and same will be returned for all controllers.

When should i use them?

Factory is mostly preferable in all cases. It can be used when you have constructor function which needs to be instantiated in different controllers.

Service is a kind of Singleton Object. The Object return from Service will be same for all controller. It can be used when you want to have single object for entire application. Eg: Authenticated user details.

For further understanding, read

http://iffycan.blogspot.in/2013/05/angular-service-or-factory.html

http://viralpatel.net/blogs/angularjs-service-factory-tutorial/

Create a simple Login page using eclipse and mysql

use this code it is working

// index.jsp or login.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

<form action="login" method="post">
Username : <input type="text" name="username"><br>
Password : <input type="password" name="pass"><br>
<input type="submit"><br>
</form>

</body>
</html>

// authentication servlet class

    import java.io.IOException;
    import java.io.PrintWriter;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    import java.sql.Statement;

    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;

    public class auth extends HttpServlet {
        private static final long serialVersionUID = 1L;

        public auth() {
            super();
        }
        protected void doGet(HttpServletRequest request,
                HttpServletResponse response) throws ServletException, IOException {

        }

        protected void doPost(HttpServletRequest request,
                HttpServletResponse response) throws ServletException, IOException {

            try {
                Class.forName("com.mysql.jdbc.Driver");
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }

            String username = request.getParameter("username");
            String pass = request.getParameter("pass");

            String sql = "select * from reg where username='" + username + "'";
            Connection conn = null;

            try {
                conn = DriverManager.getConnection("jdbc:mysql://localhost/Exam",
                        "root", "");
                Statement s = conn.createStatement();

                java.sql.ResultSet rs = s.executeQuery(sql);
                String un = null;
                String pw = null;
                String name = null;

            /* Need to put some condition in case the above query does not return any row, else code will throw Null Pointer exception */   

            PrintWriter prwr1 = response.getWriter();               
            if(!rs.isBeforeFirst()){
                prwr1.write("<h1> No Such User in Database<h1>");
            } else {

/* Conditions to be executed after at least one row is returned by query execution */ 
                while (rs.next()) {
                    un = rs.getString("username");
                    pw = rs.getString("password");
                    name = rs.getString("name");
                }

                PrintWriter pww = response.getWriter();

                if (un.equalsIgnoreCase(username) && pw.equals(pass)) {
                                // use this or create request dispatcher 
                    response.setContentType("text/html");
                    pww.write("<h1>Welcome, " + name + "</h1>");
                } else {
                    pww.write("wrong username or password\n");
                }
              }

            } catch (SQLException e) {
                e.printStackTrace();
            }

        }

    }

Paging UICollectionView by cells, not screen

This is a straight way to do this.

The case is simple, but finally quite common ( typical thumbnails scroller with fixed cell size and fixed gap between cells )

var itemCellSize: CGSize = <your cell size>
var itemCellsGap: CGFloat = <gap in between>

override func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
    let pageWidth = (itemCellSize.width + itemCellsGap)
    let itemIndex = (targetContentOffset.pointee.x) / pageWidth
    targetContentOffset.pointee.x = round(itemIndex) * pageWidth - (itemCellsGap / 2)
}

// CollectionViewFlowLayoutDelegate

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    return itemCellSize
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return itemCellsGap
}

Note that there is no reason to call a scrollToOffset or dive into layouts. The native scrolling behaviour already does everything.

Cheers All :)

The server encountered an internal error that prevented it from fulfilling this request - in servlet 3.0

I found solution. It works fine when I throw away next line from form:

enctype="multipart/form-data"

And now it pass all parameters at request ok:

 <form action="/registration" method="post">
   <%-- error messages --%>
   <div class="form-group">
    <c:forEach items="${registrationErrors}" var="error">
    <p class="error">${error}</p>
     </c:forEach>
   </div>

height: 100% for <div> inside <div> with display: table-cell

Define your .table and .cell height:100%;

    .table {
        display: table;
        height:100%;
    }

    .cell {
        border: 1px solid black;
        display: table-cell;
        vertical-align:top;
height: 100%;

    }

    .container {
        height: 100%;
        border: 10px solid green;

    }

Demo

Using Spring RestTemplate in generic method with generic parameter

My own implementation of generic restTemplate call:

private <REQ, RES> RES queryRemoteService(String url, HttpMethod method, REQ req, Class reqClass) {
    RES result = null;
    try {
        long startMillis = System.currentTimeMillis();

        // Set the Content-Type header
        HttpHeaders requestHeaders = new HttpHeaders();
        requestHeaders.setContentType(new MediaType("application","json"));            

        // Set the request entity
        HttpEntity<REQ> requestEntity = new HttpEntity<>(req, requestHeaders);

        // Create a new RestTemplate instance
        RestTemplate restTemplate = new RestTemplate();

        // Add the Jackson and String message converters
        restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
        restTemplate.getMessageConverters().add(new StringHttpMessageConverter());

        // Make the HTTP POST request, marshaling the request to JSON, and the response to a String
        ResponseEntity<RES> responseEntity = restTemplate.exchange(url, method, requestEntity, reqClass);
        result = responseEntity.getBody();
        long stopMillis = System.currentTimeMillis() - startMillis;

        Log.d(TAG, method + ":" + url + " took " + stopMillis + " ms");
    } catch (Exception e) {
         Log.e(TAG, e.getMessage());
    }
    return result;
}

To add some context, I'm consuming RESTful service with this, hence all requests and responses are wrapped into small POJO like this:

public class ValidateRequest {
  User user;
  User checkedUser;
  Vehicle vehicle;
}

and

public class UserResponse {
  User user;
  RequestResult requestResult;
}

Method which calls this is the following:

public User checkUser(User user, String checkedUserName) {
    String url = urlBuilder()
            .add(USER)
            .add(USER_CHECK)
            .build();

    ValidateRequest request = new ValidateRequest();
    request.setUser(user);
    request.setCheckedUser(new User(checkedUserName));

    UserResponse response = queryRemoteService(url, HttpMethod.POST, request, UserResponse.class);
    return response.getUser();
}

And yes, there's a List dto-s as well.

How to resolve "could not execute statement; SQL [n/a]; constraint [numbering];"?

In my case, this happens when I try to save an object in hibernate or other orm-mapping with null property which can not be null in database table. This happens when you try to save an object, but the save action doesn't comply with the contraints of the table.

insert data into database using servlet and jsp in eclipse

Same problem fetch main problem in PreparedStatement use simple statement then you successfully insert record same use below.

String  st2="insert into 
user(gender,name,address,telephone,fax,email,
     destination,sdate,edate,Participant,hcategory,
     Culture,Nature,People,Cities,Beaches,Festivals,username,password) 
values('"+gender+"','"+name+"','"+address+"','"+phone+"','"+fax+"',
       '"+email+"','"+desti+"','"+sdate+"','"+edate+"','"+parti+"',
       '"+hotel+"','"+chk1+"','"+chk2+"','"+chk3+"','"+chk4+"',
       '"+chk5+"','"+chk6+"','"+user+"','"+password+"')";


int i=stm.executeUpdate(st2);

javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake during web service communicaiton

I run my application with Java 8 and Java 8 brought security certificate onto its trust store. Then I switched to Java 7 and added the following into VM options:

-Djavax.net.ssl.trustStore=C:\<....>\java8\jre\lib\security\cacerts

Simply I pointed to the location where a certificate is.

How to move all HTML element children to another parent using JavaScript?

This answer only really works if you don't need to do anything other than transferring the inner code (innerHTML) from one to the other:

// Define old parent
var oldParent = document.getElementById('old-parent');

// Define new parent
var newParent = document.getElementById('new-parent');

// Basically takes the inner code of the old, and places it into the new one
newParent.innerHTML = oldParent.innerHTML;

// Delete / Clear the innerHTML / code of the old Parent
oldParent.innerHTML = '';

Hope this helps!

How to add a default "Select" option to this ASP.NET DropDownList control?

Although it is quite an old question, another approach is to change AppendDataBoundItems property. So the code will be:

<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"
                  OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"
                  AppendDataBoundItems="True">
     <asp:ListItem Selected="True" Value="0" Text="Select"></asp:ListItem>
</asp:DropDownList>

Spring MVC Missing URI template variable

I got this error for a stupid mistake, the variable name in the @PathVariable wasn't matching the one in the @RequestMapping

For example

@RequestMapping(value = "/whatever/{**contentId**}", method = RequestMethod.POST)
public … method(@PathVariable Integer **contentID**){
}

It may help others

Gridview get Checkbox.Checked value

    foreach (GridViewRow row in GridView1.Rows)
    {
        CheckBox chkbox = (CheckBox)row.FindControl("CheckBox1");
        if (chkbox.Checked == true)
        {
            // Your Code
        }
    }

How can I add some small utility functions to my AngularJS application?

Coming on this old thread i wanted to stress that

1°) utility functions may (should?) be added to the rootscope via module.run. There is no need to instanciate a specific root level controller for this purpose.

angular.module('myApp').run(function($rootScope){
  $rootScope.isNotString = function(str) {
   return (typeof str !== "string");
  }
});

2°) If you organize your code into separate modules you should use angular services or factory and then inject them into the function passed to the run block, as follow:

angular.module('myApp').factory('myHelperMethods', function(){
  return {
    isNotString: function(str) {
      return (typeof str !== 'string');
    }
  }
});

angular.module('myApp').run(function($rootScope, myHelperMethods){ 
  $rootScope.helpers = myHelperMethods;
});

3°) My understanding is that in views, for most of the cases you need these helper functions to apply some kind of formatting to strings you display. What you need in this last case is to use angular filters

And if you have structured some low level helper methods into angular services or factory, just inject them within your filter constructor :

angular.module('myApp').filter('myFilter', function(myHelperMethods){ 
  return function(aString){
    if (myHelperMethods.isNotString(aString)){
      return 
    }
    else{
      // something else 
    }
  }
);

And in your view :

{{ aString | myFilter }}   

How to set a header in an HTTP response?

First of all you have to understand the nature of

response.sendRedirect(newUrl);

It is giving the client (browser) 302 http code response with an URL. The browser then makes a separate GET request on that URL. And that request has no knowledge of headers in the first one.

So sendRedirect won't work if you need to pass a header from Servlet A to Servlet B.

If you want this code to work - use RequestDispatcher in Servlet A (instead of sendRedirect). Also, it is always better to use relative path.

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
    String userName=request.getParameter("userName");
    String newUrl = "ServletB";
    response.addHeader("REMOTE_USER", userName);
    RequestDispatcher view = request.getRequestDispatcher(newUrl);
    view.forward(request, response);
}

========================

public void doPost(HttpServletRequest request, HttpServletResponse response)
{
    String sss = response.getHeader("REMOTE_USER");
}

How to upload files on server folder using jsp

public class FileUploadExample extends HttpServlet {
     protected void doPost(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
            boolean isMultipart = ServletFileUpload.isMultipartContent(request);

            if (isMultipart) {
                // Create a factory for disk-based file items
                FileItemFactory factory = new DiskFileItemFactory();

                // Create a new file upload handler
                ServletFileUpload upload = new ServletFileUpload(factory);

                try {
                    // Parse the request
                    List items = upload.parseRequest(request);
                    Iterator iterator = items.iterator();
                    while (iterator.hasNext()) {
                        FileItem item = (FileItem) iterator.next();
                        if (!item.isFormField()) {
                            String fileName = item.getName();    
                            String root = getServletContext().getRealPath("/");
                            File path = new File(root + "/uploads");
                            if (!path.exists()) {
                                boolean status = path.mkdirs();
                            }

                            File uploadedFile = new File(path + "/" + fileName);
                            System.out.println(uploadedFile.getAbsolutePath());
                            item.write(uploadedFile);
                        }
                    }
                } catch (FileUploadException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }

}

How to use the DropDownList's SelectedIndexChanged event

I think this is the culprit:

cmd = new SqlCommand(query, con);

DataTable dt = Select(query);

cmd.ExecuteNonQuery();

ddtype.DataSource = dt;

I don't know what that code is supposed to do, but it looks like you want to create an SqlDataReader for that, as explained here and all over the web if you search for "SqlCommand DropDownList DataSource":

cmd = new SqlCommand(query, con);
ddtype.DataSource = cmd.ExecuteReader();

Or you can create a DataTable as explained here:

cmd = new SqlCommand(query, con);

SqlDataAdapter listQueryAdapter = new SqlDataAdapter(cmd);
DataTable listTable = new DataTable();
listQueryAdapter.Fill(listTable);

ddtype.DataSource = listTable;

Change language for bootstrap DateTimePicker

Just include your desired locale after the plugin. You can find it in locales folder on github https://github.com/uxsolutions/bootstrap-datepicker/tree/master/dist/locales

<script src="bootstrap-datepicker.XX.js" charset="UTF-8"></script>

and then add option

$('.datepicker').datepicker({
   language: 'XX'
});

Where XX is your desired locale like ru

HTML5 Canvas Resize (Downscale) Image High Quality?

This is the improved Hermite resize filter that utilises 1 worker so that the window doesn't freeze.

https://github.com/calvintwr/blitz-hermite-resize

const blitz = Blitz.create()

/* Promise */
blitz({
    source: DOM Image/DOM Canvas/jQuery/DataURL/File,
    width: 400,
    height: 600
}).then(output => {
    // handle output
})catch(error => {
    // handle error
})

/* Await */
let resized = await blizt({...})

/* Old school callback */
const blitz = Blitz.create('callback')
blitz({...}, function(output) {
    // run your callback.
})

Solve error javax.mail.AuthenticationFailedException

The solution that works for me has two steps.

  1. First step

    package com.student.mail;
    
    import java.util.Properties;
    
    import javax.mail.Authenticator;
    import javax.mail.Message;
    import javax.mail.MessagingException;
    import javax.mail.PasswordAuthentication;
    import javax.mail.Session;
    import javax.mail.Transport;
    import javax.mail.internet.InternetAddress;
    import javax.mail.internet.MimeMessage;
    
    /**
     *
     * @author jorge santos
     */
    public class GoogleMail {
        public static void main(String[] args) {
            Properties props = new Properties();
            props.put("mail.smtp.host", "smtp.gmail.com");
            props.put("mail.smtp.socketFactory.port", "465");
            props.put("mail.smtp.socketFactory.class",
                "javax.net.ssl.SSLSocketFactory");
            props.put("mail.smtp.auth", "true");
            props.put("mail.smtp.port", "465"); 
            Session session = Session.getDefaultInstance(props,
            new javax.mail.Authenticator() {
                                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication("[email protected]","Silueta95#");
                }
            });
    
        try {
    
            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("[email protected]"));
            message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse("[email protected]"));
            message.setSubject("Testing Subject");
            message.setText("Test Mail");
    
            Transport.send(message);
    
            System.out.println("Done");
    
        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }
    }
    
    }
    
  2. Enable the gmail security

    https://myaccount.google.com/u/2/lesssecureapps?pli=1&pageId=none
    

Autocompletion of @author in Intellij

You can work around that via a Live Template. Go to Settings -> Live Template, click the "Add"-Button (green plus on the right).

In the "Abbreviation" field, enter the string that should activate the template (e.g. @a), and in the "Template Text" area enter the string to complete (e.g. @author - My Name). Set the "Applicable context" to Java (Comments only maybe) and set a key to complete (on the right).

I tested it and it works fine, however IntelliJ seems to prefer the inbuild templates, so "@a + Tab" only completes "author". Setting the completion key to Space worked however.

To change the user name that is automatically inserted via the File Templates (when creating a class for example), can be changed by adding

-Duser.name=Your name

to the idea.exe.vmoptions or idea64.exe.vmoptions (depending on your version) in the IntelliJ/bin directory.

enter image description here

Restart IntelliJ

Reading and writing to serial port in C on Linux

I've solved my problems, so I post here the correct code in case someone needs similar stuff.

Open Port

int USB = open( "/dev/ttyUSB0", O_RDWR| O_NOCTTY );

Set parameters

struct termios tty;
struct termios tty_old;
memset (&tty, 0, sizeof tty);

/* Error Handling */
if ( tcgetattr ( USB, &tty ) != 0 ) {
   std::cout << "Error " << errno << " from tcgetattr: " << strerror(errno) << std::endl;
}

/* Save old tty parameters */
tty_old = tty;

/* Set Baud Rate */
cfsetospeed (&tty, (speed_t)B9600);
cfsetispeed (&tty, (speed_t)B9600);

/* Setting other Port Stuff */
tty.c_cflag     &=  ~PARENB;            // Make 8n1
tty.c_cflag     &=  ~CSTOPB;
tty.c_cflag     &=  ~CSIZE;
tty.c_cflag     |=  CS8;

tty.c_cflag     &=  ~CRTSCTS;           // no flow control
tty.c_cc[VMIN]   =  1;                  // read doesn't block
tty.c_cc[VTIME]  =  5;                  // 0.5 seconds read timeout
tty.c_cflag     |=  CREAD | CLOCAL;     // turn on READ & ignore ctrl lines

/* Make raw */
cfmakeraw(&tty);

/* Flush Port, then applies attributes */
tcflush( USB, TCIFLUSH );
if ( tcsetattr ( USB, TCSANOW, &tty ) != 0) {
   std::cout << "Error " << errno << " from tcsetattr" << std::endl;
}

Write

unsigned char cmd[] = "INIT \r";
int n_written = 0,
    spot = 0;

do {
    n_written = write( USB, &cmd[spot], 1 );
    spot += n_written;
} while (cmd[spot-1] != '\r' && n_written > 0);

It was definitely not necessary to write byte per byte, also int n_written = write( USB, cmd, sizeof(cmd) -1) worked fine.

At last, read:

int n = 0,
    spot = 0;
char buf = '\0';

/* Whole response*/
char response[1024];
memset(response, '\0', sizeof response);

do {
    n = read( USB, &buf, 1 );
    sprintf( &response[spot], "%c", buf );
    spot += n;
} while( buf != '\r' && n > 0);

if (n < 0) {
    std::cout << "Error reading: " << strerror(errno) << std::endl;
}
else if (n == 0) {
    std::cout << "Read nothing!" << std::endl;
}
else {
    std::cout << "Response: " << response << std::endl;
}

This one worked for me. Thank you all!

How to get raw text from pdf file using java

You can use iText for do such things

//iText imports

import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.parser.PdfTextExtractor;

for example:

try {     
    PdfReader reader = new PdfReader(INPUTFILE);
    int n = reader.getNumberOfPages(); 
    String str=PdfTextExtractor.getTextFromPage(reader, 2); //Extracting the content from a particular page.
    System.out.println(str);
    reader.close();
} catch (Exception e) {
    System.out.println(e);
}

another one

try {

    PdfReader reader = new PdfReader("c:/temp/test.pdf");
    System.out.println("This PDF has "+reader.getNumberOfPages()+" pages.");
    String page = PdfTextExtractor.getTextFromPage(reader, 2);
    System.out.println("Page Content:\n\n"+page+"\n\n");
    System.out.println("Is this document tampered: "+reader.isTampered());
    System.out.println("Is this document encrypted: "+reader.isEncrypted());
} catch (IOException e) {
    e.printStackTrace();
}

the above examples can only extract the text, but you need to do some more to remove hyperlinks, bullets, heading & numbers.

Redirect all output to file using Bash on Linux?

I had trouble with a crashing program *cough PHP cough* Upon crash the shell it was ran in reports the crash reason, Segmentation fault (core dumped)

To avoid this output not getting logged, the command can be run in a subshell that will capture and direct these kind of output:

sh -c 'your_command' > your_stdout.log 2> your_stderr.err
# or
sh -c 'your_command' > your_stdout.log 2>&1

Excel VBA Code: Compile Error in x64 Version ('PtrSafe' attribute required)

I'm quite sure you won't get this 32Bit DLL working in Office 64Bit. The DLL needs to be updated by the author to be compatible with 64Bit versions of Office.

The code changes you have found and supplied in the question are used to convert calls to APIs that have already been rewritten for Office 64Bit. (Most Windows APIs have been updated.)

From: http://technet.microsoft.com/en-us/library/ee681792.aspx:

"ActiveX controls and add-in (COM) DLLs (dynamic link libraries) that were written for 32-bit Office will not work in a 64-bit process."

Edit: Further to your comment, I've tried the 64Bit DLL version on Win 8 64Bit with Office 2010 64Bit. Since you are using User Defined Functions called from the Excel worksheet you are not able to see the error thrown by Excel and just end up with the #VALUE returned.

If we create a custom procedure within VBA and try one of the DLL functions we see the exact error thrown. I tried a simple function of swe_day_of_week which just has a time as an input and I get the error Run-time error '48' File not found: swedll32.dll.

Now I have the 64Bit DLL you supplied in the correct locations so it should be found which suggests it has dependencies which cannot be located as per https://stackoverflow.com/a/8607250/1733206

I've got all the .NET frameworks installed which would be my first guess, so without further information from the author it might be difficult to find the problem.

Edit2: And after a bit more investigating it appears the 64Bit version you have supplied is actually a 32Bit version. Hence the error message on the 64Bit Office. You can check this by trying to access the '64Bit' version in Office 32Bit.

How to manually include external aar package using new Gradle Android Build System

Currently referencing a local .aar file is not supported (as confirmed by Xavier Ducrochet)

What you can do instead is set up a local Maven repository (much more simple than it sounds) and reference the .aar from there.

I've written a blogpost detailing how to get it working here:

http://www.flexlabs.org/2013/06/using-local-aar-android-library-packages-in-gradle-builds

Right way to convert data.frame to a numeric matrix, when df also contains strings?

Another way of doing it is by using the read.table() argument colClasses to specify the column type by making colClasses=c(*column class types*). If there are 6 columns whose members you want as numeric, you need to repeat the character string "numeric" six times separated by commas, importing the data frame, and as.matrix() the data frame. P.S. looks like you have headers, so I put header=T.

as.matrix(read.table(SFI.matrix,header=T,
colClasses=c("numeric","numeric","numeric","numeric","numeric","numeric"),
sep=","))

How to clear exisiting dropdownlist items when its content changes?

Please use the following

ddlCity.Items.Clear();

SQL Error: 0, SQLState: 08S01 Communications link failure

The communication link between the driver and the data source to which the driver was attempting to connect failed before the function completed processing. So usually its a network error. This could be caused by packet drops or badly configured Firewall/Switch.

Regular expression replace in C#

Add the following 2 lines

var regex = new Regex(Regex.Escape(","));
sb_trim = regex.Replace(sb_trim, " ", 1);

If sb_trim= John,Smith,100000,M the above code will return "John Smith,100000,M"

How to Solve Max Connection Pool Error

Check against any long running queries in your database.

Increasing your pool size will only make your webapp live a little longer (and probably get a lot slower)

You can use sql server profiler and filter on duration / reads to see which querys need optimization.

I also see you're probably keeping a global connection?

blnMainConnectionIsCreatedLocal

Let .net do the pooling for you and open / close your connection with a using statement.

Suggestions:

  1. Always open and close a connection like this, so .net can manage your connections and you won't run out of connections:

        using (SqlConnection conn = new SqlConnection(connectionString))
        {
         conn.Open();
         // do some stuff
        } //conn disposed
    
  2. As I mentioned, check your query with sql server profiler and see if you can optimize it. Having a slow query with many requests in a web app can give these timeouts too.

Python: URLError: <urlopen error [Errno 10060]

This is because of the proxy settings. I also had the same problem, under which I could not use any of the modules which were fetching data from the internet. There are simple steps to follow:
1. open the control panel
2. open internet options
3. under connection tab open LAN settings
4. go to advance settings and unmark everything, delete every proxy in there. Or u can just unmark the checkbox in proxy server this will also do the same
5. save all the settings by clicking ok.
you are done. try to run the programme again, it must work it worked for me at least

What is the best way to conditionally apply attributes in AngularJS?

Edit: This answer is related to Angular2+! Sorry, I missed the tag!

Original answer:

As for the very simple case when you only want to apply (or set) an attribute if a certain Input value was set, it's as easy as

<my-element [conditionalAttr]="optionalValue || false">

It's the same as:

<my-element [conditionalAttr]="optionalValue ? optionalValue : false">

(So optionalValue is applied if given otherwise the expression is false and attribute is not applied.)

Example: I had the case, where I let apply a color but also arbitrary styles, where the color attribute didn't work as it was already set (even if the @Input() color wasn't given):

@Component({
  selector: "rb-icon",
  styleUrls: ["icon.component.scss"],
  template: "<span class="ic-{{icon}}" [style.color]="color==color" [ngStyle]="styleObj" ></span>",
})
export class IconComponent {
   @Input() icon: string;
   @Input() color: string;
   @Input() styles: string;

   private styleObj: object;
...
}

So, "style.color" was only set, when the color attribute was there, otherwise the color attribute in the "styles" string could be used.

Of course, this could also be achieved with

[style.color]="color" 

and

@Input color: (string | boolean) = false;

oracle.jdbc.driver.OracleDriver ClassNotFoundException

1.Right click on your java project.

2.Select "RUN AS".

3.Select "RUN CONFIGURATIOS...".

4.Here select your server at left side of the page and then u would see "CLASS PATH" tab at riht side,just click on it.

5.Here clilck on "USER ENTRIES" and select "ADD EXTERNAL JARS".

6.Select "ojdbc14.jar" file.

7.Click on Apply.

8.Click on Run.

9.Finally Restart your server then it would be execute.

browser.msie error after update to jQuery 1.9.1

The jQuery.browser options was deprecated earlier and removed in 1.9 release along with a lot of other deprecated items like .live.

For projects and external libraries which want to upgrade to 1.9 but still want to support these features jQuery have release a migration plugin for the time being.

If you need backward compatibility you can use migration plugin.

A valid provisioning profile for this executable was not found... (again)

This happened to me yesterday. What happened was that when I added the device Xcode included it in the wrong profile by default. This is easier to fix now that Apple has updated the provisioning portal:

  1. Log in to developer.apple.com/ios and click Certificates, Identifiers & Profiles
  2. Click devices and make sure that the device in question is listed
  3. Click provisioning profiles > All and select the one you want to use
  4. Click the edit button
  5. You will see another devices list which also has a label which will probably say "3 of 4 devices selected" or something of that nature.
  6. Check the select all box or scroll through the list and check the device. If your device was unchecked, this is your problem.
  7. Click "Generate"
  8. DON'T hit Download & Install – while this will work it's likely to screw up your project file if you've already installed the provisioning profile (see this question for more info).
  9. Open Xcode, open the Organizer, switch to the Devices tab, and hit the Refresh button in the lower right corner. This will pull in the changes to the provisioning profile.

Now it should work.

How to turn a vector into a matrix in R?

Just use matrix:

matrix(vec,nrow = 7,ncol = 7)

One advantage of using matrix rather than simply altering the dimension attribute as Gavin points out, is that you can specify whether the matrix is filled by row or column using the byrow argument in matrix.

Getting request payload from POST request in Java servlet

You can use Buffer Reader from request to read

    // Read from request
    StringBuilder buffer = new StringBuilder();
    BufferedReader reader = request.getReader();
    String line;
    while ((line = reader.readLine()) != null) {
        buffer.append(line);
        buffer.append(System.lineSeparator());
    }
    String data = buffer.toString()

Java java.sql.SQLException: Invalid column index on preparing statement

In date '?', the '?' is a literal string with value ?, not a parameter placeholder, so your query does not have any parameters. The date is a shorthand cast from (literal) string to date. You need to replace date '?' with ? to actually have a parameter.

Also if you know it is a date, then use setDate(..) and not setString(..) to set the parameter.

Confirm postback OnClientClick button ASP.NET

You can put the above answers into one line like this. And you don't need to write the function.

    <asp:Button runat="server" ID="btnUserDelete" Text="Delete" CssClass="GreenLightButton"
         OnClick="BtnUserDelete_Click" meta:resourcekey="BtnUserDeleteResource1"
OnClientClick="if ( !confirm('Are you sure you want to delete this user?')) return false;"  />

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver

Have you copied classes12.jar in lib folder of your web application and set the classpath in eclipse.

Right-click project in Package explorer Build path -> Add external archives...

Select your ojdbc6.jar archive

Press OK

Or

Go through this link and read and do carefully.

The library should be now referenced in the "Referenced Librairies" under the Package explorer. Now try to run your program again.

How to send redirect to JSP page in Servlet

Look at the HttpServletResponse#sendRedirect(String location) method.

Use it as:

response.sendRedirect(request.getContextPath() + "/welcome.jsp")

Alternatively, look at HttpServletResponse#setHeader(String name, String value) method.

The redirection is set by adding the location header:

response.setHeader("Location", request.getContextPath() + "/welcome.jsp");

Excel VBA Open workbook, perform actions, save as, close

I'll try and answer several different things, however my contribution may not cover all of your questions. Maybe several of us can take different chunks out of this. However, this info should be helpful for you. Here we go..

Opening A Seperate File:

ChDir "[Path here]"                          'get into the right folder here
Workbooks.Open Filename:= "[Path here]"      'include the filename in this path

'copy data into current workbook or whatever you want here

ActiveWindow.Close                          'closes out the file

Opening A File With Specified Date If It Exists:

I'm not sure how to search your directory to see if a file exists, but in my case I wouldn't bother to search for it, I'd just try to open it and put in some error checking so that if it doesn't exist then display this message or do xyz.

Some common error checking statements:

On Error Resume Next   'if error occurs continues on to the next line (ignores it)

ChDir "[Path here]"                         
Workbooks.Open Filename:= "[Path here]"      'try to open file here

Or (better option):

if one doesn't exist then bring up either a message box or dialogue box to say "the file does not exist, would you like to create a new one?

you would most likely want to use the GoTo ErrorHandler shown below to achieve this

On Error GoTo ErrorHandler:

ChDir "[Path here]"                         
Workbooks.Open Filename:= "[Path here]"      'try to open file here

ErrorHandler:
'Display error message or any code you want to run on error here

Much more info on Error handling here: http://www.cpearson.com/excel/errorhandling.htm


Also if you want to learn more or need to know more generally in VBA I would recommend Siddharth Rout's site, he has lots of tutorials and example code here: http://www.siddharthrout.com/vb-dot-net-and-excel/

Hope this helps!


Example on how to ensure error code doesn't run EVERYtime:

if you debug through the code without the Exit Sub BEFORE the error handler you'll soon realize the error handler will be run everytime regarldess of if there is an error or not. The link below the code example shows a previous answer to this question.

  Sub Macro

    On Error GoTo ErrorHandler:

    ChDir "[Path here]"                         
    Workbooks.Open Filename:= "[Path here]"      'try to open file here

    Exit Sub      'Code will exit BEFORE ErrorHandler if everything goes smoothly
                  'Otherwise, on error, ErrorHandler will be run

    ErrorHandler:
    'Display error message or any code you want to run on error here

  End Sub

Also, look at this other question in you need more reference to how this works: goto block not working VBA


Difference between AutoPostBack=True and AutoPostBack=False?

AutopostBack :

AutopostBack is a property of the controls which enables the post back on the changes of the web control.

Difference between AutopostBack=True and AutoPostBack=False:

If the AutopostBack property is set to true, a post back is sent immediately to the server

If the AutopostBack property is set to false, then no post back occurs.

HTML input file selection event not firing upon selecting the same file

<form enctype='multipart/form-data'>
    <input onchange="alert(this.value); this.value=null; return false;" type='file'>
    <br>
    <input type='submit' value='Upload'>
</form>

this.value=null; is only necessary for Chrome, Firefox will work fine just with return false;

Here is a FIDDLE

Check if one list contains element from the other

org.springframework.util.CollectionUtils

boolean containsAny(java.util.Collection<?> source, java.util.Collection<?> candidates)

Return true if any element in 'candidates' is contained in 'source'; otherwise returns false

SSL "Peer Not Authenticated" error with HttpClient 4.1

keytool -import -v -alias cacerts -keystore cacerts.jks -storepass changeit -file C:\cacerts.cer

Returning an array using C

How about this deliciously evil implementation?

array.h

#define IMPORT_ARRAY(TYPE)    \
    \
struct TYPE##Array {    \
    TYPE* contents;    \
    size_t size;    \
};    \
    \
struct TYPE##Array new_##TYPE##Array() {    \
    struct TYPE##Array a;    \
    a.contents = NULL;    \
    a.size = 0;    \
    return a;    \
}    \
    \
void array_add(struct TYPE##Array* o, TYPE value) {    \
    TYPE* a = malloc((o->size + 1) * sizeof(TYPE));    \
    TYPE i;    \
    for(i = 0; i < o->size; ++i) {    \
        a[i] = o->contents[i];    \
    }    \
    ++(o->size);    \
    a[o->size - 1] = value;    \
    free(o->contents);    \
    o->contents = a;    \
}    \
void array_destroy(struct TYPE##Array* o) {    \
    free(o->contents);    \
}    \
TYPE* array_begin(struct TYPE##Array* o) {    \
    return o->contents;    \
}    \
TYPE* array_end(struct TYPE##Array* o) {    \
    return o->contents + o->size;    \
}

main.c

#include <stdlib.h>
#include "array.h"

IMPORT_ARRAY(int);

struct intArray return_an_array() {
    struct intArray a;
    a = new_intArray();
    array_add(&a, 1);
    array_add(&a, 2);
    array_add(&a, 3);
    return a;
}

int main() {
    struct intArray a;
    int* it;
    int* begin;
    int* end;
    a = return_an_array();
    begin = array_begin(&a);
    end = array_end(&a);
    for(it = begin; it != end; ++it) {
        printf("%d ", *it);
    }
    array_destroy(&a);
    getchar();
    return 0;
}

import android packages cannot be resolved

This import android packages cannot be resolved is also occurs when your using some library and that library is not in the same path where your application is there, or if you are importing the library and not coping library to the workspace

How to solve this java.lang.NoClassDefFoundError: org/apache/commons/io/output/DeferredFileOutputStream?

You will have to download file from here https://commons.apache.org/proper/commons-io/download_io.cgi and select https://prnt.sc/tk5ewt

Now, Next add this downloaded files into your project:

Right click to your project ->Build path->Configure BuidPath -> https://prnt.sc/tk5d93

How to convert R Markdown to PDF?

Updated Answer (10 Feb 2013)

rmarkdown package: There is now an rmarkdown package available on github that interfaces with Pandoc. It includes a render function. The documentation makes it pretty clear how to convert rmarkdown to pdf among a range of other formats. This includes including output formats in the rmarkdown file or running supplying an output format to the rend function. E.g.,

render("input.Rmd", "pdf_document")

Command-line: When I run render from the command-line (e.g., using a makefile), I sometimes have issues with pandoc not being found. Presumably, it is not on the search path. The following answer explains how to add pandoc to the R environment.

So for example, on my computer running OSX, where I have a copy of pandoc through RStudio, I can use the following:

Rscript -e "Sys.setenv(RSTUDIO_PANDOC='/Applications/RStudio.app/Contents/MacOS/pandoc');library(rmarkdown);  library(utils); render('input.Rmd', 'pdf_document')"

Old Answer (circa 2012)

So, a number of people have suggested that Pandoc is the way to go. See notes below about the importance of having an up-to-date version of Pandoc.

Using Pandoc

I used the following command to convert R Markdown to HTML (i.e., a variant of this makefile), where RMDFILE is the name of the R Markdown file without the .rmd component (it also assumes that the extension is .rmd and not .Rmd).

RMDFILE=example-r-markdown  
Rscript -e "require(knitr); require(markdown); knit('$RMDFILE.rmd', '$RMDFILE.md'); markdownToHTML('$RMDFILE.md', '$RMDFILE.html', options=c('use_xhml'))"

and then this command to convert to pdf

Pandoc -s example-r-markdown.html -o example-r-markdown.pdf


A few notes about this:

  • I removed the reference in the example file which exports plots to imgur to host images.
  • I removed a reference to an image that was hosted on imgur. Figures appear to need to be local.
  • The options in the markdownToHTML function meant that image references are to files and not to data stored in the HTML file (i.e., I removed 'base64_images' from the option list).
  • The resulting output looked like this. It has clearly made a very LaTeX style document in contrast to what I get if I print the HTML file to pdf from a browser.

Getting up-to-date version of Pandoc

As mentioned by @daroczig, it's important to have an up-to-date version of Pandoc in order to output pdfs. On Ubuntu as of 15th June 2012, I was stuck with version 1.8.1 of Pandoc in the package manager, but it seems from the change log that for pdf support you need at least version 1.9+ of Pandoc.

Thus, I installed caball-install. And then ran:

cabal update
cabal install pandoc

Pandoc was installed in ~/.cabal/bin/pandoc Thus, when I ran pandoc it was still seeing the old version. See here for adding to the path.

Create a sample login page using servlet and JSP?

You're comparing the message with the empty string using ==.

First, your comparison is wrong because the message will be null (and not the empty string).

Second, it's wrong because Objects must be compared with equals() and not with ==.

Third, it's wrong because you should avoid scriptlets in JSP, and use the JSP EL, the JSTL, and other custom tags instead:

<c:id test="${!empty message}">
    <c:out value="${message}"/>
</c:if>

Detect IE version (prior to v9) in JavaScript

For ie 10 and 11:

You can use js and add a class in html to maintain the standard of conditional comments:

  var ua = navigator.userAgent,
      doc = document.documentElement;

  if ((ua.match(/MSIE 10.0/i))) {
    doc.className = doc.className + " ie10";

  } else if((ua.match(/rv:11.0/i))){
    doc.className = doc.className + " ie11";
  }

Or use a lib like bowser:

https://github.com/ded/bowser

Or modernizr for feature detection:

http://modernizr.com/

Call JavaScript function on DropDownList SelectedIndexChanged Event:

Or you can do it like as well:

<asp:DropDownList ID="ddl" runat="server"  AutoPostBack="true" onchange="javascript:CalcTotalAmt();" OnSelectedIndexChanged="ddl_SelectedIndexChanged"></asp:DropDownList>

selecting an entire row based on a variable excel vba

One needs to make sure the space between the variables and '&' sign. Check the image. (Red one showing invalid commands)

Error

The correct solution is

Dim copyToRow: copyToRow = 5      
Rows(copyToRow & ":" & copyToRow).Select

git push >> fatal: no configured push destination

The command (or the URL in it) to add the github repository as a remote isn't quite correct. If I understand your repository name correctly, it should be;

git remote add demo_app '[email protected]:levelone/demo_app.git'

How to add a reference programmatically

There are two ways to add references using VBA. .AddFromGuid(Guid, Major, Minor) and .AddFromFile(Filename). Which one is best depends on what you are trying to add a reference to. I almost always use .AddFromFile because the things I am referencing are other Excel VBA Projects and they aren't in the Windows Registry.

The example code you are showing will add a reference to the workbook the code is in. I generally don't see any point in doing that because 90% of the time, before you can add the reference, the code has already failed to compile because the reference is missing. (And if it didn't fail-to-compile, you are probably using late binding and you don't need to add a reference.)

If you are having problems getting the code to run, there are two possible issues.

  1. In order to easily use the VBE's object model, you need to add a reference to Microsoft Visual Basic for Application Extensibility. (VBIDE)
  2. In order to run Excel VBA code that changes anything in a VBProject, you need to Trust access to the VBA Project Object Model. (In Excel 2010, it is located in the Trust Center - Macro Settings.)

Aside from that, if you can be a little more clear on what your question is or what you are trying to do that isn't working, I could give a more specific answer.

Convert UTF-8 with BOM to UTF-8 with no BOM in Python

This is my implementation to convert any kind of encoding to UTF-8 without BOM and replacing windows enlines by universal format:

def utf8_converter(file_path, universal_endline=True):
    '''
    Convert any type of file to UTF-8 without BOM
    and using universal endline by default.

    Parameters
    ----------
    file_path : string, file path.
    universal_endline : boolean (True),
                        by default convert endlines to universal format.
    '''

    # Fix file path
    file_path = os.path.realpath(os.path.expanduser(file_path))

    # Read from file
    file_open = open(file_path)
    raw = file_open.read()
    file_open.close()

    # Decode
    raw = raw.decode(chardet.detect(raw)['encoding'])
    # Remove windows end line
    if universal_endline:
        raw = raw.replace('\r\n', '\n')
    # Encode to UTF-8
    raw = raw.encode('utf8')
    # Remove BOM
    if raw.startswith(codecs.BOM_UTF8):
        raw = raw.replace(codecs.BOM_UTF8, '', 1)

    # Write to file
    file_open = open(file_path, 'w')
    file_open.write(raw)
    file_open.close()
    return 0

Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer]

Check your Hibernate mapping file *.hbm.xml and check the class with which you are creating the getter and setter methods. Every property in the mapping file should exist as getters and setters in the populating class. Once you fix that the error is solved.

Also by reading the console, you can probably see the error mentioning a missing getter/setter.

Hope this helps you.

Setting Remote Webdriver to run tests in a remote computer using Java

  • First you need to create HubNode(Server) and start the HubNode(Server) from command Line/prompt using Java: -jar selenium-server-standalone-2.44.0.jar -role hub
  • Then bind the node/Client to this Hub using Hub machines IPAddress or Name with any port number >1024. For Node Machine for example: Java -jar selenium-server-standalone-2.44.0.jar -role webdriver -hub http://HubmachineIPAddress:4444/grid/register -port 5566

One more thing is that whenever we use Internet Explore or Google Chrome we need to set: System.setProperty("webdriver.ie.driver",path);

How do you align left / right a div without using float?

Very useful thing have applied today in my project. One div had to be aligned right, with no floating applied.

Applying code made my goal achieved:

.div {
  margin-right: 0px;
  margin-left: auto;
}

Android REST client, Sample?

There is plenty of libraries out there and I'm using this one: https://github.com/nerde/rest-resource. This was created by me, and, as you can see in the documentation, it's way cleaner and simpler than the other ones. It's not focused on Android, but I'm using in it and it's working pretty well.

It supports HTTP Basic Auth. It does the dirty job of serializing and deserializing JSON objects. You will like it, specially if your API is Rails like.

How to clear input buffer in C?

You can do it (also) this way:

fseek(stdin,0,SEEK_END);

generate model using user:references vs user_id:integer

Both will generate the same columns when you run the migration. In rails console, you can see that this is the case:

:001 > Micropost
=> Micropost(id: integer, user_id: integer, created_at: datetime, updated_at: datetime)

The second command adds a belongs_to :user relationship in your Micropost model whereas the first does not. When this relationship is specified, ActiveRecord will assume that the foreign key is kept in the user_id column and it will use a model named User to instantiate the specific user.

The second command also adds an index on the new user_id column.

How can I change the language (to english) in Oracle SQL Developer?

Before installation use the Control Panel Region and Language Preferences tool to change everything (Format, Keyboard default input, language for non Unicode programs) to English. Revert to the original selections after the installation.

Converting an OpenCV Image to Black and White

Approach 1

While converting a gray scale image to a binary image, we usually use cv2.threshold() and set a threshold value manually. Sometimes to get a decent result we opt for Otsu's binarization.

I have a small hack I came across while reading some blog posts.

  1. Convert your color (RGB) image to gray scale.
  2. Obtain the median of the gray scale image.
  3. Choose a threshold value either 33% above the median

enter image description here

Why 33%?

This is because 33% works for most of the images/data-set.

You can also work out the same approach by replacing median with the mean.

Approach 2

Another approach would be to take an x number of standard deviations (std) from the mean, either on the positive or negative side; and set a threshold. So it could be one of the following:

  • th1 = mean - (x * std)
  • th2 = mean + (x * std)

Note: Before applying threshold it is advisable to enhance the contrast of the gray scale image locally (See CLAHE).

Fastest way to check if a value exists in a list

Or use __contains__:

sequence.__contains__(value)

Demo:

>>> l = [1, 2, 3]
>>> l.__contains__(3)
True
>>> 

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed

This is due to using obsolete mysql-connection-java version, your MySQl is updated but not your MySQL jdbc Driver, you can update your connection jar from the official site Official MySQL Connector site. Good Luck.

asp.net: Invalid postback or callback argument

if you change UseSubmitBehavior="True" to UseSubmitBehavior="False" your problem will be solved.

<asp:Button ID="BtnDis" runat="server" CommandName="BtnDis" CommandArgument='<%#Eval("Id")%>' Text="Discription" CausesValidation="True" UseSubmitBehavior="False" />

How can I put CSS and HTML code in the same file?

There's a style tag, so you could do something like this:

<style type="text/css">
  .title 
  {
    color: blue;
    text-decoration: bold;
    text-size: 1em;
  }
</style>

How to send FormData objects with Ajax-requests in jQuery?

You can use the $.ajax beforeSend event to manipulate the header.

beforeSend: function(xhr) { 
    xhr.setRequestHeader('Content-Type', 'multipart/form-data');
}

See this link for additional information: http://msdn.microsoft.com/en-us/library/ms536752(v=vs.85).aspx

How do I get indices of N maximum values in a NumPy array?

For multidimensional arrays you can use the axis keyword in order to apply the partitioning along the expected axis.

# For a 2D array
indices = np.argpartition(arr, -N, axis=1)[:, -N:]

And for grabbing the items:

x = arr.shape[0]
arr[np.repeat(np.arange(x), N), indices.ravel()].reshape(x, N)

But note that this won't return a sorted result. In that case you can use np.argsort() along the intended axis:

indices = np.argsort(arr, axis=1)[:, -N:]

# Result
x = arr.shape[0]
arr[np.repeat(np.arange(x), N), indices.ravel()].reshape(x, N)

Here is an example:

In [42]: a = np.random.randint(0, 20, (10, 10))

In [44]: a
Out[44]:
array([[ 7, 11, 12,  0,  2,  3,  4, 10,  6, 10],
       [16, 16,  4,  3, 18,  5, 10,  4, 14,  9],
       [ 2,  9, 15, 12, 18,  3, 13, 11,  5, 10],
       [14,  0,  9, 11,  1,  4,  9, 19, 18, 12],
       [ 0, 10,  5, 15,  9, 18,  5,  2, 16, 19],
       [14, 19,  3, 11, 13, 11, 13, 11,  1, 14],
       [ 7, 15, 18,  6,  5, 13,  1,  7,  9, 19],
       [11, 17, 11, 16, 14,  3, 16,  1, 12, 19],
       [ 2,  4, 14,  8,  6,  9, 14,  9,  1,  5],
       [ 1, 10, 15,  0,  1,  9, 18,  2,  2, 12]])

In [45]: np.argpartition(a, np.argmin(a, axis=0))[:, 1:] # 1 is because the first item is the minimum one.
Out[45]:
array([[4, 5, 6, 8, 0, 7, 9, 1, 2],
       [2, 7, 5, 9, 6, 8, 1, 0, 4],
       [5, 8, 1, 9, 7, 3, 6, 2, 4],
       [4, 5, 2, 6, 3, 9, 0, 8, 7],
       [7, 2, 6, 4, 1, 3, 8, 5, 9],
       [2, 3, 5, 7, 6, 4, 0, 9, 1],
       [4, 3, 0, 7, 8, 5, 1, 2, 9],
       [5, 2, 0, 8, 4, 6, 3, 1, 9],
       [0, 1, 9, 4, 3, 7, 5, 2, 6],
       [0, 4, 7, 8, 5, 1, 9, 2, 6]])

In [46]: np.argpartition(a, np.argmin(a, axis=0))[:, -3:]
Out[46]:
array([[9, 1, 2],
       [1, 0, 4],
       [6, 2, 4],
       [0, 8, 7],
       [8, 5, 9],
       [0, 9, 1],
       [1, 2, 9],
       [3, 1, 9],
       [5, 2, 6],
       [9, 2, 6]])

In [89]: a[np.repeat(np.arange(x), 3), ind.ravel()].reshape(x, 3)
Out[89]:
array([[10, 11, 12],
       [16, 16, 18],
       [13, 15, 18],
       [14, 18, 19],
       [16, 18, 19],
       [14, 14, 19],
       [15, 18, 19],
       [16, 17, 19],
       [ 9, 14, 14],
       [12, 15, 18]])

How to search for a part of a word with ElasticSearch

I think there's no need to change any mapping. Try to use query_string, it's perfect. All scenarios will work with default standard analyzer:

We have data:

{"_id" : "1","name" : "John Doeman","function" : "Janitor"}
{"_id" : "2","name" : "Jane Doewoman","function" : "Teacher"}

Scenario 1:

{"query": {
    "query_string" : {"default_field" : "name", "query" : "*Doe*"}
} }

Response:

{"_id" : "1","name" : "John Doeman","function" : "Janitor"}
{"_id" : "2","name" : "Jane Doewoman","function" : "Teacher"}

Scenario 2:

{"query": {
    "query_string" : {"default_field" : "name", "query" : "*Jan*"}
} }

Response:

{"_id" : "1","name" : "John Doeman","function" : "Janitor"}

Scenario 3:

{"query": {
    "query_string" : {"default_field" : "name", "query" : "*oh* *oe*"}
} }

Response:

{"_id" : "1","name" : "John Doeman","function" : "Janitor"}
{"_id" : "2","name" : "Jane Doewoman","function" : "Teacher"}

EDIT - Same implementation with spring data elastic search https://stackoverflow.com/a/43579948/2357869

One more explanation how query_string is better than others https://stackoverflow.com/a/43321606/2357869

A fatal error has been detected by the Java Runtime Environment: SIGSEGV, libjvm

Here is your relief for the problem :

I have a problem of running different versions of STS this morning, the application crash with the similar way as the question did.

Excerpt of my log file.

A fatal error has been detected by the Java Runtime Environment:
#a
#  SIGSEGV (0xb) at pc=0x00007f459db082a1, pid=4577, tid=139939015632640
#
# JRE version: 6.0_30-b12
# Java VM: Java HotSpot(TM) 64-Bit Server VM 
(20.5-b03 mixed mode linux-amd64 compressed oops)
# Problematic frame:
# C  [libsoup-2.4.so.1+0x6c2a1]  short+0x11

note that exception occured at # C [libsoup-2.4.so.1+0x6c2a1] short+0x11

Okay then little below the line:

R9 =0x00007f461829e550: <offset 0xa85550> in /usr/share/java/jdk1.6.0_30/jre/lib/amd64/server/libjvm.so at 0x00007f4617819000
R10=0x00007f461750f7c0 is pointing into the stack for thread: 0x00007f4610008000
R11=0x00007f459db08290: soup_session_feature_detach+0 in /usr/lib/x86_64-linux-gnu/libsoup-2.4.so.1 at 0x00007f459da9c000
R12=0x0000000000000000 is an unknown value
R13=0x000000074404c840 is an oop
{method} 

This line tells you where the actual bug or crash is to investigate more on this crash issue please use below links to see more, but let's continue the crash investigation and how I resolved it and the novelty of this bug :)

links are :

a fATAL ERROR JAVA THIS ONE IS GREAT LOTS OF USER!

a fATAL ERROR JAVA 2

Okay, after that here's what I found out to casue this case and why it happens as general advise.

  1. Most of the time, check that if you have installed, updated recently on Ubunu and Windows there are libraries like libsoup in linux which were the casuse of my crash.

  2. Check also for a new hardware problem and try to investigate the Logfile which STS or Java generated and also syslog in linux by

    tail - f /var/lib/messages or some other file
    

Then by carfully looking at those files the one you have the crash log for ... you can really solve the issue as follows:

sudo unlink /usr/lib/i386-linux-gnu/libsoup-2.4.so.1

or

sudo unlink /usr/lib/x86_64-linux-gnu/libsoup-2.4.so.1

Done !! Cheers!!

Create a nonclustered non-unique index within the CREATE TABLE statement with SQL Server

As of SQL 2014, this can be accomplished via inline index creation:

CREATE TABLE MyTable(
    a int NOT NULL
    ,b smallint NOT NULL
    ,c smallint NOT NULL
    ,d smallint NOT NULL
    ,e smallint NOT NULL

    -- This creates a primary key
    ,CONSTRAINT PK_MyTable PRIMARY KEY CLUSTERED (a)

    -- This creates a unique nonclustered index on columns b and c
    ,CONSTRAINT IX_MyTable1 UNIQUE (b, c)

    -- This creates a standard non-clustered index on (d, e)
    ,INDEX IX_MyTable4 NONCLUSTERED (d, e)
);
GO

Prior to SQL 2014, CREATE/ALTER TABLE only accepted CONSTRAINTs to be added, not indexes. The fact that primary key and unique constraints are implemented in terms of an index is a side effect.

Force decimal point instead of comma in HTML5 number input (client-side)

HTML step Attribute

<input type="number" name="points" step="3">

Example: if step="3", legal numbers could be -3, 0, 3, 6, etc.

 

Tip: The step attribute can be used together with the max and min attributes to create a range of legal values.

Note: The step attribute works with the following input types: number, range, date, datetime, datetime-local, month, time and week.

How to resize an image to fit in the browser window?

My general lazy CSS rule:

.background{
width:100%;
height:auto;
background: url('yoururl.jpg') no-repeat center;
background-position: 50% 50%;
background-size: 100% cover!important;
overflow:hidden;
}

This may zoom in on your image if it is low-res to begin with (that's to do with your image quality and size in dimensions. To center your image, you may also try (in the CSS)

display:block;    
margin: auto 0; 

to center your image

in your HTML:

<div class="background"></div>

Object cannot be cast from DBNull to other types

Reason for the error: In an object-oriented programming language, null means the absence of a reference to an object. DBNull represents an uninitialized variant or nonexistent database column. Source:MSDN

Actual Code which I faced error:

Before changed the code:

    if( ds.Tables[0].Rows[0][0] == null ) //   Which is not working

     {
            seqno  = 1; 
      }
    else
    {
          seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
     }

After changed the code:

   if( ds.Tables[0].Rows[0][0] == DBNull.Value ) //which is working properly
        {
                    seqno  = 1; 
         }
            else
            {
                  seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
             }

Conclusion: when the database value return the null value, we recommend to use the DBNull class instead of just specifying as a null like in C# language.

Set Radiobuttonlist Selected from Codebehind

Try this option:

radio1.Items.FindByValue("1").Selected = true;

How to test my servlet using JUnit

Updated Feb 2018: OpenBrace Limited has closed down, and its ObMimic product is no longer supported.

Here's another alternative, using OpenBrace's ObMimic library of Servlet API test-doubles (disclosure: I'm its developer).

package com.openbrace.experiments.examplecode.stackoverflow5434419;

import static org.junit.Assert.*;
import com.openbrace.experiments.examplecode.stackoverflow5434419.YourServlet;
import com.openbrace.obmimic.mimic.servlet.ServletConfigMimic;
import com.openbrace.obmimic.mimic.servlet.http.HttpServletRequestMimic;
import com.openbrace.obmimic.mimic.servlet.http.HttpServletResponseMimic;
import com.openbrace.obmimic.substate.servlet.RequestParameters;
import org.junit.Before;
import org.junit.Test;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * Example tests for {@link YourServlet#doPost(HttpServletRequest,
 * HttpServletResponse)}.
 *
 * @author Mike Kaufman, OpenBrace Limited
 */
public class YourServletTest {

    /** The servlet to be tested by this instance's test. */
    private YourServlet servlet;

    /** The "mimic" request to be used in this instance's test. */
    private HttpServletRequestMimic request;

    /** The "mimic" response to be used in this instance's test. */
    private HttpServletResponseMimic response;

    /**
     * Create an initialized servlet and a request and response for this
     * instance's test.
     *
     * @throws ServletException if the servlet's init method throws such an
     *     exception.
     */
    @Before
    public void setUp() throws ServletException {
        /*
         * Note that for the simple servlet and tests involved:
         * - We don't need anything particular in the servlet's ServletConfig.
         * - The ServletContext isn't relevant, so ObMimic can be left to use
         *   its default ServletContext for everything.
         */
        servlet = new YourServlet();
        servlet.init(new ServletConfigMimic());
        request = new HttpServletRequestMimic();
        response = new HttpServletResponseMimic();
    }

    /**
     * Test the doPost method with example argument values.
     *
     * @throws ServletException if the servlet throws such an exception.
     * @throws IOException if the servlet throws such an exception.
     */
    @Test
    public void testYourServletDoPostWithExampleArguments()
            throws ServletException, IOException {

        // Configure the request. In this case, all we need are the three
        // request parameters.
        RequestParameters parameters
            = request.getMimicState().getRequestParameters();
        parameters.set("username", "mike");
        parameters.set("password", "xyz#zyx");
        parameters.set("name", "Mike");

        // Run the "doPost".
        servlet.doPost(request, response);

        // Check the response's Content-Type, Cache-Control header and
        // body content.
        assertEquals("text/html; charset=ISO-8859-1",
            response.getMimicState().getContentType());
        assertArrayEquals(new String[] { "no-cache" },
            response.getMimicState().getHeaders().getValues("Cache-Control"));
        assertEquals("...expected result from dataManager.register...",
            response.getMimicState().getBodyContentAsString());

    }

}

Notes:

  • Each "mimic" has a "mimicState" object for its logical state. This provides a clear distinction between the Servlet API methods and the configuration and inspection of the mimic's internal state.

  • You might be surprised that the check of Content-Type includes "charset=ISO-8859-1". However, for the given "doPost" code this is as per the Servlet API Javadoc, and the HttpServletResponse's own getContentType method, and the actual Content-Type header produced on e.g. Glassfish 3. You might not realise this if using normal mock objects and your own expectations of the API's behaviour. In this case it probably doesn't matter, but in more complex cases this is the sort of unanticipated API behaviour that can make a bit of a mockery of mocks!

  • I've used response.getMimicState().getContentType() as the simplest way to check Content-Type and illustrate the above point, but you could indeed check for "text/html" on its own if you wanted (using response.getMimicState().getContentTypeMimeType()). Checking the Content-Type header the same way as for the Cache-Control header also works.

  • For this example the response content is checked as character data (with this using the Writer's encoding). We could also check that the response's Writer was used rather than its OutputStream (using response.getMimicState().isWritingCharacterContent()), but I've taken it that we're only concerned with the resulting output, and don't care what API calls produced it (though that could be checked too...). It's also possible to retrieve the response's body content as bytes, examine the detailed state of the Writer/OutputStream etc.

There are full details of ObMimic and a free download at the OpenBrace website. Or you can contact me if you have any questions (contact details are on the website).

Dropdownlist validation in Asp.net Using Required field validator

I was struggling with this for a few days until I chanced on the issue when I had to build a new Dropdown. I had several DropDownList controls and attempted to get validation working with no luck. One was databound and the other was filled from the aspx page. I needed to drop the databound one and add a second manual list. In my case Validators failed if you built a dropdown like this and looked at any value (0 or -1) for either a required or compare validator:

<asp:DropDownList ID="DDL_Reason" CssClass="inputDropDown" runat="server">
<asp:ListItem>--Select--</asp:ListItem>                                                                                                
<asp:ListItem>Expired</asp:ListItem>                                                                                                
<asp:ListItem>Lost/Stolen</asp:ListItem>                                                                                                
<asp:ListItem>Location Change</asp:ListItem>                                                                                            
</asp:DropDownList>

However adding the InitialValue like this worked instantly for a compare Validator.

<asp:ListItem Text="-- Select --" Value="-1"></asp:ListItem>

Warning: implode() [function.implode]: Invalid arguments passed

You can try

echo implode(', ', (array)$ret);

How do I get rid of an element's offset using CSS?

That offset is basically the x,y position that the browser has calculated for the element based on it's position css attribute. So if you put a <br> before it or any other element, it would change the offset. For example, you could set it to 0 by:

#inputBox{position:absolute;top:0px;left:0px;}

or

#inputBox{position:relative;top:-12px;left:-2px;}

Therefore, whatever positioning issue you have, is not necessarily an issue with offset, though you could always fix it by playing with the top,left,right and bottom attributes.

Is your problem browser incompatibility?

Redirect in Spring MVC

Try this

HttpServletResponse response;       
response.sendRedirect(".../webpage.xhtml");

SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

Installing the following package on Ubuntu fixed the issue for me

sudo apt-get install libssl-dev

HTTP Status 405 - HTTP method POST is not supported by this URL java servlet

This happened to me when:

  • Even with my servlet having only the method "doPost"
  • And the form method="POST"

  • I tried to access the action using the URL directly, without using the form submitt. Since the default method for the URL is the doGet method, when you don't use the form submit, you'll see @ your console the http 405 error.

Solution: Use only the form button you mapped to your servlet action.

Sending Multipart File as POST parameters with RestTemplate requests

One of our guys does something similar with the filesystemresource. try

mvm.add("file", new FileSystemResource(pUploadDTO.getFile())); 

assuming the output of your .getFile is a java File object, that should work the same as ours, which just has a File parameter.

org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1

So For my case I noticed hibernate is trying to update the record rather than inserting it and that thrown the exception mentioned.

I finally came to find that my entity had an updatedAt timestamp column:

<timestamp name="updatedDate" column="updated_date" />

and when I was trying to initialize the object i found that the code was setting this field explicitly.

after removing that setUpdateDate(new Date()) it worked and did an insert instead.

Simple conversion between java.util.Date and XMLGregorianCalendar

I had to make some changes to make it work, as some things seem to have changed in the meantime:

  • xjc would complain that my adapter does not extend XmlAdapter
  • some bizarre and unneeded imports were drawn in (org.w3._2001.xmlschema)
  • the parsing methods must not be static when extending the XmlAdapter, obviously

Here's a working example, hope this helps (I'm using JodaTime but in this case SimpleDate would be sufficient):

import java.util.Date;
import javax.xml.bind.DatatypeConverter;
import javax.xml.bind.annotation.adapters.XmlAdapter;
import org.joda.time.DateTime;

public class DateAdapter extends XmlAdapter<Object, Object> {
    @Override
    public Object marshal(Object dt) throws Exception {
        return new DateTime((Date) dt).toString("YYYY-MM-dd");
    }

    @Override
        public Object unmarshal(Object s) throws Exception {
        return DatatypeConverter.parseDate((String) s).getTime();
    }
}

In the xsd, I have followed the excellent references given above, so I have included this xml annotation:

<xsd:appinfo>
    <jaxb:schemaBindings>
        <jaxb:package name="at.mycomp.xml" />
    </jaxb:schemaBindings>
    <jaxb:globalBindings>
        <jaxb:javaType name="java.util.Date" xmlType="xsd:date"
              parseMethod="at.mycomp.xml.DateAdapter.unmarshal"
          printMethod="at.mycomp.xml.DateAdapter.marshal" />
    </jaxb:globalBindings>
</xsd:appinfo>

How to use __doPostBack()

This is also a good way to get server-side controls to postback inside FancyBox and/or jQuery Dialog. For example, in FancyBox-div:

   <asp:Button OnClientClick="testMe('param1');" ClientIDMode="Static"  ID="MyButton"  runat="server" Text="Ok" >
</asp:Button>

JavaScript:

function testMe(params) {
    var btnID= '<%=MyButton.ClientID %>';          
    __doPostBack(btnID, params);
}

Server-side Page_Load:

 string parameter = Request["__EVENTARGUMENT"];
 if (parameter == "param1")
     MyButton_Click(sender, e);

How can I find where I will be redirected using cURL?

To make cURL follow a redirect, use:

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

Erm... I don't think you're actually executing the curl... Try:

curl_exec($ch);

...after setting the options, and before the curl_getinfo() call.

EDIT: If you just want to find out where a page redirects to, I'd use the advice here, and just use Curl to grab the headers and extract the Location: header from them:

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$result = curl_exec($ch);
if (preg_match('~Location: (.*)~i', $result, $match)) {
   $location = trim($match[1]);
}

Deleting elements from std::set while iterating

Just to warn, that in case of a deque container, all solutions that check for the deque iterator equality to numbers.end() will likely fail on gcc 4.8.4. Namely, erasing an element of the deque generally invalidates pointer to numbers.end():

#include <iostream>
#include <deque>

using namespace std;
int main() 
{

  deque<int> numbers;

  numbers.push_back(0);
  numbers.push_back(1);
  numbers.push_back(2);
  numbers.push_back(3);
  //numbers.push_back(4);

  deque<int>::iterator  it_end = numbers.end();

  for (deque<int>::iterator it = numbers.begin(); it != numbers.end(); ) {
    if (*it % 2 == 0) {
      cout << "Erasing element: " << *it << "\n";
      numbers.erase(it++);
      if (it_end == numbers.end()) {
    cout << "it_end is still pointing to numbers.end()\n";
      } else {
    cout << "it_end is not anymore pointing to numbers.end()\n";
      }
    }
    else {
      cout << "Skipping element: " << *it << "\n";
      ++it;
    }
  }
}

Output:

Erasing element: 0
it_end is still pointing to numbers.end()
Skipping element: 1
Erasing element: 2
it_end is not anymore pointing to numbers.end()

Note that while the deque transformation is correct in this particular case, the end pointer has been invalidated along the way. With the deque of a different size the error is more apparent:

int main() 
{

  deque<int> numbers;

  numbers.push_back(0);
  numbers.push_back(1);
  numbers.push_back(2);
  numbers.push_back(3);
  numbers.push_back(4);

  deque<int>::iterator  it_end = numbers.end();

  for (deque<int>::iterator it = numbers.begin(); it != numbers.end(); ) {
    if (*it % 2 == 0) {
      cout << "Erasing element: " << *it << "\n";
      numbers.erase(it++);
      if (it_end == numbers.end()) {
    cout << "it_end is still pointing to numbers.end()\n";
      } else {
    cout << "it_end is not anymore pointing to numbers.end()\n";
      }
    }
    else {
      cout << "Skipping element: " << *it << "\n";
      ++it;
    }
  }
}

Output:

Erasing element: 0
it_end is still pointing to numbers.end()
Skipping element: 1
Erasing element: 2
it_end is still pointing to numbers.end()
Skipping element: 3
Erasing element: 4
it_end is not anymore pointing to numbers.end()
Erasing element: 0
it_end is not anymore pointing to numbers.end()
Erasing element: 0
it_end is not anymore pointing to numbers.end()
...
Segmentation fault (core dumped)

Here is one of the ways to fix this:

#include <iostream>
#include <deque>

using namespace std;
int main() 
{

  deque<int> numbers;
  bool done_iterating = false;

  numbers.push_back(0);
  numbers.push_back(1);
  numbers.push_back(2);
  numbers.push_back(3);
  numbers.push_back(4);

  if (!numbers.empty()) {
    deque<int>::iterator it = numbers.begin();
    while (!done_iterating) {
      if (it + 1 == numbers.end()) {
    done_iterating = true;
      } 
      if (*it % 2 == 0) {
    cout << "Erasing element: " << *it << "\n";
      numbers.erase(it++);
      }
      else {
    cout << "Skipping element: " << *it << "\n";
    ++it;
      }
    }
  }
}

Map enum in JPA with fixed values?

For versions earlier than JPA 2.1, JPA provides only two ways to deal with enums, by their name or by their ordinal. And the standard JPA doesn't support custom types. So:

  • If you want to do custom type conversions, you'll have to use a provider extension (with Hibernate UserType, EclipseLink Converter, etc). (the second solution). ~or~
  • You'll have to use the @PrePersist and @PostLoad trick (the first solution). ~or~
  • Annotate getter and setter taking and returning the int value ~or~
  • Use an integer attribute at the entity level and perform a translation in getters and setters.

I'll illustrate the latest option (this is a basic implementation, tweak it as required):

@Entity
@Table(name = "AUTHORITY_")
public class Authority implements Serializable {

    public enum Right {
        READ(100), WRITE(200), EDITOR (300);

        private int value;

        Right(int value) { this.value = value; }    

        public int getValue() { return value; }

        public static Right parse(int id) {
            Right right = null; // Default
            for (Right item : Right.values()) {
                if (item.getValue()==id) {
                    right = item;
                    break;
                }
            }
            return right;
        }

    };

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "AUTHORITY_ID")
    private Long id;

    @Column(name = "RIGHT_ID")
    private int rightId;

    public Right getRight () {
        return Right.parse(this.rightId);
    }

    public void setRight(Right right) {
        this.rightId = right.getValue();
    }

}

How to increase Java heap space for a tomcat app

For Windows Service, you need to run tomcat9w.exe (or 6w/7w/8w) depending on your version of tomcat. First, make sure tomcat is stopped. Then double click on tomcat9w.exe. Navigate to the Java tab. If you know you have 64 bit Windows with 64 bit Java and 64 bit Tomcat, then feel free to set the memory higher than 512. You'll need to do some task manager monitoring to determine how high to set it. For most apps developed in 2019... I'd recommend an initial memory pool of 1024, and the maximum memory pool of 2048. Of course if your computer has tons of RAM... feel free to go as high as you want. Also, see this answer: How to increase Maximum Memory Pool Size? Apache Tomcat 9

How to parse JSON in Java

Use minimal-json which is very fast and easy to use. You can parse from String obj and Stream.

Sample data:

{
  "order": 4711,
  "items": [
    {
      "name": "NE555 Timer IC",
      "cat-id": "645723",
      "quantity": 10,
    },
    {
      "name": "LM358N OpAmp IC",
      "cat-id": "764525",
      "quantity": 2
    }
  ]
}

Parsing:

JsonObject object = Json.parse(input).asObject();
int orders = object.get("order").asInt();
JsonArray items = object.get("items").asArray();

Creating JSON:

JsonObject user = Json.object().add("name", "Sakib").add("age", 23);

Maven:

<dependency>
  <groupId>com.eclipsesource.minimal-json</groupId>
  <artifactId>minimal-json</artifactId>
  <version>0.9.4</version>
</dependency>

doGet and doPost in Servlets

If you do <form action="identification" > for your html form, data will be passed using 'Get' by default and hence you can catch this using doGet function in your java servlet code. This way data will be passed under the HTML header and hence will be visible in the URL when submitted. On the other hand if you want to pass data in HTML body, then USE Post: <form action="identification" method="post"> and catch this data in doPost function. This was, data will be passed under the html body and not the html header, and you will not see the data in the URL after submitting the form.

Examples from my html:

<body>  
<form action="StartProcessUrl" method="post">
.....
.....

Examples from my java servlet code:

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        PrintWriter out = response.getWriter();
         String surname = request.getParameter("txtSurname");
         String firstname = request.getParameter("txtForename");
         String rqNo = request.getParameter("txtRQ6");
         String nhsNo = request.getParameter("txtNHSNo");

         String attachment1 = request.getParameter("base64textarea1");
         String attachment2 = request.getParameter("base64textarea2");

.........
.........

Convert string in base64 to image and save on filesystem in Python

You could probably use the PyPNG package's png.Reader object to do this - decode the base64 string into a regular string (via the base64 standard library), and pass it to the constructor.

How to evaluate http response codes from bash/shell script?

Another variation:

       status=$(curl -sS  -I https://www.healthdata.gov/user/login  2> /dev/null | head -n 1 | cut -d' ' -f2)
status_w_desc=$(curl -sS  -I https://www.healthdata.gov/user/login  2> /dev/null | head -n 1 | cut -d' ' -f2-)

Viewing full output of PS command

you can set output format,eg to see only the command and the process id.

ps -eo pid,args

see the man page of ps for more output format. alternatively, you can use the -w or --width n options.

If all else fails, here's another workaround, (just to see your long cmds)

awk '{ split(FILENAME,f,"/") ; printf "%s: %s\n", f[3],$0 }' /proc/[0-9]*/cmdline

Java: recommended solution for deep cloning/copying an instance

Since version 2.07 Kryo supports shallow/deep cloning:

Kryo kryo = new Kryo();
SomeClass someObject = ...
SomeClass copy1 = kryo.copy(someObject);
SomeClass copy2 = kryo.copyShallow(someObject);

Kryo is fast, at the and of their page you may find a list of companies which use it in production.

How to use JavaScript regex over multiple lines?

In addition to above-said examples, it is an alternate.

^[\\w\\s]*$

Where \w is for words and \s is for white spaces

Show hide div using codebehind

There are a few ways to handle rendering/showing controls on the page and you should take note to what happens with each method.

Rendering and Visibility

There are some instances where elements on your page don't need to be rendered for the user because of some type of logic or database value. In this case, you can prevent rendering (creating the control on the returned web page) altogether. You would want to do this if the control doesn't need to be shown later on the client side because no matter what, the user viewing the page never needs to see it.

Any controls or elements can have their visibility set from the server side. If it is a plain old html element, you just need to set the runat attribute value to server on the markup page.

<div id="myDiv" runat="server"></div>

The decision to render the div or not can now be done in the code behind class like so:

myDiv.Visible = someConditionalBool;

If set to true, it will be rendered on the page and if it's false it won't be rendered at all, not even hidden.

Client Side Hiding

Hiding an element is done on the client side only. Meaning, it's rendered but it has a display CSS style set on it which instructs your browser to not show it to the user. This is beneficial when you want to hide/show things based on user input. It's important to know that the element CAN be hidden on the server side too as long as the element/control has runat=server set just as I explained in the previous example.

Hiding in the Code Behind Class

To hide an element that you want rendered to the page but hidden is another simple single line of code:

myDiv.Style["display"] = "none";

If you have a need to remove the display style server side, it can be done by removing the display style, or setting it to a different value like inline or block (values described here).

myDiv.Style.Remove("display");
// -- or --
myDiv.Style["display"] = "inline";

Hiding on the Client Side with javascript

Using plain old javascript, you can easily hide the same element in this manner

var myDivElem = document.getElementById("myDiv");
myDivElem.style.display = "none";

// then to show again
myDivElem.style.display = "";

jQuery makes hiding elements a little simpler if you prefer to use jQuery:

var myDiv = $("#<%=myDiv.ClientID%>");
myDiv.hide();

// ... and to show 
myDiv.show();

Is the Scala 2.8 collections library a case of "the longest suicide note in history"?

Don't know Scala at all, however a few weeks ago I could not read Clojure. Now I can read most of it, but can not write anything yet beyond the most simplistic examples. I suspect Scala is no different. You need a good book or course depending on how you learn. Just reading the map declaration above, I got maybe 1/3 of it.

I believe the bigger problems are not the syntax of these languages, but adopting and internalizing the paradigms that make them usable in everyday production code. For me Java was not a huge leap from C++, which was not a huge leap from C, which was not a leap at all from Pascal, nor Basic etc... But coding in a functional language like Clojure is a huge leap (for me anyway). I guess in Scala you can code in Java style or Scala style. But in Clojure you will create quite the mess trying to keep your imperative habits from Java.

What does "commercial use" exactly mean?

I suggest this discriminative question:

Is the open-source tool necessary in your process of making money?

  • a blog engine on your commercial web site is necessary: commercial use.
  • winamp for listening to music is not necessary: non-commercial use.

How can I calculate an md5 checksum of a directory?

Using md5deep:

md5deep -r FOLDER | awk '{print $1}' | sort | md5sum

Javascript: best Singleton pattern

Extending the above post by Tom, if you need a class type declaration and access the singleton instance using a variable, the code below might be of help. I like this notation as the code is little self guiding.

function SingletonClass(){
    if ( arguments.callee.instance )
        return arguments.callee.instance;
    arguments.callee.instance = this;
}


SingletonClass.getInstance = function() {
    var singletonClass = new SingletonClass();
    return singletonClass;
};

To access the singleton, you would

var singleTon = SingletonClass.getInstance();

java.lang.NoClassDefFoundError: javax/mail/Authenticator, whats wrong?

While it's possible that this is due to a jar file missing from your classpath, it may not be.

It is important to keep two or three different exceptions strait in our head in this case:

  1. java.lang.ClassNotFoundException This exception indicates that the class was not found on the classpath. This indicates that we were trying to load the class definition, and the class did not exist on the classpath.

  2. java.lang.NoClassDefFoundError This exception indicates that the JVM looked in its internal class definition data structure for the definition of a class and did not find it. This is different than saying that it could not be loaded from the classpath. Usually this indicates that we previously attempted to load a class from the classpath, but it failed for some reason - now we're trying again, but we're not even going to try to load it, because we failed loading it earlier. The earlier failure could be a ClassNotFoundException or an ExceptionInInitializerError (indicating a failure in the static initialization block) or any number of other problems. The point is, a NoClassDefFoundError is not necessarily a classpath problem.

I would look at the source for javax.mail.Authenticator, and see what it is doing in it's static initializer. (Look at static variable initialization and the static block, if there is one.) If you aren't getting a ClassNotFoundException prior to the NoClassDefFoundError, you're almost guaranteed that it's a static initialization problem.

I have seen similar errors quite frequently when the hosts file incorrectly defines the localhost address, and the static initialization block relies on InetAddress.getLocalHost(). 127.0.0.1 should point to 'localhost' (and probably also localhost.localdomain). It should NOT point to the actual host name of the machine (although for some reason, many older RedHat Linux installers liked to set it incorrectly).

ASP.NET postback with JavaScript

While Phairoh's solution seems theoretically sound, I have also found another solution to this problem. By passing the UpdatePanels id as a paramater (event target) for the doPostBack function the update panel will post back but not the entire page.

__doPostBack('myUpdatePanelId','')

*note: second parameter is for addition event args

hope this helps someone!

EDIT: so it seems this same piece of advice was given above as i was typing :)

Ant build failed: "Target "build..xml" does not exist"

in the folder where the build.xml resides run command only -

ant

and not the command - `

ant build.xml

`

. if you are using the ant file as build xml then the below steps helps you Steps : open cmd Prompt >> switch to the project location >>type ant and click enter key

Best way to retrieve variable values from a text file?

But what i'll love is to refer to the variable direclty, as i declared it in the python script..

Assuming you're happy to change your syntax slightly, just use python and import the "config" module.

# myconfig.py:

var_a = 'home'
var_b = 'car'
var_c = 15.5

Then do

from myconfig import *

And you can reference them by name in your current context.

Efficiency of Java "Double Brace Initialization"?

One property of this approach that has not been pointed out so far is that because you create inner classes, the whole containing class is captured in its scope. This means that as long as your Set is alive, it will retain a pointer to the containing instance (this$0) and keep that from being garbage-collected, which could be an issue.

This, and the fact that a new class gets created in the first place even though a regular HashSet would work just fine (or even better), makes me not want to use this construct (even though I really long for the syntactic sugar).

Second question: The new HashSet must be the "this" used in the instance initializer ... can anyone shed light on the mechanism? I'd have naively expected "this" to refer to the object initializing "flavors".

This is just how inner classes work. They get their own this, but they also have pointers to the parent instance, so that you can call methods on the containing object as well. In case of a naming conflict, the inner class (in your case HashSet) takes precedence, but you can prefix "this" with a classname to get the outer method as well.

public class Test {

    public void add(Object o) {
    }

    public Set<String> makeSet() {
        return new HashSet<String>() {
            {
              add("hello"); // HashSet
              Test.this.add("hello"); // outer instance 
            }
        };
    }
}

To be clear on the anonymous subclass being created, you could define methods in there as well. For example override HashSet.add()

    public Set<String> makeSet() {
        return new HashSet<String>() {
            {
              add("hello"); // not HashSet anymore ...
            }

            @Override
            boolean add(String s){

            }

        };
    }

Eclipse/Java code completion not working

Check that you did not filter out many options inside the Window > Preferences > Java > Appearance > Type Filters

Items in this list will not be appear in quick fix, be autocompleted, or appear in other various places like the Open Type dialog.

How to detect the physical connected state of a network cable/connector?

tail -f /var/log/syslog | grep -E 'link (up|down)'

or for me faster gets:

tail -f /var/log/syslog | grep 'link \(up\|down\)'

It will listen to the syslog file.

Result (if disconnect and after 4 seconds connect again):

Jan 31 13:21:09 user kernel: [19343.897157] r8169 0000:06:00.0 enp6s0: link down
Jan 31 13:21:13 user kernel: [19347.143506] r8169 0000:06:00.0 enp6s0: link up

Timeout a command in bash without unnecessary delay

My problem was maybe a bit different : I start a command via ssh on a remote machine and want to kill the shell and childs if the command hangs.

I now use the following :

ssh server '( sleep 60 && kill -9 0 ) 2>/dev/null & my_command; RC=$? ; sleep 1 ; pkill -P $! ; exit $RC'

This way the command returns 255 when there was a timeout or the returncode of the command in case of success

Please note that killing processes from a ssh session is handled different from an interactive shell. But you can also use the -t option to ssh to allocate a pseudo terminal, so it acts like an interactive shell

CSS3's border-radius property and border-collapse:collapse don't mix. How can I use border-radius to create a collapsed table with rounded corners?

I started experiment with "display" and I found that: border-radius, border, margin, padding, in a table are displayed with:

display: inline-table;

For example

table tbody tr {
  display: inline-table;
  width: 960px; 
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  border-radius: 5px;
}

But we need set a width of every column

tr td.first-column {
  width: 100px;
}
tr td.second-column {
  width: 860px;
}

What's causing my java.net.SocketException: Connection reset?

The javadoc for SocketException states that it is

Thrown to indicate that there is an error in the underlying protocol such as a TCP error

In your case it seems that the connection has been closed by the server end of the connection. This could be an issue with the request you are sending or an issue at their end.

To aid debugging you could look at using a tool such as Wireshark to view the actual network packets. Also, is there an alternative client to your Java code that you could use to test the web service? If this was successful it could indicate a bug in the Java code.

As you are using Commons HTTP Client have a look at the Common HTTP Client Logging Guide. This will tell you how to log the request at the HTTP level.

ASP.NET / C#: DropDownList SelectedIndexChanged in server control not firing

I had the same problem but got round it by setting AutoPostBack to true and in an update panel set the trigger to the dropdownlist control id and event name to SelectedIndexChanged e.g.

    <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Always" enableViewState="true">
        <Triggers>
            <asp:AsyncPostBackTrigger ControlID="ddl1" EventName="SelectedIndexChanged" />
        </Triggers>
        <ContentTemplate>
            <asp:DropDownList ID="ddl1" runat="server" ClientIDMode="Static" OnSelectedIndexChanged="ddl1_SelectedIndexChanged" AutoPostBack="true" ViewStateMode="Enabled">
                <asp:ListItem Text="--Please select a item--" Value="0" />
            </asp:DropDownList>
        </ContentTemplate>
    </asp:UpdatePanel>

Error - SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM

The code you have for the two columns looks ok. Look for any other datetime columns on that mapping class. Also, enable logging on the datacontext to see the query and parameters.

dc.Log = Console.Out;

DateTime is initialized to c#'s 0 - which is 0001-01-01. This is transmitted by linqtosql to the database via sql string literal : '0001-01-01'. Sql cannot parse a T-Sql datetime from this date.

There's a couple ways to deal with this:

  • Make sure you initialize all date times with a value that SQL can handle (such as Sql's 0 : 1900-01-01 )
  • Make sure any date times that may occasionally be omitted are nullable datetimes

Is JavaScript's "new" keyword considered harmful?

The rationale behind not using the new keyword, is simple:

By not using it at all, you avoid the pitfall that comes with accidentally omitting it. The construction pattern that YUI uses, is an example of how you can avoid the new keyword altogether"

var foo = function () {
    var pub= { };
    return pub;
}
var bar = foo();

Alternatively you could so this:

function foo() { }
var bar = new foo();

But by doing so you run risk of someone forgetting to use the new keyword, and the this operator being all fubar. AFAIK there is no advantage to doing this (other than you are used to it).

At The End Of The Day: It's about being defensive. Can you use the new statement? Yes. Does it make your code more dangerous? Yes.

If you have ever written C++, it's akin to setting pointers to NULL after you delete them.

Why do people hate SQL cursors so much?

In Oracle PL/SQL cursors will not result in table locks and it is possible to use bulk-collecting/bulk-fetching.

In Oracle 10 the often used implicit cursor

  for x in (select ....) loop
    --do something 
  end loop;

fetches implicitly 100 rows at a time. Explicit bulk-collecting/bulk-fetching is also possible.

However PL/SQL cursors are something of a last resort, use them when you are unable to solve a problem with set-based SQL.

Another reason is parallelization, it is easier for the database to parallelize big set-based statements than row-by-row imperative code. It is the same reason why functional programming becomes more and more popular (Haskell, F#, Lisp, C# LINQ, MapReduce ...), functional programming makes parallelization easier. The number CPUs per computer is rising so parallelization becomes more and more an issue.

Is there a simple way to convert C++ enum to string?

QT is able to pull that of (thanks to the meta object compiler):

QNetworkReply::NetworkError error;

error = fetchStuff();

if (error != QNetworkReply::NoError) {

    QString errorValue;

    QMetaObject meta = QNetworkReply::staticMetaObject;

    for (int i=0; i < meta.enumeratorCount(); ++i) {

        QMetaEnum m = meta.enumerator(i);

        if (m.name() == QLatin1String("NetworkError")) {

            errorValue = QLatin1String(m.valueToKey(error));

            break;

        }

    }

    QMessageBox box(QMessageBox::Information, "Failed to fetch",

                "Fetching stuff failed with error '%1`").arg(errorValue),

                QMessageBox::Ok);

    box.exec();

    return 1;

}

In Qt every class that has the Q_OBJECT macro will automatically have a static member "staticMetaObject" of the type QMetaObject. You can then find all sorts of cool things like the properties, signals, slots and indeed enums.

Source

ORA-03113: end-of-file on communication channel after long inactivity in ASP.Net app

This error message can be thrown in the application logs when the actual issue is that the oracle database server ran out of space.

After correcting the space issue, this particular error message disappeared.

C++ IDE for Linux?

why wouldn't you also use it for C++? CDT meets every requirement you've mentioned.

I didn't use eclipse at first because I wasn't sure that it was equally good at giving me the means of developing in C++ (efficiently). Besides that, I was also convinced that there had to be better, more specialized tools available for c++ development in Linux:

and I really like that [eclipse] IDE for java, but is it any good for c++ and won't I miss out on something that is even better?

I honestly believe that, although some tools (like eclipse) are great at many things, it is best to look for other options as well (and I don't mean that for IDE's only, but in general and even in real life)...
Like in this case, vim is really great, and I would have missed out on it if I sticked to something I already knew.

LINQ-to-SQL vs stored procedures?

Create PROCEDURE userInfoProcedure
    -- Add the parameters for the stored procedure here
    @FirstName varchar,
    @LastName varchar
AS
BEGIN

    SET NOCOUNT ON;

    -- Insert statements for procedure here
    SELECT FirstName  , LastName,Age from UserInfo where FirstName=@FirstName
    and LastName=@FirstName
END
GO

http://www.totaldotnet.com/Article/ShowArticle121_StoreProcBasic.aspx

What does the M stand for in C# Decimal literal notation?

Well, i guess M represent the mantissa. Decimal can be used to save money, but it doesn't mean, decimal only used for money.

https connection using CURL from command line

Here you could find the CA certs with instructions to download and convert Mozilla CA certs. Once you get ca-bundle.crt or cacert.pem you just use:

curl.exe --cacert cacert.pem https://www.google.com

or

curl.exe --cacert ca-bundle.crt https://www.google.com

Simple way to create matrix of random numbers

numpy.random.rand(row, column) generates random numbers between 0 and 1, according to the specified (m,n) parameters given. So use it to create a (m,n) matrix and multiply the matrix for the range limit and sum it with the high limit.

Analyzing: If zero is generated just the low limit will be held, but if one is generated just the high limit will be held. In order words, generating the limits using rand numpy you can generate the extreme desired numbers.

import numpy as np

high = 10
low = 5
m,n = 2,2

a = (high - low)*np.random.rand(m,n) + low

Output:

a = array([[5.91580065, 8.1117106 ],
          [6.30986984, 5.720437  ]])

How to put a delay on AngularJS instant search?

(See answer below for a Angular 1.3 solution.)

The issue here is that the search will execute every time the model changes, which is every keyup action on an input.

There would be cleaner ways to do this, but probably the easiest way would be to switch the binding so that you have a $scope property defined inside your Controller on which your filter operates. That way you can control how frequently that $scope variable is updated. Something like this:

JS:

var App = angular.module('App', []);

App.controller('DisplayController', function($scope, $http, $timeout) {
    $http.get('data.json').then(function(result){
        $scope.entries = result.data;
    });

    // This is what you will bind the filter to
    $scope.filterText = '';

    // Instantiate these variables outside the watch
    var tempFilterText = '',
        filterTextTimeout;
    $scope.$watch('searchText', function (val) {
        if (filterTextTimeout) $timeout.cancel(filterTextTimeout);

        tempFilterText = val;
        filterTextTimeout = $timeout(function() {
            $scope.filterText = tempFilterText;
        }, 250); // delay 250 ms
    })
});

HTML:

<input id="searchText" type="search" placeholder="live search..." ng-model="searchText" />
<div class="entry" ng-repeat="entry in entries | filter:filterText">
    <span>{{entry.content}}</span>
</div>

Determining the path that a yum package installed to

I don't know about yum, but rpm -ql will list the files in a particular .rpm file. If you can find the package file on your system you should be good to go.

How do I display a decimal value to 2 decimal places?

https://msdn.microsoft.com/en-us/library/dwhawy9k%28v=vs.110%29.aspx

This link explains in detail how you can handle your problem and what you can do if you want to learn more. For simplicity purposes, what you want to do is

double whateverYouWantToChange = whateverYouWantToChange.ToString("F2");

if you want this for a currency, you can make it easier by typing "C2" instead of "F2"

Add Insecure Registry to Docker

For me the solution was to add the registry to here:

/etc/sysconfig/docker-registries

DOCKER_REGISTRIES=''
DOCKER_EXTRA_REGISTRIES='--insecure-registry  b.example.com'

Send FormData and String Data Together Through JQuery AJAX?

I found that, if somehow(like your ModelState is false on server.) and page post again to server then it was taking old value to the server. So i found that solution for that.

   var data = new FormData();
   $.each($form.serializeArray(), function (key, input) {
        if (data.has(input.name)) {
            data.set(input.name, input.value);
        } else {
            data.append(input.name, input.value);
        }
    });

warning: incompatible implicit declaration of built-in function ‘xyz’

I met these warnings on mempcpy function. Man page says this function is a GNU extension and synopsis shows:

#define _GNU_SOURCE
#include <string.h>

When #define is added to my source before the #include, declarations for the GNU extensions are made visible and warnings disappear.

jQuery remove options from select

It works on either option tag or text field:

$("#idname option[value='option1']").remove();

Access camera from a browser

    <style type="text/css">
        #container {
            margin: 0px auto;
            width: 500px;
            height: 375px;
            border: 10px #333 solid;
        }

        #videoElement {
          width: 500px;
          height: 375px;
          background-color: #777;
        }
    </style>    
<div id="container">
            <video autoplay="true" id="videoElement"></video>
        </div>
        <script type="text/javascript">
          var video = document.querySelector("#videoElement");
          navigator.getUserMedia = navigator.getUserMedia||navigator.webkitGetUserMedia||navigator.mozGetUserMedia||navigator.msGetUserMedia||navigator.oGetUserMedia;
    
          if(navigator.getUserMedia) {
            navigator.getUserMedia({video:true}, handleVideo, videoError);
          }
    
          function handleVideo(stream) {
            video.srcObject=stream;
            video.play();
          }
    
          function videoError(e) {
    
          }
        </script>

Send POST data using XMLHttpRequest

Just for feature readers finding this question. I found that the accepted answer works fine as long as you have a given path, but if you leave it blank it will fail in IE. Here is what I came up with:

function post(path, data, callback) {
    "use strict";
    var request = new XMLHttpRequest();

    if (path === "") {
        path = "/";
    }
    request.open('POST', path, true);
    request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
    request.onload = function (d) {
        callback(d.currentTarget.response);
    };
    request.send(serialize(data));
}

You can you it like so:

post("", {orem: ipsum, name: binny}, function (response) {
    console.log(respone);
})

Nesting queries in SQL

If it has to be "nested", this would be one way, to get your job done:

SELECT o.name AS country, o.headofstate 
FROM   country o
WHERE  o.headofstate like 'A%'
AND   (
    SELECT i.population
    FROM   city i
    WHERE  i.id = o.capital
    ) > 100000

A JOIN would be more efficient than a correlated subquery, though. Can it be, that who ever gave you that task is not up to speed himself?

What's the difference between window.location= and window.location.replace()?

TLDR;

use location.href or better use window.location.href;

However if you read this you will gain undeniable proof.

The truth is it's fine to use but why do things that are questionable. You should take the higher road and just do it the way that it probably should be done.

location = "#/mypath/otherside"
var sections = location.split('/')

This code is perfectly correct syntax-wise, logic wise, type-wise you know the only thing wrong with it?

it has location instead of location.href

what about this

var mystring = location = "#/some/spa/route"

what is the value of mystring? does anyone really know without doing some test. No one knows what exactly will happen here. Hell I just wrote this and I don't even know what it does. location is an object but I am assigning a string will it pass the string or pass the location object. Lets say there is some answer to how this should be implemented. Can you guarantee all browsers will do the same thing?

This i can pretty much guess all browsers will handle the same.

var mystring = location.href = "#/some/spa/route"

What about if you place this into typescript will it break because the type compiler will say this is suppose to be an object?

This conversation is so much deeper than just the location object however. What this conversion is about what kind of programmer you want to be?

If you take this short-cut, yea it might be okay today, ye it might be okay tomorrow, hell it might be okay forever, but you sir are now a bad programmer. It won't be okay for you and it will fail you.

There will be more objects. There will be new syntax.

You might define a getter that takes only a string but returns an object and the worst part is you will think you are doing something correct, you might think you are brilliant for this clever method because people here have shamefully led you astray.

var Person.name = {first:"John":last:"Doe"}
console.log(Person.name) // "John Doe"

With getters and setters this code would actually work, but just because it can be done doesn't mean it's 'WISE' to do so.

Most people who are programming love to program and love to get better. Over the last few years I have gotten quite good and learn a lot. The most important thing I know now especially when you write Libraries is consistency and predictability.

Do the things that you can consistently do.

+"2" <-- this right here parses the string to a number. should you use it? or should you use parseInt("2")?

what about var num =+"2"?

From what you have learn, from the minds of stackoverflow i am not too hopefully.

If you start following these 2 words consistent and predictable. You will know the right answer to a ton of questions on stackoverflow.

Let me show you how this pays off. Normally I place ; on every line of javascript i write. I know it's more expressive. I know it's more clear. I have followed my rules. One day i decided not to. Why? Because so many people are telling me that it is not needed anymore and JavaScript can do without it. So what i decided to do this. Now because I have become sure of my self as a programmer (as you should enjoy the fruit of mastering a language) i wrote something very simple and i didn't check it. I erased one comma and I didn't think I needed to re-test for such a simple thing as removing one comma.

I wrote something similar to this in es6 and babel

var a = "hello world"
(async function(){
  //do work
})()

This code fail and took forever to figure out. For some reason what it saw was

var a = "hello world"(async function(){})()

hidden deep within the source code it was telling me "hello world" is not a function.

For more fun node doesn't show the source maps of transpiled code.

Wasted so much stupid time. I was presenting to someone as well about how ES6 is brilliant and then I had to start debugging and demonstrate how headache free and better ES6 is. Not convincing is it.

I hope this answered your question. This being an old question it's more for the future generation, people who are still learning.

Question when people say it doesn't matter either way works. Chances are a wiser more experienced person will tell you other wise.

what if someone overwrite the location object. They will do a shim for older browsers. It will get some new feature that needs to be shimmed and your 3 year old code will fail.

My last note to ponder upon.

Writing clean, clear purposeful code does something for your code that can't be answer with right or wrong. What it does is it make your code an enabler.

You can use more things plugins, Libraries with out fear of interruption between the codes.

for the record. use

window.location.href

#pragma once vs include guards?

Atop explanation by Konrad Kleine above.

A brief summary:

  • when we use # pragma once it is much of the compiler responsibility, not to allow its inclusion more than once. Which means, after you mention the code-snippet in the file, it is no more your responsibility.

Now, compiler looks, for this code-snippet at the beginning of the file, and skips it from being included (if already included once). This definitely will reduce the compilation-time (on an average and in huge-system). However, in case of mocks/test environment, will make the test-cases implementation difficult, due to circular etc dependencies.

  • Now, when we use the #ifndef XYZ_H for the headers, it is more of the developers responsibility to maintain the dependency of headers. Which means, whenever due to some new header file, there is possibility of the circular dependency, compiler will just flag some "undefined .." error messages at compile time, and it is user to check the logical connection/flow of the entities and rectify the improper includes.

This definitely will add to the compilation time (as needs to rectified and re-run). Also, as it works on the basis of including the file, based on the "XYZ_H" defined-state, and still complains, if not able to get all the definitions.

Therefore, to avoid situations like this, we should use, as;

#pragma once
#ifndef XYZ_H
#define XYZ_H
...
#endif

i.e. the combination of both.

Redirect to specified URL on PHP script completion?

<?php

// do something here

header("Location: http://example.com/thankyou.php");
?>

How do I get the information from a meta tag with JavaScript?

function getMetaContentByName(name,content){
   var content = (content==null)?'content':content;
   return document.querySelector("meta[name='"+name+"']").getAttribute(content);
}

Used in this way:

getMetaContentByName("video");

The example on this page:

getMetaContentByName("twitter:domain");

In C++, what is a virtual base class?

In addition to what has already been said about multiple and virtual inheritance(s), there is a very interesting article on Dr Dobb's Journal: Multiple Inheritance Considered Useful

Calculating a 2D Vector's Cross Product

In short: It's a shorthand notation for a mathematical hack.

Long explanation:

You can't do a cross product with vectors in 2D space. The operation is not defined there.

However, often it is interesting to evaluate the cross product of two vectors assuming that the 2D vectors are extended to 3D by setting their z-coordinate to zero. This is the same as working with 3D vectors on the xy-plane.

If you extend the vectors that way and calculate the cross product of such an extended vector pair you'll notice that only the z-component has a meaningful value: x and y will always be zero.

That's the reason why the z-component of the result is often simply returned as a scalar. This scalar can for example be used to find the winding of three points in 2D space.

From a pure mathematical point of view the cross product in 2D space does not exist, the scalar version is the hack and a 2D cross product that returns a 2D vector makes no sense at all.

CSS3 transitions inside jQuery .css()

Your code can get messy fast when dealing with CSS3 transitions. I would recommend using a plugin such as jQuery Transit that handles the complexity of CSS3 animations/transitions.

Moreover, the plugin uses webkit-transform rather than webkit-transition, which allows for mobile devices to use hardware acceleration in order to give your web apps that native look and feel when the animations occur.

JS Fiddle Live Demo

Javascript:

$("#startTransition").on("click", function()
{

    if( $(".boxOne").is(":visible")) 
    {
        $(".boxOne").transition({ x: '-100%', opacity: 0.1 }, function () { $(".boxOne").hide(); });
        $(".boxTwo").css({ x: '100%' });
        $(".boxTwo").show().transition({ x: '0%', opacity: 1.0 });
        return;        
    }

    $(".boxTwo").transition({ x: '-100%', opacity: 0.1 }, function () { $(".boxTwo").hide(); });
    $(".boxOne").css({ x: '100%' });
    $(".boxOne").show().transition({ x: '0%', opacity: 1.0 });

});

Most of the hard work of getting cross-browser compatibility is done for you as well and it works like a charm on mobile devices.

Apache VirtualHost 403 Forbidden

This works on Linux Fedora for VirtualHost : ( Lampp/Xampp )

Go to : /opt/lampp/etc/extra

Open : httpd-vhosts.conf

Insert this in httpd-vhosts.conf

<VirtualHost *:80>
ServerAdmin [email protected]
DocumentRoot "/opt/lampp/APPS/My_App"
ServerName votemo.test
ServerAlias www.votemo.test
ErrorLog "logs/votemo.test-error_log"
CustomLog "logs/votemo.test-access_log" common
<Directory "/opt/lampp/APPS/My_App">
    Options FollowSymLinks
    AllowOverride None
    Require all granted
</Directory>

p.s. : Don't forget to comment the previous exemple already present in httpd-vhosts.conf

Set your hosts system file :

Go to : /etc/ folder find hosts file ( /etc/hosts )

I insert this : (but not sure to 100% if this good)

127.0.0.1       votemo.test

::1         votemo.test

-> Open or Restart Apache.

Open a console and paste this command for open a XAMPP graphic interface :

sudo /opt/lampp/manager-linux-x64.run

Note : Adjust path how you want to your app folder

ex: DocumentRoot "/home/USER/Desktop/My_Project"

and set directory path too :

ex : ... <Directory "/home/USER/Desktop/My_Project"> ...

But this should be tested, comment if this work ...

Additionnal notes :

  • Localisation Lampp folder : (Path) /opt/lampp

  • Start Lampp : sudo /opt/lampp/lampp start

  • Adjust rights if needed : sudo chmod o+w /opt/lampp/manager-linux-x64.run

  • Path to hosts file : /etc/hosts

Why do table names in SQL Server start with "dbo"?

dbo is the default schema in SQL Server. You can create your own schemas to allow you to better manage your object namespace.

Delete files or folder recursively on Windows CMD

You can use this in the bat script:

rd /s /q "c:\folder a"

Now, just change c:\folder a to your folder's location. Quotation is only needed when your folder name contains spaces.

How to repeat a string a variable number of times in C++?

I know this is an old question, but I was looking to do the same thing and have found what I think is a simpler solution. It appears that cout has this function built in with cout.fill(), see the link for a 'full' explanation

http://www.java-samples.com/showtutorial.php?tutorialid=458

cout.width(11);
cout.fill('.');
cout << "lolcat" << endl;

outputs

.....lolcat

error: No resource identifier found for attribute 'adSize' in package 'com.google.example' main.xml

for me, I have to add

xmlns:ads="http://schemas.android.com/apk/lib/com.google.ads"

right after:

xmlns:android="http://schemas.android.com/apk/res/android"

in res/layout/main.xml

How to add text to JFrame?

You can add a multi-line label with the following:

JLabel label = new JLabel("My label");

label.setText("<html>This is a<br>multline label!<br> Try it yourself!</html>");

From here, simply add the label to the frame using the add() method, and you're all set!

How do I redirect with JavaScript?

To redirect to another page, you can use:

window.location = "http://www.yoururl.com";

EL access a map value by Integer key

If you just happen to have a Map with Integer keys you cannot change, you could write a custom EL function to convert a Long to Integer. This would allow you to do something like:

<c:out value="${map[myLib:longToInteger(1)]}"/>

Shrink a YouTube video to responsive width

I used the CSS in the accepted answer here for my responsive YouTube videos - worked great right up until YouTube updated their system around the start of August 2015. The videos on YouTube are the same dimensions but for whatever reason the CSS in the accepted answer now letterboxes all our videos. Black bands across top and bottom.

I've tickered around with the sizes and settled on getting rid of the top padding and changing the bottom padding to 56.45%. Seems to look good.

.videowrapper {
    position: relative;
    padding-bottom: 56.45%;
    height: 0;
}

How to parse unix timestamp to time.Time

The time.Parse function does not do Unix timestamps. Instead you can use strconv.ParseInt to parse the string to int64 and create the timestamp with time.Unix:

package main

import (
    "fmt"
    "time"
    "strconv"
)

func main() {
    i, err := strconv.ParseInt("1405544146", 10, 64)
    if err != nil {
        panic(err)
    }
    tm := time.Unix(i, 0)
    fmt.Println(tm)
}

Output:

2014-07-16 20:55:46 +0000 UTC

Playground: http://play.golang.org/p/v_j6UIro7a

Edit:

Changed from strconv.Atoi to strconv.ParseInt to avoid int overflows on 32 bit systems.

Connection timeout for SQL server

Hmmm...

As Darin said, you can specify a higher connection timeout value, but I doubt that's really the issue.

When you get connection timeouts, it's typically a problem with one of the following:

  1. Network configuration - slow connection between your web server/dev box and the SQL server. Increasing the timeout may correct this, but it'd be wise to investigate the underlying problem.

  2. Connection string. I've seen issues where an incorrect username/password will, for some reason, give a timeout error instead of a real error indicating "access denied." This shouldn't happen, but such is life.

  3. Connection String 2: If you're specifying the name of the server incorrectly, or incompletely (for instance, mysqlserver instead of mysqlserver.webdomain.com), you'll get a timeout. Can you ping the server using the server name exactly as specified in the connection string from the command line?

  4. Connection string 3 : If the server name is in your DNS (or hosts file), but the pointing to an incorrect or inaccessible IP, you'll get a timeout rather than a machine-not-found-ish error.

  5. The query you're calling is timing out. It can look like the connection to the server is the problem, but, depending on how your app is structured, you could be making it all the way to the stage where your query is executing before the timeout occurs.

  6. Connection leaks. How many processes are running? How many open connections? I'm not sure if raw ADO.NET performs connection pooling, automatically closes connections when necessary ala Enterprise Library, or where all that is configured. This is probably a red herring. When working with WCF and web services, though, I've had issues with unclosed connections causing timeouts and other unpredictable behavior.

Things to try:

  1. Do you get a timeout when connecting to the server with SQL Management Studio? If so, network config is likely the problem. If you do not see a problem when connecting with Management Studio, the problem will be in your app, not with the server.

  2. Run SQL Profiler, and see what's actually going across the wire. You should be able to tell if you're really connecting, or if a query is the problem.

  3. Run your query in Management Studio, and see how long it takes.

Good luck!

What is the $? (dollar question mark) variable in shell scripting?

$? is the exit status of a command, such that you can daisy-chain a series of commands.

Example

command1 && command2 && command3

command2 will run if command1's $? yields a success (0) and command3 will execute if $? of command2 will yield a success

Retrieve the maximum length of a VARCHAR column in SQL Server

Many times you want to identify the row that has that column with the longest length, especially if you are troubleshooting to find out why the length of a column on a row in a table is so much longer than any other row, for instance. This query will give you the option to list an identifier on the row in order to identify which row it is.

select ID, [description], len([description]) as descriptionlength
FROM [database1].[dbo].[table1]
where len([description]) = 
 (select max(len([description]))
  FROM [database1].[dbo].[table1]

what is the difference between json and xml

They are both data formats for hierarchical data, so while the syntax is quite different, the structure is similar. Example:

JSON:

{
  "persons": [
    {
      "name": "Ford Prefect",
      "gender": "male"
    },
    {
      "name": "Arthur Dent",
      "gender": "male"
    },
    {
      "name": "Tricia McMillan",
      "gender": "female"
    }
  ]
}

XML:

<persons>
  <person>
    <name>Ford Prefect</name>
    <gender>male</gender>
  </person>
  <person>
    <name>Arthur Dent</name>
    <gender>male</gender>
  </person>
  <person>
    <name>Tricia McMillan</name>
    <gender>female</gender>
  </person>
</persons>

The XML format is more advanced than shown by the example, though. You can for example add attributes to each element, and you can use namespaces to partition elements. There are also standards for defining the format of an XML file, the XPATH language to query XML data, and XSLT for transforming XML into presentation data.

The XML format has been around for some time, so there is a lot of software developed for it. The JSON format is quite new, so there is a lot less support for it.

While XML was developed as an independent data format, JSON was developed specifically for use with Javascript and AJAX, so the format is exactly the same as a Javascript literal object (that is, it's a subset of the Javascript code, as it for example can't contain expressions to determine values).

Finding diff between current and last version

As pointed out on a comment by amalloy, if by "current and last versions" you mean the last commit and the commit before that, you could simply use

git show

ReDim Preserve to a Multi-Dimensional Array in Visual Basic 6

If you not want include other function like 'ReDimPreserve' could use temporal matrix for resizing. On based to your code:

 Dim n As Integer, m As Integer, i as Long, j as Long
 Dim arrTemporal() as Variant

    n = 1
    m = 0
    Dim arrCity() As String
    ReDim arrCity(n, m)

    n = n + 1
    m = m + 1

    'VBA automatically adapts the size of the receiving matrix.
    arrTemporal = arrCity
    ReDim arrCity(n, m)

    'Loop for assign values to arrCity
    For i = 1 To UBound(arrTemporal , 1)
        For j = 1 To UBound(arrTemporal , 2)
            arrCity(i, j) = arrTemporal (i, j)
        Next
    Next

If you not declare of type VBA assume that is Variant.

Dim n as Integer, m As Integer

How to call external url in jquery?

Follow the below simple steps you will able to get the result

Step 1- Create one internal function getDetailFromExternal in your back end. step 2- In that function call the external url by using cUrl like below function

 function getDetailFromExternal($p1,$p2) {

        $url = "http://request url with parameters";
        $ch = curl_init();
        curl_setopt_array($ch, array(
            CURLOPT_URL => $url,
            CURLOPT_RETURNTRANSFER => true            
        ));

        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
        $output = curl_exec($ch);
        curl_close($ch);
        echo $output;
        exit;
    }

Step 3- Call that internal function from your front end by using javascript/jquery Ajax.

How to convert a full date to a short date in javascript?

I wanted the date to be shown in the type='time' field.

The normal conversion skips the zeros and the form field does not show the value and puts forth an error in the console saying the format needs to be yyyy-mm-dd.

Hence I added a small statement (check)?(true):(false) as follows:

makeShortDate=(date)=>{
yy=date.getFullYear()
mm=date.getMonth()
dd=date.getDate()
shortDate=`${yy}-${(mm<10)?0:''}${mm+1}-${(dd<10)?0:''}${dd}`;
return shortDate;
}

Write to UTF-8 file in Python

I believe the problem is that codecs.BOM_UTF8 is a byte string, not a Unicode string. I suspect the file handler is trying to guess what you really mean based on "I'm meant to be writing Unicode as UTF-8-encoded text, but you've given me a byte string!"

Try writing the Unicode string for the byte order mark (i.e. Unicode U+FEFF) directly, so that the file just encodes that as UTF-8:

import codecs

file = codecs.open("lol", "w", "utf-8")
file.write(u'\ufeff')
file.close()

(That seems to give the right answer - a file with bytes EF BB BF.)

EDIT: S. Lott's suggestion of using "utf-8-sig" as the encoding is a better one than explicitly writing the BOM yourself, but I'll leave this answer here as it explains what was going wrong before.

How to remove hashbang from url?

The default mode for vue-router is hash mode - it uses the URL hash to simulate a full URL so that the page won't be reloaded when the URL changes. To get rid of the hash, we can use the router's history mode, which leverages the history.pushState API to achieve URL navigation without a page reload:

import {routes} from './routes'; //import the routes from routes.js    

const router = new VueRouter({
    routes,
    mode: "history",
});

new Vue({
    el: '#app',
    router,
    render: h => h(App)
});

routes.js

import ComponentName from './ComponentName';

export const routes = [
   {
      path:'/your-path'
      component:ComponentName
   }
]

Reference

How to use ES6 Fat Arrow to .filter() an array of objects

You can't implicitly return with an if, you would need the braces:

let adults = family.filter(person => { if (person.age > 18) return person} );

It can be simplified though:

let adults = family.filter(person => person.age > 18);

How do I grep recursively?

Just for fun, a quick and dirty search of *.txt files if the @christangrant answer is too much to type :-)

grep -r texthere .|grep .txt

How to get height and width of device display in angular2 using typescript?

You may use the typescript getter method for this scenario. Like this

public get height() {
  return window.innerHeight;
}

public get width() {
  return window.innerWidth;
}

And use that in template like this:

<section [ngClass]="{ 'desktop-view': width >= 768, 'mobile-view': width < 768 
}"></section>

Print the value

console.log(this.height, this.width);

You won't need any event handler to check for resizing of window, this method will check for size every time automatically.

Default property value in React component using TypeScript

Default props with class component

Using static defaultProps is correct. You should also be using interfaces, not classes, for the props and state.

Update 2018/12/1: TypeScript has improved the type-checking related to defaultProps over time. Read on for latest and greatest usage down to older usages and issues.

For TypeScript 3.0 and up

TypeScript specifically added support for defaultProps to make type-checking work how you'd expect. Example:

interface PageProps {
  foo: string;
  bar: string;
}

export class PageComponent extends React.Component<PageProps, {}> {
    public static defaultProps = {
        foo: "default"
    };

    public render(): JSX.Element {
        return (
            <span>Hello, { this.props.foo.toUpperCase() }</span>
        );
    }
}

Which can be rendered and compile without passing a foo attribute:

<PageComponent bar={ "hello" } />

Note that:

  • foo is not marked optional (ie foo?: string) even though it's not required as a JSX attribute. Marking as optional would mean that it could be undefined, but in fact it never will be undefined because defaultProps provides a default value. Think of it similar to how you can mark a function parameter optional, or with a default value, but not both, yet both mean the call doesn't need to specify a value. TypeScript 3.0+ treats defaultProps in a similar way, which is really cool for React users!
  • The defaultProps has no explicit type annotation. Its type is inferred and used by the compiler to determine which JSX attributes are required. You could use defaultProps: Pick<PageProps, "foo"> to ensure defaultProps matches a sub-set of PageProps. More on this caveat is explained here.
  • This requires @types/react version 16.4.11 to work properly.

For TypeScript 2.1 until 3.0

Before TypeScript 3.0 implemented compiler support for defaultProps you could still make use of it, and it worked 100% with React at runtime, but since TypeScript only considered props when checking for JSX attributes you'd have to mark props that have defaults as optional with ?. Example:

interface PageProps {
    foo?: string;
    bar: number;
}

export class PageComponent extends React.Component<PageProps, {}> {
    public static defaultProps: Partial<PageProps> = {
        foo: "default"
    };

    public render(): JSX.Element {
        return (
            <span>Hello, world</span>
        );
    }
}

Note that:

  • It's a good idea to annotate defaultProps with Partial<> so that it type-checks against your props, but you don't have to supply every required property with a default value, which makes no sense since required properties should never need a default.
  • When using strictNullChecks the value of this.props.foo will be possibly undefined and require a non-null assertion (ie this.props.foo!) or type-guard (ie if (this.props.foo) ...) to remove undefined. This is annoying since the default prop value means it actually will never be undefined, but TS didn't understand this flow. That's one of the main reasons TS 3.0 added explicit support for defaultProps.

Before TypeScript 2.1

This works the same but you don't have Partial types, so just omit Partial<> and either supply default values for all required props (even though those defaults will never be used) or omit the explicit type annotation completely.

Default props with Functional Components

You can use defaultProps on function components as well, but you have to type your function to the FunctionComponent (StatelessComponent in @types/react before version 16.7.2) interface so that TypeScript knows about defaultProps on the function:

interface PageProps {
  foo?: string;
  bar: number;
}

const PageComponent: FunctionComponent<PageProps> = (props) => {
  return (
    <span>Hello, {props.foo}, {props.bar}</span>
  );
};

PageComponent.defaultProps = {
  foo: "default"
};

Note that you don't have to use Partial<PageProps> anywhere because FunctionComponent.defaultProps is already specified as a partial in TS 2.1+.

Another nice alternative (this is what I use) is to destructure your props parameters and assign default values directly:

const PageComponent: FunctionComponent<PageProps> = ({foo = "default", bar}) => {
  return (
    <span>Hello, {foo}, {bar}</span>
  );
};

Then you don't need the defaultProps at all! Be aware that if you do provide defaultProps on a function component it will take precedence over default parameter values, because React will always explicitly pass the defaultProps values (so the parameters are never undefined, thus the default parameter is never used.) So you'd use one or the other, not both.

How can I get useful error messages in PHP?

PHP Configuration

2 entries in php.ini dictate the output of errors:

  1. display_errors
  2. error_reporting

In production, display_errors is usually set to Off (Which is a good thing, because error display in production sites is generally not desirable!).

However, in development, it should be set to On, so that errors get displayed. Check!

error_reporting (as of PHP 5.3) is set by default to E_ALL & ~E_NOTICE & ~E_STRICT & ~E_DEPRECATED (meaning, everything is shown except for notices, strict standards and deprecation notices). When in doubt, set it to E_ALL to display all the errors. Check!

Whoa whoa! No check! I can't change my php.ini!

That's a shame. Usually shared hosts do not allow the alteration of their php.ini file, and so, that option is sadly unavailable. But fear not! We have other options!

Runtime configuration

In the desired script, we can alter the php.ini entries in runtime! Meaning, it'll run when the script runs! Sweet!

error_reporting(E_ALL);
ini_set("display_errors", "On");

These two lines will do the same effect as altering the php.ini entries as above! Awesome!

I still get a blank page/500 error!

That means that the script hadn't even run! That usually happens when you have a syntax error!

With syntax errors, the script doesn't even get to runtime. It fails at compile time, meaning that it'll use the values in php.ini, which if you hadn't changed, may not allow the display of errors.

Error logs

In addition, PHP by default logs errors. In shared hosting, it may be in a dedicated folder or on the same folder as the offending script.

If you have access to php.ini, you can find it under the error_log entry.

Using SUMIFS with multiple AND OR conditions

You might consider referencing the actual date/time in the source column for Quote_Month, then you could transform your OR into a couple of ANDs, something like (assuing the date's in something I've chosen to call Quote_Date)

=SUMIFS(Quote_Value,"<=90",Quote_Date,">="&DATE(2013,11,1),Quote_Date,"<="&DATE(2013,12,31),Salesman,"=JBloggs",Days_To_Close)

(I moved the interesting conditions to the front).

This approach works here because that "OR" condition is actually specifying a date range - it might not work in other cases.

Download File Using jQuery

Yes, you would have to change the window.location.href to the url of the file you would want to download.

window.location.href = 'http://www.com/path/to/file';

scrollable div inside container

i have just added (overflow:scroll;) in (div3) with fixed height.

see the fiddle:- http://jsfiddle.net/fMs67/10/

JavaScript - cannot set property of undefined

In javascript almost everything is an object, null and undefined are exception.

Instances of Array is an object. so you can set property of an array, for the same reason,you can't set property of a undefined, because its NOT an object

No value accessor for form control with name: 'recipient'

Make sure you import MaterialModule as well since you are using md-input which does not belong to FormsModule

How to add hyperlink in JLabel?

You can do this using a JLabel, but an alternative would be to style a JButton. That way, you don't have to worry about accessibility and can just fire events using an ActionListener.

  public static void main(String[] args) throws URISyntaxException {
    final URI uri = new URI("http://java.sun.com");
    class OpenUrlAction implements ActionListener {
      @Override public void actionPerformed(ActionEvent e) {
        open(uri);
      }
    }
    JFrame frame = new JFrame("Links");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(100, 400);
    Container container = frame.getContentPane();
    container.setLayout(new GridBagLayout());
    JButton button = new JButton();
    button.setText("<HTML>Click the <FONT color=\"#000099\"><U>link</U></FONT>"
        + " to go to the Java website.</HTML>");
    button.setHorizontalAlignment(SwingConstants.LEFT);
    button.setBorderPainted(false);
    button.setOpaque(false);
    button.setBackground(Color.WHITE);
    button.setToolTipText(uri.toString());
    button.addActionListener(new OpenUrlAction());
    container.add(button);
    frame.setVisible(true);
  }

  private static void open(URI uri) {
    if (Desktop.isDesktopSupported()) {
      try {
        Desktop.getDesktop().browse(uri);
      } catch (IOException e) { /* TODO: error handling */ }
    } else { /* TODO: error handling */ }
  }

How to set a tkinter window to a constant size

Here is the most simple way.

import tkinter as tk

root = tk.Tk()

root.geometry('200x200')
root.resizable(width=0, height=0)

root.mainloop()

I don't think there is anything to specify. It's pretty straight forward.

How can I override inline styles with external CSS?

used !important in CSS property

<div style="color: red;">
    Hello World, How Can I Change The Color To Blue?
</div>

div {
        color: blue !important;
    }

Disable LESS-CSS Overwriting calc()

Using an escaped string (a.k.a. escaped value):

width: ~"calc(100% - 200px)";

Also, in case you need to mix Less math with escaped strings:

width: calc(~"100% - 15rem +" (10px+5px) ~"+ 2em");

Compiles to:

width: calc(100% - 15rem + 15px + 2em);

This works as Less concatenates values (the escaped strings and math result) with a space by default.

Difference between View and table in sql

A table contains data, a view is just a SELECT statement which has been saved in the database (more or less, depending on your database).

The advantage of a view is that it can join data from several tables thus creating a new view of it. Say you have a database with salaries and you need to do some complex statistical queries on it.

Instead of sending the complex query to the database all the time, you can save the query as a view and then SELECT * FROM view

not-null property references a null or transient value

Every InvoiceItem must have an Invoice attached to it because of the not-null="true" in the many-to-one mapping.

So the basic idea is you need to set up that explicit relationship in code. There are many ways to do that. On your class I see a setItems method. I do NOT see an addInvoiceItem method. When you set items, you need to loop through the set and call item.setInvoice(this) on all of the items. If you implement an addItem method, you need to do the same thing. Or you need to otherwise set the Invoice of every InvoiceItem in the collection.

How to disable GCC warnings for a few lines of code

TL;DR: If it works, avoid, or use specifiers like __attribute__, otherwise _Pragma.

This is a short version of my blog article Suppressing Warnings in GCC and Clang.

Consider the following Makefile

CPPFLAGS:=-std=c11 -W -Wall -pedantic -Werror

.PHONY: all
all: puts

for building the following puts.c source code

#include <stdio.h>

int main(int argc, const char *argv[])
{
    while (*++argv) puts(*argv);
    return 0;
}

It will not compile because argc is unused, and the settings are hardcore (-W -Wall -pedantic -Werror).

There are 5 things you could do:

  • Improve the source code, if possible
  • Use a declaration specifier, like __attribute__
  • Use _Pragma
  • Use #pragma
  • Use a command line option.

Improving the source

The first attempt should be checking if the source code can be improved to get rid of the warning. In this case we don't want to change the algorithm just because of that, as argc is redundant with !*argv (NULL after last element).

Using a declaration specifier, like __attribute__

#include <stdio.h>

int main(__attribute__((unused)) int argc, const char *argv[])
{
    while (*++argv) puts(*argv);
    return 0;
}

If you're lucky, the standard provides a specifier for your situation, like _Noreturn.

__attribute__ is proprietary GCC extension (supported by Clang and some other compilers like armcc as well) and will not be understood by many other compilers. Put __attribute__((unused)) inside a macro if you want portable code.

_Pragma operator

_Pragma can be used as an alternative to #pragma.

#include <stdio.h>

_Pragma("GCC diagnostic push")
_Pragma("GCC diagnostic ignored \"-Wunused-parameter\"")

int main(int argc, const char *argv[])
{
    while (*++argv) puts(*argv);
    return 0;
}
_Pragma("GCC diagnostic pop")

The main advantage of the _Pragma operator is that you could put it inside macros, which is not possible with the #pragma directive.

Downside: It's almost a tactical nuke, as it works line-based instead of declaration-based.

The _Pragma operator was introduced in C99.

#pragma directive.

We could change the source code to suppress the warning for a region of code, typically an entire function:

#include <stdio.h>

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
int main(int argc, const char *argv[])
{
    while (*++argc) puts(*argv);
    return 0;
}
#pragma GCC diagnostic pop

Downside: It's almost a tactical nuke, as it works line-based instead of declaration-based.

Note that a similar syntax exists in clang.

Suppressing the warning on the command line for a single file

We could add the following line to the Makefile to suppress the warning specifically for puts:

CPPFLAGS:=-std=c11 -W -Wall -pedantic -Werror

.PHONY: all
all: puts

puts.o: CPPFLAGS+=-Wno-unused-parameter

This is probably not want you want in your particular case, but it may help other reads who are in similar situations.

With ' N ' no of nodes, how many different Binary and Binary Search Trees possible?

The correct answer should be 2nCn/(n+1) for unlabelled nodes and if the nodes are labelled then (2nCn)*n!/(n+1).

Make flex items take content width, not width of parent container

In addtion to align-self you can also consider auto margin which will do almost the same thing

_x000D_
_x000D_
.container {_x000D_
  background: red;_x000D_
  height: 200px;_x000D_
  flex-direction: column;_x000D_
  padding: 10px;_x000D_
  display: flex;_x000D_
}_x000D_
a {_x000D_
  margin-right:auto;_x000D_
  padding: 10px 40px;_x000D_
  background: pink;_x000D_
}
_x000D_
<div class="container">_x000D_
  <a href="#">Test</a>_x000D_
</div>
_x000D_
_x000D_
_x000D_

lexers vs parsers

To answer the question as asked (without repeating unduly what appears in other answers)

Lexers and parsers are not very different, as suggested by the accepted answer. Both are based on simple language formalisms: regular languages for lexers and, almost always, context-free (CF) languages for parsers. They both are associated with fairly simple computational models, the finite state automaton and the push-down stack automaton. Regular languages are a special case of context-free languages, so that lexers could be produced with the somewhat more complex CF technology. But it is not a good idea for at least two reasons.

A fundamental point in programming is that a system component should be buit with the most appropriate technology, so that it is easy to produce, to understand and to maintain. The technology should not be overkill (using techniques much more complex and costly than needed), nor should it be at the limit of its power, thus requiring technical contortions to achieve the desired goal.

That is why "It seems fashionable to hate regular expressions". Though they can do a lot, they sometimes require very unreadable coding to achieve it, not to mention the fact that various extensions and restrictions in implementation somewhat reduce their theoretical simplicity. Lexers do not usually do that, and are usually a simple, efficient, and appropriate technology to parse token. Using CF parsers for token would be overkill, though it is possible.

Another reason not to use CF formalism for lexers is that it might then be tempting to use the full CF power. But that might raise sructural problems regarding the reading of programs.

Fundamentally, most of the structure of program text, from which meaning is extracted, is a tree structure. It expresses how the parse sentence (program) is generated from syntax rules. Semantics is derived by compositional techniques (homomorphism for the mathematically oriented) from the way syntax rules are composed to build the parse tree. Hence the tree structure is essential. The fact that tokens are identified with a regular set based lexer does not change the situation, because CF composed with regular still gives CF (I am speaking very loosely about regular transducers, that transform a stream of characters into a stream of token).

However, CF composed with CF (via CF transducers ... sorry for the math), does not necessarily give CF, and might makes things more general, but less tractable in practice. So CF is not the appropriate tool for lexers, even though it can be used.

One of the major differences between regular and CF is that regular languages (and transducers) compose very well with almost any formalism in various ways, while CF languages (and transducers) do not, not even with themselves (with a few exceptions).

(Note that regular transducers may have others uses, such as formalization of some syntax error handling techniques.)

BNF is just a specific syntax for presenting CF grammars.

EBNF is a syntactic sugar for BNF, using the facilities of regular notation to give terser version of BNF grammars. It can always be transformed into an equivalent pure BNF.

However, the regular notation is often used in EBNF only to emphasize these parts of the syntax that correspond to the structure of lexical elements, and should be recognized with the lexer, while the rest with be rather presented in straight BNF. But it is not an absolute rule.

To summarize, the simpler structure of token is better analyzed with the simpler technology of regular languages, while the tree oriented structure of the language (of program syntax) is better handled by CF grammars.

I would suggest also looking at AHR's answer.

But this leaves a question open: Why trees?

Trees are a good basis for specifying syntax because

  • they give a simple structure to the text

  • there are very convenient for associating semantics with the text on the basis of that structure, with a mathematically well understood technology (compositionality via homomorphisms), as indicated above. It is a fundamental algebraic tool to define the semantics of mathematical formalisms.

Hence it is a good intermediate representation, as shown by the success of Abstract Syntax Trees (AST). Note that AST are often different from parse tree because the parsing technology used by many professionals (Such as LL or LR) applies only to a subset of CF grammars, thus forcing grammatical distorsions which are later corrected in AST. This can be avoided with more general parsing technology (based on dynamic programming) that accepts any CF grammar.

Statement about the fact that programming languages are context-sensitive (CS) rather than CF are arbitrary and disputable.

The problem is that the separation of syntax and semantics is arbitrary. Checking declarations or type agreement may be seen as either part of syntax, or part of semantics. The same would be true of gender and number agreement in natural languages. But there are natural languages where plural agreement depends on the actual semantic meaning of words, so that it does not fit well with syntax.

Many definitions of programming languages in denotational semantics place declarations and type checking in the semantics. So stating as done by Ira Baxter that CF parsers are being hacked to get a context sensitivity required by syntax is at best an arbitrary view of the situation. It may be organized as a hack in some compilers, but it does not have to be.

Also it is not just that CS parsers (in the sense used in other answers here) are hard to build, and less efficient. They are are also inadequate to express perspicuously the kinf of context-sensitivity that might be needed. And they do not naturally produce a syntactic structure (such as parse-trees) that is convenient to derive the semantics of the program, i.e. to generate the compiled code.

Re-ordering columns in pandas dataframe based on column name

One use-case is that you have named (some of) your columns with some prefix, and you want the columns sorted with those prefixes all together and in some particular order (not alphabetical).

For example, you might start all of your features with Ft_, labels with Lbl_, etc, and you want all unprefixed columns first, then all features, then the label. You can do this with the following function (I will note a possible efficiency problem using sum to reduce lists, but this isn't an issue unless you have a LOT of columns, which I do not):

def sortedcols(df, groups = ['Ft_', 'Lbl_'] ):
    return df[ sum([list(filter(re.compile(r).search, list(df.columns).copy())) for r in (lambda l: ['^(?!(%s))' % '|'.join(l)] + ['^%s' % i  for i in l ] )(groups)   ], [])  ]

Parser Error: '_Default' is not allowed here because it does not extend class 'System.Web.UI.Page' & MasterType declaration

I had copied and renamed the page (aspx/cs). The page name was "mainpage" so the class name at the top of the cs file as follows:

enter image description here

After renaming the class to match this error was resolved.

Factory Pattern. When to use factory methods?

They're also useful when you need several "constructors" with the same parameter type but with different behavior.

Javascript/Jquery Convert string to array

Change

var trainindIdArray = traingIds.split(',');

to

var trainindIdArray = traingIds.replace("[","").replace("]","").split(',');

That will basically remove [ and ] and then split the string

How do I concatenate strings?

To concatenate multiple strings into a single string, separated by another character, there are a couple of ways.

The nicest I have seen is using the join method on an array:

fn main() {
    let a = "Hello";
    let b = "world";
    let result = [a, b].join("\n");

    print!("{}", result);
}

Depending on your use case you might also prefer more control:

fn main() {
    let a = "Hello";
    let b = "world";
    let result = format!("{}\n{}", a, b);

    print!("{}", result);
}

There are some more manual ways I have seen, some avoiding one or two allocations here and there. For readability purposes I find the above two to be sufficient.

Grouped bar plot in ggplot

First you need to get the counts for each category, i.e. how many Bads and Goods and so on are there for each group (Food, Music, People). This would be done like so:

raw <- read.csv("http://pastebin.com/raw.php?i=L8cEKcxS",sep=",")
raw[,2]<-factor(raw[,2],levels=c("Very Bad","Bad","Good","Very Good"),ordered=FALSE)
raw[,3]<-factor(raw[,3],levels=c("Very Bad","Bad","Good","Very Good"),ordered=FALSE)
raw[,4]<-factor(raw[,4],levels=c("Very Bad","Bad","Good","Very Good"),ordered=FALSE)

raw=raw[,c(2,3,4)] # getting rid of the "people" variable as I see no use for it

freq=table(col(raw), as.matrix(raw)) # get the counts of each factor level

Then you need to create a data frame out of it, melt it and plot it:

Names=c("Food","Music","People")     # create list of names
data=data.frame(cbind(freq),Names)   # combine them into a data frame
data=data[,c(5,3,1,2,4)]             # sort columns

# melt the data frame for plotting
data.m <- melt(data, id.vars='Names')

# plot everything
ggplot(data.m, aes(Names, value)) +   
  geom_bar(aes(fill = variable), position = "dodge", stat="identity")

Is this what you're after?

enter image description here

To clarify a little bit, in ggplot multiple grouping bar you had a data frame that looked like this:

> head(df)
  ID Type Annee X1PCE X2PCE X3PCE X4PCE X5PCE X6PCE
1  1    A  1980   450   338   154    36    13     9
2  2    A  2000   288   407   212    54    16    23
3  3    A  2020   196   434   246    68    19    36
4  4    B  1980   111   326   441    90    21    11
5  5    B  2000    63   298   443   133    42    21
6  6    B  2020    36   257   462   162    55    30

Since you have numerical values in columns 4-9, which would later be plotted on the y axis, this can be easily transformed with reshape and plotted.

For our current data set, we needed something similar, so we used freq=table(col(raw), as.matrix(raw)) to get this:

> data
   Names Very.Bad Bad Good Very.Good
1   Food        7   6    5         2
2  Music        5   5    7         3
3 People        6   3    7         4

Just imagine you have Very.Bad, Bad, Good and so on instead of X1PCE, X2PCE, X3PCE. See the similarity? But we needed to create such structure first. Hence the freq=table(col(raw), as.matrix(raw)).

How do files get into the External Dependencies in Visual Studio C++?

The External Dependencies folder is populated by IntelliSense: the contents of the folder do not affect the build at all (you can in fact disable the folder in the UI).

You need to actually include the header (using a #include directive) to use it. Depending on what that header is, you may also need to add its containing folder to the "Additional Include Directories" property and you may need to add additional libraries and library folders to the linker options; you can set all of these in the project properties (right click the project, select Properties). You should compare the properties with those of the project that does build to determine what you need to add.

Get Application Directory

PackageManager m = getPackageManager();
String s = getPackageName();
PackageInfo p = m.getPackageInfo(s, 0);
s = p.applicationInfo.dataDir;

If eclipse worries about an uncaught NameNotFoundException, you can use:

PackageManager m = getPackageManager();
String s = getPackageName();
try {
    PackageInfo p = m.getPackageInfo(s, 0);
    s = p.applicationInfo.dataDir;
} catch (PackageManager.NameNotFoundException e) {
    Log.w("yourtag", "Error Package name not found ", e);
}

How to convert FormData (HTML5 object) to JSON

I think this is the simplest way to get the result you want from a formData FormData object:

const jsonData = {};

for(const [key, value] of formData) {
    jsonData[key] = value;
}

Java ArrayList - how can I tell if two lists are equal, order not mattering?

Best of both worlds [@DiddiZ, @Chalkos]: this one mainly builds upon @Chalkos method, but fixes a bug (ifst.next()), and improves initial checks (taken from @DiddiZ) as well as removes the need to copy the first collection (just removes items from a copy of the second collection).

Not requiring a hashing function or sorting, and enabling an early exist on un-equality, this is the most efficient implementation yet. That is unless you have a collection length in the thousands or more, and a very simple hashing function.

public static <T> boolean isCollectionMatch(Collection<T> one, Collection<T> two) {
    if (one == two)
        return true;

    // If either list is null, return whether the other is empty
    if (one == null)
        return two.isEmpty();
    if (two == null)
        return one.isEmpty();

    // If lengths are not equal, they can't possibly match
    if (one.size() != two.size())
        return false;

    // copy the second list, so it can be modified
    final List<T> ctwo = new ArrayList<>(two);

    for (T itm : one) {
        Iterator<T> it = ctwo.iterator();
        boolean gotEq = false;
        while (it.hasNext()) {
            if (itm.equals(it.next())) {
                it.remove();
                gotEq = true;
                break;
            }
        }
        if (!gotEq) return false;
    }
    // All elements in one were found in two, and they're the same size.
    return true;
}

Pause Console in C++ program

I just want to add that there is a way to get what you want, but it will require to use some a third party library (or that you write the platform dependent code yourself).

As far as I'm concerned, the biggest drawback with cin is that you are required to hit Return, and not just any key.

Assuming you had a key-listener you could quite easily write a function that waits for the user to hit any key. However finding a platform independent key listener is no trivial task, and will most likely require you to load parts of a larger library.

I am thinking something along the lines of:

char wait_for_key() {
    int key;
    while ( ! (key == key_pressed(ANY)) ) {
          this_thread::yield();
    }
    return convert_virtual_key_to_char(key);
}

The actual function would obviously be quite different from what I wrote, depending on the library you use.

I know the following libraries have keylisteners (Feel free to add more in an edit if you know of any.):

Comparison of C++ unit test frameworks

API Sanity Checker — test framework for C/C++ libraries:

An automatic generator of basic unit tests for a shared C/C++ library. It is able to generate reasonable (in most, but unfortunately not all, cases) input data for parameters and compose simple ("sanity" or "shallow"-quality) test cases for every function in the API through the analysis of declarations in header files.

The quality of generated tests allows to check absence of critical errors in simple use cases. The tool is able to build and execute generated tests and detect crashes (segfaults), aborts, all kinds of emitted signals, non-zero program return code and program hanging.

Unique features in comparison with CppUnit, Boost and Google Test:

  • Automatic generation of test data and input arguments (even for complex data types)
  • Modern and highly reusable specialized types instead of fixtures and templates

How do I convert Word files to PDF programmatically?

PDFCreator has a COM component, callable from .NET or VBScript (samples included in the download).

But, it seems to me that a printer is just what you need - just mix that with Word's automation, and you should be good to go.

How are cookies passed in the HTTP protocol?

The server sends the following in its response header to set a cookie field.

Set-Cookie:name=value

If there is a cookie set, then the browser sends the following in its request header.

Cookie:name=value

See the HTTP Cookie article at Wikipedia for more information.

Android statusbar icons color

Setting windowLightStatusBar to true not works with Mi phones, some Meizu phones, Blackview phones, WileyFox etc. I've found such hack for Mi and Meizu devices. This is not a comprehensive solution of this perfomance problem, but maybe it would be useful to somebody.

And I think, it would be better to tell your customer that coloring status bar (for example) white - is not a good idea. instead of using different hacks it would be better to define appropriate colorPrimaryDark according to the guidelines

Android : How to set onClick event for Button in List item of ListView

I find

final Button yourButton = (Button)view.findViewById(R.id.your_button);
yourButton.setFocusable(false);
yourButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
        ...///);

can solve the problem. If you want to get some data when clicking the button, using tags is helpful. Here the button is declared final because it will be used within inner class.

PostgreSQL unnest() with element number

Try:

select v.*, row_number() over (partition by id order by elem) rn from
(select
    id,
    unnest(string_to_array(elements, ',')) AS elem
 from myTable) v

Get properties of a class

Use these

export class TableColumns<T> {
   constructor(private t: new () => T) {
        var fields: string[] = Object.keys(new t())

        console.log('fields', fields)
        console.log('t', t)

    }
}

Usage

columns_logs = new TableColumns<LogItem>(LogItem);

Output

fields (12) ["id", "code", "source", "title", "deleted", "checked", "body", "json", "dt_insert", "dt_checked", "screenshot", "uid"]

js class

t class LogItem {
constructor() {
    this.id = 0;
    this.code = 0;
    this.source = '';
    this.title = '';
    this.deleted = false;
    this.checked = false;
  …

How to add title to seaborn boxplot

Seaborn box plot returns a matplotlib axes instance. Unlike pyplot itself, which has a method plt.title(), the corresponding argument for an axes is ax.set_title(). Therefore you need to call

sns.boxplot('Day', 'Count', data= gg).set_title('lalala')

A complete example would be:

import seaborn as sns
import matplotlib.pyplot as plt

tips = sns.load_dataset("tips")
sns.boxplot(x=tips["total_bill"]).set_title("LaLaLa")

plt.show()

Of course you could also use the returned axes instance to make it more readable:

ax = sns.boxplot('Day', 'Count', data= gg)
ax.set_title('lalala')
ax.set_ylabel('lololo')

What special characters must be escaped in regular expressions?

https://perldoc.perl.org/perlre.html#Quoting-metacharacters and https://perldoc.perl.org/functions/quotemeta.html

In the official documentation, such characters are called metacharacters. Example of quoting:

my $regex = quotemeta($string)
s/$regex/something/

How to determine whether a year is a leap year?

If you don't want to import calendar and apply .isleap method you can try this:

def isleapyear(year):
    if year % 4 == 0 and (year % 100 != 0 or year % 400 == 0):
        return True
    return False

Data structure for maintaining tabular data in memory?

Have a Table class whose rows is a list of dict or better row objects

In table do not directly add rows but have a method which update few lookup maps e.g. for name if you are not adding rows in order or id are not consecutive you can have idMap too e.g.

class Table(object):
    def __init__(self):
        self.rows =  []# list of row objects, we assume if order of id
        self.nameMap = {} # for faster direct lookup for row by name

    def addRow(self, row):
        self.rows.append(row)
        self.nameMap[row['name']] = row

    def getRow(self, name):
        return self.nameMap[name]


table = Table()
table.addRow({'ID':1,'name':'a'})

How to query GROUP BY Month in a Year

I would be inclined to include the year in the output. One way:

select to_char(DATE_CREATED, 'YYYY-MM'), sum(Num_of_Pictures)
from pictures_table
group by to_char(DATE_CREATED, 'YYYY-MM')
order by 1

Another way (more standard SQL):

select extract(year from date_created) as yr, extract(month from date_created) as mon,
       sum(Num_of_Pictures)
from pictures_table
group by extract(year from date_created), extract(month from date_created)
order by yr, mon;

Remember the order by, since you presumably want these in order, and there is no guarantee about the order that rows are returned in after a group by.

MySQL select statement with CASE or IF ELSEIF? Not sure how to get the result

Syntax:

CASE value WHEN [compare_value] THEN result 
[WHEN [compare_value] THEN result ...] 
[ELSE result] 
END

Alternative: CASE WHEN [condition] THEN result [WHEN [condition] THEN result ...]

mysql> SELECT CASE  WHEN 2>3 THEN 'this is true' ELSE 'this is false' END; 
+-------------------------------------------------------------+
| CASE  WHEN 2>3 THEN 'this is true' ELSE 'this is false' END |
+-------------------------------------------------------------+
| this is false                                               | 
+-------------------------------------------------------------+

I am use:

SELECT  act.*,
    CASE 
        WHEN (lises.session_date IS NOT NULL AND ses.session_date IS NULL) THEN lises.location_id
        WHEN (lises.session_date IS NULL AND ses.session_date IS NOT NULL) THEN ses.location_id
        WHEN (lises.session_date IS NOT NULL AND ses.session_date IS NOT NULL AND lises.session_date>ses.session_date) THEN ses.location_id
        WHEN (lises.session_date IS NOT NULL AND ses.session_date IS NOT NULL AND lises.session_date<ses.session_date) THEN lises.location_id
    END AS location_id
FROM activity AS act
LEFT JOIN li_sessions AS lises ON lises.activity_id = act.id AND  lises.session_date >= now()
LEFT JOIN session AS ses ON  ses.activity_id = act.id AND  ses.session_date >= now()
WHERE act.id

Mongoose, Select a specific field with find

There's a better way to handle it using Native MongoDB code in Mongoose.

exports.getUsers = function(req, res, next) {

    var usersProjection = { 
        __v: false,
        _id: false
    };

    User.find({}, usersProjection, function (err, users) {
        if (err) return next(err);
        res.json(users);
    });    
}

http://docs.mongodb.org/manual/reference/method/db.collection.find/

Note:

var usersProjection

The list of objects listed here will not be returned / printed.

How to parse a CSV file in Bash?

We can parse csv files with quoted strings and delimited by say | with following code

while read -r line
do
    field1=$(echo "$line" | awk -F'|' '{printf "%s", $1}' | tr -d '"')
    field2=$(echo "$line" | awk -F'|' '{printf "%s", $2}' | tr -d '"')

    echo "$field1 $field2"
done < "$csvFile"

awk parses the string fields to variables and tr removes the quote.

Slightly slower as awk is executed for each field.

What would be the Unicode character for big bullet in the middle of the character?

You can search for “bullet” when using e.g. BabelPad (which has a Character Map where you can search by character name), but you will hardly find anything larger than U+2022 BULLET (though the size depends on font). Searching for “circle” finds many characters, too many, as the string appears in so many names. The largest simple circle is probably U+25CF BLACK CIRCLE “?”. If it’s too large U+26AB MEDIUM BLACK CIRCLE “?” might be suitable.

Beware that few fonts contain these characters.

Configuring user and password with Git Bash

If your repo is of HTTPS repo, git config -e give this command in the git bash. Update the username and password by opening in insert mode, change the password or username give :x and Cntrl+z keys it will save and exit

So, From then while you pull / push the code to the repository it will not ask for password.

Cannot use special principal dbo: Error 15405

To fix this, open the SQL Server Management Studio and click New Query. Then type:

USE mydatabase
exec sp_changedbowner 'sa', 'true'

Get int from String, also containing letters, in Java

Replace all non-digit with blank: the remaining string contains only digits.

Integer.parseInt(s.replaceAll("[\\D]", ""))

This will also remove non-digits inbetween digits, so "x1x1x" becomes 11.

If you need to confirm that the string consists of a sequence of digits (at least one) possibly followed a letter, then use this:

s.matches("[\\d]+[A-Za-z]?")

What is AndroidX?

Just some bits addition from my side to all available answers

Need of AndroidX

  1. As said in amazing answer by @KhemRaj,

With the current naming convention, it isn’t clear which packages are bundled with the Android operating system, and which are packaged with your application’s APK (Android Package Kit). To clear up this confusion, all the unbundled libraries will be moved to AndroidX’s androidx.* namespace, while the android.* package hierarchy will be reserved for packages that ship with the Android operating system.

  1. Other than this,

    Initially, the name of each package indicated the minimum API level supported by that package, for example support-v4. However, version 26.0.0 of the Support Library increased the minimum API to 14, so today many of the package names have nothing to do with the minimum supported API level. When support-v4 and the support-v7 packages both have a minimum API of 14, it’s easy to see why people get confused!. So now with AndroidX, there is no dependence on the API level.

Another important change is that the AndroidX artifacts will update independently, so you’ll be able to update individual AndroidX libraries in your project, rather than having to change every dependency at once. Those frustrating “All com.android.support libraries must use the exact same version specification” messages should become a thing of the past!

hash keys / values as array

var a = {"apples": 3, "oranges": 4, "bananas": 42};    

var array_keys = new Array();
var array_values = new Array();

for (var key in a) {
    array_keys.push(key);
    array_values.push(a[key]);
}

alert(array_keys);
alert(array_values);

vagrant login as root by default

I know this is an old question, but looking at the original question, it looks like the user just wanted to run a command as root, that's what I need to do when I was searching for an answer and stumbled across the question.

So this one is worth knowing in my opinion:

vagrant ssh servername -c "echo vagrant | sudo -S shutdown 0"

vagrant is the password being echoed into the the sudo command, because as we all know, the vagrant account has sudo privileges and when you sudo, you need to specify the password of the user account, not root..and of course by default, the vagrant user's password is vagrant !

By default you need root privileges to shutdown so I guess doing a shutdown is a good test.

Obviously you don't need to specify a server name if there is only one for that vagrant environment. Also, we're talking about local vagrant virtual machine to the host, so there isn't really any security issue that I can see.

Hope this helps.

.htaccess not working apache

For completeness, if "AllowOverride All" doesn't fix your problem, you could debug this problem using:

  1. Run apachectl -S and see if you have more than one namevhost. It might be that httpd is looking for .htaccess of another DocumentRoot.

  2. Use strace -f apachectl -X and look for where it's loading (or not loading) .htaccess from.

How to set div width using ng-style

The syntax of ng-style is not quite that. It accepts a dictionary of keys (attribute names) and values (the value they should take, an empty string unsets them) rather than only a string. I think what you want is this:

<div ng-style="{ 'width' : width, 'background' : bgColor }"></div>

And then in your controller:

$scope.width = '900px';
$scope.bgColor = 'red';

This preserves the separation of template and the controller: the controller holds the semantic values while the template maps them to the correct attribute name.

How to get domain URL and application name?

If you are being passed a url as a String and want to extract the context root of that application, you can use this regex to extract it. It will work for full urls or relative urls that begin with the context root.

url.replaceAll("^(.*\\/\\/)?.*?\\/(.+?)\\/.*|\\/(.+)$", "$2$3")

Convert a SQL Server datetime to a shorter date format

Just add date keyword. E.g. select date(orderdate),count(1) from orders where orderdate > '2014-10-01' group by date(orderdate);

orderdate is in date time. This query will show the orders for that date rather than datetime.

Date keyword applied on a datetime column will change it to short date.

Query a parameter (postgresql.conf setting) like "max_connections"

You can use SHOW:

SHOW max_connections;

This returns the currently effective setting. Be aware that it can differ from the setting in postgresql.conf as there are a multiple ways to set run-time parameters in PostgreSQL. To reset the "original" setting from postgresql.conf in your current session:

RESET max_connections;

However, not applicable to this particular setting. The manual:

This parameter can only be set at server start.

To see all settings:

SHOW ALL;

There is also pg_settings:

The view pg_settings provides access to run-time parameters of the server. It is essentially an alternative interface to the SHOW and SET commands. It also provides access to some facts about each parameter that are not directly available from SHOW, such as minimum and maximum values.

For your original request:

SELECT *
FROM   pg_settings
WHERE  name = 'max_connections';

Finally, there is current_setting(), which can be nested in DML statements:

SELECT current_setting('max_connections');

Related:

How to restart a node.js server

If I am just run the node app from console (not using forever etc) I use control + C, not sure if OSX has the same key combination to terminate but much faster than finding the process id and killing it, you could also add the following code to the chat app you are using and then type 'exit' in the console whenever you want to close down the app.

process.stdin.resume();
process.stdin.setEncoding('utf8');

process.stdin.on('data', function(data) {
  if (data == 'exit\n') process.exit();
});

Pdf.js: rendering a pdf file using a base64 file source instead of url

According to the examples base64 encoding is directly supported, although I've not tested it myself. Take your base64 string (derived from a file or loaded with any other method, POST/GET, websockets etc), turn it to a binary with atob, and then parse this to getDocument on the PDFJS API likePDFJS.getDocument({data: base64PdfData}); Codetoffel answer does work just fine for me though.

Jquery Date picker Default Date

interesting, datepicker default date is current date as I found,

but you can set date by

$("#yourinput").datepicker( "setDate" , "7/11/2011" );

don't forget to check you system date :)

Decoding a Base64 string in Java

If you don't want to use apache, you can use Java8:

byte[] decodedBytes = Base64.getDecoder().decode("YWJjZGVmZw=="); 
System.out.println(new String(decodedBytes) + "\n");

Prevent double curly brace notation from displaying momentarily before angular.js compiles/interpolates document

To improve the effectiveness of class='ng-cloak' approach when scripts are loaded last, make sure the following css is loaded in the head of the document:

.ng-cloak { display:none; }

How to get the last element of an array in Ruby?

Use -1 index (negative indices count backward from the end of the array):

a[-1] # => 5
b[-1] # => 6

or Array#last method:

a.last # => 5
b.last # => 6

How can I declare optional function parameters in JavaScript?

With ES6: This is now part of the language:

function myFunc(a, b = 0) {
   // function body
}

Please keep in mind that ES6 checks the values against undefined and not against truthy-ness (so only real undefined values get the default value - falsy values like null will not default).


With ES5:

function myFunc(a,b) {
  b = b || 0;

  // b will be set either to b or to 0.
}

This works as long as all values you explicitly pass in are truthy. Values that are not truthy as per MiniGod's comment: null, undefined, 0, false, ''

It's pretty common to see JavaScript libraries to do a bunch of checks on optional inputs before the function actually starts.

C# RSA encryption/decryption with transmission

Honestly, I have difficulty implementing it because there's barely any tutorials I've searched that displays writing the keys into the files. The accepted answer was "fine". But for me I had to improve it so that both keys gets saved into two separate files. I've written a helper class so y'all just gotta copy and paste it. Hope this helps lol.

using Microsoft.Win32;
using System;
using System.IO;
using System.Security.Cryptography;

namespace RsaCryptoExample
{
    class RSAFileHelper
    {
        readonly string pubKeyPath = "public.key";//change as needed
        readonly string priKeyPath = "private.key";//change as needed
        public void MakeKey()
        {
            //lets take a new CSP with a new 2048 bit rsa key pair
            RSACryptoServiceProvider csp = new RSACryptoServiceProvider(2048);

            //how to get the private key
            RSAParameters privKey = csp.ExportParameters(true);

            //and the public key ...
            RSAParameters pubKey = csp.ExportParameters(false);
            //converting the public key into a string representation
            string pubKeyString;
            {
                //we need some buffer
                var sw = new StringWriter();
                //we need a serializer
                var xs = new System.Xml.Serialization.XmlSerializer(typeof(RSAParameters));
                //serialize the key into the stream
                xs.Serialize(sw, pubKey);
                //get the string from the stream
                pubKeyString = sw.ToString();
                File.WriteAllText(pubKeyPath, pubKeyString);
            }
            string privKeyString;
            {
                //we need some buffer
                var sw = new StringWriter();
                //we need a serializer
                var xs = new System.Xml.Serialization.XmlSerializer(typeof(RSAParameters));
                //serialize the key into the stream
                xs.Serialize(sw, privKey);
                //get the string from the stream
                privKeyString = sw.ToString();
                File.WriteAllText(priKeyPath, privKeyString);
            }
        }
        public void EncryptFile(string filePath)
        {
            //converting the public key into a string representation
            string pubKeyString;
            {
                using (StreamReader reader = new StreamReader(pubKeyPath)){pubKeyString = reader.ReadToEnd();}
            }
            //get a stream from the string
            var sr = new StringReader(pubKeyString);

            //we need a deserializer
            var xs = new System.Xml.Serialization.XmlSerializer(typeof(RSAParameters));

            //get the object back from the stream
            RSACryptoServiceProvider csp = new RSACryptoServiceProvider();
            csp.ImportParameters((RSAParameters)xs.Deserialize(sr));
            byte[] bytesPlainTextData = File.ReadAllBytes(filePath);

            //apply pkcs#1.5 padding and encrypt our data 
            var bytesCipherText = csp.Encrypt(bytesPlainTextData, false);
            //we might want a string representation of our cypher text... base64 will do
            string encryptedText = Convert.ToBase64String(bytesCipherText);
            File.WriteAllText(filePath,encryptedText);
        }
        public void DecryptFile(string filePath)
        {
            //we want to decrypt, therefore we need a csp and load our private key
            RSACryptoServiceProvider csp = new RSACryptoServiceProvider();

            string privKeyString;
            {
                privKeyString = File.ReadAllText(priKeyPath);
                //get a stream from the string
                var sr = new StringReader(privKeyString);
                //we need a deserializer
                var xs = new System.Xml.Serialization.XmlSerializer(typeof(RSAParameters));
                //get the object back from the stream
                RSAParameters privKey = (RSAParameters)xs.Deserialize(sr);
                csp.ImportParameters(privKey);
            }
            string encryptedText;
            using (StreamReader reader = new StreamReader(filePath)) { encryptedText = reader.ReadToEnd(); }
            byte[] bytesCipherText = Convert.FromBase64String(encryptedText);

            //decrypt and strip pkcs#1.5 padding
            byte[] bytesPlainTextData = csp.Decrypt(bytesCipherText, false);

            //get our original plainText back...
            File.WriteAllBytes(filePath, bytesPlainTextData);
        }
    }
}

How To Create Table with Identity Column

CREATE TABLE [dbo].[History](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [RequestID] [int] NOT NULL,
    [EmployeeID] [varchar](50) NOT NULL,
    [DateStamp] [datetime] NOT NULL,
 CONSTRAINT [PK_History] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON)
) ON [PRIMARY]

jQuery validate Uncaught TypeError: Cannot read property 'nodeName' of null

The problem happened because I was trying to bind a HTML element before it was created.

My script was loaded on top of the HTML and it needs to be loaded at the bottom of my HTML code.

Display only date and no time

You can modify your ViewModel as below:

[DisplayFormat(DataFormatString = "{0:dd/MM/yyyy}",ApplyFormatInEditMode = true)]

Java abstract interface

It's not necessary, as interfaces are by default abstract as all the methods in an interface are abstract.

Select records from today, this week, this month php mysql

Everybody seems to refer to date being a column in the table.
I dont think this is good practice. The word date might just be a keyword in some coding language (maybe Oracle) so please change the columnname date to maybe JDate.
So will the following work better:

SELECT * FROM jokes WHERE JDate >= CURRENT_DATE() ORDER BY JScore DESC;

So we have a table called Jokes with columns JScore and JDate.

Python function pointer

It's much nicer to be able to just store the function itself, since they're first-class objects in python.

import mypackage

myfunc = mypackage.mymodule.myfunction
myfunc(parameter1, parameter2)

But, if you have to import the package dynamically, then you can achieve this through:

mypackage = __import__('mypackage')
mymodule = getattr(mypackage, 'mymodule')
myfunction = getattr(mymodule, 'myfunction')

myfunction(parameter1, parameter2)

Bear in mind however, that all of that work applies to whatever scope you're currently in. If you don't persist them somehow, you can't count on them staying around if you leave the local scope.

Bundler::GemNotFound: Could not find rake-10.3.2 in any of the sources

bundle install --path vendor/cache

generally fixes it as that is the more common problem. Basically, your bundler path configuration is messed up. See their documentation (first paragraph) for where to find those configurations and change them manually if needed.

Javascript parse float is ignoring the decimals after my comma

parseFloat parses according to the JavaScript definition of a decimal literal, not your locale's definition. (E.g., parseFloat is not locale-aware.) Decimal literals in JavaScript use . for the decimal point.

mysql update query with sub query

For the impatient:

UPDATE target AS t
INNER JOIN (
  SELECT s.id, COUNT(*) AS count
  FROM source_grouped AS s
  -- WHERE s.custom_condition IS (true)
  GROUP BY s.id
) AS aggregate ON aggregate.id = t.id
SET t.count = aggregate.count

That's @mellamokb's answer, as above, reduced to the max.

Running Python on Windows for Node.js dependencies

The following worked for me from the command line as admin:

Installing windows-build-tools (this can take 15-20 minutes):

 npm --add-python-to-path='true' --debug install --global windows-build-tools

Adding/updating the environment variable:

setx PYTHON "%USERPROFILE%\.windows-build-tools\python27\python.exe"

Installing node-gyp:

npm install --global node-gyp

Changing the name of the exe file from Python to Python2.7.

C:\Users\username\.windows-build-tools\python27\Python2.7

npm install module_name --save

Pass in an array of Deferreds to $.when()

To pass an array of values to any function that normally expects them to be separate parameters, use Function.prototype.apply, so in this case you need:

$.when.apply($, my_array).then( ___ );

See http://jsfiddle.net/YNGcm/21/

In ES6, you can use the ... spread operator instead:

$.when(...my_array).then( ___ );

In either case, since it's unlikely that you'll known in advance how many formal parameters the .then handler will require, that handler would need to process the arguments array in order to retrieve the result of each promise.

change values in array when doing foreach

The callback is passed the element, the index, and the array itself.

arr.forEach(function(part, index, theArray) {
  theArray[index] = "hello world";
});

edit — as noted in a comment, the .forEach() function can take a second argument, which will be used as the value of this in each call to the callback:

arr.forEach(function(part, index) {
  this[index] = "hello world";
}, arr); // use arr as this

That second example shows arr itself being set up as this in the callback.One might think that the array involved in the .forEach() call might be the default value of this, but for whatever reason it's not; this will be undefined if that second argument is not provided.

(Note: the above stuff about this does not apply if the callback is a => function, because this is never bound to anything when such functions are invoked.)

Also it's important to remember that there is a whole family of similar utilities provided on the Array prototype, and many questions pop up on Stackoverflow about one function or another such that the best solution is to simply pick a different tool. You've got:

  • forEach for doing a thing with or to every entry in an array;
  • filter for producing a new array containing only qualifying entries;
  • map for making a one-to-one new array by transforming an existing array;
  • some to check whether at least one element in an array fits some description;
  • every to check whether all entries in an array match a description;
  • find to look for a value in an array

and so on. MDN link

Redirecting unauthorized controller in ASP.NET MVC

In your Startup.Auth.cs file add this line:

LoginPath = new PathString("/Account/Login"),

Example:

// Enable the application to use a cookie to store information for the signed in user
// and to use a cookie to temporarily store information about a user logging in with a third party login provider
// Configure the sign in cookie
app.UseCookieAuthentication(new CookieAuthenticationOptions
{
    AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
    LoginPath = new PathString("/Account/Login"),
    Provider = new CookieAuthenticationProvider
    {
        // Enables the application to validate the security stamp when the user logs in.
        // This is a security feature which is used when you change a password or add an external login to your account.  
        OnValidateIdentity = SecurityStampValidator.OnValidateIdentity<ApplicationUserManager, ApplicationUser>(
        validateInterval: TimeSpan.FromMinutes(30),
        regenerateIdentity: (manager, user) => user.GenerateUserIdentityAsync(manager))
    }
});

Count number of records returned by group by

Following for PrestoDb, where FirstField can have multiple values:

select *
            , concat(cast(cast((ThirdTable.Total_Records_in_Group * 100 / ThirdTable.Total_Records_in_baseTable) as DECIMAL(5,2)) as varchar), '%') PERCENTage
from 
(
    SELECT FirstTable.FirstField, FirstTable.SecondField, SecondTable.Total_Records_in_baseTable, count(*) Total_Records_in_Group
    FROM BaseTable FirstTable
    JOIN (
            SELECT FK1, count(*) AS Total_Records_in_baseTable 
            FROM BaseTable
            GROUP BY FK1
        ) SecondTable
    ON FirstTable.FirstField = SecondTable.FK1
    GROUP BY FirstTable.FirstField, FirstTable.SecondField, SecondTable.Total_Records_in_baseTable
    ORDER BY FirstTable.FirstField, FirstTable.SecondField
) ThirdTable

Count unique values with pandas per groups

You need nunique:

df = df.groupby('domain')['ID'].nunique()

print (df)
domain
'facebook.com'    1
'google.com'      1
'twitter.com'     2
'vk.com'          3
Name: ID, dtype: int64

If you need to strip ' characters:

df = df.ID.groupby([df.domain.str.strip("'")]).nunique()
print (df)
domain
facebook.com    1
google.com      1
twitter.com     2
vk.com          3
Name: ID, dtype: int64

Or as Jon Clements commented:

df.groupby(df.domain.str.strip("'"))['ID'].nunique()

You can retain the column name like this:

df = df.groupby(by='domain', as_index=False).agg({'ID': pd.Series.nunique})
print(df)
    domain  ID
0       fb   1
1      ggl   1
2  twitter   2
3       vk   3

The difference is that nunique() returns a Series and agg() returns a DataFrame.

Merging 2 branches together in GIT

Case: If you need to ignore the merge commit created by default, follow these steps.

Say, a new feature branch is checked out from master having 2 commits already,

  • "Added A" , "Added B"

Checkout a new feature_branch

  • "Added C" , "Added D"

Feature branch then adds two commits-->

  • "Added E", "Added F"

enter image description here

Now if you want to merge feature_branch changes to master, Do git merge feature_branch sitting on the master.

This will add all commits into master branch (4 in master + 2 in feature_branch = total 6) + an extra merge commit something like 'Merge branch 'feature_branch'' as the master is diverged.

If you really need to ignore these commits (those made in FB) and add the whole changes made in feature_branch as a single commit like 'Integrated feature branch changes into master', Run git merge feature_merge --no-commit.

With --no-commit, it perform the merge and stop just before creating a merge commit, We will have all the added changes in feature branch now in master and get a chance to create a new commit as our own.

Read here for more : https://git-scm.com/docs/git-merge

What is the difference between aggregation, composition and dependency?

Aggregation and composition are terms that most people in the OO world have acquired via UML. And UML does a very poor job at defining these terms, as has been demonstrated by, for example, Henderson-Sellers and Barbier ("What is This Thing Called Aggregation?", "Formalization of the Whole-Part Relationship in the Unified Modeling Language"). I don't think that a coherent definition of aggregation and composition can be given if you are interested in being UML-compliant. I suggest you look at the cited works.

Regarding dependency, that's a highly abstract relationship between types (not objects) that can mean almost anything.

How to distinguish between left and right mouse click with jQuery

$.event.special.rightclick = {
    bindType: "contextmenu",
    delegateType: "contextmenu"
};

$(document).on("rightclick", "div", function() {
    console.log("hello");
    return false;
});

http://jsfiddle.net/SRX3y/8/

What is the difference between venv, pyvenv, pyenv, virtualenv, virtualenvwrapper, pipenv, etc?

I would just avoid the use of virtualenv after Python3.3+ and instead use the standard shipped library venv. To create a new virtual environment you would type:

$ python3 -m venv <MYVENV>  

virtualenv tries to copy the Python binary into the virtual environment's bin directory. However it does not update library file links embedded into that binary, so if you build Python from source into a non-system directory with relative path names, the Python binary breaks. Since this is how you make a copy distributable Python, it is a big flaw. BTW to inspect embedded library file links on OS X, use otool. For example from within your virtual environment, type:

$ otool -L bin/python
python:
    @executable_path/../Python (compatibility version 3.4.0, current version 3.4.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1238.0.0)

Consequently I would avoid virtualenvwrapper and pipenv. pyvenv is deprecated. pyenv seems to be used often where virtualenv is used but I would stay away from it also since I think venv also does what pyenv is built for.

venv creates virtual environments in the shell that are fresh and sandboxed, with user-installable libraries, and it's multi-python safe. Fresh because virtual environments only start with the standard libraries that ship with python, you have to install any other libraries all over again with pip install while the virtual environment is active. Sandboxed because none of these new library installs are visible outside the virtual environment, so you can delete the whole environment and start again without worrying about impacting your base python install. User-installable libraries because the virtual environment's target folder is created without sudo in some directory you already own, so you won't need sudo permissions to install libraries into it. Finally it is multi-python safe, since when virtual environments activate, the shell only sees the python version (3.4, 3.5 etc.) that was used to build that virtual environment.

pyenv is similar to venv in that it lets you manage multiple python environments. However with pyenv you can't conveniently rollback library installs to some start state and you will likely need admin privileges at some point to update libraries. So I think it is also best to use venv.

In the last couple of years I have found many problems in build systems (emacs packages, python standalone application builders, installers...) that ultimately come down to issues with virtualenv. I think python will be a better platform when we eliminate this additional option and only use venv.

EDIT: Tweet of the BDFL,

I use venv (in the stdlib) and a bunch of shell aliases to quickly switch.

— Guido van Rossum (@gvanrossum) October 22, 2020

Convert string with commas to array

Example using Array.filter:

var str = 'a,b,hi,ma,n,yu';

var strArr = Array.prototype.filter.call(str, eachChar => eachChar !== ',');

Reset the Value of a Select Box

This works for me:

$('select').prop('selectedIndex', 0);

FIDDLE

Byte Array in Python

In Python 3, we use the bytes object, also known as str in Python 2.

# Python 3
key = bytes([0x13, 0x00, 0x00, 0x00, 0x08, 0x00])

# Python 2
key = ''.join(chr(x) for x in [0x13, 0x00, 0x00, 0x00, 0x08, 0x00])

I find it more convenient to use the base64 module...

# Python 3
key = base64.b16decode(b'130000000800')

# Python 2
key = base64.b16decode('130000000800')

You can also use literals...

# Python 3
key = b'\x13\0\0\0\x08\0'

# Python 2
key = '\x13\0\0\0\x08\0'

Types in Objective-C on iOS

Note that you can also use the C99 fixed-width types perfectly well in Objective-C:

#import <stdint.h>
...
int32_t x; // guaranteed to be 32 bits on any platform

The wikipedia page has a decent description of what's available in this header if you don't have a copy of the C standard (you should, though, since Objective-C is just a tiny extension of C). You may also find the headers limits.h and inttypes.h to be useful.

How to Install pip for python 3.7 on Ubuntu 18?

A quick add-on to mpenkov's answer above (didn't want this to get lost in the comments)

For me, I had to install pip for 3.6 first

sudo apt install python3-pip

now you can install python 3.7

sudo apt install python3.7

and then I could install pip for 3.7

python3.7 -m pip install pip

and as a bonus, to install other modules just preface with

python3.7 -m pip install <module>

EDIT 1 (12/2019):

I know this is obvious for most. but if you want python 3.8, just substitute python3.8 in place of python3.7

EDIT 2 (5/2020):

For those that are able to upgrade, Python 3.8 is available out-of-the-box for Ubuntu 20.04 which was released a few weeks ago.

Editing legend (text) labels in ggplot

The tutorial @Henrik mentioned is an excellent resource for learning how to create plots with the ggplot2 package.

An example with your data:

# transforming the data from wide to long
library(reshape2)
dfm <- melt(df, id = "TY")

# creating a scatterplot
ggplot(data = dfm, aes(x = TY, y = value, color = variable)) + 
  geom_point(size=5) +
  labs(title = "Temperatures\n", x = "TY [°C]", y = "Txxx", color = "Legend Title\n") +
  scale_color_manual(labels = c("T999", "T888"), values = c("blue", "red")) +
  theme_bw() +
  theme(axis.text.x = element_text(size = 14), axis.title.x = element_text(size = 16),
        axis.text.y = element_text(size = 14), axis.title.y = element_text(size = 16),
        plot.title = element_text(size = 20, face = "bold", color = "darkgreen"))

this results in:

enter image description here

As mentioned by @user2739472 in the comments: If you only want to change the legend text labels and not the colours from ggplot's default palette, you can use scale_color_hue(labels = c("T999", "T888")) instead of scale_color_manual().

Custom style to jquery ui dialogs

You can specify a custom class to the top element of the dialog via the option dialogClass

$("#success").dialog({
    ...
    dialogClass:"myClass",
    ...
});

Then you can target this class in CSS via .myClass.ui-dialog.

How to parse XML using vba

Add reference Project->References Microsoft XML, 6.0 and you can use example code:

    Dim xml As String

    xml = "<root><person><name>Me </name> </person> <person> <name>No Name </name></person></root> "
    Dim oXml As MSXML2.DOMDocument60
    Set oXml = New MSXML2.DOMDocument60
    oXml.loadXML xml
    Dim oSeqNodes, oSeqNode As IXMLDOMNode

    Set oSeqNodes = oXml.selectNodes("//root/person")
    If oSeqNodes.length = 0 Then
       'show some message
    Else
        For Each oSeqNode In oSeqNodes
             Debug.Print oSeqNode.selectSingleNode("name").Text
        Next
    End If 

be careful with xml node //Root/Person is not same with //root/person, also selectSingleNode("Name").text is not same with selectSingleNode("name").text

How to find what code is run by a button or element in Chrome using Developer Tools

Alexander Pavlov's answer gets the closest to what you want.

Due to the extensiveness of jQuery's abstraction and functionality, a lot of hoops have to be jumped in order to get to the meat of the event. I have set up this jsFiddle to demonstrate the work.


1. Setting up the Event Listener Breakpoint

You were close on this one.

  1. Open the Chrome Dev Tools (F12), and go to the Sources tab.
  2. Drill down to Mouse -> Click
    Chrome Dev Tools -> Sources tab -> Mouse -> Click
    (click to zoom)

2. Click the button!

Chrome Dev Tools will pause script execution, and present you with this beautiful entanglement of minified code:

Chrome Dev Tools paused script execution (click to zoom)


3. Find the glorious code!

Now, the trick here is to not get carried away pressing the key, and keep an eye out on the screen.

  1. Press the F11 key (Step In) until desired source code appears
  2. Source code finally reached
    • In the jsFiddle sample provided above, I had to press F11 108 times before reaching the desired event handler/function
    • Your mileage may vary, depending on the version of jQuery (or framework library) used to bind the events
    • With enough dedication and time, you can find any event handler/function

Desired event handler/function


4. Explanation

I don't have the exact answer, or explanation as to why jQuery goes through the many layers of abstractions it does - all I can suggest is that it is because of the job it does to abstract away its usage from the browser executing the code.

Here is a jsFiddle with a debug version of jQuery (i.e., not minified). When you look at the code on the first (non-minified) breakpoint, you can see that the code is handling many things:

    // ...snip...

    if ( !(eventHandle = elemData.handle) ) {
        eventHandle = elemData.handle = function( e ) {
            // Discard the second event of a jQuery.event.trigger() and
            // when an event is called after a page has unloaded
            return typeof jQuery !== strundefined && jQuery.event.triggered !== e.type ?
                jQuery.event.dispatch.apply( elem, arguments ) : undefined;
        };
    }

    // ...snip...

The reason I think you missed it on your attempt when the "execution pauses and I jump line by line", is because you may have used the "Step Over" function, instead of Step In. Here is a StackOverflow answer explaining the differences.

Finally, the reason why your function is not directly bound to the click event handler is because jQuery returns a function that gets bound. jQuery's function in turn goes through some abstraction layers and checks, and somewhere in there, it executes your function.

conversion from string to json object android

Using Kotlin

    val data = "{\"ApiInfo\":{\"description\":\"userDetails\",\"status\":\"success\"},\"userDetails\":{\"Name\":\"somename\",\"userName\":\"value\"},\"pendingPushDetails\":[]}\n"
    
try {
      val jsonObject = JSONObject(data)
      val infoObj = jsonObject.getJSONObject("ApiInfo")
    } catch (e: Exception) {
    }

In excel how do I reference the current row but a specific column?

If you dont want to hard-code the cell addresses you can use the ROW() function.

eg: =AVERAGE(INDIRECT("A" & ROW()), INDIRECT("C" & ROW()))

Its probably not the best way to do it though! Using Auto-Fill and static columns like @JaiGovindani suggests would be much better.

What is the meaning of "int(a[::-1])" in Python?

The notation that is used in

a[::-1]

means that for a given string/list/tuple, you can slice the said object using the format

<object_name>[<start_index>, <stop_index>, <step>]

This means that the object is going to slice every "step" index from the given start index, till the stop index (excluding the stop index) and return it to you.

In case the start index or stop index is missing, it takes up the default value as the start index and stop index of the given string/list/tuple. If the step is left blank, then it takes the default value of 1 i.e it goes through each index.

So,

a = '1234'
print a[::2]

would print

13

Now the indexing here and also the step count, support negative numbers. So, if you give a -1 index, it translates to len(a)-1 index. And if you give -x as the step count, then it would step every x'th value from the start index, till the stop index in the reverse direction. For example

a = '1234'
print a[3:0:-1]

This would return

432

Note, that it doesn't return 4321 because, the stop index is not included.

Now in your case,

str(int(a[::-1]))

would just reverse a given integer, that is stored in a string, and then convert it back to a string

i.e "1234" -> "4321" -> 4321 -> "4321"

If what you are trying to do is just reverse the given string, then simply a[::-1] would work .

How to set caret(cursor) position in contenteditable element (div)?

Most answers you find on contenteditable cursor positioning are fairly simplistic in that they only cater for inputs with plain vanilla text. Once you using html elements within the container the text entered gets split into nodes and distributed liberally across a tree structure.

To set the cursor position I have this function which loops round all the child text nodes within the supplied node and sets a range from the start of the initial node to the chars.count character:

function createRange(node, chars, range) {
    if (!range) {
        range = document.createRange()
        range.selectNode(node);
        range.setStart(node, 0);
    }

    if (chars.count === 0) {
        range.setEnd(node, chars.count);
    } else if (node && chars.count >0) {
        if (node.nodeType === Node.TEXT_NODE) {
            if (node.textContent.length < chars.count) {
                chars.count -= node.textContent.length;
            } else {
                range.setEnd(node, chars.count);
                chars.count = 0;
            }
        } else {
           for (var lp = 0; lp < node.childNodes.length; lp++) {
                range = createRange(node.childNodes[lp], chars, range);

                if (chars.count === 0) {
                    break;
                }
            }
        }
    } 

    return range;
};

I then call the routine with this function:

function setCurrentCursorPosition(chars) {
    if (chars >= 0) {
        var selection = window.getSelection();

        range = createRange(document.getElementById("test").parentNode, { count: chars });

        if (range) {
            range.collapse(false);
            selection.removeAllRanges();
            selection.addRange(range);
        }
    }
};

The range.collapse(false) sets the cursor to the end of the range. I've tested it with the latest versions of Chrome, IE, Mozilla and Opera and they all work fine.

PS. If anyone is interested I get the current cursor position using this code:

function isChildOf(node, parentId) {
    while (node !== null) {
        if (node.id === parentId) {
            return true;
        }
        node = node.parentNode;
    }

    return false;
};

function getCurrentCursorPosition(parentId) {
    var selection = window.getSelection(),
        charCount = -1,
        node;

    if (selection.focusNode) {
        if (isChildOf(selection.focusNode, parentId)) {
            node = selection.focusNode; 
            charCount = selection.focusOffset;

            while (node) {
                if (node.id === parentId) {
                    break;
                }

                if (node.previousSibling) {
                    node = node.previousSibling;
                    charCount += node.textContent.length;
                } else {
                     node = node.parentNode;
                     if (node === null) {
                         break
                     }
                }
           }
      }
   }

    return charCount;
};

The code does the opposite of the set function - it gets the current window.getSelection().focusNode and focusOffset and counts backwards all text characters encountered until it hits a parent node with id of containerId. The isChildOf function just checks before running that the suplied node is actually a child of the supplied parentId.

The code should work straight without change, but I have just taken it from a jQuery plugin I've developed so have hacked out a couple of this's - let me know if anything doesn't work!

Output an Image in PHP

If you have the liberty to configure your webserver yourself, tools like mod_xsendfile (for Apache) are considerably better than reading and printing the file in PHP. Your PHP code would look like this:

header("Content-type: $type");
header("X-Sendfile: $file"); # make sure $file is the full path, not relative
exit();

mod_xsendfile picks up the X-Sendfile header and sends the file to the browser itself. This can make a real difference in performance, especially for big files. Most of the proposed solutions read the whole file into memory and then print it out. That's OK for a 20kbyte image file, but if you have a 200 MByte TIFF file, you're bound to get problems.

How do you set autocommit in an SQL Server session?

With SQLServer 2005 Express, what I found was that even with autocommit off, insertions into a Db table were committed without my actually issuing a commit command from the Management Studio session. The only difference was, when autocommit was off, I could roll back all the insertions; with *autocommit on, I could not.* Actually, I was wrong. With autocommit mode off, I see the changes only in the QA (Query Analyzer) window from which the commands were issued. If I popped a new QA (Query Analyzer) window, I do not see the changes made by the first window (session), i.e. they are NOT committed! I had to issue explicit commit or rollback commands to make changes visible to other sessions(QA windows) -- my bad! Things are working correctly.

How to find the kafka version in linux

go to kafka/libs folder we can see multiple jars search for something similar kafka_2.11-0.10.1.1.jar.asc in this case the kafka version is 0.10.1.1

How do I loop through or enumerate a JavaScript object?

Object.keys(obj) : Array

retrieves all string-valued keys of all enumerable own (non-inherited) properties.

So it gives the same list of keys as you intend by testing each object key with hasOwnProperty. You don't need that extra test operation than and Object.keys( obj ).forEach(function( key ){}) is supposed to be faster. Let's prove it:

_x000D_
_x000D_
var uniqid = function(){_x000D_
   var text = "",_x000D_
     i = 0,_x000D_
     possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";_x000D_
   for( ; i < 32; i++ ) {_x000D_
     text += possible.charAt( Math.floor( Math.random() * possible.length ) );_x000D_
   }_x000D_
   return text;_x000D_
  }, _x000D_
  CYCLES = 100000,_x000D_
  obj = {}, _x000D_
  p1,_x000D_
  p2,_x000D_
  p3,_x000D_
  key;_x000D_
_x000D_
// Populate object with random properties_x000D_
Array.apply( null, Array( CYCLES ) ).forEach(function(){_x000D_
 obj[ uniqid() ] = new Date()_x000D_
});_x000D_
_x000D_
// Approach #1_x000D_
p1 = performance.now();_x000D_
Object.keys( obj ).forEach(function( key ){_x000D_
 var waste = obj[ key ];_x000D_
});_x000D_
_x000D_
p2 = performance.now();_x000D_
console.log( "Object.keys approach took " + (p2 - p1) + " milliseconds.");_x000D_
_x000D_
// Approach #2_x000D_
for( key in obj ) {_x000D_
 if ( obj.hasOwnProperty( key ) ) {_x000D_
  var waste = obj[ key ];_x000D_
 }_x000D_
}_x000D_
_x000D_
p3 = performance.now();_x000D_
console.log( "for...in/hasOwnProperty approach took " + (p3 - p2) + " milliseconds.");
_x000D_
_x000D_
_x000D_

In my Firefox I have following results

  • Object.keys approach took 40.21101451665163 milliseconds.
  • for...in/hasOwnProperty approach took 98.26163508463651 milliseconds.

PS. on Chrome the difference even bigger http://codepen.io/dsheiko/pen/JdrqXa

PS2: In ES6 (EcmaScript 2015) you can iterate iterable object nicer:

_x000D_
_x000D_
let map = new Map().set('a', 1).set('b', 2);_x000D_
for (let pair of map) {_x000D_
    console.log(pair);_x000D_
}_x000D_
_x000D_
// OR _x000D_
let map = new Map([_x000D_
    [false, 'no'],_x000D_
    [true,  'yes'],_x000D_
]);_x000D_
map.forEach((value, key) => {_x000D_
    console.log(key, value);_x000D_
});
_x000D_
_x000D_
_x000D_

How to change an Android app's name?

You might have to change the name of your main activity "android:label" also, as explained in Naming my application in android

How to copy the first few lines of a giant file, and add a line of text at the end of it using some Linux commands?

The head command can get the first n lines. Variations are:

head -7 file
head -n 7 file
head -7l file

which will get the first 7 lines of the file called "file". The command to use depends on your version of head. Linux will work with the first one.

To append lines to the end of the same file, use:

echo 'first line to add' >>file
echo 'second line to add' >>file
echo 'third line to add' >>file

or:

echo 'first line to add
second line to add
third line to add' >>file

to do it in one hit.

So, tying these two ideas together, if you wanted to get the first 10 lines of the input.txt file to output.txt and append a line with five "=" characters, you could use something like:

( head -10 input.txt ; echo '=====' ) > output.txt

In this case, we do both operations in a sub-shell so as to consolidate the output streams into one, which is then used to create or overwrite the output file.

How to sort the letters in a string alphabetically in Python

You can use reduce

>>> a = 'ZENOVW'
>>> reduce(lambda x,y: x+y, sorted(a))
'ENOVWZ'

How should a model be structured in MVC?

Disclaimer: the following is a description of how I understand MVC-like patterns in the context of PHP-based web applications. All the external links that are used in the content are there to explain terms and concepts, and not to imply my own credibility on the subject.

The first thing that I must clear up is: the model is a layer.

Second: there is a difference between classical MVC and what we use in web development. Here's a bit of an older answer I wrote, which briefly describes how they are different.

What a model is NOT:

The model is not a class or any single object. It is a very common mistake to make (I did too, though the original answer was written when I began to learn otherwise), because most frameworks perpetuate this misconception.

Neither is it an Object-Relational Mapping technique (ORM) nor an abstraction of database tables. Anyone who tells you otherwise is most likely trying to 'sell' another brand-new ORM or a whole framework.

What a model is:

In proper MVC adaptation, the M contains all the domain business logic and the Model Layer is mostly made from three types of structures:

  • Domain Objects

    A domain object is a logical container of purely domain information; it usually represents a logical entity in the problem domain space. Commonly referred to as business logic.

    This would be where you define how to validate data before sending an invoice, or to compute the total cost of an order. At the same time, Domain Objects are completely unaware of storage - neither from where (SQL database, REST API, text file, etc.) nor even if they get saved or retrieved.

  • Data Mappers

    These objects are only responsible for the storage. If you store information in a database, this would be where the SQL lives. Or maybe you use an XML file to store data, and your Data Mappers are parsing from and to XML files.

  • Services

    You can think of them as "higher level Domain Objects", but instead of business logic, Services are responsible for interaction between Domain Objects and Mappers. These structures end up creating a "public" interface for interacting with the domain business logic. You can avoid them, but at the penalty of leaking some domain logic into Controllers.

    There is a related answer to this subject in the ACL implementation question - it might be useful.

The communication between the model layer and other parts of the MVC triad should happen only through Services. The clear separation has a few additional benefits:

  • it helps to enforce the single responsibility principle (SRP)
  • provides additional 'wiggle room' in case the logic changes
  • keeps the controller as simple as possible
  • gives a clear blueprint, if you ever need an external API

 

How to interact with a model?

Prerequisites: watch lectures "Global State and Singletons" and "Don't Look For Things!" from the Clean Code Talks.

Gaining access to service instances

For both the View and Controller instances (what you could call: "UI layer") to have access these services, there are two general approaches:

  1. You can inject the required services in the constructors of your views and controllers directly, preferably using a DI container.
  2. Using a factory for services as a mandatory dependency for all of your views and controllers.

As you might suspect, the DI container is a lot more elegant solution (while not being the easiest for a beginner). The two libraries, that I recommend considering for this functionality would be Syfmony's standalone DependencyInjection component or Auryn.

Both the solutions using a factory and a DI container would let you also share the instances of various servers to be shared between the selected controller and view for a given request-response cycle.

Alteration of model's state

Now that you can access to the model layer in the controllers, you need to start actually using them:

public function postLogin(Request $request)
{
    $email = $request->get('email');
    $identity = $this->identification->findIdentityByEmailAddress($email);
    $this->identification->loginWithPassword(
        $identity,
        $request->get('password')
    );
}

Your controllers have a very clear task: take the user input and, based on this input, change the current state of business logic. In this example the states that are changed between are "anonymous user" and "logged in user".

Controller is not responsible for validating user's input, because that is part of business rules and controller is definitely not calling SQL queries, like what you would see here or here (please don't hate on them, they are misguided, not evil).

Showing user the state-change.

Ok, user has logged in (or failed). Now what? Said user is still unaware of it. So you need to actually produce a response and that is the responsibility of a view.

public function postLogin()
{
    $path = '/login';
    if ($this->identification->isUserLoggedIn()) {
        $path = '/dashboard';
    }
    return new RedirectResponse($path); 
}

In this case, the view produced one of two possible responses, based on the current state of model layer. For a different use-case you would have the view picking different templates to render, based on something like "current selected of article" .

The presentation layer can actually get quite elaborate, as described here: Understanding MVC Views in PHP.

But I am just making a REST API!

Of course, there are situations, when this is a overkill.

MVC is just a concrete solution for Separation of Concerns principle. MVC separates user interface from the business logic, and it in the UI it separated handling of user input and the presentation. This is crucial. While often people describe it as a "triad", it's not actually made up from three independent parts. The structure is more like this:

MVC separation

It means, that, when your presentation layer's logic is close to none-existent, the pragmatic approach is to keep them as single layer. It also can substantially simplify some aspects of model layer.

Using this approach the login example (for an API) can be written as:

public function postLogin(Request $request)
{
    $email = $request->get('email');
    $data = [
        'status' => 'ok',
    ];
    try {
        $identity = $this->identification->findIdentityByEmailAddress($email);
        $token = $this->identification->loginWithPassword(
            $identity,
            $request->get('password')
        );
    } catch (FailedIdentification $exception) {
        $data = [
            'status' => 'error',
            'message' => 'Login failed!',
        ]
    }

    return new JsonResponse($data);
}

While this is not sustainable, when you have complicate logic for rendering a response body, this simplification is very useful for more trivial scenarios. But be warned, this approach will become a nightmare, when attempting to use in large codebases with complex presentation logic.

 

How to build the model?

Since there is not a single "Model" class (as explained above), you really do not "build the model". Instead you start from making Services, which are able to perform certain methods. And then implement Domain Objects and Mappers.

An example of a service method:

In the both approaches above there was this login method for the identification service. What would it actually look like. I am using a slightly modified version of the same functionality from a library, that I wrote .. because I am lazy:

public function loginWithPassword(Identity $identity, string $password): string
{
    if ($identity->matchPassword($password) === false) {
        $this->logWrongPasswordNotice($identity, [
            'email' => $identity->getEmailAddress(),
            'key' => $password, // this is the wrong password
        ]);

        throw new PasswordMismatch;
    }

    $identity->setPassword($password);
    $this->updateIdentityOnUse($identity);
    $cookie = $this->createCookieIdentity($identity);

    $this->logger->info('login successful', [
        'input' => [
            'email' => $identity->getEmailAddress(),
        ],
        'user' => [
            'account' => $identity->getAccountId(),
            'identity' => $identity->getId(),
        ],
    ]);

    return $cookie->getToken();
}

As you can see, at this level of abstraction, there is no indication of where the data was fetched from. It might be a database, but it also might be just a mock object for testing purposes. Even the data mappers, that are actually used for it, are hidden away in the private methods of this service.

private function changeIdentityStatus(Entity\Identity $identity, int $status)
{
    $identity->setStatus($status);
    $identity->setLastUsed(time());
    $mapper = $this->mapperFactory->create(Mapper\Identity::class);
    $mapper->store($identity);
}

Ways of creating mappers

To implement an abstraction of persistence, on the most flexible approaches is to create custom data mappers.

Mapper diagram

From: PoEAA book

In practice they are implemented for interaction with specific classes or superclasses. Lets say you have Customer and Admin in your code (both inheriting from a User superclass). Both would probably end up having a separate matching mapper, since they contain different fields. But you will also end up with shared and commonly used operations. For example: updating the "last seen online" time. And instead of making the existing mappers more convoluted, the more pragmatic approach is to have a general "User Mapper", which only update that timestamp.

Some additional comments:

  1. Database tables and model

    While sometimes there is a direct 1:1:1 relationship between a database table, Domain Object, and Mapper, in larger projects it might be less common than you expect:

    • Information used by a single Domain Object might be mapped from different tables, while the object itself has no persistence in the database.

      Example: if you are generating a monthly report. This would collect information from different of tables, but there is no magical MonthlyReport table in the database.

    • A single Mapper can affect multiple tables.

      Example: when you are storing data from the User object, this Domain Object could contain collection of other domain objects - Group instances. If you alter them and store the User, the Data Mapper will have to update and/or insert entries in multiple tables.

    • Data from a single Domain Object is stored in more than one table.

      Example: in large systems (think: a medium-sized social network), it might be pragmatic to store user authentication data and often-accessed data separately from larger chunks of content, which is rarely required. In that case you might still have a single User class, but the information it contains would depend of whether full details were fetched.

    • For every Domain Object there can be more than one mapper

      Example: you have a news site with a shared codebased for both public-facing and the management software. But, while both interfaces use the same Article class, the management needs a lot more info populated in it. In this case you would have two separate mappers: "internal" and "external". Each performing different queries, or even use different databases (as in master or slave).

  2. A view is not a template

    View instances in MVC (if you are not using the MVP variation of the pattern) are responsible for the presentational logic. This means that each View will usually juggle at least a few templates. It acquires data from the Model Layer and then, based on the received information, chooses a template and sets values.

    One of the benefits you gain from this is re-usability. If you create a ListView class, then, with well-written code, you can have the same class handing the presentation of user-list and comments below an article. Because they both have the same presentation logic. You just switch templates.

    You can use either native PHP templates or use some third-party templating engine. There also might be some third-party libraries, which are able to fully replace View instances.

  3. What about the old version of the answer?

    The only major change is that, what is called Model in the old version, is actually a Service. The rest of the "library analogy" keeps up pretty well.

    The only flaw that I see is that this would be a really strange library, because it would return you information from the book, but not let you touch the book itself, because otherwise the abstraction would start to "leak". I might have to think of a more fitting analogy.

  4. What is the relationship between View and Controller instances?

    The MVC structure is composed of two layers: ui and model. The main structures in the UI layer are views and controller.

    When you are dealing with websites that use MVC design pattern, the best way is to have 1:1 relation between views and controllers. Each view represents a whole page in your website and it has a dedicated controller to handle all the incoming requests for that particular view.

    For example, to represent an opened article, you would have \Application\Controller\Document and \Application\View\Document. This would contain all the main functionality for UI layer, when it comes to dealing with articles (of course you might have some XHR components that are not directly related to articles).

Android background music service

way too late for the party here but i will still add my $0.02, Google has released a free sample called universal music player with which you can learn to stream music across all android platforms(auto, watch,mobile,tv..) it uses service to play music in the background, do check it out very helpful. here's the link to the project
https://github.com/googlesamples/android-UniversalMusicPlayer

How to write a test which expects an Error to be thrown in Jasmine?

I replace Jasmine's toThrow matcher with the following, which lets you match on the exception's name property or its message property. For me this makes tests easier to write and less brittle, as I can do the following:

throw {
   name: "NoActionProvided",
   message: "Please specify an 'action' property when configuring the action map."
}

and then test with the following:

expect (function () {
   .. do something
}).toThrow ("NoActionProvided");

This lets me tweak the exception message later without breaking tests, when the important thing is that it threw the expected type of exception.

This is the replacement for toThrow that allows this:

jasmine.Matchers.prototype.toThrow = function(expected) {
  var result = false;
  var exception;
  if (typeof this.actual != 'function') {
    throw new Error('Actual is not a function');
  }
  try {
    this.actual();
  } catch (e) {
    exception = e;
  }
  if (exception) {
      result = (expected === jasmine.undefined || this.env.equals_(exception.message || exception, expected.message || expected) || this.env.equals_(exception.name, expected));
  }

  var not = this.isNot ? "not " : "";

  this.message = function() {
    if (exception && (expected === jasmine.undefined || !this.env.equals_(exception.message || exception, expected.message || expected))) {
      return ["Expected function " + not + "to throw", expected ? expected.name || expected.message || expected : " an exception", ", but it threw", exception.name || exception.message || exception].join(' ');
    } else {
      return "Expected function to throw an exception.";
    }
  };

  return result;
};

How to open a URL in a new Tab using JavaScript or jQuery?

You can easily create a new tab; do like the following:

function newTab() {
     var form = document.createElement("form");
     form.method = "GET";
     form.action = "http://www.example.com";
     form.target = "_blank";
     document.body.appendChild(form);
     form.submit();
}

PHP import Excel into database (xls & xlsx)

If you can convert .xls to .csv before processing, you can use the query below to import the csv to the database:

load data local infile 'FILE.CSV' into table TABLENAME fields terminated by ',' enclosed by '"' lines terminated by '\n' (FIELD1,FIELD2,FIELD3)

How to send POST request?

You can't achieve POST requests using urllib (only for GET), instead try using requests module, e.g.:

Example 1.0:

import requests

base_url="www.server.com"
final_url="/{0}/friendly/{1}/url".format(base_url,any_value_here)

payload = {'number': 2, 'value': 1}
response = requests.post(final_url, data=payload)

print(response.text) #TEXT/HTML
print(response.status_code, response.reason) #HTTP

Example 1.2:

>>> import requests

>>> payload = {'key1': 'value1', 'key2': 'value2'}

>>> r = requests.post("http://httpbin.org/post", data=payload)
>>> print(r.text)
{
  ...
  "form": {
    "key2": "value2",
    "key1": "value1"
  },
  ...
}

Example 1.3:

>>> import json

>>> url = 'https://api.github.com/some/endpoint'
>>> payload = {'some': 'data'}

>>> r = requests.post(url, data=json.dumps(payload))

If/else else if in Jquery for a condition

See this answer. val() is comparing a string, not a numeric value.

Anaconda site-packages

I encountered this issue in my conda environment. The reason is that packages have been installed into two different folders, only one of which is recognised by the Python executable.

~/anaconda2/envs/[my_env]/site-packages ~/anaconda2/envs/[my_env]/lib/python2.7/site-packages

A proved solution is to add both folders to python path, using the following steps in command line (Please replace [my_env] with your own environment):

  1. conda activate [my_env].
  2. conda-develop ~/anaconda2/envs/[my_env]/site-packages
  3. conda-develop ~/anaconda2/envs/[my_env]/lib/python2.7/site-packages (conda-develop is to add a .pth file to the folder so that the Python executable knows of this folder when searching for packages.)

To ensure this works, try to activate Python in this environment, and import the package that was not found.

Modulo operator with negative values

The sign in such cases (i.e when one or both operands are negative) is implementation-defined. The spec says in §5.6/4 (C++03),

The binary / operator yields the quotient, and the binary % operator yields the remainder from the division of the first expression by the second. If the second operand of / or % is zero the behavior is undefined; otherwise (a/b)*b + a%b is equal to a. If both operands are nonnegative then the remainder is nonnegative; if not, the sign of the remainder is implementation-defined.

That is all the language has to say, as far as C++03 is concerned.

Setting graph figure size

Write it as a one-liner:

figure('position', [0, 0, 200, 500])  % create new figure with specified size  

enter image description here

Search for executable files using find command

This worked for me & thought of sharing...

find ./ -type f -name "*" -not -name "*.o" -exec sh -c '
    case "$(head -n 1 "$1")" in
      ?ELF*) exit 0;;
      MZ*) exit 0;;
      #!*/ocamlrun*)exit0;;
    esac
exit 1
' sh {} \; -print

How can I create a temp file with a specific extension with .NET?

Based on answers I found from the internet, I come to my code as following:

public static string GetTemporaryFileName()
{       
    string tempFilePath = Path.Combine(Path.GetTempPath(), "SnapshotTemp");
    Directory.Delete(tempFilePath, true);
    Directory.CreateDirectory(tempFilePath);
    return Path.Combine(tempFilePath, DateTime.Now.ToString("MMddHHmm") + "-" + Guid.NewGuid().ToString() + ".png");
}

And as C# Cookbook by Jay Hilyard, Stephen Teilhet pointed in Using a Temporary File in Your Application:

  • you should use a temporary file whenever you need to store information temporarily for later retrieval.

  • The one thing you must remember is to delete this temporary file before the application that created it is terminated.

  • If it is not deleted, it will remain in the user’s temporary directory until the user manually deletes it.

Cannot find R.layout.activity_main

or you can write

import.R.layout // at the top

It will work for sure

socket.error:[errno 99] cannot assign requested address and namespace in python

when you bind localhost or 127.0.0.1, it means you can only connect to your service from local.

you cannot bind 10.0.0.1 because it not belong to you, you can only bind ip owned by your computer

you can bind 0.0.0.0 because it means all ip on your computer, so any ip can connect to your service if they can connect to any of your ip

Concatenate in jQuery Selector

Your concatenation syntax is correct.

Most likely the callback function isn't even being called. You can test that by putting an alert(), console.log() or debugger line in that function.

If it isn't being called, most likely there's an AJAX error. Look at chaining a .fail() handler after $.post() to find out what the error is, e.g.:

$.post('ajaxskeleton.php', {
    red: text       
}, function(){
    $('#part' + number).html(text);
}).fail(function(jqXHR, textStatus, errorThrown) {
    console.log(arguments);
});

Required attribute on multiple checkboxes with the same name?

A little jQuery fix:

$(function(){
    var chbxs = $(':checkbox[required]');
    var namedChbxs = {};
    chbxs.each(function(){
        var name = $(this).attr('name');
        namedChbxs[name] = (namedChbxs[name] || $()).add(this);
    });
    chbxs.change(function(){
        var name = $(this).attr('name');
        var cbx = namedChbxs[name];
        if(cbx.filter(':checked').length>0){
            cbx.removeAttr('required');
        }else{
            cbx.attr('required','required');
        }
    });
});

How to declare Return Types for Functions in TypeScript

External return type declaration to use with multiple functions:

type ValidationReturnType = string | boolean;

function isEqual(number1: number, number2: number): ValidationReturnType {
    return number1 == number2 ? true : 'Numbers are not equal.';
}

Test for array of string type in TypeScript

there is a little problem here because the

if (typeof item !== 'string') {
    return false
}

will not stop the foreach. So the function will return true even if the array does contain none string values.

This seems to wok for me:

function isStringArray(value: any): value is number[] {
  if (Object.prototype.toString.call(value) === '[object Array]') {
     if (value.length < 1) {
       return false;
     } else {
       return value.every((d: any) => typeof d === 'string');
     }
  }
  return false;
}

Greetings, Hans

Using Linq select list inside list

list.Where(m => m.application == "applicationName" && 
           m.users.Any(u => u.surname=="surname"));

if you want to filter users as TimSchmelter commented, you can use

list.Where(m => m.application == "applicationName")
    .Select(m => new Model
    {
        application = m.application,
        users = m.users.Where(u => u.surname=="surname").ToList()
    });

Javascript Drag and drop for touch devices

You can use the Jquery UI for drag and drop with an additional library that translates mouse events into touch which is what you need, the library I recommend is https://github.com/furf/jquery-ui-touch-punch, with this your drag and drop from Jquery UI should work on touch devises

or you can use this code which I am using, it also converts mouse events into touch and it works like magic.

function touchHandler(event) {
    var touch = event.changedTouches[0];

    var simulatedEvent = document.createEvent("MouseEvent");
        simulatedEvent.initMouseEvent({
        touchstart: "mousedown",
        touchmove: "mousemove",
        touchend: "mouseup"
    }[event.type], true, true, window, 1,
        touch.screenX, touch.screenY,
        touch.clientX, touch.clientY, false,
        false, false, false, 0, null);

    touch.target.dispatchEvent(simulatedEvent);
    event.preventDefault();
}

function init() {
    document.addEventListener("touchstart", touchHandler, true);
    document.addEventListener("touchmove", touchHandler, true);
    document.addEventListener("touchend", touchHandler, true);
    document.addEventListener("touchcancel", touchHandler, true);
}

And in your document.ready just call the init() function

code found from Here

Bash array with spaces in elements

I agree with others that it's likely how you're accessing the elements that is the problem. Quoting the file names in the array assignment is correct:

FILES=(
  "2011-09-04 21.43.02.jpg"
  "2011-09-05 10.23.14.jpg"
  "2011-09-09 12.31.16.jpg"
  "2011-09-11 08.43.12.jpg"
)

for f in "${FILES[@]}"
do
  echo "$f"
done

Using double quotes around any array of the form "${FILES[@]}" splits the array into one word per array element. It doesn't do any word-splitting beyond that.

Using "${FILES[*]}" also has a special meaning, but it joins the array elements with the first character of $IFS, resulting in one word, which is probably not what you want.

Using a bare ${array[@]} or ${array[*]} subjects the result of that expansion to further word-splitting, so you'll end up with words split on spaces (and anything else in $IFS) instead of one word per array element.

Using a C-style for loop is also fine and avoids worrying about word-splitting if you're not clear on it:

for (( i = 0; i < ${#FILES[@]}; i++ ))
do
  echo "${FILES[$i]}"
done

SQL Server : trigger how to read value for Insert, Update, Delete

Here is the syntax to create a trigger:

CREATE TRIGGER trigger_name
ON { table | view }
[ WITH ENCRYPTION ]
{
    { { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] }
        [ WITH APPEND ]
        [ NOT FOR REPLICATION ]
        AS
        [ { IF UPDATE ( column )
            [ { AND | OR } UPDATE ( column ) ]
                [ ...n ]
        | IF ( COLUMNS_UPDATED ( ) { bitwise_operator } updated_bitmask )
                { comparison_operator } column_bitmask [ ...n ]
        } ]
        sql_statement [ ...n ]
    }
} 

If you want to use On Update you only can do it with the IF UPDATE ( column ) section. That's not possible to do what you are asking.

TypeError: not all arguments converted during string formatting python

django raw sql query in view

"SELECT * FROM VendorReport_vehicledamage WHERE requestdate BETWEEN '{0}' AND '{1}'".format(date_from, date_to)

models.py

class VehicleDamage(models.Model):
    requestdate = models.DateTimeField("requestdate")
    vendor_name = models.CharField("vendor_name", max_length=50)
    class Meta:
        managed=False

views.py

def location_damageReports(request):
    #static date for testing
    date_from = '2019-11-01'
    date_to = '2019-21-01'
    vehicle_damage_reports = VehicleDamage.objects.raw("SELECT * FROM VendorReport_vehicledamage WHERE requestdate BETWEEN '{0}' AND '{1}'".format(date_from, date_to))
    damage_report = DashboardDamageReportSerializer(vehicle_damage_reports, many=True)
    data={"data": damage_report.data}
    return HttpResponse(json.dumps(data), content_type="application/json")

Note: using python 3.5 and django 1.11

How organize uploaded media in WP?

I don't believe this can be done "out of the box" in wordpress; The closest thing is storing media uploads by date-based subfolders, as per the option Organize my uploads into month- and year-based folders on the media settings screen.

Next best might be to create a "dummy" page hierarchy that serves as your folder tree, and then attach your images to these. This would give you a logical grouping, which could exist in relative isolation from your actual page or post hierarchy. But of course this won't give you the files organised like this in the file system, eg you couldn't of course FTP to this structure.

Otherwise I think you'll need to find a plugin or write something yourself to handle this.

Some plugins I found after a quick google for "wordpress plugin media folders":

While these might not be precisely what you want, they might give you clues/direction towards implementing something yourself. (Although that first one looks promising.)

Just FYI at least one similar question has been asked over on Wordpress.stackexchange:

https://wordpress.stackexchange.com/questions/13030/media-library-plugins-for-better-file-management

It might pay to have a good hunt about over there for something more substantial . Good luck!

How to convert a Base64 string into a Bitmap image to show it in a ImageView?

I have tried all the solutions and this one worked for me

let temp = base64String.components(separatedBy: ",")
let dataDecoded : Data = Data(base64Encoded: temp[1], options: 
 .ignoreUnknownCharacters)!
let decodedimage = UIImage(data: dataDecoded)

yourImage.image = decodedimage

catch forEach last iteration

const arr= [1, 2, 3]
arr.forEach(function(element){
 if(arr[arr.length-1] === element){
  console.log("Last Element")
 }
})

Android Imagebutton change Image OnClick

It is very simple

public void onClick(View v) {

        imgButton.setImageResource(R.drawable.ic_launcher);

    }

Using set Background image resource will chanage the background of the button

HTML Code for text checkbox '?'

Use the Unicode Character

&#10004;   =   ✔


EditText, inputType values (xml)

You can use the properties tab in eclipse to set various values.

here are all the possible values

  • none
  • text
  • textCapCharacters
  • textCapWords
  • textCapSentences
  • textAutoCorrect
  • textAutoComplete
  • textMultiLine
  • textImeMultiLine
  • textNoSuggestions
  • textUri
  • textEmailAddress
  • textEmailSubject
  • textShortMessage
  • textLongMessage
  • textPersonName
  • textPostalAddress
  • textPassword
  • textVisiblePassword
  • textWebEditText
  • textFilter
  • textPhonetic
  • textWebEmailAddress
  • textWebPassword
  • number
  • numberSigned
  • numberDecimal
  • numberPassword
  • phone
  • datetime
  • date
  • time

Check here for explanations: http://developer.android.com/reference/android/widget/TextView.html#attr_android:inputType

Checking if form has been submitted - PHP

Try this

 <form action="" method="POST" id="formaddtask">
      Add Task: <input type="text"name="newtaskname" />
      <input type="submit" value="Submit"/>
 </form>

    //Check if the form is submitted
    if($_SERVER['REQUEST_METHOD'] == 'POST' && !empty($_POST['newtaskname'])){

    }

What is an HttpHandler in ASP.NET

An HttpHandler (or IHttpHandler) is basically anything that is responsible for serving content. An ASP.NET page (aspx) is a type of handler.

You might write your own, for example, to serve images etc from a database rather than from the web-server itself, or to write a simple POX service (rather than SOAP/WCF/etc)

Check whether a value is a number in JavaScript or jQuery

function isNumber(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

show more/Less text with just HTML and JavaScript

I'm not an expert, but I did a lot of looking to implement this for myself. I found something different, but modified it to accomplish this. It's really quite simple:

The function takes two arguments, a div containing only the words "show more" [or whatever] and a div containing the originally hidden text and the words "show less." The function displays the one div and hides the other.

NOTE: If more than one show/hide on page, assign different ids to divs Colors can be changed

<p>Here is text that is originally displayed</p>

<div id="div1">
<p style="color:red;" onclick="showFunction('div2','div1')">show more</p></div>
<div id="div2" style="display:none">

<p>Put expanded text here</p>

<p style="color:red;" onclick="showFunction('div1','div2')">show less</p></div>

<p>more text</p>

Here is the Script:

<script>
function showFunction(diva, divb) {
    var x = document.getElementById(diva);
    var y = document.getElementById(divb);
          x.style.display = 'block';
          y.style.display = 'none';
}
</script>

How do I open a new window using jQuery?

Those are by no means the same. The first will simply send you to whatever URL you have assigned to window.location.href (in the same window you're currently in). The second makes a GET AJAX request.

Try this page: http://www.codebelt.com/jquery/open-new-browser-window-with-jquery-custom-size/

It gives a great example on how to open a new window*.

If you wish to use raw javascript then this is what you're looking for:

window.open(URL,name,specs,replace)

As seen in http://www.w3schools.com/jsref/met_win_open.asp

CSS - make div's inherit a height

The Problem

When an element is floated, its parent no longer contains it because the float is removed from the flow. The floated element is out of the natural flow, so all block elements will render as if the floated element is not even there, so a parent container will not fully expand to hold the floated child element.

Take a look at the following article to get a better idea of how the CSS Float property works:

The Mystery Of The CSS Float Property


A Potential Solution

Now, I think the following article resembles what you're trying to do. Take a look at it and see if you can solve your problem.

Equal Height Columns with Cross-Browser CSS

I hope this helps.

Difference between RegisterStartupScript and RegisterClientScriptBlock?

Here's an old discussion thread where I listed the main differences and the conditions in which you should use each of these methods. I think you may find it useful to go through the discussion.

To explain the differences as relevant to your posted example:

a. When you use RegisterStartupScript, it will render your script after all the elements in the page (right before the form's end tag). This enables the script to call or reference page elements without the possibility of it not finding them in the Page's DOM.

Here is the rendered source of the page when you invoke the RegisterStartupScript method:

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1"><title></title></head>
<body>
    <form name="form1" method="post" action="StartupScript.aspx" id="form1">
        <div>
            <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="someViewstategibberish" />
        </div>
        <div> <span id="lblDisplayDate">Label</span>
            <br />
            <input type="submit" name="btnPostback" value="Register Startup Script" id="btnPostback" />
            <br />
            <input type="submit" name="btnPostBack2" value="Register" id="btnPostBack2" />
        </div>
        <div>
            <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="someViewstategibberish" />
        </div>
        <!-- Note this part -->
        <script language='javascript'>
            var lbl = document.getElementById('lblDisplayDate');
            lbl.style.color = 'red';
        </script>
    </form>
    <!-- Note this part -->
</body>
</html>

b. When you use RegisterClientScriptBlock, the script is rendered right after the Viewstate tag, but before any of the page elements. Since this is a direct script (not a function that can be called, it will immediately be executed by the browser. But the browser does not find the label in the Page's DOM at this stage and hence you should receive an "Object not found" error.

Here is the rendered source of the page when you invoke the RegisterClientScriptBlock method:

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1"><title></title></head>
<body>
    <form name="form1" method="post" action="StartupScript.aspx" id="form1">
        <div>
            <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="someViewstategibberish" />
        </div>
        <script language='javascript'>
            var lbl = document.getElementById('lblDisplayDate');
            // Error is thrown in the next line because lbl is null.
            lbl.style.color = 'green';

Therefore, to summarize, you should call the latter method if you intend to render a function definition. You can then render the call to that function using the former method (or add a client side attribute).

Edit after comments:


For instance, the following function would work:

protected void btnPostBack2_Click(object sender, EventArgs e) 
{ 
  System.Text.StringBuilder sb = new System.Text.StringBuilder(); 
  sb.Append("<script language='javascript'>function ChangeColor() {"); 
  sb.Append("var lbl = document.getElementById('lblDisplayDate');"); 
  sb.Append("lbl.style.color='green';"); 
  sb.Append("}</script>"); 

  //Render the function definition. 
  if (!ClientScript.IsClientScriptBlockRegistered("JSScriptBlock")) 
  {
    ClientScript.RegisterClientScriptBlock(this.GetType(), "JSScriptBlock", sb.ToString()); 
  }

  //Render the function invocation. 
  string funcCall = "<script language='javascript'>ChangeColor();</script>"; 

  if (!ClientScript.IsStartupScriptRegistered("JSScript"))
  { 
    ClientScript.RegisterStartupScript(this.GetType(), "JSScript", funcCall); 
  } 
} 

Running a cron every 30 seconds

Why not just adding 2 consecutive command entries, both starting at different second?

0 * * * * /bin/bash -l -c 'cd /srv/last_song/releases/20120308133159 && script/rails runner -e production '\''Song.insert_latest'\'''
30 * * * * /bin/bash -l -c 'cd /srv/last_song/releases/20120308133159 && script/rails runner -e production '\''Song.insert_latest'\'''

jQuery count number of divs with a certain class?

And for the plain js answer if anyone might be interested;

var count = document.getElementsByClassName("item");

Cheers.

Reference: https://www.w3schools.com/jsref/met_document_getelementsbyclassname.asp

What is SuppressWarnings ("unchecked") in Java?

A warning by which the compiler indicates that it cannot ensure type safety. The term "unchecked" warning is misleading. It does not mean that the warning is unchecked in any way. The term "unchecked" refers to the fact that the compiler and the runtime system do not have enough type information to perform all type checks that would be necessary to ensure type safety. In this sense, certain operations are "unchecked".

The most common source of "unchecked" warnings is the use of raw types. "unchecked" warnings are issued when an object is accessed through a raw type variable, because the raw type does not provide enough type information to perform all necessary type checks.

Example (of unchecked warning in conjunction with raw types):

TreeSet set = new TreeSet(); 
set.add("abc");        // unchecked warning 
set.remove("abc");
warning: [unchecked] unchecked call to add(E) as a member of the raw type java.util.TreeSet 
               set.add("abc");  
                      ^

When the add method is invoked the compiler does not know whether it is safe to add a String object to the collection. If the TreeSet is a collection that contains String s (or a supertype thereof), then it would be safe. But from the type information provided by the raw type TreeSet the compiler cannot tell. Hence the call is potentially unsafe and an "unchecked" warning is issued.

"unchecked" warnings are also reported when the compiler finds a cast whose target type is either a parameterized type or a type parameter.

Example (of an unchecked warning in conjunction with a cast to a parameterized type or type variable):

  class Wrapper<T> { 
  private T wrapped ; 
  public Wrapper (T arg) {wrapped = arg;} 
  ... 
  public Wrapper <T> clone() { 
    Wrapper<T> clon = null; 
     try {  
       clon = (Wrapper<T>) super.clone(); // unchecked warning 
     } catch (CloneNotSupportedException e) {  
       throw new InternalError();  
     } 
     try {  
       Class<?> clzz = this.wrapped.getClass(); 
       Method   meth = clzz.getMethod("clone", new Class[0]); 
       Object   dupl = meth.invoke(this.wrapped, new Object[0]); 
       clon.wrapped = (T) dupl; // unchecked warning 
     } catch (Exception e) {} 
     return clon; 
  } 
} 
warning: [unchecked] unchecked cast 
found   : java.lang.Object 
required: Wrapper <T> 
                  clon = ( Wrapper <T>)super.clone();  
                                                ^ 
warning: [unchecked] unchecked cast 
found   : java.lang.Object 
required: T 
                  clon. wrapped = (T)dupl;

A cast whose target type is either a (concrete or bounded wildcard) parameterized type or a type parameter is unsafe, if a dynamic type check at runtime is involved. At runtime, only the type erasure is available, not the exact static type that is visible in the source code. As a result, the runtime part of the cast is performed based on the type erasure, not on the exact static type.

In the example, the cast to Wrapper would check whether the object returned from super.clone is a Wrapper , not whether it is a wrapper with a particular type of members. Similarly, the casts to the type parameter T are cast to type Object at runtime, and probably optimized away altogether. Due to type erasure, the runtime system is unable to perform more useful type checks at runtime.

In a way, the source code is misleading, because it suggests that a cast to the respective target type is performed, while in fact the dynamic part of the cast only checks against the type erasure of the target type. The "unchecked" warning is issued to draw the programmer's attention to this mismatch between the static and dynamic aspect of the cast.

Please refer: What is an "unchecked" warning?

How to push changes to github after jenkins build completes?

Actually, the "Checkout to specific local branch" from Claus's answer isn't needed as well.

You can just do changes, execute git commit -am "message" and then use "Git Publisher" with "Branch to push" = /refs/heads/master (or develop or whatever branch you need to push to), "Target remote name" = origin.

Best practice when adding whitespace in JSX

If the goal is to seperate two elements, you can use CSS like below:

A<span style={{paddingLeft: '20px'}}>B</span>

Creating Accordion Table with Bootstrap

For anyone who came here looking for how to get the true accordion effect and only allow one row to be expanded at a time, you can add an event handler for show.bs.collapse like so:

$('.collapse').on('show.bs.collapse', function () {
    $('.collapse.in').collapse('hide');
});

I modified this example to do so here: http://jsfiddle.net/QLfMU/116/

How to initialize a vector with fixed length in R

If you want to initialize a vector with numeric values other than zero, use rep

n <- 10
v <- rep(0.05, n)
v

which will give you:

[1] 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05

Cordova : Requirements check failed for JDK 1.8 or greater

Uninstall all previous JDK including 1.8 Install JDK 1.8

Properties order in Margin

Margin="1,2,3,4"
  1. Left,
  2. Top,
  3. Right,
  4. Bottom

It is also possible to specify just two sizes like this:

Margin="1,2"
  1. Left AND right
  2. Top AND bottom

Finally you can specify a single size:

Margin="1"
  1. used for all sides

The order is the same as in WinForms.

Convert IQueryable<> type object to List<T> type?

The List class's constructor can convert an IQueryable for you:

public static List<TResult> ToList<TResult>(this IQueryable source)
{
    return new List<TResult>(source);
}

or you can just convert it without the extension method, of course:

var list = new List<T>(queryable);

How can I INSERT data into two tables simultaneously in SQL Server?

You could write a stored procedure that iterates over the transaction that you have proposed. The iterator would be the cursor for the table that contains the source data.

Windows-1252 to UTF-8 encoding

Use the iconv command.

To make sure the file is in Windows-1252, open it in Notepad (under Windows), then click Save As. Notepad suggests current encoding as the default; if it's Windows-1252 (or any 1-byte codepage, for that matter), it would say "ANSI".

What is the equivalent of Java's System.out.println() in Javascript?

console.log().

Chrome, Safari, and IE 8+ come with built-in consoles (as part of a larger set of development tools). If you're using Firefox, getfirebug.com.

How to compare times in Python?

datetime have comparison capability

>>> import datetime
>>> import time
>>> a =  datetime.datetime.now()
>>> time.sleep(2.0)
>>> b =  datetime.datetime.now()
>>> print a < b
True
>>> print a == b
False

what is numeric(18, 0) in sql server 2008 r2

This page explains it pretty well.

As a numeric the allowable range that can be stored in that field is -10^38 +1 to 10^38 - 1.

The first number in parentheses is the total number of digits that will be stored. Counting both sides of the decimal. In this case 18. So you could have a number with 18 digits before the decimal 18 digits after the decimal or some combination in between.

The second number in parentheses is the total number of digits to be stored after the decimal. Since in this case the number is 0 that basically means only integers can be stored in this field.

So the range that can be stored in this particular field is -(10^18 - 1) to (10^18 - 1)

Or -999999999999999999 to 999999999999999999 Integers only

Selector on background color of TextView

For who is searching to do it without creating a background sector, just add those lines to the TextView

android:background="?android:attr/selectableItemBackground"
android:clickable="true"

Also to make it selectable use:

android:textIsSelectable="true"

Syntax behind sorted(key=lambda: ...)

Since the usage of lambda was asked in the context of sorted(), take a look at this as well https://wiki.python.org/moin/HowTo/Sorting/#Key_Functions