Programs & Examples On #Keyboard layout

How to put/get multiple JSONObjects to JSONArray?

From android API Level 19, when I want to instance JSONArray object I put JSONObject directly as parameter like below:

JSONArray jsonArray=new JSONArray(jsonObject);

JSONArray has constructor to accept object.

How to filter array in subdocument with MongoDB

Above solution works best if multiple matching sub documents are required. $elemMatch also comes in very use if single matching sub document is required as output

db.test.find({list: {$elemMatch: {a: 1}}}, {'list.$': 1})

Result:

{
  "_id": ObjectId("..."),
  "list": [{a: 1}]
}

Eclipse Generate Javadoc Wizard: what is "Javadoc Command"?

Had this problem and solved typing this : C:\Program Files (x86)\Java\jdk1.7.0_51\bin\javadoc.exe

what is right way to do API call in react js?

This part from React v16 documentation will answer your question, read on about componentDidMount():

componentDidMount()

componentDidMount() is invoked immediately after a component is mounted. Initialization that requires DOM nodes should go here. If you need to load data from a remote endpoint, this is a good place to instantiate the network request. This method is a good place to set up any subscriptions. If you do that, don’t forget to unsubscribe in componentWillUnmount().

As you see, componentDidMount is considered the best place and cycle to do the api call, also access the node, means by this time it's safe to do the call, update the view or whatever you could do when document is ready, if you are using jQuery, it should somehow remind you document.ready() function, where you could make sure everything is ready for whatever you want to do in your code...

How to write connection string in web.config file and read from it?

After opening the web.config file in application, add sample db connection in connectionStrings section like this:

<connectionStrings>  
    <add name="yourconnectinstringName" connectionString="Data Source= DatabaseServerName; Integrated Security=true;Initial Catalog= YourDatabaseName; uid=YourUserName; Password=yourpassword; " providerName="System.Data.SqlClient" />   
</connectionStrings>  

Declaring connectionStrings in web.config file:

 <add name="dbconnection" connectionString="Data Source=Soumalya;Integrated Security=true;Initial Catalog=MySampleDB" providerName="System.Data.SqlClient" />   

There is no need of username and password to access the database server. Now, write the code to get the connection string from web.config file in our codebehind file. Add the following namespace in codebehind file.

using System.Configuration;

This namespace is used to get configuration section details from web.config file.

using System;  
using System.Data.SqlClient;  
using System.Configuration;  
public partial class _Default: System.Web.UI.Page {  
    protected void Page_Load(object sender, EventArgs e) {  
        //Get connection string from web.config file  
        string strcon = ConfigurationManager.ConnectionStrings["dbconnection"].ConnectionString;  
        //create new sqlconnection and connection to database by using connection string from web.config file  
        SqlConnection con = new SqlConnection(strcon);  
        con.Open();  
    }  
}  

How can I download HTML source in C#

basically:

using System.Net;
using System.Net.Http;  // in LINQPad, also add a reference to System.Net.Http.dll

WebRequest req = HttpWebRequest.Create("http://google.com");
req.Method = "GET";

string source;
using (StreamReader reader = new StreamReader(req.GetResponse().GetResponseStream()))
{
    source = reader.ReadToEnd();
}

Console.WriteLine(source);

How to make a countdown timer in Android?

Try this way:

private void startTimer() {
    startTimer = new CountDownTimer(30000, 1000) {

        public void onTick(long millisUntilFinished) {

            long sec = (TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) -
 TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished)));

            Log.e(TAG, "onTick: "+sec );
            tv_timer.setText(String.format("( %02d SEC )", sec));
            if(sec == 1)
            {

                new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        tv_timer.setText("( 00 SEC )");
                    }
                }, 1000);
            }


        }

        public void onFinish() {
            tv_timer.setText("Timer finish");
        }
    }.start();
}

Using generic std::function objects with member functions in one class

Unfortunately, C++ does not allow you to directly get a callable object referring to an object and one of its member functions. &Foo::doSomething gives you a "pointer to member function" which refers to the member function but not the associated object.

There are two ways around this, one is to use std::bind to bind the "pointer to member function" to the this pointer. The other is to use a lambda that captures the this pointer and calls the member function.

std::function<void(void)> f = std::bind(&Foo::doSomething, this);
std::function<void(void)> g = [this](){doSomething();};

I would prefer the latter.

With g++ at least binding a member function to this will result in an object three-pointers in size, assigning this to an std::function will result in dynamic memory allocation.

On the other hand, a lambda that captures this is only one pointer in size, assigning it to an std::function will not result in dynamic memory allocation with g++.

While I have not verified this with other compilers, I suspect similar results will be found there.

How do I disable "missing docstring" warnings at a file-level in Pylint?

  1. Ctrl + Shift + P

  2. Then type and click on > preferences:configure language specific settings

  3. and then type "python" after that. Paste the code

     {
         "python.linting.pylintArgs": [
             "--load-plugins=pylint_django", "--errors-only"
         ],
     }
    

How To Set Up GUI On Amazon EC2 Ubuntu server

So I follow first answer, but my vnc viewer gives me grey screen when I connect to it. And I found this Ask Ubuntu link to solve that.

The only difference with previous answer is you need to install these extra packages:

apt-get install gnome-panel gnome-settings-daemon metacity nautilus gnome-terminal

And use this ~/.vnc/xstartup file:

#!/bin/sh

export XKL_XMODMAP_DISABLE=1
unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS

[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &

gnome-panel &
gnome-settings-daemon &
metacity &
nautilus &
gnome-terminal &

Everything else is the same.

Tested on EC2 Ubuntu 14.04 LTS.

Most concise way to convert a Set<T> to a List<T>

Try this for Set:

Set<String> listOfTopicAuthors = .....
List<String> setList = new ArrayList<String>(listOfTopicAuthors); 

Try this for Map:

Map<String, String> listOfTopicAuthors = .....
// List of values:
List<String> mapValueList = new ArrayList<String>(listOfTopicAuthors.values());
// List of keys:
List<String> mapKeyList = new ArrayList<String>(listOfTopicAuthors.KeySet());

How to detect duplicate values in PHP array?

To get rid use array_unique(). To detect if have any use count(array_unique()) and compare to count($array).

A url resource that is a dot (%2E)

It's actually not really clearly stated in the standard (RFC 3986) whether a percent-encoded version of . or .. is supposed to have the same this-folder/up-a-folder meaning as the unescaped version. Section 3.3 only talks about “The path segments . and ..”, without clarifying whether they match . and .. before or after pct-encoding.

Personally I find Firefox's interpretation that %2E does not mean . most practical, but unfortunately all the other browsers disagree. This would mean that you can't have a path component containing only . or ...

I think the only possible suggestion is “don't do that”! There are other path components that are troublesome too, typically due to server limitations: %2F, %00 and %5C sequences in paths may also be blocked by some web servers, and the empty path segment can also cause problems. So in general it's not possible to fit all possible byte sequences into a path component.

Disable SSL fallback and use only TLS for outbound connections in .NET? (Poodle mitigation)

@Eddie Loeffen's answer seems to be the most popular answer to this question, but it has some bad long term effects. If you review the documentation page for System.Net.ServicePointManager.SecurityProtocol here the remarks section implies that the negotiation phase should just address this (and forcing the protocol is bad practice because in the future, TLS 1.2 will be compromised as well). However, we wouldn't be looking for this answer if it did.

Researching, it appears that the ALPN negotiation protocol is required to get to TLS1.2 in the negotiation phase. We took that as our starting point and tried newer versions of the .Net framework to see where support starts. We found that .Net 4.5.2 does not support negotiation to TLS 1.2, but .Net 4.6 does.

So, even though forcing TLS1.2 will get the job done now, I recommend that you upgrade to .Net 4.6 instead. Since this is a PCI DSS issue for June 2016, the window is short, but the new framework is a better answer.

UPDATE: Working from the comments, I built this:

ServicePointManager.SecurityProtocol = 0;    
foreach (SecurityProtocolType protocol in SecurityProtocolType.GetValues(typeof(SecurityProtocolType)))
    {
        switch (protocol)
        {
            case SecurityProtocolType.Ssl3:
            case SecurityProtocolType.Tls:
            case SecurityProtocolType.Tls11:
                break;
            default:
                ServicePointManager.SecurityProtocol |= protocol;
            break;
        }
    }

In order to validate the concept, I or'd together SSL3 and TLS1.2 and ran the code targeting a server that supports only TLS 1.0 and TLS 1.2 (1.1 is disabled). With the or'd protocols, it seems to connect fine. If I change to SSL3 and TLS 1.1, that failed to connect. My validation uses HttpWebRequest from System.Net and just calls GetResponse(). For instance, I tried this and failed:

        HttpWebRequest request = WebRequest.Create("https://www.contoso.com/my/web/resource") as HttpWebRequest;
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls11;
        request.GetResponse();

while this worked:

        HttpWebRequest request = WebRequest.Create("https://www.contoso.com/my/web/resource") as HttpWebRequest;
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls12;
        request.GetResponse();

This has an advantage over forcing TLS 1.2 in that, if the .Net framework is upgraded so that there are more entries in the Enum, they will be supported by the code as is. It has a disadvantage over just using .Net 4.6 in that 4.6 uses ALPN and should support new protocols if no restriction is specified.

Edit 4/29/2019 - Microsoft published this article last October. It has a pretty good synopsis of their recommendation of how this should be done in the various versions of .net framework.

"Could not find bundler" error

Make sure you're entering "bundle" update, if you have the bundler gem installed.

bundle update

If you don't have bundler installed, do gem install bundler.

How to create dynamic href in react render function?

You can use ES6 backtick syntax too

<a href={`/customer/${item._id}`} >{item.get('firstName')} {item.get('lastName')}</a>

More info on es6 template literals

How to select rows with no matching entry in another table?

I Dont Knew Which one Is Optimized (compared to @AdaTheDev ) but This one seems to be quicker when I use (atleast for me)

SELECT id  FROM  table_1 EXCEPT SELECT DISTINCT (table1_id) table1_id FROM table_2

If You want to get any other specific attribute you can use:

SELECT COUNT(*) FROM table_1 where id in (SELECT id  FROM  table_1 EXCEPT SELECT DISTINCT (table1_id) table1_id FROM table_2);

C# Test if user has write access to a folder

I faced the same problem: how to verify if I can read/write in a particular directory. I ended up with the easy solution to...actually test it. Here is my simple though effective solution.

 class Program
{

    /// <summary>
    /// Tests if can read files and if any are present
    /// </summary>
    /// <param name="dirPath"></param>
    /// <returns></returns>
    private genericResponse check_canRead(string dirPath)
    {
        try
        {
            IEnumerable<string> files = Directory.EnumerateFiles(dirPath);
            if (files.Count().Equals(0))
                return new genericResponse() { status = true, idMsg = genericResponseType.NothingToRead };

            return new genericResponse() { status = true, idMsg = genericResponseType.OK };
        }
        catch (DirectoryNotFoundException ex)
        {

            return new genericResponse() { status = false, idMsg = genericResponseType.ItemNotFound };

        }
        catch (UnauthorizedAccessException ex)
        {

            return new genericResponse() { status = false, idMsg = genericResponseType.CannotRead };

        }

    }

    /// <summary>
    /// Tests if can wirte both files or Directory
    /// </summary>
    /// <param name="dirPath"></param>
    /// <returns></returns>
    private genericResponse check_canWrite(string dirPath)
    {

        try
        {
            string testDir = "__TESTDIR__";
            Directory.CreateDirectory(string.Join("/", dirPath, testDir));

            Directory.Delete(string.Join("/", dirPath, testDir));


            string testFile = "__TESTFILE__.txt";
            try
            {
                TextWriter tw = new StreamWriter(string.Join("/", dirPath, testFile), false);
                tw.WriteLine(testFile);
                tw.Close();
                File.Delete(string.Join("/", dirPath, testFile));

                return new genericResponse() { status = true, idMsg = genericResponseType.OK };
            }
            catch (UnauthorizedAccessException ex)
            {

                return new genericResponse() { status = false, idMsg = genericResponseType.CannotWriteFile };

            }


        }
        catch (UnauthorizedAccessException ex)
        {

            return new genericResponse() { status = false, idMsg = genericResponseType.CannotWriteDir };

        }
    }


}

public class genericResponse
{

    public bool status { get; set; }
    public genericResponseType idMsg { get; set; }
    public string msg { get; set; }

}

public enum genericResponseType
{

    NothingToRead = 1,
    OK = 0,
    CannotRead = -1,
    CannotWriteDir = -2,
    CannotWriteFile = -3,
    ItemNotFound = -4

}

Hope it helps !

Difference between Amazon EC2 and AWS Elastic Beanstalk

First off, EC2 and Elastic Compute Cloud are the same thing.

Next, AWS encompasses the range of Web Services that includes EC2 and Elastic Beanstalk. It also includes many others such as S3, RDS, DynamoDB, and all the others.

EC2

EC2 is Amazon's service that allows you to create a server (AWS calls these instances) in the AWS cloud. You pay by the hour and only what you use. You can do whatever you want with this instance as well as launch n number of instances.

Elastic Beanstalk

Elastic Beanstalk is one layer of abstraction away from the EC2 layer. Elastic Beanstalk will setup an "environment" for you that can contain a number of EC2 instances, an optional database, as well as a few other AWS components such as a Elastic Load Balancer, Auto-Scaling Group, Security Group. Then Elastic Beanstalk will manage these items for you whenever you want to update your software running in AWS. Elastic Beanstalk doesn't add any cost on top of these resources that it creates for you. If you have 10 hours of EC2 usage, then all you pay is 10 compute hours.

Running Wordpress

For running Wordpress, it is whatever you are most comfortable with. You could run it straight on a single EC2 instance, you could use a solution from the AWS Marketplace, or you could use Elastic Beanstalk.

What to pick?

In the case that you want to reduce system operations and just focus on the website, then Elastic Beanstalk would be the best choice for that. Elastic Beanstalk supports a PHP stack (as well as others). You can keep your site in version control and easily deploy to your environment whenever you make changes. It will also setup an Autoscaling group which can spawn up more EC2 instances if traffic is growing.

Here's the first result off of Google when searching for "elastic beanstalk wordpress": https://www.otreva.com/blog/deploying-wordpress-amazon-web-services-aws-ec2-rds-via-elasticbeanstalk/

Two dimensional array in python

a = [[] for index in range(1, n)]

Create session factory in Hibernate 4

The method buildSessionFactory is deprecated from the Hibernate 4 release and it is replaced with the new API. If you are using the Hibernate 4.3.0 and above, your code has to be:

Configuration configuration = new Configuration().configure();

StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder()
        .applySettings(configuration.getProperties());

SessionFactory factory = configuration.buildSessionFactory(builder.build());

How to create an empty array in Swift?

Here you go:

var yourArray = [String]()

The above also works for other types and not just strings. It's just an example.

Adding Values to It

I presume you'll eventually want to add a value to it!

yourArray.append("String Value")

Or

let someString = "You can also pass a string variable, like this!"
yourArray.append(someString)

Add by Inserting

Once you have a few values, you can insert new values instead of appending. For example, if you wanted to insert new objects at the beginning of the array (instead of appending them to the end):

yourArray.insert("Hey, I'm first!", atIndex: 0)

Or you can use variables to make your insert more flexible:

let lineCutter = "I'm going to be first soon."
let positionToInsertAt = 0
yourArray.insert(lineCutter, atIndex: positionToInsertAt)

You May Eventually Want to Remove Some Stuff

var yourOtherArray = ["MonkeysRule", "RemoveMe", "SwiftRules"]
yourOtherArray.remove(at: 1)

The above works great when you know where in the array the value is (that is, when you know its index value). As the index values begin at 0, the second entry will be at index 1.

Removing Values Without Knowing the Index

But what if you don't? What if yourOtherArray has hundreds of values and all you know is you want to remove the one equal to "RemoveMe"?

if let indexValue = yourOtherArray.index(of: "RemoveMe") {
    yourOtherArray.remove(at: indexValue)
}

This should get you started!

How do I increase the RAM and set up host-only networking in Vagrant?

To increase the memory or CPU count when using Vagrant 2, add this to your Vagrantfile

Vagrant.configure("2") do |config|
    # usual vagrant config here

    config.vm.provider "virtualbox" do |v|
        v.memory = 1024
        v.cpus = 2
    end
end

Github "Updates were rejected because the remote contains work that you do not have locally."

You may refer to: How to deal with "refusing to merge unrelated histories" error:

$ git pull --allow-unrelated-histories
$ git push -f origin master

Awk if else issues

Try the code

awk '{s=($3==0)?"-":$3/$4; print s}'

How to replace a set of tokens in a Java String?

String.format("Hello %s Please find attached %s which is due on %s", name, invoice, date)

Python threading. How do I lock a thread?

import threading 

# global variable x 
x = 0

def increment(): 
    """ 
    function to increment global variable x 
    """
    global x 
    x += 1

def thread_task(): 
    """ 
    task for thread 
    calls increment function 100000 times. 
    """
    for _ in range(100000): 
        increment() 

def main_task(): 
    global x 
    # setting global variable x as 0 
    x = 0

    # creating threads 
    t1 = threading.Thread(target=thread_task) 
    t2 = threading.Thread(target=thread_task) 

    # start threads 
    t1.start() 
    t2.start() 

    # wait until threads finish their job 
    t1.join() 
    t2.join() 

if __name__ == "__main__": 
    for i in range(10): 
        main_task() 
        print("Iteration {0}: x = {1}".format(i,x))

Auto populate columns in one sheet from another sheet

In Google Sheets you can use =ArrayFormula(Sheet1!B2:B)on the first cell and it will populate all column contents not sure if that will work in excel

Android 6.0 multiple permissions

Here is detailed example with multiple permission requests:-

The app needs 2 permissions at startup . SEND_SMS and ACCESS_FINE_LOCATION (both are mentioned in manifest.xml).

I am using Support Library v4 which is prepared to handle Android pre-Marshmallow and so no need to check build versions.

As soon as the app starts up, it asks for multiple permissions together. If both permissions are granted the normal flow goes.

enter image description here

enter image description here

public static final int REQUEST_ID_MULTIPLE_PERMISSIONS = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if(checkAndRequestPermissions()) {
        // carry on the normal flow, as the case of  permissions  granted.
    }
}

private  boolean checkAndRequestPermissions() {
    int permissionSendMessage = ContextCompat.checkSelfPermission(this,
            Manifest.permission.SEND_SMS);
    int locationPermission = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
    List<String> listPermissionsNeeded = new ArrayList<>();
    if (locationPermission != PackageManager.PERMISSION_GRANTED) {
        listPermissionsNeeded.add(Manifest.permission.ACCESS_FINE_LOCATION);
    }
    if (permissionSendMessage != PackageManager.PERMISSION_GRANTED) {
        listPermissionsNeeded.add(Manifest.permission.SEND_SMS);
    }
    if (!listPermissionsNeeded.isEmpty()) {
        ActivityCompat.requestPermissions(this, listPermissionsNeeded.toArray(new String[listPermissionsNeeded.size()]),REQUEST_ID_MULTIPLE_PERMISSIONS);
        return false;
    }
    return true;
}

ContextCompat.checkSelfPermission(), ActivityCompat.requestPermissions(), ActivityCompat.shouldShowRequestPermissionRationale() are part of support library.

In case one or more permissions are not granted, ActivityCompat.requestPermissions() will request permissions and the control goes to onRequestPermissionsResult() callback method.

You should check the value of shouldShowRequestPermissionRationale() flag in onRequestPermissionsResult() callback method.

There are only two cases:--

Case 1:-Any time user clicks Deny permissions (including the very first time), it will return true. So when the user denies, we can show more explanation and keep asking again

Case 2:-Only if user select “never asks again” it will return false. In this case, we can continue with limited functionality and guide user to activate the permissions from settings for more functionalities, or we can finish the setup, if the permissions are trivial for the app.

CASE -1

enter image description here

CASE-2

enter image description here

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        Log.d(TAG, "Permission callback called-------");
        switch (requestCode) {
            case REQUEST_ID_MULTIPLE_PERMISSIONS: {

                Map<String, Integer> perms = new HashMap<>();
                // Initialize the map with both permissions
                perms.put(Manifest.permission.SEND_SMS, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.ACCESS_FINE_LOCATION, PackageManager.PERMISSION_GRANTED);
                // Fill with actual results from user
                if (grantResults.length > 0) {
                    for (int i = 0; i < permissions.length; i++)
                        perms.put(permissions[i], grantResults[i]);
                    // Check for both permissions
                    if (perms.get(Manifest.permission.SEND_SMS) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                        Log.d(TAG, "sms & location services permission granted");
                        // process the normal flow
                        //else any one or both the permissions are not granted
                    } else {
                            Log.d(TAG, "Some permissions are not granted ask again ");
                            //permission is denied (this is the first time, when "never ask again" is not checked) so ask again explaining the usage of permission
//                        // shouldShowRequestPermissionRationale will return true
                            //show the dialog or snackbar saying its necessary and try again otherwise proceed with setup.
                            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.SEND_SMS) || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)) {
                                showDialogOK("SMS and Location Services Permission required for this app",
                                        new DialogInterface.OnClickListener() {
                                            @Override
                                            public void onClick(DialogInterface dialog, int which) {
                                                switch (which) {
                                                    case DialogInterface.BUTTON_POSITIVE:
                                                        checkAndRequestPermissions();
                                                        break;
                                                    case DialogInterface.BUTTON_NEGATIVE:
                                                        // proceed with logic by disabling the related features or quit the app.
                                                        break;
                                                }
                                            }
                                        });
                            }
                            //permission is denied (and never ask again is  checked)
                            //shouldShowRequestPermissionRationale will return false
                            else {
                                Toast.makeText(this, "Go to settings and enable permissions", Toast.LENGTH_LONG)
                                        .show();
    //                            //proceed with logic by disabling the related features or quit the app.
                            }
                    }
                }
            }
        }

    }

    private void showDialogOK(String message, DialogInterface.OnClickListener okListener) {
        new AlertDialog.Builder(this)
                .setMessage(message)
                .setPositiveButton("OK", okListener)
                .setNegativeButton("Cancel", okListener)
                .create()
                .show();
    }

How can I remove an element from a list, with lodash?

As lyyons pointed out in the comments, more idiomatic and lodashy way to do this would be to use _.remove, like this

_.remove(obj.subTopics, {
    subTopicId: stToDelete
});

Apart from that, you can pass a predicate function whose result will be used to determine if the current element has to be removed or not.

_.remove(obj.subTopics, function(currentObject) {
    return currentObject.subTopicId === stToDelete;
});

Alternatively, you can create a new array by filtering the old one with _.filter and assign it to the same object, like this

obj.subTopics = _.filter(obj.subTopics, function(currentObject) {
    return currentObject.subTopicId !== stToDelete;
});

Or

obj.subTopics = _.filter(obj.subTopics, {subTopicId: stToKeep});

Go to next item in ForEach-Object

I know this is an old post, but I wanted to add something I learned for the next folks who land here while googling.

In Powershell 5.1, you want to use continue to move onto the next item in your loop. I tested with 6 items in an array, had a foreach loop through, but put an if statement with:

foreach($i in $array){    
    write-host -fore green "hello $i"
    if($i -like "something"){
        write-host -fore red "$i is bad"
        continue
        write-host -fore red "should not see this"
    }
}

Of the 6 items, the 3rd one was something. As expected, it looped through the first 2, then the matching something gave me the red line where $i matched, I saw something is bad and then it went on to the next item in the array without saying should not see this. I tested with return and it exited the loop altogether.

center image in div with overflow hidden

Most recent solution:

HTML

<div class="parent">
    <img src="image.jpg" height="600" width="600"/>
</div>

CSS

.parent {
    width: 200px;
    height: 200px;
    overflow: hidden;
    /* Magic */
    display: flex;
    align-items: center; /* vertical */
    justify-content: center; /* horizontal */
}

Removing the title text of an iOS UIBarButtonItem

This works for me to display just the 'back' chevron without any text:

self.navigationController.navigationBar.topItem.title = @"";

Set this property in viewDidLoad of the View Controller presenting the navigation bar and it will do the trick.

Note: I have only tested it in iOS 7, which is within scope of the question.

How to install sshpass on mac?

Please follow the steps below to install sshpass in mac.

curl -O -L https://fossies.org/linux/privat/sshpass-1.06.tar.gz && tar xvzf sshpass-1.06.tar.gz

cd sshpass-1.06

./configure

sudo make install

Execute raw SQL using Doctrine 2

Here's an example of a raw query in Doctrine 2 that I'm doing:

public function getAuthoritativeSportsRecords()
{   
    $sql = " 
        SELECT name,
               event_type,
               sport_type,
               level
          FROM vnn_sport
    ";

    $em = $this->getDoctrine()->getManager();
    $stmt = $em->getConnection()->prepare($sql);
    $stmt->execute();
    return $stmt->fetchAll();
}   

What event handler to use for ComboBox Item Selected (Selected Item not necessarily changed)

For UWP (Windows Store) apps none of the above will work (PointerPressed doesn't fire; no Preview, DropDownClosed or SelectedIndexChanged events exist)

I had to resort to a transparent button overlaying the ComboBox (but not its drop down arrow). When you press on the arrow, the list drops down as usual and the Combo Box's SelectionChanged event fires. When you click anywhere else on the Combo Box the transparent button's click event fires allowing you to re-select the Combo Box's current value.

Some working XAML code:

                <Grid x:Name="ComboOverlay" Margin="0,0,5,0"> <!--See comments in code behind at ClickedComboButValueHasntChanged event handler-->
                    <ComboBox x:Name="NewFunctionSelect" Width="97" ItemsSource="{x:Bind Functions}"
                          SelectedItem="{x:Bind ChosenFunction}" SelectionChanged="Function_SelectionChanged"/>
                    <Button x:Name="OldFunctionClick" Height="30" Width="73" Background="Transparent" Click="ClickedComboButValueHasntChanged"/>
                </Grid>

Some working C# code:

    /// <summary>
    /// It is impossible to simply click a ComboBox to select the shown value again. It always drops down the list of options but
    ///     doesn't raise SelectionChanged event if the value selected from the list is the same as before
    ///     
    /// To handle this, a transparent button is overlaid over the ComboBox (but not its dropdown arrow) to allow reselecting the old value
    /// Thus clicking over the dropdown arrow allows the user to select a new option from the list, but
    ///     clicking anywhere else in the Combo re-selects the previous value
    /// </summary>
    private void ClickedComboButValueHasntChanged(object sender, RoutedEventArgs e)
    {
        //You could also dummy up a SelectionChangedEvent event and raise it to invoke Function_SelectionChanged handler, below 
        FunctionEntered(NewFunctionSelect.SelectedValue as string);
    }

    private void Function_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        FunctionEntered(e.AddedItems[0] as string);
    }

Adding an identity to an existing column

You can't alter the existing columns for identity.

You have 2 options,

  1. Create a new table with identity & drop the existing table

  2. Create a new column with identity & drop the existing column

Approach 1. (New table) Here you can retain the existing data values on the newly created identity column. Note that you will lose all data if 'if not exists' is not satisfied, so make sure you put the condition on the drop as well!

CREATE TABLE dbo.Tmp_Names
    (
      Id int NOT NULL
             IDENTITY(1, 1),
      Name varchar(50) NULL
    )
ON  [PRIMARY]
go

SET IDENTITY_INSERT dbo.Tmp_Names ON
go

IF EXISTS ( SELECT  *
            FROM    dbo.Names ) 
    INSERT  INTO dbo.Tmp_Names ( Id, Name )
            SELECT  Id,
                    Name
            FROM    dbo.Names TABLOCKX
go

SET IDENTITY_INSERT dbo.Tmp_Names OFF
go

DROP TABLE dbo.Names
go

Exec sp_rename 'Tmp_Names', 'Names'

Approach 2 (New column) You can’t retain the existing data values on the newly created identity column, The identity column will hold the sequence of number.

Alter Table Names
Add Id_new Int Identity(1, 1)
Go

Alter Table Names Drop Column ID
Go

Exec sp_rename 'Names.Id_new', 'ID', 'Column'

See the following Microsoft SQL Server Forum post for more details:

How to alter column to identity(1,1)

How to uninstall Eclipse?

Look for an installation subdirectory, likely named eclipse. Under that subdirectory, if you see files like eclipse.ini, icon.xpm and subdirectories like plugins and dropins, remove the subdirectory parent (the one named eclipse).

That will remove your installation except for anything you've set up yourself (like workspaces, projects, etc.).

Hope this helps.

Disable submit button ONLY after submit

$(document).ready(function() {
    $(body).submit(function () {
        var btn = $(this).find("input[type=submit]:focus");
        if($(btn).prop("id") == "YourButtonID")
            $(btn).attr("disabled", "true");
    });
}

CodeIgniter removing index.php from url

Note the difference with the added "?" character after ".php", especially when dealing with CodeIgniter:

RewriteRule ^(.*)$ index.php/$1 [L]

vs.

RewriteRule ^(.*)$ index.php?/$1 [L]

It depends on several other things.. if doesn't work, try the other option!

What are sessions? How do they work?

Because HTTP is stateless, in order to associate a request to any other request, you need a way to store user data between HTTP requests.

Cookies or URL parameters ( for ex. like http://example.com/myPage?asd=lol&boo=no ) are both suitable ways to transport data between 2 or more request. However they are not good in case you don't want that data to be readable/editable on client side.

The solution is to store that data server side, give it an "id", and let the client only know (and pass back at every http request) that id. There you go, sessions implemented. Or you can use the client as a convenient remote storage, but you would encrypt the data and keep the secret server-side.

Of course there are other aspects to consider, like you don't want people to hijack other's sessions, you want sessions to not last forever but to expire, and so on.

In your specific example, the user id (could be username or another unique ID in your user database) is stored in the session data, server-side, after successful identification. Then for every HTTP request you get from the client, the session id (given by the client) will point you to the correct session data (stored by the server) that contains the authenticated user id - that way your code will know what user it is talking to.

How to make String.Contains case insensitive?

bool b = list.Contains("Hello", StringComparer.CurrentCultureIgnoreCase);

[EDIT] extension code:

public static bool Contains(this string source, string cont
                                                    , StringComparison compare)
{
    return source.IndexOf(cont, compare) >= 0;
}

This could work :)

How do I disable fail_on_empty_beans in Jackson?

If you are using Spring Boot, you can set the following property in application.properties file. spring.jackson.serialization.FAIL_ON_EMPTY_BEANS=false

How to find minimum value from vector?

#include <iostream>
#include <vector>
#include <algorithm> // std::min_element
#include <iterator>  // std::begin, std::end

int main() {
    std::vector<int> v = {5,14,2,4,6};
    auto result = std::min_element(std::begin(v), std::end(v));
    if (std::end(v)!=result)
        std::cout << *result << '\n';
}

The program you show has a few problems, the primary culprit being the for condition: i<v[n]. You initialize the array, setting the first 5 elements to various values and the rest to zero. n is set to the number of elements you explicitly initialized so v[n] is the first element that was implicitly initialized to zero. Therefore the loop condition is false the first time around and the loop does not run at all; your code simply prints out the first element.

Some minor issues:

  • avoid raw arrays; they behave strangely and inconsistently (e.g., implicit conversion to pointer to the array's first element, can't be assigned, can't be passed to/returned from functions by value)

  • avoid magic numbers. int v[100] is an invitation to a bug if you want your array to get input from somewhere and then try to handle more than 100 elements.

  • avoid using namespace std; It's not a big deal in implementation files, although IMO it's better to just get used to explicit qualification, but it can cause problems if you blindly use it everywhere because you'll put it in header files and start causing unnecessary name conflicts.

JavaScript: How to get parent element by selector?

Here's the most basic version:

function collectionHas(a, b) { //helper function (see below)
    for(var i = 0, len = a.length; i < len; i ++) {
        if(a[i] == b) return true;
    }
    return false;
}
function findParentBySelector(elm, selector) {
    var all = document.querySelectorAll(selector);
    var cur = elm.parentNode;
    while(cur && !collectionHas(all, cur)) { //keep going up until you find a match
        cur = cur.parentNode; //go up
    }
    return cur; //will return null if not found
}

var yourElm = document.getElementById("yourElm"); //div in your original code
var selector = ".yes";
var parent = findParentBySelector(yourElm, selector);

Deleting Row in SQLite in Android

Try this one:

public void deleteEntry(long rowId) {
    database.delete(DATABASE_TABLE , KEY_ROWID 
        + " = " + rowId, null);}

ASP.NET Temporary files cleanup

Just an update on more current OS's (Vista, Win7, etc.) - the temp file path has changed may be different based on several variables. The items below are not definitive, however, they are a few I have encountered:

"temp" environment variable setting - then it would be:

%temp%\Temporary ASP.NET Files

Permissions and what application/process (VS, IIS, IIS Express) is running the .Net compiler. Accessing the C:\WINDOWS\Microsoft.NET\Framework folders requires elevated permissions and if you are not developing under an account with sufficient permissions then this folder might be used:

c:\Users\[youruserid]\AppData\Local\Temp\Temporary ASP.NET Files

There are also cases where the temp folder can be set via config for a machine or site specific using this:

<compilation tempDirectory="d:\MyTempPlace" />

I even have a funky setup at work where we don't run Admin by default, plus the IT guys have login scripts that set %temp% and I get temp files in 3 different locations depending on what is compiling things! And I'm still not certain about how these paths get picked....sigh.

Still, dthrasher is correct, you can just delete these and VS and IIS will just recompile them as needed.

Converting timestamp to time ago in PHP e.g 1 day ago, 2 days ago...

Just to throw in another option...

Whilst I prefer the DateTime method posting here, I didn't like the fact it displayed 0 years etc.

/* 
 * Returns a string stating how long ago this happened
 */

private function timeElapsedString($ptime){
    $diff = time() - $ptime;
    $calc_times = array();
    $timeleft   = array();

    // Prepare array, depending on the output we want to get.
    $calc_times[] = array('Year',   'Years',   31557600);
    $calc_times[] = array('Month',  'Months',  2592000);
    $calc_times[] = array('Day',    'Days',    86400);
    $calc_times[] = array('Hour',   'Hours',   3600);
    $calc_times[] = array('Minute', 'Minutes', 60);
    $calc_times[] = array('Second', 'Seconds', 1);

    foreach ($calc_times AS $timedata){
        list($time_sing, $time_plur, $offset) = $timedata;

        if ($diff >= $offset){
            $left = floor($diff / $offset);
            $diff -= ($left * $offset);
            $timeleft[] = "{$left} " . ($left == 1 ? $time_sing : $time_plur);
        }
    }

    return $timeleft ? (time() > $ptime ? null : '-') . implode(' ', $timeleft) : 0;
}

Is there a function to copy an array in C/C++?

Firstly, because you are switching to C++, vector is recommended to be used instead of traditional array. Besides, to copy an array or vector, std::copy is the best choice for you.

Visit this page to get how to use copy function: http://en.cppreference.com/w/cpp/algorithm/copy

Example:

std::vector<int> source_vector;
source_vector.push_back(1);
source_vector.push_back(2);
source_vector.push_back(3);
std::vector<int> dest_vector(source_vector.size());
std::copy(source_vector.begin(), source_vector.end(), dest_vector.begin());

What's the proper way to compare a String to an enum value?

I'm gathering from your question that userPick is a String value. You can compare it like this:

if (userPick.equalsIgnoreCase(computerPick.name())) . . .

As an aside, if you are guaranteed that computer is always one of the values 1, 2, or 3 (and nothing else), you can convert it to a Gesture enum with:

Gesture computerPick = Gesture.values()[computer - 1];

How to execute cmd commands via Java

Each of your exec calls creates a process. You second and third calls do not run in the same shell process you create in the first one. Try putting all commands in a bat script and running it in one call: rt.exec("cmd myfile.bat"); or similar

Android Studio not showing modules in project structure

Open settings.gradle and add the module as below,

include ':app',':bottomnav'

here i have added my newly imported module ':bottomnav' separated with a comma. then Sync your project. your module will be visible to dependency. Android Studio only displays those module, which are defined in the settings.gradle file of your application. after defining the module in settings.gradle, you will be able to add the module as dependency of your application.

How do you comment an MS-access Query?

NOTE: Confirmed with Access 2003, don't know about earlier versions.

For a query in an MDB you can right-click in the query designer (anywhere in the empty space where the tables are), select Properties from the context menu, and enter text in the Description property.

You're limited to 256 characters, but it's better than nothing.

You can get at the description programatically with something like this:

Dim db As Database
Dim qry As QueryDef

Set db = Application.CurrentDb
Set qry = db.QueryDefs("myQuery")

Debug.Print qry.Properties("Description")

Changing factor levels with dplyr mutate

With the forcats package from the tidyverse this is easy, too.

mutate(dat, x = fct_recode(x, "B" = "A"))

How to add http:// if it doesn't exist in the URL

nickf's solution modified:

function addhttp($url) {
    if (!preg_match("@^https?://@i", $url) && !preg_match("@^ftps?://@i", $url)) {
        $url = "http://" . $url;
    }
    return $url;
}

Using a custom typeface in Android

Absolutely possible. Many ways to do it. The fastest way, create condition with try - catch method.. try your certain font style condition, catch the error, and define the other font style.

Excel Define a range based on a cell value

Based on answer by @Cici I give here a more generic solution:

=SUM(INDIRECT(CONCATENATE(B1,C1)):INDIRECT(CONCATENATE(B2,C2)))

In Italian version of Excel:

=SOMMA(INDIRETTO(CONCATENA(B1;C1)):INDIRETTO(CONCATENA(B2;C2)))

Where B1-C2 cells hold these values:

  • A, 1
  • A, 5

You can change these valuese to change the final range at wish.


Splitting the formula in parts:

  • SUM(INDIRECT(CONCATENATE(B1,C1)):INDIRECT(CONCATENATE(B2,C2)))
  • CONCATENATE(B1,C1) - result is A1
  • INDIRECT(CONCATENATE(B1,C1)) - result is reference to A1

Hence:

=SUM(INDIRECT(CONCATENATE(B1,C1)):INDIRECT(CONCATENATE(B2,C2)))

results in

=SUM(A1:A5)


I'll write down here a couple of SEO keywords for Italian users:

  • come creare dinamicamente l'indirizzo di un intervallo in excel
  • formula per definire un intervallo di celle in excel.

Con la formula indicata qui sopra basta scrivere nelle caselle da B1 a C2 gli estremi dell'intervallo per vedelo cambiare dentro la formula stessa.

How to Get enum item name from its value

I have had excellent success with a technique which resembles the X macros pointed to by @RolandXu. We made heavy use of the stringize operator, too. The technique mitigates the maintenance nightmare when you have an application domain where items appear both as strings and as numerical tokens.

It comes in particularily handy when machine readable documentation is available so that the macro X(...) lines can be auto-generated. A new documentation would immediately result in a consistent program update covering the strings, enums and the dictionaries translating between them in both directions. (We were dealing with PCL6 tokens).

And while the preprocessor code looks pretty ugly, all those technicalities can be hidden in the header files which never have to be touched again, and neither do the source files. Everything is type safe. The only thing that changes is a text file containing all the X(...) lines, and that is possibly auto generated.

Display a angular variable in my html page

In your template, you have access to all the variables that are members of the current $scope. So, tobedone should be $scope.tobedone, and then you can display it with {{tobedone}}, or [[tobedone]] in your case.

MySQL convert date string to Unix timestamp

For current date just use UNIX_TIMESTAMP() in your MySQL query.

What does it mean if a Python object is "subscriptable" or not?

Off the top of my head, the following are the only built-ins that are subscriptable:

string:  "foobar"[3] == "b"
tuple:   (1,2,3,4)[3] == 4
list:    [1,2,3,4][3] == 4
dict:    {"a":1, "b":2, "c":3}["c"] == 3

But mipadi's answer is correct - any class that implements __getitem__ is subscriptable

How do I find ' % ' with the LIKE operator in SQL Server?

Try this:

declare @var char(3)
set @var='[%]'
select Address from Accomodation where Address like '%'+@var+'%' 

You must use [] cancels the effect of wildcard, so you read % as a normal character, idem about character _

Greyscale Background Css Images

Here you go:

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>bluantinoo CSS Grayscale Bg Image Sample</title>
<style type="text/css">
    div {
        border: 1px solid black;
        padding: 5px;
        margin: 5px;
        width: 600px;
        height: 600px;
        float: left;
        color: white;
    }
     .grayscale {
         background: url(yourimagehere.jpg);
         -moz-filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
         -o-filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
         -webkit-filter: grayscale(100%);
         filter: gray;
         filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
     }

    .nongrayscale {
        background: url(yourimagehere.jpg);
    }
</style>
</head>
<body>
    <div class="nongrayscale">
        this is a non-grayscale of the bg image
    </div>
    <div class="grayscale">
        this is a grayscale of the bg image
    </div>
</body>
</html>

Tested it in FireFox, Chrome and IE. I've also attached an image to show my results of my implementation of this.Grayscale Background Image in DIV Sample

EDIT: Also, if you want the image to just toggle back and forth with jQuery, here's the page source for that...I've included the web link to jQuery and and image that's online so you should just be able to copy/paste to test it out:

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>bluantinoo CSS Grayscale Bg Image Sample</title>
<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
<style type="text/css">
    div {
        border: 1px solid black;
        padding: 5px;
        margin: 5px;
        width: 600px;
        height: 600px;
        float: left;
        color: white;
    }
     .grayscale {
         background: url(http://www.polyrootstattoo.com/images/Artists/Buda/40.jpg);
         -moz-filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
         -o-filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
         -webkit-filter: grayscale(100%);
         filter: gray;
         filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
     }

    .nongrayscale {
        background: url(http://www.polyrootstattoo.com/images/Artists/Buda/40.jpg);
    }
</style>
    <script type="text/javascript">
        $(document).ready(function () {
            $("#image").mouseover(function () {
                $(".nongrayscale").removeClass().fadeTo(400,0.8).addClass("grayscale").fadeTo(400, 1);
            });
            $("#image").mouseout(function () {
                $(".grayscale").removeClass().fadeTo(400, 0.8).addClass("nongrayscale").fadeTo(400, 1);
            });
        });
</script>
</head>
<body>
    <div id="image" class="nongrayscale">
        rollover this image to toggle grayscale
    </div>
</body>
</html>

EDIT 2 (For IE10-11 Users): The solution above will not work with the changes Microsoft has made to the browser as of late, so here's an updated solution that will allow you to grayscale (or desaturate) your images.

_x000D_
_x000D_
<svg>_x000D_
  <defs>_x000D_
    <filter xmlns="http://www.w3.org/2000/svg" id="desaturate">_x000D_
      <feColorMatrix type="saturate" values="0" />_x000D_
    </filter>_x000D_
  </defs>_x000D_
  <image xlink:href="http://www.polyrootstattoo.com/images/Artists/Buda/40.jpg" width="600" height="600" filter="url(#desaturate)" />_x000D_
</svg>
_x000D_
_x000D_
_x000D_

CHECK constraint in MySQL is not working

Unfortunately MySQL does not support SQL check constraints. You can define them in your DDL query for compatibility reasons but they are just ignored.

There is a simple alternative

You can create BEFORE INSERT and BEFORE UPDATE triggers which either cause an error or set the field to its default value when the requirements of the data are not met.

Example for BEFORE INSERT working after MySQL 5.5

DELIMITER $$
CREATE TRIGGER `test_before_insert` BEFORE INSERT ON `Test`
FOR EACH ROW
BEGIN
    IF CHAR_LENGTH( NEW.ID ) < 4 THEN
        SIGNAL SQLSTATE '12345'
            SET MESSAGE_TEXT := 'check constraint on Test.ID failed';
    END IF;
END$$   
DELIMITER ;  

Prior to MySQL 5.5 you had to cause an error, e.g. call a undefined procedure.

In both cases this causes an implicit transaction rollback. MySQL does not allow the ROLLBACK statement itself within procedures and triggers.

If you don't want to rollback the transaction ( INSERT / UPDATE should pass even with a failed "check constraint" you can overwrite the value using SET NEW.ID = NULL which will set the id to the fields default value, doesn't really make sense for an id tho

Edit: Removed the stray quote.

Concerning the := operator:

Unlike =, the := operator is never interpreted as a comparison operator. This means you can use := in any valid SQL statement (not just in SET statements) to assign a value to a variable.

https://dev.mysql.com/doc/refman/5.6/en/assignment-operators.html

Concerning backtick identifier quotes:

The identifier quote character is the backtick (“`”)

If the ANSI_QUOTES SQL mode is enabled, it is also permissible to quote identifiers within double quotation marks

http://dev.mysql.com/doc/refman/5.6/en/identifiers.html

Javascript set img src

document["pic1"].src = searchPic.src

should work

Adding 1 hour to time variable

try this it is worked for me.

$time="10:09";
$time = date('H:i', strtotime($time.'+1 hour'));
echo $time;

check if array is empty (vba excel)

@jeminar has the best solution above.

I cleaned it up a bit though.

I recommend adding this to a FunctionsArray module

  • isInitialised=false is not needed because Booleans are false when created
  • On Error GoTo 0 wrap and indent code inside error blocks similar to with blocks for visibility. these methods should be avoided as much as possible but ... VBA ...
Function isInitialised(ByRef a() As Variant) As Boolean
    On Error Resume Next
    isInitialised = IsNumeric(UBound(a))
    On Error GoTo 0
End Function

Force browser to download image files on click

A more modern approach using Promise and async/await :

toDataURL(url) {
    return fetch(url).then((response) => {
            return response.blob();
        }).then(blob => {
            return URL.createObjectURL(blob);
        });
}

then

async download() {
        const a = document.createElement("a");
        a.href = await toDataURL("https://cdn1.iconfinder.com/data/icons/ninja-things-1/1772/ninja-simple-512.png");
        a.download = "myImage.png";
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
}

Find documentation here: https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch

How do I determine whether my calculation of pi is accurate?

You could try computing sin(pi/2) (or cos(pi/2) for that matter) using the (fairly) quickly converging power series for sin and cos. (Even better: use various doubling formulas to compute nearer x=0 for faster convergence.)

BTW, better than using series for tan(x) is, with computing say cos(x) as a black box (e.g. you could use taylor series as above) is to do root finding via Newton. There certainly are better algorithms out there, but if you don't want to verify tons of digits this should suffice (and it's not that tricky to implement, and you only need a bit of calculus to understand why it works.)

External resource not being loaded by AngularJs

Had the same issue here. I needed to bind to Youtube links. What worked for me, as a global solution, was to add the following to my config:

.config(['$routeProvider', '$sceDelegateProvider',
        function ($routeProvider, $sceDelegateProvider) {

    $sceDelegateProvider.resourceUrlWhitelist(['self', new RegExp('^(http[s]?):\/\/(w{3}.)?youtube\.com/.+$')]);

}]);

Adding 'self' in there is important - otherwise will fail to bind to any URL. From the angular docs

'self' - The special string, 'self', can be used to match against all URLs of the same domain as the application document using the same protocol.

With that in place, I'm now able to bind directly to any Youtube link.

You'll obviously have to customise the regex to your needs. Hope it helps!

Encrypt and decrypt a password in Java

You can use java.security.MessageDigest with SHA as your algorithm choice.

For reference,

Try available example here

document.getElementById vs jQuery $()

All the answers are old today as of 2019 you can directly access id keyed filds in javascript simply try it

<p id="mytext"></p>
<script>mytext.innerText = 'Yes that works!'</script>

Online Demo! - https://codepen.io/frank-dspeed/pen/mdywbre

Why is the default value of the string type null instead of an empty string?

You could also use the following, as of C# 6.0

string myString = null;
string result = myString?.ToUpper();

The string result will be null.

How to print a stack trace in Node.js?

Any Error object has a stack member that traps the point at which it was constructed.

var stack = new Error().stack
console.log( stack )

or more simply:

console.trace("Here I am!")

How to change row color in datagridview?

Just a note about setting DefaultCellStyle.BackColor...you can't set it to any transparent value except Color.Empty. That's the default value. That falsely implies (to me, anyway) that transparent colors are OK. They're not. Every row I set to a transparent color just draws the color of selected-rows.

I spent entirely too much time beating my head against the wall over this issue.

Boxplot in R showing the mean

abline(h=mean(x))

for a horizontal line (use v instead of h for vertical if you orient your boxplot horizontally), or

points(mean(x))

for a point. Use the parameter pch to change the symbol. You may want to colour them to improve visibility too.

Note that these are called after you have drawn the boxplot.

If you are using the formula interface, you would have to construct the vector of means. For example, taking the first example from ?boxplot:

boxplot(count ~ spray, data = InsectSprays, col = "lightgray")
means <- tapply(InsectSprays$count,InsectSprays$spray,mean)
points(means,col="red",pch=18)

If your data contains missing values, you might want to replace the last argument of the tapply function with function(x) mean(x,na.rm=T)

How do I enable Java in Microsoft Edge web browser?

As other folks have mentioned, Java, ActiveX, Silverlight, Browser Helper Objects (BHOs) and other plugins are not supported in Microsoft Edge. Most modern browsers are moving away from plugins and toward standard HTML5 controls and technologies.

If you must continue to use the Java plugin in a corporate web app, consider adding the site to an Enterprise Mode site list. This will automatically prompt the user to open in IE.

How to truncate string using SQL server

I think the answers here are great, but I would like to add a scenario.

Several times I've wanted to take a certain amount of characters off the front of a string, without worrying about it's length. There are several ways of doing this with RIGHT() and SUBSTRING(), but they all need to know the length of the string which can sometimes slow things down.

I've use the STUFF() function instead:

SET @Result = STUFF(@Result, 1, @LengthToRemove, '')

This replaces the length of unneeded string with an empty string.

How do you change the document font in LaTeX?

For a different approach, I would suggest using the XeTeX or LuaTex system. They allow you to access system fonts (TrueType, OpenType, etc) and set font features. In a typical LaTeX document, you just need to include this in your headers:

\usepackage{fontspec}
\defaultfontfeatures{Mapping=tex-text,Scale=MatchLowercase}
\setmainfont{Times}
\setmonofont{Lucida Sans Typewriter}

It's the fontspec package that allows for \setmainfont and \setmonofont. The ability to choose a multitude of font features is beyond my expertise, but I would suggest looking up some examples and seeing if this would suit your needs.

Just don't forget to replace your favorite latex compiler by the appropriate one (xelatex or lualatex).

C# : Converting Base Class to Child Class

I would recommend identifying the functionality you need from any subclasses, and make a generic method to cast into the right subclass.

I had this same problem, but really didn't feel like creating some mapping class or importing a library.

Let's say you need the 'Authenticate' method to take behavior from the right subclass. In your NetworkClient:

protected bool Authenticate(string username, string password) {
  //...
}
protected bool DoAuthenticate<T>(NetworkClient nc, string username, string password) where T : NetworkClient {
//Do a cast into the sub class.
  T subInst = (T) nc;
  return nc.Authenticate(username, password);
}

How to compare two Carbon Timestamps?

Carbon has a bunch of comparison functions with mnemonic names:

  • equalTo()
  • notEqualTo()
  • greaterThan()
  • greaterThanOrEqualTo()
  • lessThan()
  • lessThanOrEqualTo()

Usage:

 if($model->edited_at->greaterThan($model->created_at)){
     // edited at is newer than created at
 }

Valid for nesbot/carbon 1.36.2

if you are not sure what Carbon version you are on, run this

$composer show "nesbot/carbon"

documentation: https://carbon.nesbot.com/docs/#api-comparison

Duplicate headers received from server

Just put a pair of double quotes around your file name like this:

this.Response.AddHeader("Content-disposition", $"attachment; filename=\"{outputFileName}\"");

How can I strip first and last double quotes?

IMPORTANT: I'm extending the question/answer to strip either single or double quotes. And I interpret the question to mean that BOTH quotes must be present, and matching, to perform the strip. Otherwise, the string is returned unchanged.

To "dequote" a string representation, that might have either single or double quotes around it (this is an extension of @tgray's answer):

def dequote(s):
    """
    If a string has single or double quotes around it, remove them.
    Make sure the pair of quotes match.
    If a matching pair of quotes is not found, return the string unchanged.
    """
    if (s[0] == s[-1]) and s.startswith(("'", '"')):
        return s[1:-1]
    return s

Explanation:

startswith can take a tuple, to match any of several alternatives. The reason for the DOUBLED parentheses (( and )) is so that we pass ONE parameter ("'", '"') to startswith(), to specify the permitted prefixes, rather than TWO parameters "'" and '"', which would be interpreted as a prefix and an (invalid) start position.

s[-1] is the last character in the string.

Testing:

print( dequote("\"he\"l'lo\"") )
print( dequote("'he\"l'lo'") )
print( dequote("he\"l'lo") )
print( dequote("'he\"l'lo\"") )

=>

he"l'lo
he"l'lo
he"l'lo
'he"l'lo"

(For me, regex expressions are non-obvious to read, so I didn't try to extend @Alex's answer.)

Download file through an ajax call php

I have accomplished this with a hidden iframe. I use perl, not php, so will just give concept, not code solution.

Client sends Ajax request to server, causing the file content to be generated. This is saved as a temp file on the server, and the filename is returned to the client.

Client (javascript) receives filename, and sets the iframe src to some url that will deliver the file, like:

$('iframe_dl').src="/app?download=1&filename=" + the_filename

Server slurps the file, unlinks it, and sends the stream to the client, with these headers:

Content-Type:'application/force-download'
Content-Disposition:'attachment; filename=the_filename'

Works like a charm.

Invoking Java main method with parameters from Eclipse

AFAIK there isn't a built-in mechanism in Eclipse for this.

The closest you can get is to create a wrapper that prompts you for these values and invokes the (hardcoded) main. You then get you execution history as long as you don't clear terminated processes. Two variations on this are either to use JUNit, or to use injection or parameter so that your wrapper always connects to the correct class for its main.

What does "use strict" do in JavaScript, and what is the reasoning behind it?

use strict is a way to make your code safer, because you can't use dangerous features that can work not as you expect. And, as was written before, it makes code more strict.

Valid characters of a hostname?

A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.). Note that periods are only allowed when they serve to delimit components of "domain style names". (See RFC-921, "Domain Name System Implementation Schedule", for background). No blank or space characters are permitted as part of a name. No distinction is made between upper and lower case. The first character must be an alpha character. The last character must not be a minus sign or period. A host which serves as a GATEWAY should have "-GATEWAY" or "-GW" as part of its name. Hosts which do not serve as Internet gateways should not use "-GATEWAY" and "-GW" as part of their names. A host which is a TAC should have "-TAC" as the last part of its host name, if it is a DoD host. Single character names or nicknames are not allowed.

This is provided in http://support.microsoft.com/kb/149044

Using JavaScript to display a Blob

You can convert your string into a Uint8Array to get the raw data. Then create a Blob for that data and pass to URL.createObjectURL(blob) to convert the Blob into a URL that you pass to img.src.

var data = '424D5E070000000000003E00000028000000EF...';

// Convert the string to bytes
var bytes = new Uint8Array(data.length / 2);

for (var i = 0; i < data.length; i += 2) {
    bytes[i / 2] = parseInt(data.substring(i, i + 2), /* base = */ 16);
}

// Make a Blob from the bytes
var blob = new Blob([bytes], {type: 'image/bmp'});

// Use createObjectURL to make a URL for the blob
var image = new Image();
image.src = URL.createObjectURL(blob);
document.body.appendChild(image);

You can try the complete example at: http://jsfiddle.net/nj82y73d/

Why am I getting an OPTIONS request instead of a GET request?

It's looking like Firefox and Opera (tested on mac as well) don't like the cross domainness of this (but Safari is fine with it).

You might have to call a local server side code to curl the remote page.

How to remove all the null elements inside a generic list in one go?

List<EmailParameterClass> parameterList = new List<EmailParameterClass>{param1, param2, param3...};

parameterList = parameterList.Where(param => param != null).ToList();

Parcelable encountered IOException writing serializable object getactivity()

I faced Same issue, the issues was there are some inner classes with the static keyword.After removing the static keyword it started working and also the inner class should implements to Serializable

Issue scenario

class A implements Serializable{ 
  class static B{
  } 
}

Resolved By

class A implements Serializable{ 
      class B implements Serializable{
      } 
    }

Service has zero application (non-infrastructure) endpoints

My problem was when I renamed my default Service1 class for .svc file to a more meaningful name, which caused web.config behaviorConfiguration and endpoint to correspond to old naming convention. Try to fix your web.config.

Invert "if" statement to reduce nesting

The idea of only returning at the end of a function came back from the days before languages had support for exceptions. It enabled programs to rely on being able to put clean-up code at the end of a method, and then being sure it would be called and some other programmer wouldn't hide a return in the method that caused the cleanup code to be skipped. Skipped cleanup code could result in a memory or resource leak.

However, in a language that supports exceptions, it provides no such guarantees. In a language that supports exceptions, the execution of any statement or expression can cause a control flow that causes the method to end. This means clean-up must be done through using the finally or using keywords.

Anyway, I'm saying I think a lot of people quote the 'only return at the end of a method' guideline without understanding why it was ever a good thing to do, and that reducing nesting to improve readability is probably a better aim.

How to read input from console in a batch file?

If you're just quickly looking to keep a cmd instance open instead of exiting immediately, simply doing the following is enough

set /p asd="Hit enter to continue"

at the end of your script and it'll keep the window open.

Note that this'll set asd as an environment variable, and can be replaced with anything else.

Count distinct value pairs in multiple columns in SQL

You can also do something like:

SELECT COUNT(DISTINCT id + name + address) FROM mytable

When should I use a List vs a LinkedList

I asked a similar question related to performance of the LinkedList collection, and discovered Steven Cleary's C# implement of Deque was a solution. Unlike the Queue collection, Deque allows moving items on/off front and back. It is similar to linked list, but with improved performance.

jQuery Validation using the class instead of the name value

Since for me, some elements are created on page load, and some are dynamically added by the user; I used this to make sure everything stayed DRY.

On submit, find everything with class x, remove class x, add rule x.

$('#form').on('submit', function(e) {
    $('.alphanumeric_dash').each(function() {
        var $this = $(this);
        $this.removeClass('alphanumeric_dash');
        $(this).rules('add', {
            alphanumeric_dash: true
        });
    });
});

PHP - remove all non-numeric characters from a string

You can use preg_replace in this case;

$res = preg_replace("/[^0-9]/", "", "Every 6 Months" );

$res return 6 in this case.

If want also to include decimal separator or thousand separator check this example:

$res = preg_replace("/[^0-9.]/", "", "$ 123.099");

$res returns "123.099" in this case

Include period as decimal separator or thousand separator: "/[^0-9.]/"

Include coma as decimal separator or thousand separator: "/[^0-9,]/"

Include period and coma as decimal separator and thousand separator: "/[^0-9,.]/"

mappedBy reference an unknown target entity property

public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @Column(name = "USER_ID")
    Long userId;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "sender", cascade = CascadeType.ALL)
    List<Notification> sender;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "receiver", cascade = CascadeType.ALL)
    List<Notification> receiver;
}

public class Notification implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id

    @Column(name = "NOTIFICATION_ID")
    Long notificationId;

    @Column(name = "TEXT")
    String text;

    @Column(name = "ALERT_STATUS")
    @Enumerated(EnumType.STRING)
    AlertStatus alertStatus = AlertStatus.NEW;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "SENDER_ID")
    @JsonIgnore
    User sender;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "RECEIVER_ID")
    @JsonIgnore
    User receiver;
}

What I understood from the answer. mappedy="sender" value should be the same in the notification model. I will give you an example..

User model:

@OneToMany(fetch = FetchType.LAZY, mappedBy = "**sender**", cascade = CascadeType.ALL)
    List<Notification> sender;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "**receiver**", cascade = CascadeType.ALL)
    List<Notification> receiver;

Notification model:

@OneToMany(fetch = FetchType.LAZY, mappedBy = "sender", cascade = CascadeType.ALL)
    List<Notification> **sender**;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "receiver", cascade = CascadeType.ALL)
    List<Notification> **receiver**;

I gave bold font to user model and notification field. User model mappedBy="sender " should be equal to notification List sender; and mappedBy="receiver" should be equal to notification List receiver; If not, you will get error.

How to get file extension from string in C++

If you consider the extension as the last dot and the possible characters after it, but only if they don't contain the directory separator character, the following function returns the extension starting index, or -1 if no extension found. When you have that you can do what ever you want, like strip the extension, change it, check it etc.

long get_extension_index(string path, char dir_separator = '/') {
    // Look from the end for the first '.',
    // but give up if finding a dir separator char first
    for(long i = path.length() - 1; i >= 0; --i) {
        if(path[i] == '.') {
            return i;
        }
        if(path[i] == dir_separator) {
            return -1;
        }
    }
    return -1;
}

Pandas get the most frequent values of a column

You could try argmax like this:

dataframe['name'].value_counts().argmax() Out[13]: 'alex'

The value_counts will return a count object of pandas.core.series.Series and argmax could be used to achieve the key of max values.

Call a React component method from outside

You can just add an onClick handler to the div with the function (onClick is React's own implementation of onClick) and you can access the property within { } curly braces, and your alert message will appear.

In case you wish to define static methods that can be called on the component class - you should use statics. Although:

"Methods defined within this block are static, meaning that you can run them before any component instances are created, and the methods do not have access to the props or state of your components. If you want to check the value of props in a static method, have the caller pass in the props as an argument to the static method." (source)

Some example code:

    const Hello = React.createClass({

        /*
            The statics object allows you to define static methods that can be called on the component class. For example:
        */
        statics: {
            customMethod: function(foo) {
              return foo === 'bar';
            }
        },


        alertMessage: function() {
            alert(this.props.name);                             
        },

        render: function () {
            return (
                <div onClick={this.alertMessage}>
                Hello {this.props.name}
                </div>
            );
        }
    });

    React.render(<Hello name={'aworld'} />, document.body);

Hope this helps you a bit, because i don't know if I understood your question correctly, so correct me if i interpreted it wrong:)

Gunicorn worker timeout error

Could it be this? http://docs.gunicorn.org/en/latest/settings.html#timeout

Other possibilities could be your response is taking too long or is stuck waiting.

How to get the string size in bytes?

Use strlen to get the length of a null-terminated string.

sizeof returns the length of the array not the string. If it's a pointer (char *s), not an array (char s[]), it won't work, since it will return the size of the pointer (usually 4 bytes on 32-bit systems). I believe an array will be passed or returned as a pointer, so you'd lose the ability to use sizeof to check the size of the array.

So, only if the string spans the entire array (e.g. char s[] = "stuff"), would using sizeof for a statically defined array return what you want (and be faster as it wouldn't need to loop through to find the null-terminator) (if the last character is a null-terminator, you will need to subtract 1). If it doesn't span the entire array, it won't return what you want.

An alternative to all this is actually storing the size of the string.

Printing column separated by comma using Awk command line

Try:

awk -F',' '{print $3}' myfile.txt

Here in -F you are saying to awk that use "," as field separator.

Spring Boot Adding Http Request Interceptors

I had the same issue of WebMvcConfigurerAdapter being deprecated. When I searched for examples, I hardly found any implemented code. Here is a piece of working code.

create a class that extends HandlerInterceptorAdapter

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

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import me.rajnarayanan.datatest.DataTestApplication;
@Component
public class EmployeeInterceptor extends HandlerInterceptorAdapter {
    private static final Logger logger = LoggerFactory.getLogger(DataTestApplication.class);
    @Override
    public boolean preHandle(HttpServletRequest request, 
            HttpServletResponse response, Object handler) throws Exception {

            String x = request.getMethod();
            logger.info(x + "intercepted");
        return true;
    }

}

then Implement WebMvcConfigurer interface

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import me.rajnarayanan.datatest.interceptor.EmployeeInterceptor;
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
    @Autowired
    EmployeeInterceptor employeeInterceptor ;

    @Override
    public void addInterceptors(InterceptorRegistry registry){
        registry.addInterceptor(employeeInterceptor).addPathPatterns("/employee");
    }
}

How to get URL parameters with Javascript?

function getURLParameter(name) {
  return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec(location.search) || [null, ''])[1].replace(/\+/g, '%20')) || null;
}

So you can use:

myvar = getURLParameter('myvar');

inject bean reference into a Quartz job in Spring?

Here is what the code looks like with @Component:

Main class that schedules the job:

public class NotificationScheduler {

private SchedulerFactory sf;
private Scheduler scheduler;

@PostConstruct
public void initNotificationScheduler() {
    try {
    sf = new StdSchedulerFactory("spring/quartz.properties");
    scheduler = sf.getScheduler();
    scheduler.start();
            // test out sending a notification at startup, prepare some parameters...
    this.scheduleImmediateNotificationJob(messageParameters, recipients);
        try {
            // wait 20 seconds to show jobs
            logger.info("sleeping...");
            Thread.sleep(40L * 1000L); 
            logger.info("finished sleeping");
           // executing...
        } catch (Exception ignore) {
        }

      } catch (SchedulerException e) {
    e.printStackTrace();
    throw new RuntimeException("NotificationScheduler failed to retrieve a Scheduler instance: ", e);
    }
}


public void scheduleImmediateNotificationJob(){
  try {
    JobKey jobKey = new JobKey("key");
    Date fireTime = DateBuilder.futureDate(delayInSeconds, IntervalUnit.SECOND);
    JobDetail emailJob = JobBuilder.newJob(EMailJob.class)
    .withIdentity(jobKey.toString(), "immediateEmailsGroup")
        .build();

    TriggerKey triggerKey = new TriggerKey("triggerKey");
    SimpleTrigger trigger = (SimpleTrigger) TriggerBuilder.newTrigger() 
        .withIdentity(triggerKey.toString(), "immediateEmailsGroup")
        .startAt(fireTime)
        .build();

    // schedule the job to run
    Date scheduleTime1 = scheduler.scheduleJob(emailJob, trigger);
  } catch (SchedulerException e) {
    logger.error("error scheduling job: " + e.getMessage(), e);
    e.printStackTrace();
      }
}

@PreDestroy
public void cleanup(){
    sf = null;
    try {
        scheduler.shutdown();
    } catch (SchedulerException e) {
        e.printStackTrace();
    }
}

The EmailJob is the same as in my first posting except for the @Component annotation:

@Component
public class EMailJob implements Job { 
  @Autowired
  private JavaMailSenderImpl mailSenderImpl;
... }

And the Spring's configuration file has:

...
<context:property-placeholder location="classpath:spring/*.properties" />
<context:spring-configured/>
<context:component-scan base-package="com.mybasepackage">
  <context:exclude-filter expression="org.springframework.stereotype.Controller"
        type="annotation" />
</context:component-scan>
<bean id="mailSenderImpl" class="org.springframework.mail.javamail.JavaMailSenderImpl">
    <property name="host" value="${mail.host}"/>
    <property name="port" value="${mail.port}"/>
    ...
</bean>
<bean id="notificationScheduler" class="com.mybasepackage.notifications.NotificationScheduler">
</bean>

Thanks for all the help!

Marina

Difference Between Select and SelectMany

The SelectMany() method is used to flatten a sequence in which each of the elements of the sequence is a separate.

I have class user same like this

class User
    {
        public string UserName { get; set; }
        public List<string> Roles { get; set; }
    }

main:

var users = new List<User>
            {
                new User { UserName = "Reza" , Roles = new List<string>{"Superadmin" } },
                new User { UserName = "Amin" , Roles = new List<string>{"Guest","Reseption" } },
                new User { UserName = "Nima" , Roles = new List<string>{"Nurse","Guest" } },
            };

var query = users.SelectMany(user => user.Roles, (user, role) => new { user.UserName, role });

foreach (var obj in query)
{
    Console.WriteLine(obj);
}
//output

//{ UserName = Reza, role = Superadmin }
//{ UserName = Amin, role = Guest }
//{ UserName = Amin, role = Reseption }
//{ UserName = Nima, role = Nurse }
//{ UserName = Nima, role = Guest }

You can use operations on any item of sequence

int[][] numbers = {
                new[] {1, 2, 3},
                new[] {4},
                new[] {5, 6 , 6 , 2 , 7, 8},
                new[] {12, 14}
            };

IEnumerable<int> result = numbers
                .SelectMany(array => array.Distinct())
                .OrderBy(x => x);

//output

//{ 1, 2 , 2 , 3, 4, 5, 6, 7, 8, 12, 14 }
 List<List<int>> numbers = new List<List<int>> {
                new List<int> {1, 2, 3},
                new List<int> {12},
                new List<int> {5, 6, 5, 7},
                new List<int> {10, 10, 10, 12}
            };

 IEnumerable<int> result = numbers
                .SelectMany(list => list)
                .Distinct()
                .OrderBy(x=>x);

//output

// { 1, 2, 3, 5, 6, 7, 10, 12 }

SyntaxError: missing ; before statement

Or you might have something like this (redeclaring a variable):

var data = [];
var data = 

Android turn On/Off WiFi HotSpot programmatically

WifiManager wifiManager = (WifiManager)this.context.getSystemService(Context.WIFI_SERVICE);
wifiManager.setWifiEnabled(status);

where status may be true or false

add permission manifest: <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />

SSRS 2008 R2 - SSRS 2012 - ReportViewer: Reports are blank in Safari and Chrome

My solution based on the ideas above.

function pageLoad() {
    var element = document.querySelector('table[id*=_fixedTable] > tbody > tr:last-child > td:last-child > div');
    if (element) {
        element.style.overflow = "visible";
    } 
}

It's not limited to a certain id plus you don't need to include any other library such as jQuery.

Loop through all the resources in a .resx file

Blogged about it on my blog :) Short version is, to find the full names of the resources(unless you already know them):

var assembly = Assembly.GetExecutingAssembly();

foreach (var resourceName in assembly.GetManifestResourceNames())
    System.Console.WriteLine(resourceName);

To use all of them for something:

foreach (var resourceName in assembly.GetManifestResourceNames())
{
    using(var stream = assembly.GetManifestResourceStream(resourceName))
    {
        // Do something with stream
    }
}

To use resources in other assemblies than the executing one, you'd just get a different assembly object by using some of the other static methods of the Assembly class. Hope it helps :)

Email and phone Number Validation in android

public boolean checkForEmail() {
        Context c;
        EditText mEtEmail=(EditText)findViewById(R.id.etEmail);
        String mStrEmail = mEtEmail.getText().toString();
        if (android.util.Patterns.EMAIL_ADDRESS.matcher(mStrEmail).matches()) {
            return true;
        }
        Toast.makeText(this,"Email is not valid", Toast.LENGTH_LONG).show();
        return false;
    }


    public boolean checkForMobile() {
        Context c;
        EditText mEtMobile=(EditText)findViewById(R.id.etMobile);
        String mStrMobile = mEtMobile.getText().toString();
        if (android.util.Patterns.PHONE.matcher(mStrMobile).matches()) {
            return true;
        }
        Toast.makeText(this,"Phone No is not valid", Toast.LENGTH_LONG).show();
        return false;
    }

CSS-moving text from left to right

If I understand you question correctly, you could create a wrapper around your marquee and then assign a width (or max-width) to the wrapping element. For example:

<div id="marquee-wrapper">
    <div class="marquee">This is a marquee!</div>   
</div>

And then #marquee-wrapper { width: x }.

How to replace DOM element in place using Javascript?

A.replaceWith(span) - No parent needed

Generic form:

target.replaceWith(element)

Way better/cleaner than the previous method.

For your use case:

A.replaceWith(span)

Advanced usage

  1. You can pass multiple values (or use spread operator ...).
  2. Any string value will be added as a text element.

Examples:

// Initially [child1, target, child3]

target.replaceWith(span, "foo")     // [child1, span, "foo", child3]

const list = ["bar", span]
target.replaceWith(...list, "fizz")  // [child1, "bar", span, "fizz", child3]

Safely handling null target

If your target has a chance to be null, you can consider using the newish ?. optional chaining operator. Nothing will happen if target doesn't exist. Read more here.

target?.replaceWith(element)

Related DOM methods

  1. Read More - child.before and child.after
  2. Read More - parent.prepend and parent.append

Mozilla Docs

Supported Browsers - 94% Apr 2020

Why my $.ajax showing "preflight is invalid redirect error"?

The error indicates that the preflight is getting a redirect response. This can happen for a number of reasons. Find out where you are getting redirected to for clues to why it is happening. Check the network tab in Developer Tools.

One reason, as @Peter T mentioned, is that the API likely requires HTTPS connections rather than HTTP and all requests over HTTP get redirected. The Location header returned by the 302 response would say the same url with http changed to https in this case.

Another reason might be that your authentication token is not getting sent, or is not correct. Most servers are set up to redirect all requests that don't include an authentication token to the login page. Again, check your Location header to see if this is where you're getting sent and also take a look to make sure the browser sent your auth token with the request.

Oftentimes, a server will be configured to always redirect requests that don't have auth tokens to the login page - including your preflight/OPTIONS requests. This is a problem. Change the server configuration to permit OPTIONS requests from non-authenticated users.

MySQL remove all whitespaces from the entire column

Working Query:

SELECT replace(col_name , ' ','') FROM table_name;

While this doesn't :

SELECT trim(col_name) FROM table_name;

Javascript Confirm popup Yes, No button instead of OK and Cancel

the very specific answer to the point is confirm dialogue Js Function:

confirm('Do you really want to do so');

It show dialogue box with ok cancel buttons,to replace these button with yes no is not so simple task,for that you need to write jQuery function.

Package name does not correspond to the file path - IntelliJ

Maybe someone encounters a similar warning I had with a Scala project.

Package names doesn't correspond to directories structure, this may cause problems with resolve to classes from this file Inspection for files with package statement which does not correspond to package structure.

The file was in the right location, so the helper solutions the IDE provides are not helpfulenter image description here The Move File says file already exists (which is true) and Rename Package would actually move it to the incorrect package.

The problem is that if you have Scala Objects, you have to make sure that the first object in the file has the same name as the filename, so the solution is to move the objects inside the file.

How to add leading zeros for for-loop in shell?

From bash 4.0 onward, you can use Brace Expansion with fixed length strings. See below for the original announcement.

It will do just what you need, and does not require anything external to the shell.

$ echo {01..05}
01 02 03 04 05

for num in {01..05}
do
  echo $num
done
01
02
03
04
05

CHANGES, release bash-4.0, section 3

This is a terse description of the new features added to bash-4.0 since the release of bash-3.2.

. . .

z. Brace expansion now allows zero-padding of expanded numeric values and will add the proper number of zeroes to make sure all values contain the same number of digits.

Angular 1 - get current URL parameters

You could inject $routeParams to your controller and access all the params that where used when the route was resolved.

E.g.:

// route was: app.dev/backend/:type/:id

function MyCtrl($scope, $routeParams, $log) {
    // use the params
    $log.info($routeParams.type, $routeParams.id);
};

See angular $routeParams documentation for further information.

how to set the background image fit to browser using html

HTML

<img src="images/bg.jpg" id="bg" alt="">

CSS

#bg {
  position: fixed; 
  top: 0; 
  left: 0; 

  /* Preserve aspet ratio */
  min-width: 100%;
  min-height: 100%;
}

Removing an element from an Array (Java)

Copy your original array into another array, without the element to be removed.

A simplier way to do that is to use a List, Set... and use the remove() method.

Error:Cannot fit requested classes in a single dex file.Try supplying a main-dex list. # methods: 72477 > 65536

I have no idea why, maybe it is because I develop in Kotlin but to fix this error I finally have to create a class that extends MultiDexApplication like this:

class MyApplication : MultiDexApplication() {
}

and in my Manifest.xml I have to set

<application
        ...
        android:name=".MyApplication">

to not confuse anyone, I also do:

multiDexEnabled true
implementation 'com.android.support:multidex:1.0.3'

for androidx, this also works for me:

implementation 'androidx.multidex:multidex:2.0.0'

...

<application android:name="android.support.multidex.MultiDexApplication">

does not work for me

finding the type of an element using jQuery

You can use .prop() with tagName as the name of the property that you want to get:

$("#elementId").prop('tagName'); 

Character Limit in HTML

In addition to the above, I would like to point out that client-side validation (HTML code, javascript, etc.) is never enough. Also check the length server-side, or just don't check at all (if it's not so important that people can be allowed to get around it, then it's not important enough to really warrant any steps to prevent that, either).

Also, fellows, he (or she) said HTML, not XHTML. ;)

“Origin null is not allowed by Access-Control-Allow-Origin” error for request made by application running from a file:// URL

There is a small problem in the solution posted by CodeGroover above , where if you change a file, you'll have to restart the server to actually use the updated file (at least, in my case).

So searching a bit, I found this one To use:

sudo npm -g install simple-http-server # to install
nserver # to use

And then it will serve at http://localhost:8000.

display html page with node.js

but it ONLY shows the index.html file and NOTHING attached to it, so no images, no effects or anything that the html file should display.

That's because in your program that's the only thing that you return to the browser regardless of what the request looks like.

You can take a look at a more complete example that will return the correct files for the most common web pages (HTML, JPG, CSS, JS) in here https://gist.github.com/hectorcorrea/2573391

Also, take a look at this blog post that I wrote on how to get started with node. I think it might clarify a few things for you: http://hectorcorrea.com/blog/introduction-to-node-js

Computational complexity of Fibonacci Sequence

Just ask yourself how many statements need to execute for F(n) to complete.

For F(1), the answer is 1 (the first part of the conditional).

For F(n), the answer is F(n-1) + F(n-2).

So what function satisfies these rules? Try an (a > 1):

an == a(n-1) + a(n-2)

Divide through by a(n-2):

a2 == a + 1

Solve for a and you get (1+sqrt(5))/2 = 1.6180339887, otherwise known as the golden ratio.

So it takes exponential time.

SPA best practices for authentication and session management

I would go for the second, the token system.

Did you know about ember-auth or ember-simple-auth? They both use the token based system, like ember-simple-auth states:

A lightweight and unobtrusive library for implementing token based authentication in Ember.js applications. http://ember-simple-auth.simplabs.com

They have session management, and are easy to plug into existing projects too.

There is also an Ember App Kit example version of ember-simple-auth: Working example of ember-app-kit using ember-simple-auth for OAuth2 authentication.

How do I convert strings in a Pandas data frame to a 'date' data type?

Essentially equivalent to @waitingkuo, but I would use to_datetime here (it seems a little cleaner, and offers some additional functionality e.g. dayfirst):

In [11]: df
Out[11]:
   a        time
0  1  2013-01-01
1  2  2013-01-02
2  3  2013-01-03

In [12]: pd.to_datetime(df['time'])
Out[12]:
0   2013-01-01 00:00:00
1   2013-01-02 00:00:00
2   2013-01-03 00:00:00
Name: time, dtype: datetime64[ns]

In [13]: df['time'] = pd.to_datetime(df['time'])

In [14]: df
Out[14]:
   a                time
0  1 2013-01-01 00:00:00
1  2 2013-01-02 00:00:00
2  3 2013-01-03 00:00:00

Handling ValueErrors
If you run into a situation where doing

df['time'] = pd.to_datetime(df['time'])

Throws a

ValueError: Unknown string format

That means you have invalid (non-coercible) values. If you are okay with having them converted to pd.NaT, you can add an errors='coerce' argument to to_datetime:

df['time'] = pd.to_datetime(df['time'], errors='coerce')

Java Scanner class reading strings

use sc.nextLine(); two time so that we can read the last line of string

sc.nextLine() sc.nextLine()

How can I stop float left?

There's a class in bootstrap for it

class="clearfix";

How to install SQL Server Management Studio 2012 (SSMS) Express?

Easiest way to install MSSQL 2012 MS SQL INSTALLATION

Here i am showing the easiest way to install ms sql 2012.

My opinion is the installation will be easier with windows 8.1 rather than windows 7.

This is my personnal opinion only.

We can install in windows 7 as well.

The steps to be followed:

Download any one of the link using the following URL

http://www.microsoft.com/en-us/download/details.aspx?id=43351

SQLEXPRWT_x86_ENU.exe or SQLEXPRWT_x64_ENU.exe

http://www.microsoft.com/en-us/download/details.aspx?id=42299

SQLEXPRWT_x86_ENU.exe or SQLEXPRWT_x64_ENU.exe

Right click on .exe file and run it

We should leave everything default while installing.

During installation, there will be 2 options:

1)If you are New user,then click on new sql-server stand alone application.

2)If you have already MS SQL application then you can upgrade by using the other option.

Then accept the Licence terms and click Next.

Now you will move on to Product Updates and press next then Setup support rules.

After this Feature selection.According to me we can check all the boxes except localdb.

Next it will take you to Instance Configuration where you should select Named Instance as

"SQLEXPRESS".

Then go to Server Configuration and press next.

Now Database engine configuration:

Authentication Mode:we can click on any one that is windows authentication mode or mixed.

Windows authentication mode (default for windows).

Mixed authentication mode:then should create username and password.

Then move on Error reporting,we can move further by clicking next to install process.

Finally we can see the Complete windows by showing the products added .

We can close and run the MSSQL server.

I hope it's useful.

Regards

Ramya

How to check visibility of software keyboard in Android?

I was having difficulty maintaining keyboard state when changing orientation of fragments within a viewpager. I'm not sure why, but it just seems to be wonky and acts differently from a standard Activity.

To maintain keyboard state in this case, first you should add android:windowSoftInputMode = "stateUnchanged" to your AndroidManifest.xml. You may notice, though, that this doesn't actually solve the entire problem -- the keyboard didn't open for me if it was previously opened before orientation change. In all other cases, the behavior seemed to be correct.

Then, we need to implement one of the solutions mentioned here. The cleanest one I found was George Maisuradze's--use the boolean callback from hideSoftInputFromWindow:

InputMethodManager imm = (InputMethodManager) getSystemService(Activity.INPUT_METHOD_SERVICE);
return imm.hideSoftInputFromWindow(mViewPager.getWindowToken(), 0);

I stored this value in my Fragment's onSaveInstanceState method and retrieved it onCreate. Then, I forcibly showed the keyboard in onCreateView if it had a value of true (it returns true if the keyboard is visible before actually hiding it prior to the Fragment destruction).

break statement in "if else" - java

The issue is that you are trying to have multiple statements in an if without using {}. What you currently have is interpreted like:

if( choice==5 )
{
    System.out.println( ... );
}
break;
else
{
    //...
}

You really want:

if( choice==5 )
{
    System.out.println( ... );
    break;
}
else
{
    //...
}

Also, as Farce has stated, it would be better to use else if for all the conditions instead of if because if choice==1, it will still go through and check if choice==5, which would fail, and it will still go into your else block.

if( choice==1 )
    //...
else if( choice==2 )
    //...
else if( choice==3 )
    //...
else if( choice==4 )
    //...
else if( choice==5 )
{
    //...
}
else
    //...

A more elegant solution would be using a switch statement. However, break only breaks from the most inner "block" unless you use labels. So you want to label your loop and break from that if the case is 5:

LOOP:
for(;;)
{
    System.out.println("---> Your choice: ");
    choice = input.nextInt();
    switch( choice )
    {
        case 1:
            playGame();
            break;
        case 2:
            loadGame();
            break;
        case 2:
            options();
            break;
        case 4:
            credits();
            break;
        case 5:
            System.out.println("End of Game\n Thank you for playing with us!");
            break LOOP;
        default:
            System.out.println( ... );
    }
}

Instead of labeling the loop, you could also use a flag to tell the loop to stop.

bool finished = false;
while( !finished )
{
    switch( choice )
    {
        // ...
        case 5:
            System.out.println( ... )
            finished = true;
            break;
        // ...
    }
}

Rails Root directory path?

Simply By writing Rails.root and append anything by Rails.root.join(*%w( app assets)).to_s

How do I read the file content from the Internal storage - Android App

To read a file from internal storage:

Call openFileInput() and pass it the name of the file to read. This returns a FileInputStream. Read bytes from the file with read(). Then close the stream with close().

code::

StringBuilder sb = new StringBuilder();
        try{
            BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line).append("\n");
            }
            is.close();
        } catch(OutOfMemoryError om){
            om.printStackTrace();
        } catch(Exception ex){
            ex.printStackTrace();
        }
        String result = sb.toString();

using mailto to send email with an attachment

Nope, this is not possible at all. There is no provision for it in the mailto: protocol, and it would be a gaping security hole if it were possible.

The best idea to send a file, but have the client send the E-Mail that I can think of is:

  • Have the user choose a file
  • Upload the file to a server
  • Have the server return a random file name after upload
  • Build a mailto: link that contains the URL to the uploaded file in the message body

Create a pointer to two-dimensional array

Here you wanna make a pointer to the first element of the array

uint8_t (*matrix_ptr)[20] = l_matrix;

With typedef, this looks cleaner

typedef uint8_t array_of_20_uint8_t[20];
array_of_20_uint8_t *matrix_ptr = l_matrix;

Then you can enjoy life again :)

matrix_ptr[0][1] = ...;

Beware of the pointer/array world in C, much confusion is around this.


Edit

Reviewing some of the other answers here, because the comment fields are too short to do there. Multiple alternatives were proposed, but it wasn't shown how they behave. Here is how they do

uint8_t (*matrix_ptr)[][20] = l_matrix;

If you fix the error and add the address-of operator & like in the following snippet

uint8_t (*matrix_ptr)[][20] = &l_matrix;

Then that one creates a pointer to an incomplete array type of elements of type array of 20 uint8_t. Because the pointer is to an array of arrays, you have to access it with

(*matrix_ptr)[0][1] = ...;

And because it's a pointer to an incomplete array, you cannot do as a shortcut

matrix_ptr[0][0][1] = ...;

Because indexing requires the element type's size to be known (indexing implies an addition of an integer to the pointer, so it won't work with incomplete types). Note that this only works in C, because T[] and T[N] are compatible types. C++ does not have a concept of compatible types, and so it will reject that code, because T[] and T[10] are different types.


The following alternative doesn't work at all, because the element type of the array, when you view it as a one-dimensional array, is not uint8_t, but uint8_t[20]

uint8_t *matrix_ptr = l_matrix; // fail

The following is a good alternative

uint8_t (*matrix_ptr)[10][20] = &l_matrix;

You access it with

(*matrix_ptr)[0][1] = ...;
matrix_ptr[0][0][1] = ...; // also possible now

It has the benefit that it preserves the outer dimension's size. So you can apply sizeof on it

sizeof (*matrix_ptr) == sizeof(uint8_t) * 10 * 20

There is one other answer that makes use of the fact that items in an array are contiguously stored

uint8_t *matrix_ptr = l_matrix[0];

Now, that formally only allows you to access the elements of the first element of the two dimensional array. That is, the following condition hold

matrix_ptr[0] = ...; // valid
matrix_ptr[19] = ...; // valid

matrix_ptr[20] = ...; // undefined behavior
matrix_ptr[10*20-1] = ...; // undefined behavior

You will notice it probably works up to 10*20-1, but if you throw on alias analysis and other aggressive optimizations, some compiler could make an assumption that may break that code. Having said that, i've never encountered a compiler that fails on it (but then again, i've not used that technique in real code), and even the C FAQ has that technique contained (with a warning about its UB'ness), and if you cannot change the array type, this is a last option to save you :)

ORA-00942: table or view does not exist (works when a separate sql, but does not work inside a oracle function)

A very simple solution is to add the database name with your table name like if your DB name is DBMS and table is info then it will be DBMS.info for any query.

If your query is

select * from STUDENTREC where ROLL_NO=1;

it might show an error but

select * from DBMS.STUDENTREC where ROLL_NO=1; 

it doesn't because now actually your table is found.

How can I change image source on click with jQuery?

You can use jQuery's attr() function, like $("#id").attr('src',"source").

How to disable postback on an asp Button (System.Web.UI.WebControls.Button)

The others are right that you need your callback to return false; however I'd like to add that doing it by setting the onclick is an ugly old way of doing things. I'd recommend reading about unobtrusive javascript. Using a library like jQuery could make your life easier, and the HTML less coupled to your javascript (and jQuery's supported by Microsoft now!)

Yes/No message box using QMessageBox

QT can be as simple as that of Windows. The equivalent code is

if (QMessageBox::Yes == QMessageBox(QMessageBox::Information, "title", "Question", QMessageBox::Yes|QMessageBox::No).exec()) 
{

}

What special characters must be escaped in regular expressions?

Modern RegEx Flavors (PCRE)

Includes C, C++, Delphi, EditPad, Java, JavaScript, Perl, PHP (preg), PostgreSQL, PowerGREP, PowerShell, Python, REALbasic, Real Studio, Ruby, TCL, VB.Net, VBScript, wxWidgets, XML Schema, Xojo, XRegExp.
PCRE compatibility may vary

    Anywhere: . ^ $ * + - ? ( ) [ ] { } \ |


Legacy RegEx Flavors (BRE/ERE)

Includes awk, ed, egrep, emacs, GNUlib, grep, PHP (ereg), MySQL, Oracle, R, sed.
PCRE support may be enabled in later versions or by using extensions

ERE/awk/egrep/emacs

    Outside a character class: . ^ $ * + ? ( ) [ { } \ |
    Inside a character class: ^ - [ ]

BRE/ed/grep/sed

    Outside a character class: . ^ $ * [ \
    Inside a character class: ^ - [ ]
    For literals, don't escape: + ? ( ) { } |
    For standard regex behavior, escape: \+ \? \( \) \{ \} \|


Notes

  • If unsure about a specific character, it can be escaped like \xFF
  • Alphanumeric characters cannot be escaped with a backslash
  • Arbitrary symbols can be escaped with a backslash in PCRE, but not BRE/ERE (they must only be escaped when required). For PCRE ] - only need escaping within a character class, but I kept them in a single list for simplicity
  • Quoted expression strings must also have the surrounding quote characters escaped, and often with backslashes doubled-up (like "(\")(/)(\\.)" versus /(")(\/)(\.)/ in JavaScript)
  • Aside from escapes, different regex implementations may support different modifiers, character classes, anchors, quantifiers, and other features. For more details, check out regular-expressions.info, or use regex101.com to test your expressions live

Adding null values to arraylist

Yes, you can always use null instead of an object. Just be careful because some methods might throw error.

It would be 1.

also nulls would be factored in in the for loop, but you could use

 for(Item i : itemList) {
        if (i!= null) {
               //code here
        }
 }

Only using @JsonIgnore during serialization, but not deserialization

Since version 2.6: a more intuitive way is to use the com.fasterxml.jackson.annotation.JsonProperty annotation on the field:

@JsonProperty(access = Access.WRITE_ONLY)
private String myField;

Even if a getter exists, the field value is excluded from serialization.

JavaDoc says:

/**
 * Access setting that means that the property may only be written (set)
 * for deserialization,
 * but will not be read (get) on serialization, that is, the value of the property
 * is not included in serialization.
 */
WRITE_ONLY

In case you need it the other way around, just use Access.READ_ONLY.

Add timer to a Windows Forms application

Bit more detail:

    private void Form1_Load(object sender, EventArgs e)
    {
        Timer MyTimer = new Timer();
        MyTimer.Interval = (45 * 60 * 1000); // 45 mins
        MyTimer.Tick += new EventHandler(MyTimer_Tick);
        MyTimer.Start();
    }

    private void MyTimer_Tick(object sender, EventArgs e)
    {
        MessageBox.Show("The form will now be closed.", "Time Elapsed");
        this.Close();
    }

Recursive sub folder search and return files in a list python

I will translate John La Rooy's list comprehension to nested for's, just in case anyone else has trouble understanding it.

result = [y for x in os.walk(PATH) for y in glob(os.path.join(x[0], '*.txt'))]

Should be equivalent to:

import glob
import os

result = []

for x in os.walk(PATH):
    for y in glob.glob(os.path.join(x[0], '*.txt')):
        result.append(y)

Here's the documentation for list comprehension and the functions os.walk and glob.glob.

Convert int to ASCII and back in Python

ASCII to int:

ord('a')

gives 97

And back to a string:

  • in Python2: str(unichr(97))
  • in Python3: chr(97)

gives 'a'

With MySQL, how can I generate a column containing the record index in a table?

You can also use

SELECT @curRow := ifnull(@curRow,0) + 1 Row, ...

to initialise the counter variable.

C++ performance vs. Java/C#

If you're a Java/C# programmer learning C++, you'll be tempted to keep thinking in terms of Java/C# and translate verbatim to C++ syntax. In that case, you only get the earlier mentioned benefits of native code vs. interpreted/JIT. To get the biggest performance gain in C++ vs. Java/C#, you have to learn to think in C++ and design code specifically to exploit the strengths of C++.

To paraphrase Edsger Dijkstra: [your first language] mutilates the mind beyond recovery.
To paraphrase Jeff Atwood: you can write [your first language] in any new language.

How to add the JDBC mysql driver to an Eclipse project?

if you are getting this exception again and again then download my-sql connector and paste in tomcat/WEB-INF/lib folder...note that some times WEB-INF folder does not contains lib folder, at that time manually create lib folder and paste mysql connector in that folder..definitely this will work.if still you got problem then check that your jdk must match your system. i.e if your system is 64 bit then jdk must be 64 bit

How can I search for a commit message on GitHub?

Since this has been removed from GitHub, I've been using gitk on Linux to do this.

From terminal go to your repository and type gitk.

In the middle of the GUI, there's a search box. It provides a good selection of filters:

Search bar

Scope - containing, touching paths, adding/removing string, changing line matching

Match type - Exact/IgnCase/Regexp

Search fields - All fields/Headline/Comments/Committer

PHP Fatal error when trying to access phpmyadmin mb_detect_encoding

One options is: disabled this extension_dir = "ext"

and the other is:

go to wamp icon and see php and the click on php error logs then from error log u can find exact error.

this error occurs only if paths are not properly set.

Build Step Progress Bar (css and jquery)

This is what I did:

  1. Create jQuery .progressbar() to load a div into a progress bar.
  2. Create the step title on the bottom of the progress bar. Position them with CSS.
  3. Then I create function in jQuery that change the value of the progressbar everytime user move on to next step.

HTML

<div id="divProgress"></div>
<div id="divStepTitle">
    <span class="spanStep">Step 1</span> <span class="spanStep">Step 2</span> <span class="spanStep">Step 3</span>
</div>

<input type="button" id="btnPrev" name="btnPrev" value="Prev" />
<input type="button" id="btnNext" name="btnNext" value="Next" />

CSS

#divProgress
{
    width: 600px;
}

#divStepTitle
{
    width: 600px;
}

.spanStep
{
    text-align: center;
    width: 200px;
}

Javascript/jQuery

var progress = 0;

$(function({
    //set step progress bar
    $("#divProgress").progressbar();

    //event handler for prev and next button
    $("#btnPrev, #btnNext").click(function(){
        step($(this));
    });
});

function step(obj)
{
    //switch to prev/next page
    if (obj.val() == "Prev")
    {
        //set new value for progress bar
        progress -= 20;
        $("#divProgress").progressbar({ value: progress });

        //do extra step for showing previous page
    }
    else if (obj.val() == "Next")
    {
        //set new value for progress bar
        progress += 20;
        $("#divProgress").progressbar({ value: progress });

        //do extra step for showing next page
    }
}

How can I use an array of function pointers?

Oh, there are tons of example. Just have a look at anything within glib or gtk. You can see the work of function pointers in work there all the way.

Here e.g the initialization of the gtk_button stuff.


static void
gtk_button_class_init (GtkButtonClass *klass)
{
  GObjectClass *gobject_class;
  GtkObjectClass *object_class;
  GtkWidgetClass *widget_class;
  GtkContainerClass *container_class;

  gobject_class = G_OBJECT_CLASS (klass);
  object_class = (GtkObjectClass*) klass;
  widget_class = (GtkWidgetClass*) klass;
  container_class = (GtkContainerClass*) klass;

  gobject_class->constructor = gtk_button_constructor;
  gobject_class->set_property = gtk_button_set_property;
  gobject_class->get_property = gtk_button_get_property;

And in gtkobject.h you find the following declarations:


struct _GtkObjectClass
{
  GInitiallyUnownedClass parent_class;

  /* Non overridable class methods to set and get per class arguments */
  void (*set_arg) (GtkObject *object,
           GtkArg    *arg,
           guint      arg_id);
  void (*get_arg) (GtkObject *object,
           GtkArg    *arg,
           guint      arg_id);

  /* Default signal handler for the ::destroy signal, which is
   *  invoked to request that references to the widget be dropped.
   *  If an object class overrides destroy() in order to perform class
   *  specific destruction then it must still invoke its superclass'
   *  implementation of the method after it is finished with its
   *  own cleanup. (See gtk_widget_real_destroy() for an example of
   *  how to do this).
   */
  void (*destroy)  (GtkObject *object);
};

The (*set_arg) stuff is a pointer to function and this can e.g be assigned another implementation in some derived class.

Often you see something like this

struct function_table {
   char *name;
   void (*some_fun)(int arg1, double arg2);
};

void function1(int  arg1, double arg2)....


struct function_table my_table [] = {
    {"function1", function1},
...

So you can reach into the table by name and call the "associated" function.

Or maybe you use a hash table in which you put the function and call it "by name".

Regards
Friedrich

Truststore and Keystore Definitions

In a SSL handshake the purpose of trustStore is to verify credentials and the purpose of keyStore is to provide credential.

keyStore

keyStore in Java stores private key and certificates corresponding to their public keys and require if you are SSL Server or SSL requires client authentication.

TrustStore

TrustStore stores certificates from third party, your Java application communicate or certificates signed by CA(certificate authorities like Verisign, Thawte, Geotrust or GoDaddy) which can be used to identify third party.

TrustManager

TrustManager determines whether remote connection should be trusted or not i.e. whether remote party is who it claims to and KeyManager decides which authentication credentials should be sent to the remote host for authentication during SSL handshake.

If you are an SSL Server you will use private key during key exchange algorithm and send certificates corresponding to your public keys to client, this certificate is acquired from keyStore. On SSL client side, if its written in Java, it will use certificates stored in trustStore to verify identity of Server. SSL certificates are most commonly comes as .cer file which is added into keyStore or trustStore by using any key management utility e.g. keytool.

Source: http://javarevisited.blogspot.ch

How to display raw html code in PRE or something like it but without escaping it

Essentially the original question can be broken down in 2 parts:

  • Main objective/challenge: embedding(/transporting) a raw formatted code-snippet (any kind of code) in a web-page's markup (for simple copy/paste/edit due to no encoding/escaping)
  • correctly displaying/rendering that code-snippet (possibly edit it) in the browser

The short (but) ambiguous answer is: you can't, ...but you can (get very close).
(I know, that are 3 contradicting answers, so read on...)

(polyglot)(x)(ht)ml Markup-languages rely on wrapping (almost) everything between begin/opening and end/closing tags/character(sequences).
So, to embed any kind of raw code/snippet inside your markup-language, one will always have to escape/encode every instance (inside that snippet) that resembles the character(-sequence) that would close the wrapping 'container' element in the markup. (During this post I'll refer to this as rule no 1.)
Think of "some "data" here" or <i>..close italics with '</i>'-tag</i>, where it is obvious one should escape/encode (something in) </i and " (or change container's quote-character from " to ').

So, because of rule no 1, you can't 'just' embed 'any' unknown raw code-snippet inside markup.
Because, if one has to escape/encode even one character inside the raw snippet, then that snippet would no longer be the same original 'pure raw code' that anyone can copy/paste/edit in the document's markup without further thought. It would lead to malformed/illegal markup and Mojibake (mainly) because of entities.
Also, should that snippet contain such characters, you'd still need some javascript to 'translate' that character(sequence) from (and to) it's escaped/encoded representation to display the snippet correctly in the 'webpage' (for copy/paste/edit).

That brings us to (some of) the datatypes that markup-languages specify. These datatypes essentially define what are considered 'valid characters' and their meaning (per tag, property, etc.):

  • PCDATA (Parsed Character DATA): will expand entities and one must escape <, & (and > depending on markup language/version).
    Most tags like body, div, pre, etc, but also textarea (until HTML5) fall under this type.
    So not only do you need to encode all the container's closing character-sequences inside the snippet, you also have to encode all <, & (,>) characters (at minimum).
    Needless to say, encoding/escaping this many characters falls outside this objective's scope of embedding a raw snippet in the markup.
    '..But a textarea seems to work...', yes, either because of the browsers error-engine trying to make something out of it, or because HTML5:

  • RCDATA (Replaceable Character DATA): will not not treat tags inside the text as markup (but are still governed by rule 1), so one doesn't need to encode < (>). BUT entities are still expanded, so they and 'ambiguous ampersands' (&) need special care.
    The current HTML5 spec says the textarea is now a RCDATA field and (quote):

    The text in raw text and RCDATA elements must not contain any occurrences of the string "</" (U+003C LESS-THAN SIGN, U+002F SOLIDUS) followed by characters that case-insensitively match the tag name of the element followed by one of U+0009 CHARACTER TABULATION (tab), U+000A LINE FEED (LF), U+000C FORM FEED (FF), U+000D CARRIAGE RETURN (CR), U+0020 SPACE, U+003E GREATER-THAN SIGN (>), or U+002F SOLIDUS (/).

    Thus no matter what, textarea needs a hefty entity translation handler or it will eventually Mojibake on entities!

  • CDATA (Character Data) will not treat tags inside the text as markup and will not expand entities.
    So as long as the raw snippet code does not violate rule 1 (that one can't have the containers closing character(sequence) inside the snippet), this requires no other escaping/encoding.

Clearly this boils down to: how can we minimize the number of characters/character-sequences that still need to be encoded in the snippet's raw source and the number of times that character(sequence) might appear in an average snippet; something that is also of importance for the javascript that handles the translation of these characters (if they occur).

So what 'containers' have this CDATA context?

Most value properties of tags are CDATA, so one could (ab)use a hidden input's value property (proof of concept jsfiddle here).
However (conform rule 1) this creates an encoding/escape problem with nested quotes (" and ') in the raw snippet and one needs some javascript to get/translate and set the snippet in another (visible) element (or simply setting it as a text-area's value). Somehow this gave me problems with entities in FF (just like in a textarea). But it doesn't really matter, since the 'price' of having to escape/encode nested quotes is higher then a (HTML5) textarea (quotes are quite common in source code..).

What about trying to (ab)use <![CDATA[<tag>bla & bla</tag>]]>?
As Jukka points out in his extended answer, this would only work in (rare) 'real xhtml'.
I thought of using a script-tag (with or without such a CDATA wrapper inside the script-tag) together with a multi-line comment /* */ that wraps the raw snippet (script-tags can have an id and you can access them by count). But since this obviously introduces a escaping problem with */, ]]> and </script in the raw snippet, this doesn't seem like a solution either.

Please post other viable 'containers' in the comments to this answer.

By the way, encoding or counting the number of - characters and balancing them out inside a comment tag <!-- --> is just insane for this purpose (apart from rule 1).


That leaves us with Jukka K. Korpela's excellent answer: the <xmp> tag seems the best option!

The 'forgotten' <xmp> holds CDATA, is intended for this purpose AND is indeed still in the current HTML 5 spec (and has been at least since HTML3.2); exactly what we need! It's also widely supported, even in IE6 (that is.. until it suffers from the same regression as the scrolling table-body).
Note: as Jukka pointed out, this will not work in true xhtml or polyglot (that will treat it as a pre) and the xmp tag must still adhere to rule no 1. But that's the 'only' rule.

Consider the following markup:

<!-- ATTENTION: replace any occurrence of &lt;/xmp with </xmp -->
<xmp id="snippet-container">
<div>
    <div>this is an example div &amp; holds an xmp tag:<br />
        <xmp> 
<html><head>  <!-- indentation col 0!! -->
    <title>My Title</title>
</head><body>
    <p>hello world !!</p>
</body></html>
        &lt;/xmp>  <!-- note this encoded/escaped tag -->
    </div>
    This line is also part of the snippet
</div>
</xmp>

The above codeblok illustrates a raw piece of markup where <xmp id="snippet-container"> contains an (almost raw) code-snippet (containing div>div>xmp>html-document).
Notice the encoded closing tag in this markup? To comply with rule no 1, this was encoded/escaped).

So embedding/transporting the (sometimes almost) raw code is/seems solved.

What about displaying/rendering the snippet (and that encoded &lt;/xmp>)?

The browser will (or it should) render the snippet (the contents inside snippet-container) exactly the way you see it in the codeblock above (with some discrepancy amongst browsers whether or not the snippet starts with a blank line).
That includes the formatting/indentation, entities (like the string &amp;), full tags, comments AND the encoded closing tag &lt;/xmp> (just like it was encoded in the markup). And depending on browser(version) one could even try use the property contenteditable="true" to edit this snippet (all that without javascript enabled). Doing something like textarea.value=xmp.innerHTML is also a breeze.

So you can... if the snippet doesn't contain the containers closing character-sequence.

However, should a raw snippet contain the closing character-sequence </xmp (because it is an example of xmp itself or it contains some regex, etc), you must accept that you have to encode/escape that sequence in the raw snippet AND need a javascript handler to translate that encoding to display/render the encoded &lt;/xmp> like </xmp> inside a textarea (for editing/posting) or (for example) a pre just to correctly render the snippet's code (or so it seems).

A very rudimentary jsfiddle example of this here. Note that getting/embedding/displaying/retrieving-to-textarea worked perfect even in IE6. But setting the xmp's innerHTML revealed some interesting 'would-be-intelligent' behavior on IE's part. There is a more extensive note and workaround on that in the fiddle.

But now comes the important kicker (another reason why you only get very close): Just as an over-simplified example, imagine this rabbit-hole:

Intended raw code-snippet:

<!-- remember to translate between </xmp> and &lt;/xmp> -->
<xmp>
<p>a paragraph</p>
</xmp>

Well, to comply with rule 1, we 'only' need to encode those </xmp[> \n\r\t\f\/] sequences, right?

So that gives us the following markup (using just a possible encoding):

<xmp id="container">
<!-- remember to translate between &lt;/xmp> and &lt;/xmp> -->
<xmp>
<p>a paragraph</p>
&lt;/xmp>
</xmp>

Hmm.. shalt I get my crystal ball or flip a coin? No, let the computer look at its system-clock and state that a derived number is 'random'. Yes, that should do it..

Using a regex like: xmp.innerHTML.replace(/&lt;(?=\/xmp[> \n\r\t\f\/])/gi, '<');, would translate 'back' to this:

<!-- remember to translate between </xmp> and </xmp> -->
<xmp>
<p>a paragraph</p>
</xmp>

Hmm.. seems this random generator is broken... Houston..?
Should you have missed the joke/problem, read again starting at the 'intended raw code-snippet'.

Wait, I know, we (also) need to encode .... to ....
Ok, rewind to 'intended raw code-snippet' and read again.
Somehow this all begins to smell like the famous hilarious-but-true rexgex-answer on SO, a good read for people fluent in mojibake.

Maybe someone knows a clever algorithm or solution to fix this problem, but I assume that the embedded raw code will get more and more obscure to the point where you'd be better of properly escaping/encoding just your <, & (and >), just like the rest of the world.

Conclusion: (using the xmp tag)

  • it can be done with known snippets that do not contain the container's closing character-sequence,
  • we can get very close to the original objective with known snippets that only use 'basic first-level' escaping/encoding so we don't fall in the rabbithole,
  • but ultimately it seems that one can't do this reliably in a 'production-environment' where people can/should copy/paste/edit 'any unknown' raw snippets while not knowing/understanding the implications/rules/rabbithole (depending on your implementation of handling/translating for rule 1 and the rabbit-hole).

Hope this helps!

PS: Whilst I would appreciate an upvote if you find this explanation useful, I kind of think Jukka's answer should be the accepted answer (should no better option/answer come along), since he was the one who remembered the xmp tag (that I forgot about over the years and got 'distracted' by the commonly advocated PCDATA elements like pre, textarea, etc.).
This answer originated in explaining why you can't do it (with any unknown raw snippet) and explain some obvious pitfalls that some other (now deleted) answers overlooked when advising a textarea for embedding/transport. I've expanded my existing explanation to also support and further explain Jukka's answer (since all that entity and *CDATA stuff is almost harder than code-pages).

Targeting both 32bit and 64bit with Visual Studio in same solution/project

Let's say you have the DLLs build for both platforms, and they are in the following location:

C:\whatever\x86\whatever.dll
C:\whatever\x64\whatever.dll

You simply need to edit your .csproj file from this:

<HintPath>C:\whatever\x86\whatever.dll</HintPath>

To this:

<HintPath>C:\whatever\$(Platform)\whatever.dll</HintPath>

You should then be able to build your project targeting both platforms, and MSBuild will look in the correct directory for the chosen platform.

Get specific ArrayList item

You can simply get your answer from ArrayList API doc.

Please always refer API documentation .. it helps

Your call will looklike following :

mainList.get(3);

Here is simple tutorial for understanding ArrayList with Basics :) :

http://www.javadeveloper.co.in/java/java-arraylist-tutorial.html

Add Bootstrap Glyphicon to Input Box

You can use its Unicode HTML

So to add a user icon, just add &#xe008; to the placeholder attribute, or wherever you want it.

You may want to check this cheat sheet.

Example:

_x000D_
_x000D_
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">_x000D_
<input type="text" class="form-control" placeholder="&#xe008; placeholder..." style="font-family: 'Glyphicons Halflings', Arial">_x000D_
<input type="text" class="form-control" value="&#xe008; value..." style="font-family: 'Glyphicons Halflings', Arial">_x000D_
<input type="submit" class="btn btn-primary" value="&#xe008; submit-button" style="font-family: 'Glyphicons Halflings', Arial">
_x000D_
_x000D_
_x000D_

Don't forget to set the input's font to the Glyphicon one, using the following code: font-family: 'Glyphicons Halflings', Arial, where Arial is the font of the regular text in the input.

Excel VBA Copy a Range into a New Workbook

Modify to suit your specifics, or make more generic as needed:

Private Sub CopyItOver()
  Set NewBook = Workbooks.Add
  Workbooks("Whatever.xlsx").Worksheets("output").Range("A1:K10").Copy
  NewBook.Worksheets("Sheet1").Range("A1").PasteSpecial (xlPasteValues)
  NewBook.SaveAs FileName:=NewBook.Worksheets("Sheet1").Range("E3").Value
End Sub

Find and Replace string in all files recursive using grep and sed

The GNU guys REALLY messed up when they introduced recursive file searching to grep. grep is for finding REs in files and printing the matching line (g/re/p remember?) NOT for finding files. There's a perfectly good tool with a very obvious name for FINDing files. Whatever happened to the UNIX mantra of do one thing and do it well?

Anyway, here's how you'd do what you want using the traditional UNIX approach (untested):

find /path/to/folder -type f -print |
while IFS= read -r file
do
   awk -v old="$oldstring" -v new="$newstring" '
      BEGIN{ rlength = length(old) }
      rstart = index($0,old) { $0 = substr($0,rstart-1) new substr($0,rstart+rlength) }
      { print }
   ' "$file" > tmp &&
   mv tmp "$file"
done

Not that by using awk/index() instead of sed and grep you avoid the need to escape all of the RE metacharacters that might appear in either your old or your new string plus figure out a character to use as your sed delimiter that can't appear in your old or new strings, and that you don't need to run grep since the replacement will only occur for files that do contain the string you want. Having said all of that, if you don't want the file timestamp to change if you don't modify the file, then just do a diff on tmp and the original file before doing the mv or throw in an fgrep -q before the awk.

Caveat: The above won't work for file names that contain newlines. If you have those then let us know and we can show you how to handle them.

Get an object attribute

You can do the following:

class User(object):
    fullName = "John Doe"

    def __init__(self, name):
        self.SName = name

    def print_names(self):
        print "Names: full name: '%s', name: '%s'" % (self.fullName, self.SName)

user = User('Test Name')

user.fullName # "John Doe"
user.SName # 'Test Name'
user.print_names() # will print you Names: full name: 'John Doe', name: 'Test Name'

E.g any object attributes could be retrieved using istance.

Pretty git branch graphs

gitg: a gtk-based repository viewer, that's new but interesting and useful
http://git.gnome.org/browse/gitg
I use it currently

Extract values in Pandas value_counts()

If anyone missed it out in the comments, try this:

dataframe[column].value_counts().to_frame()

What is the preferred syntax for initializing a dict: curly brace literals {} or the dict() function?

Sometimes dict() is a good choice:

a=dict(zip(['Mon','Tue','Wed','Thu','Fri'], [x for x in range(1, 6)]))

mydict=dict(zip(['mon','tue','wed','thu','fri','sat','sun'],

[random.randint(0,100) for x in range(0,7)]))

How to make an introduction page with Doxygen

Have a look at the mainpage command.

Also, have a look this answer to another thread: How to include custom files in Doxygen. It states that there are three extensions which doxygen classes as additional documentation files: .dox, .txt and .doc. Files with these extensions do not appear in the file index but can be used to include additional information into your final documentation - very useful for documentation that is necessary but that is not really appropriate to include with your source code (for example, an FAQ)

So I would recommend having a mainpage.dox (or similarly named) file in your project directory to introduce you SDK. Note that inside this file you need to put one or more C/C++ style comment blocks.

How to redirect the output of a PowerShell to a file during its execution

One possible solution, if your situation allows it:

  1. Rename MyScript.ps1 to TheRealMyScript.ps1
  2. Create a new MyScript.ps1 that looks like:

    .\TheRealMyScript.ps1 > output.txt

What are the main performance differences between varchar and nvarchar SQL Server data types?

For that last few years all of our projects have used NVARCHAR for everything, since all of these projects are multilingual. Imported data from external sources (e.g. an ASCII file, etc.) is up-converted to Unicode before being inserted into the database.

I've yet to encounter any performance-related issues from the larger indexes, etc. The indexes do use more memory, but memory is cheap.

Whether you use stored procedures or construct SQL on the fly ensure that all string constants are prefixed with N (e.g. SET @foo = N'Hello world.';) so the constant is also Unicode. This avoids any string type conversion at runtime.

YMMV.

Is it possible to run one logrotate check manually?

If you want to force-run a single specific directory or daemon's log files, you can usually find the configuration in /etc/logrotate.d, and they will work standalone.

Keep in mind that global configuration specified in /etc/logrotate.conf will not apply, so if you do this you should ensure you specify all the options you want in the /etc/logrotate.d/[servicename] config file specifically.

You can try it out with -d to see what would happen:

logrotate -df /etc/logrotate.d/nginx

Then you can run (using nginx as an example):

logrotate -f /etc/logrotate.d/nginx

And the nginx logs alone will be rotated.

java.lang.ClassNotFoundException: sun.jdbc.odbc.JdbcOdbcDriver Exception occurring. Why?

in JDK 8, jdbc odbc bridge is no longer used and thus removed fro the JDK. to use Microsoft Access database in JAVA, you need 5 extra JAR libraries.

1- hsqldb.jar

2- jackcess 2.0.4.jar

3- commons-lang-2.6.jar

4- commons-logging-1.1.1.jar

5- ucanaccess-2.0.8.jar

add these libraries to your java project and start with following lines.

Connection conn=DriverManager.getConnection("jdbc:ucanaccess://<Path to your database i.e. MS Access DB>");
Statement s = conn.createStatement();

path could be like E:/Project/JAVA/DBApp

and then your query to be executed. Like

ResultSet rs = s.executeQuery("SELECT * FROM Course");
while(rs.next())
    System.out.println(rs.getString("Title") + " " + rs.getString("Code") + " " + rs.getString("Credits"));

certain imports to be used. try catch block must be used and some necessary things no to be forgotten.

Remember, no need of bridging drivers like jdbc odbc or any stuff.

How to use confirm using sweet alert?

I have been having this issue with SweetAlert2 as well. SA2 differs from 1 and puts everything inside the result object. The following above can be accomplished with the following code.

Swal.fire({
    title: 'A cool title',
    icon: 'info',
    confirmButtonText: 'Log in'
  }).then((result) => {
    if (result['isConfirmed']){
      // Put your function here
    }
  })

Everything placed inside the then result will run. Result holds a couple of parameters which can be used to do the trick. Pretty simple technique. Not sure if it works the same on SweetAlert1 but I really wouldn't know why you would choose that one above the newer version.

Difference between signed / unsigned char

There's no dedicated "character type" in C language. char is an integer type, same (in that regard) as int, short and other integer types. char just happens to be the smallest integer type. So, just like any other integer type, it can be signed or unsigned.

It is true that (as the name suggests) char is mostly intended to be used to represent characters. But characters in C are represented by their integer "codes", so there's nothing unusual in the fact that an integer type char is used to serve that purpose.

The only general difference between char and other integer types is that plain char is not synonymous with signed char, while with other integer types the signed modifier is optional/implied.

How to get everything after a certain character?

$string = "233718_This_is_a_string";
$withCharacter = strstr($string, '_'); // "_This_is_a_string"
echo substr($withCharacter, 1); // "This_is_a_string"

In a single statement it would be.

echo substr(strstr("233718_This_is_a_string", '_'), 1); // "This_is_a_string"

Best way to encode text data for XML

Depending on how much you know about the input, you may have to take into account that not all Unicode characters are valid XML characters.

Both Server.HtmlEncode and System.Security.SecurityElement.Escape seem to ignore illegal XML characters, while System.XML.XmlWriter.WriteString throws an ArgumentException when it encounters illegal characters (unless you disable that check in which case it ignores them). An overview of library functions is available here.

Edit 2011/8/14: seeing that at least a few people have consulted this answer in the last couple years, I decided to completely rewrite the original code, which had numerous issues, including horribly mishandling UTF-16.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

/// <summary>
/// Encodes data so that it can be safely embedded as text in XML documents.
/// </summary>
public class XmlTextEncoder : TextReader {
    public static string Encode(string s) {
        using (var stream = new StringReader(s))
        using (var encoder = new XmlTextEncoder(stream)) {
            return encoder.ReadToEnd();
        }
    }

    /// <param name="source">The data to be encoded in UTF-16 format.</param>
    /// <param name="filterIllegalChars">It is illegal to encode certain
    /// characters in XML. If true, silently omit these characters from the
    /// output; if false, throw an error when encountered.</param>
    public XmlTextEncoder(TextReader source, bool filterIllegalChars=true) {
        _source = source;
        _filterIllegalChars = filterIllegalChars;
    }

    readonly Queue<char> _buf = new Queue<char>();
    readonly bool _filterIllegalChars;
    readonly TextReader _source;

    public override int Peek() {
        PopulateBuffer();
        if (_buf.Count == 0) return -1;
        return _buf.Peek();
    }

    public override int Read() {
        PopulateBuffer();
        if (_buf.Count == 0) return -1;
        return _buf.Dequeue();
    }

    void PopulateBuffer() {
        const int endSentinel = -1;
        while (_buf.Count == 0 && _source.Peek() != endSentinel) {
            // Strings in .NET are assumed to be UTF-16 encoded [1].
            var c = (char) _source.Read();
            if (Entities.ContainsKey(c)) {
                // Encode all entities defined in the XML spec [2].
                foreach (var i in Entities[c]) _buf.Enqueue(i);
            } else if (!(0x0 <= c && c <= 0x8) &&
                       !new[] { 0xB, 0xC }.Contains(c) &&
                       !(0xE <= c && c <= 0x1F) &&
                       !(0x7F <= c && c <= 0x84) &&
                       !(0x86 <= c && c <= 0x9F) &&
                       !(0xD800 <= c && c <= 0xDFFF) &&
                       !new[] { 0xFFFE, 0xFFFF }.Contains(c)) {
                // Allow if the Unicode codepoint is legal in XML [3].
                _buf.Enqueue(c);
            } else if (char.IsHighSurrogate(c) &&
                       _source.Peek() != endSentinel &&
                       char.IsLowSurrogate((char) _source.Peek())) {
                // Allow well-formed surrogate pairs [1].
                _buf.Enqueue(c);
                _buf.Enqueue((char) _source.Read());
            } else if (!_filterIllegalChars) {
                // Note that we cannot encode illegal characters as entity
                // references due to the "Legal Character" constraint of
                // XML [4]. Nor are they allowed in CDATA sections [5].
                throw new ArgumentException(
                    String.Format("Illegal character: '{0:X}'", (int) c));
            }
        }
    }

    static readonly Dictionary<char,string> Entities =
        new Dictionary<char,string> {
            { '"', "&quot;" }, { '&', "&amp;"}, { '\'', "&apos;" },
            { '<', "&lt;" }, { '>', "&gt;" },
        };

    // References:
    // [1] http://en.wikipedia.org/wiki/UTF-16/UCS-2
    // [2] http://www.w3.org/TR/xml11/#sec-predefined-ent
    // [3] http://www.w3.org/TR/xml11/#charsets
    // [4] http://www.w3.org/TR/xml11/#sec-references
    // [5] http://www.w3.org/TR/xml11/#sec-cdata-sect
}

Unit tests and full code can be found here.

How to execute a raw update sql with dynamic binding in rails

I needed to use raw sql because I failed at getting composite_primary_keys to function with activerecord 2.3.8. So in order to access the sqlserver 2000 table with a composite primary key, raw sql was required.

sql = "update [db].[dbo].[#{Contacts.table_name}] " +
      "set [COLUMN] = 0 " +
      "where [CLIENT_ID] = '#{contact.CLIENT_ID}' and CONTACT_ID = '#{contact.CONTACT_ID}'"
st = ActiveRecord::Base.connection.raw_connection.prepare(sql)
st.execute

If a better solution is available, please share.

CSS background opacity with rgba not working in IE 8

Create a png which is larger than 1x1 pixel (thanks thirtydot), and which matches the transparency of your background.

EDIT : to fall back for IE6+ support, you can specify bkgd chunk for the png, this is a color which will replace the true alpha transparency if it is not supported. You can fix it with gimp eg.

Why can't I duplicate a slice with `copy()`?

NOTE: This is an incorrect solution as @benlemasurier proved

Here is a way to copy a slice. I'm a bit late, but there is a simpler, and faster answer than @Dave's. This are the instructions generated from a code like @Dave's. These is the instructions generated by mine. As you can see there are far fewer instructions. What is does is it just does append(slice), which copies the slice. This code:

package main

import "fmt"

func main() {
    var foo = []int{1, 2, 3, 4, 5}
    fmt.Println("foo:", foo)
    var bar = append(foo)
    fmt.Println("bar:", bar)
    bar = append(bar, 6)
    fmt.Println("foo after:", foo)
    fmt.Println("bar after:", bar)
}

Outputs this:

foo: [1 2 3 4 5]
bar: [1 2 3 4 5]
foo after: [1 2 3 4 5]
bar after: [1 2 3 4 5 6]

Datanode process not running in Hadoop

I was having the same problem running a single-node pseudo-distributed instance. Couldn't figure out how to solve it, but a quick workaround is to manually start a DataNode with
hadoop-x.x.x/bin/hadoop datanode

Android emulator not able to access the internet

[UPDATE 2020] for Mac Users

  1. System Preferences
  2. Network
  3. WiFi > Select Advanced
  4. From Advanced Choose DNS tab
  5. Add DNS Server 8.8.8.8

How to export table data in MySql Workbench to csv?

U can use mysql dump or query to export data to csv file

SELECT *
INTO OUTFILE '/tmp/products.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
ESCAPED BY '\\'
LINES TERMINATED BY '\n'
FROM products

Organizing a multiple-file Go project

I would recommend reviewing this page on How to Write Go Code

It documents both how to structure your project in a go build friendly way, and also how to write tests. Tests do not need to be a cmd using the main package. They can simply be TestX named functions as part of each package, and then go test will discover them.

The structure suggested in that link in your question is a bit outdated, now with the release of Go 1. You no longer would need to place a pkg directory under src. The only 3 spec-related directories are the 3 in the root of your GOPATH: bin, pkg, src . Underneath src, you can simply place your project mypack, and underneath that is all of your .go files including the mypack_test.go

go build will then build into the root level pkg and bin.

So your GOPATH might look like this:

~/projects/
    bin/
    pkg/
    src/
      mypack/
        foo.go
        bar.go
        mypack_test.go

export GOPATH=$HOME/projects

$ go build mypack
$ go test mypack

Update: as of >= Go 1.11, the Module system is now a standard part of the tooling and the GOPATH concept is close to becoming obsolete.

Filtering Pandas DataFrames on dates

I'm not allowed to write any comments yet, so I'll write an answer, if somebody will read all of them and reach this one.

If the index of the dataset is a datetime and you want to filter that just by (for example) months, you can do following:

df.loc[df.index.month == 3]

That will filter the dataset for you by March.

ASP.net page without a code behind

There are two very different types of pages in SharePoint: Application Pages and Site Pages.

If you are going to use your page as an Application Page, you can safely use inline code or code behind in your page, as Application pages live on the file system.

If it's going to be a Site page, you can safely write inline code as long as you have it like that in the initial deployment. However if your site page is going to be customized at some point in the future, the inline code will no longer work because customized site pages live in the database and are executed in asp.net's "no compile" mode.

Bottom line is - you can write aspx pages with inline code. The only problem is with customized Site pages... which will no longer care for your inline code.

How do I group Windows Form radio buttons?

All radio buttons inside of a share container are in the same group by default. Means, if you check one of them - others will be unchecked. If you want to create independent groups of radio buttons, you must situate them into different containers such as Group Box, or control their Checked state through code behind.

How do you set the title color for the new Toolbar?

I struggled with this for a few hours today because all of these answers are kind of out of date now what with MDC and the new theming capabilities I just could not see how to override app:titleTextColor app wide as a style.

The answer is that titleTextColor is available in the styles.xml is you are overriding something that inherits from Widget.AppCompat.Toolbar. Today I think the best choice is supposed to be Widget.MaterialComponents.Toolbar:

<style name="Widget.LL.Toolbar" parent="@style/Widget.MaterialComponents.Toolbar">
     <item name="titleTextAppearance">@style/TextAppearance.LL.Toolbar</item>
     <item name="titleTextColor">@color/white</item>
     <item name="android:background">?attr/colorSecondary</item>
</style>

<style name="TextAppearance.LL.Toolbar" parent="@style/TextAppearance.Widget.AppCompat.Toolbar.Title">
     <item name="android:textStyle">bold</item>
</style>

And in your app theme, specify the toolbarStyle:

<item name="toolbarStyle">@style/Widget.LL.Toolbar</item>

Now you can leave the xml where you specify the tool bar unchanged. For a long time I thought changing the android:textColor in the toolbar title text appearance should be working, but for some reason it does not.

Kill some processes by .exe file name

If you have the process ID (PID) you can kill this process as follow:

Process processToKill = Process.GetProcessById(pid);
processToKill.Kill();

Close/kill the session when the browser or tab is closed

I do it like this:

$(window).bind('unload', function () {
    if(event.clientY < 0) {  
        alert('Thank you for using this app.');
        endSession(); // here you can do what you want ...
    }  
    });
window.onbeforeunload = function () {
    $(window).unbind('unload');
    //If a string is returned, you automatically ask the 
    //user if he wants to logout or not...
    //return ''; //'beforeunload event'; 
    if (event.clientY < 0) {
        alert('Thank you for using this service.');
        endSession();
    }  
}  

How can I read a whole file into a string variable

I'm not with computer,so I write a draft. You might be clear of what I say.

func main(){
    const dir = "/etc/"
    filesInfo, e := ioutil.ReadDir(dir)
    var fileNames = make([]string, 0, 10)
    for i,v:=range filesInfo{
        if !v.IsDir() {
            fileNames = append(fileNames, v.Name())
        }
    }

    var fileNumber = len(fileNames)
    var contents = make([]string, fileNumber, 10)
    wg := sync.WaitGroup{}
    wg.Add(fileNumber)

    for i,_:=range content {
        go func(i int){
            defer wg.Done()
            buf,e := ioutil.Readfile(fmt.Printf("%s/%s", dir, fileName[i]))
            defer file.Close()  
            content[i] = string(buf)
        }(i)   
    }
    wg.Wait()
}

How do I replace multiple spaces with a single space in C#?

Regex can be rather slow even with simple tasks. This creates an extension method that can be used off of any string.

    public static class StringExtension
    {
        public static String ReduceWhitespace(this String value)
        {
            var newString = new StringBuilder();
            bool previousIsWhitespace = false;
            for (int i = 0; i < value.Length; i++)
            {
                if (Char.IsWhiteSpace(value[i]))
                {
                    if (previousIsWhitespace)
                    {
                        continue;
                    }

                    previousIsWhitespace = true;
                }
                else
                {
                    previousIsWhitespace = false;
                }

                newString.Append(value[i]);
            }

            return newString.ToString();
        }
    }

It would be used as such:

string testValue = "This contains     too          much  whitespace."
testValue = testValue.ReduceWhitespace();
// testValue = "This contains too much whitespace."

How can I get the domain name of my site within a Django template?

If you want the actual HTTP Host header, see Daniel Roseman's comment on @Phsiao's answer. The other alternative is if you're using the contrib.sites framework, you can set a canonical domain name for a Site in the database (mapping the request domain to a settings file with the proper SITE_ID is something you have to do yourself via your webserver setup). In that case you're looking for:

from django.contrib.sites.models import Site

current_site = Site.objects.get_current()
current_site.domain

you'd have to put the current_site object into a template context yourself if you want to use it. If you're using it all over the place, you could package that up in a template context processor.

Excel Date Conversion from yyyymmdd to mm/dd/yyyy

Found another (manual) answer which worked well for me

  1. Select the column.
  2. Choose Data tab
  3. Text to Columns - opens new box
  4. (choose Delimited), Next
  5. (uncheck all boxes, use "none" for text qualifier), Next
  6. use the ymd option from the Date dropdown.
  7. Click Finish

'dependencies.dependency.version' is missing error, but version is managed in parent

If anyone finds their way here with the same problem I was having, my problem was that I was missing the <dependencyManagement> tags around dependencies I had copied from the child pom.

C - reading command line parameters

Parsing command line arguments in a primitive way as explained in the above answers is reasonable as long as the number of parameters that you need to deal with is not too much.

I strongly suggest you to use an industrial strength library for handling the command line arguments.

This will make your code more professional.

Such a library for C++ is available in the following website. I have used this library in many of my projects, hence I can confidently say that this one of the easiest yet useful library for command line argument parsing. Besides, since it is just a template library, it is easier to import into your project. http://tclap.sourceforge.net/

A similar library is available for C as well. http://argtable.sourceforge.net/

Datepicker: How to popup datepicker when click on edittext

editText1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            DatePickerDialog.OnDateSetListener dpd = new DatePickerDialog.OnDateSetListener() {
                @Override
                public void onDateSet(DatePicker view, int year, int monthOfYear,
                                      int dayOfMonth) {

                    int s = monthOfYear + 1;
                    String a = dayOfMonth + "/" + s + "/" + year;
                    editText1.setText(a);
                }
            };

            Time date = new Time();
            DatePickerDialog d = new DatePickerDialog(UpdateStore.this, dpd, date.year, date.month, date.monthDay);
            d.show();

        }
    });

React PropTypes : Allow different types of PropTypes for one prop

import React from 'react';              <--as normal
import PropTypes from 'prop-types';     <--add this as a second line

    App.propTypes = {
        monkey: PropTypes.string,           <--omit "React."
        cat: PropTypes.number.isRequired    <--omit "React."
    };

    Wrong:  React.PropTypes.string
    Right:  PropTypes.string