Programs & Examples On #Credentials

Credentials in information systems are widely used to control access to information or other resources. The classic combination of a user account number or name and a secret password is a widely-used example of IT credentials.

git clone: Authentication failed for <URL>

I'm facing exactly same error when I'm trying to clone a repository on a brand new machine. I'm using Git bash as my Git client. When I ran Git's command to clone a repository it was not prompting me for user id and password which will be used for authentication. It was a fresh machine where not a single credential was cached by Windows credential manager.

As a last resort, I manually added my credentials in credentials manager.

Go to > Control Panel\User Accounts\Credential Manager > Windows Credentials

Click Add a Windows credential link and then Supply the details as shown in the form below and you're done:

enter image description here

I had put the details as below:

Internet or network address: <gitRepoServerNameOrIPAddress>
User Name: MyCompanysDomainName\MyUserName
Password: MyPassword

Next time you run any Git command targeting a repository set up on above address this manually created credential will be used.

It is also important if you have a git command line you close it and reopen it for changes to be applied.

Android: Storing username and password?

You should use the Android AccountManager. It's purpose-built for this scenario. It's a little bit cumbersome but one of the things it does is invalidate the local credentials if the SIM card changes, so if somebody swipes your phone and throws a new SIM in it, your credentials won't be compromised.

This also gives the user a quick and easy way to access (and potentially delete) the stored credentials for any account they have on the device, all from one place.

SampleSyncAdapter (like @Miguel mentioned) is an example that makes use of stored account credentials.

Remove credentials from Git

  1. Go to C:\Users\<current-user>
  2. check for .git-credentials file
  3. Delete content or modify as per your requirement
  4. Restart your terminal

HttpWebRequest using Basic authentication

I finally got it!

string url = @"https://telematicoprova.agenziadogane.it/TelematicoServiziDiUtilitaWeb/ServiziDiUtilitaAutServlet?UC=22&SC=1&ST=2";
WebRequest request = WebRequest.Create(url);
request.Credentials = GetCredential();
request.PreAuthenticate = true;

and this is GetCredential()

private CredentialCache GetCredential()
{
    string url = @"https://telematicoprova.agenziadogane.it/TelematicoServiziDiUtilitaWeb/ServiziDiUtilitaAutServlet?UC=22&SC=1&ST=2";
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
    CredentialCache credentialCache = new CredentialCache();
    credentialCache.Add(new System.Uri(url), "Basic", new NetworkCredential(ConfigurationManager.AppSettings["ead_username"], ConfigurationManager.AppSettings["ead_password"]));
    return credentialCache;
}

YAY!

Configuring user and password with Git Bash

For those who are using access token and a Windows environment, there is a simple way to do it:

Start menu ? Credential Manager ? Windows Credentials ? find the line (Git: https://whatever/your-repository/url) ? edit, user name is "PersonalAccessToken" and password is your access token.

SVN change username

You could ask your colleague to create a patch, which will collapse all the changes that have been made into a single file that you can apply to your own check out. This will update all of your files appropriately and then you can revert the changes on his side and check yours in.

Using cURL with a username and password?

You can also just send the user name by writing:

curl -u USERNAME http://server.example

Curl will then ask you for the password, and the password will not be visible on the screen (or if you need to copy/paste the command).

How to save username and password in Git?

You will be more secure if you use SSH authentication than username/password authentication.

If you are using a Mac, SSH client authentication is integrated into the MacOS keychain. Once you have created an SSH key, type into your terminal:

ssh-add -K ~/.ssh/id_rsa

This will add the SSH private key to the MacOS keychain. The git client will use ssh when it connects to the remote server. As long as you have registered your ssh public key with the server, you will be fine.

What is the most appropriate way to store user settings in Android application

Okay; it's been a while since the answer is kind-of mixed, but here's a few common answers. I researched this like crazy and it was hard to build a good answer

  1. The MODE_PRIVATE method is considered generally safe, if you assume that the user didn't root the device. Your data is stored in plain text in a part of the file system that can only be accessed by the original program. This makings grabbing the password with another app on a rooted device easy. Then again, do you want to support rooted devices?

  2. AES is still the best encryption you can do. Remember to look this up if you are starting a new implementation if it's been a while since I posted this. The largest issue with this is "What to do with the encryption key?"

So, now we are at the "What to do with the key?" portion. This is the hard part. Getting the key turns out to be not that bad. You can use a key derivation function to take some password and make it a pretty secure key. You do get into issues like "how many passes do you do with PKFDF2?", but that's another topic

  1. Ideally, you store the AES key off the device. You have to figure out a good way to retrieve the key from the server safely, reliably, and securely though

  2. You have a login sequence of some sort (even the original login sequence you do for remote access). You can do two runs of your key generator on the same password. How this works is that you derive the key twice with a new salt and a new secure initialization vector. You store one of those generated passwords on the device, and you use the second password as the AES key.

When you log in, you re-derive the key on the local login and compare it to the stored key. Once that is done, you use derive key #2 for AES.

  1. Using the "generally safe" approach, you encrypt the data using AES and store the key in MODE_PRIVATE. This is recommended by a recent-ish Android blog post. Not incredibly secure, but way better for some people over plain text

You can do a lot of variations of these. For example, instead of a full login sequence, you can do a quick PIN (derived). The quick PIN might not be as secure as a full login sequence, but it's many times more secure than plain text

How do I find my host and username on mysql?

The default username is root. You can reset the root password if you do not know it: http://dev.mysql.com/doc/refman/5.0/en/resetting-permissions.html. You should not, however, use the root account from PHP, set up a limited permission user to do that: http://dev.mysql.com/doc/refman/5.1/en/adding-users.html

If MySql is running on the same computer as your webserver, you can just use "localhost" as the host

AWS : The config profile (MyName) could not be found

In my case, I had the variable named "AWS_PROFILE" on Environment variables with an old value.

enter image description here

Selecting non-blank cells in Excel with VBA

I know I'm am very late on this, but here some usefull samples:

'select the used cells in column 3 of worksheet wks
wks.columns(3).SpecialCells(xlCellTypeConstants).Select

or

'change all formulas in col 3 to values
with sheet1.columns(3).SpecialCells(xlCellTypeFormulas)
    .value = .value
end with

To find the last used row in column, never rely on LastCell, which is unreliable (it is not reset after deleting data). Instead, I use someting like

 lngLast = cells(rows.count,3).end(xlUp).row

Function for 'does matrix contain value X?'

Many ways to do this. ismember is the first that comes to mind, since it is a set membership action you wish to take. Thus

X = primes(20);
ismember([15 17],X)
ans =
      0    1

Since 15 is not prime, but 17 is, ismember has done its job well here.

Of course, find (or any) will also work. But these are not vectorized in the sense that ismember was. We can test to see if 15 is in the set represented by X, but to test both of those numbers will take a loop, or successive tests.

~isempty(find(X == 15))
~isempty(find(X == 17))

or,

any(X == 15)
any(X == 17)

Finally, I would point out that tests for exact values are dangerous if the numbers may be true floats. Tests against integer values as I have shown are easy. But tests against floating point numbers should usually employ a tolerance.

tol = 10*eps;
any(abs(X - 3.1415926535897932384) <= tol)

Anaconda / Python: Change Anaconda Prompt User Path

Go to Start and search for "Anaconda Prompt" - right click this and choose "Open File Location", which will open a folder of shortcuts. Right click the "Anaconda Prompt" shortcut, choose "Properties" and you can adjust the starting dir in the "Start in" box.

Python basics printing 1 to 100

because if you change your code with

def gukan(count):
    while count!=100:
      print(count)
      count=count+3;
gukan(0)

count reaches 99 and then, at the next iteration 102.

So

count != 100

never evaluates true and the loop continues forever

If you want to count up to 100 you may use

def gukan(count):
    while count <= 100:
      print(count)
      count=count+3;
gukan(0)

or (if you want 100 always printed)

def gukan(count):
    while count <= 100:
      print(count)
      count=count+3;
      if count > 100:
          count = 100
gukan(0)

Why should we include ttf, eot, woff, svg,... in a font-face

Woff is a compressed (zipped) form of the TrueType - OpenType font. It is small and can be delivered over the network like a graphic file. Most importantly, this way the font is preserved completely including rendering rule tables that very few people care about because they use only Latin script.

Take a look at [dead URL removed]. The font you see is an experimental web delivered smartfont (woff) that has thousands of combined characters making complex shapes. The underlying text is simple Latin code of romanized Singhala. (Copy and paste to Notepad and see).

Only woff can do this because nobody has this font and yet it is seen anywhere (Mac, Win, Linux and even on smartphones by all browsers except by IE. IE does not have full support for Open Types).

read subprocess stdout line by line

It's been a long time since I last worked with Python, but I think the problem is with the statement for line in proc.stdout, which reads the entire input before iterating over it. The solution is to use readline() instead:

#filters output
import subprocess
proc = subprocess.Popen(['python','fake_utility.py'],stdout=subprocess.PIPE)
while True:
  line = proc.stdout.readline()
  if not line:
    break
  #the real code does filtering here
  print "test:", line.rstrip()

Of course you still have to deal with the subprocess' buffering.

Note: according to the documentation the solution with an iterator should be equivalent to using readline(), except for the read-ahead buffer, but (or exactly because of this) the proposed change did produce different results for me (Python 2.5 on Windows XP).

How to change Tkinter Button state from disabled to normal?

You simply have to set the state of the your button self.x to normal:

self.x['state'] = 'normal'

or

self.x.config(state="normal")

This code would go in the callback for the event that will cause the Button to be enabled.


Also, the right code should be:

self.x = Button(self.dialog, text="Download", state=DISABLED, command=self.download)
self.x.pack(side=LEFT)

The method pack in Button(...).pack() returns None, and you are assigning it to self.x. You actually want to assign the return value of Button(...) to self.x, and then, in the following line, use self.x.pack().

Conversion hex string into ascii in bash command line

This worked for me.

$ echo 54657374696e672031203220330 | xxd -r -p
Testing 1 2 3$

-r tells it to convert hex to ascii as opposed to its normal mode of doing the opposite

-p tells it to use a plain format.

Visual Studio loading symbols

Unchecking "Enable JavaScript debugging for ASP.NET (Chrome and IE)" in Tools->Options->Debugging->General resolved my case with unavailability to launch VS2017 debugger with pre-set breakpoints.

What is the difference between user and kernel modes in operating systems?

These are two different modes in which your computer can operate. Prior to this, when computers were like a big room, if something crashes – it halts the whole computer. So computer architects decide to change it. Modern microprocessors implement in hardware at least 2 different states.

User mode:

  • mode where all user programs execute. It does not have access to RAM and hardware. The reason for this is because if all programs ran in kernel mode, they would be able to overwrite each other’s memory. If it needs to access any of these features – it makes a call to the underlying API. Each process started by windows except of system process runs in user mode.

Kernel mode:

  • mode where all kernel programs execute (different drivers). It has access to every resource and underlying hardware. Any CPU instruction can be executed and every memory address can be accessed. This mode is reserved for drivers which operate on the lowest level

How the switch occurs.

The switch from user mode to kernel mode is not done automatically by CPU. CPU is interrupted by interrupts (timers, keyboard, I/O). When interrupt occurs, CPU stops executing the current running program, switch to kernel mode, executes interrupt handler. This handler saves the state of CPU, performs its operations, restore the state and returns to user mode.

http://en.wikibooks.org/wiki/Windows_Programming/User_Mode_vs_Kernel_Mode

http://tldp.org/HOWTO/KernelAnalysis-HOWTO-3.html

http://en.wikipedia.org/wiki/Direct_memory_access

http://en.wikipedia.org/wiki/Interrupt_request

Setting Oracle 11g Session Timeout

Check applications connection Pool settings, rather than altering any session timout settings on the oracle db. It's normal that they time out.

Have a look here: http://grails.org/doc/1.0.x/guide/3.%20Configuration.html#3.3%20The%20DataSource

Are you sure that you have set the "pooled" parameter correctly?

Greetings, Lars


EDIT:
Your config seems ok on first glimpse. I came across this issue today. Maybe it is related to your pain:
"Infinite loop of exceptions if the application is started when the database is down for maintenance"

How do you rename a Git tag?

In addition to the other answers:

First you need to build an alias of the old tag name, pointing to the original commit:

git tag new old^{}

Then you need to delete the old one locally:

git tag -d old

Then delete the tag on you remote location(s):

# Check your remote sources:
git remote -v
# The argument (3rd) is your remote location,
# the one you can see with `git remote`. In this example: `origin`
git push origin :refs/tags/old

Finally you need to add your new tag to the remote location. Until you have done this, the new tag(s) will not be added:

git push origin --tags

Iterate this for every remote location.

Be aware, of the implications that a Git Tag change has to consumers of a package!

Are vectors passed to functions by value or by reference in C++

void foo(vector<int> test)

vector would be passed by value in this.

You have more ways to pass vectors depending on the context:-

1) Pass by reference:- This will let function foo change your contents of the vector. More efficient than pass by value as copying of vector is avoided.

2) Pass by const-reference:- This is efficient as well as reliable when you don't want function to change the contents of the vector.

Ignore 'Security Warning' running script from command line

Did you download the script from internet?

Then remove NTFS stream from the file using sysinternal's streams.exe on command line.

cmd> streams.exe .\my.ps1

Now try to run the script again.

How to fix curl: (60) SSL certificate: Invalid certificate chain

After updating to OS X 10.9.2, I started having invalid SSL certificate issues with Homebrew, Textmate, RVM, and Github.

When I initiate a brew update, I was getting the following error:

fatal: unable to access 'https://github.com/Homebrew/homebrew/': SSL certificate problem: Invalid certificate chain
Error: Failure while executing: git pull -q origin refs/heads/master:refs/remotes/origin/master

I was able to alleviate some of the issue by just disabling the SSL verification in Git. From the console (a.k.a. shell or terminal):

git config --global http.sslVerify false

I am leary to recommend this because it defeats the purpose of SSL, but it is the only advice I've found that works in a pinch.

I tried rvm osx-ssl-certs update all which stated Already are up to date.

In Safari, I visited https://github.com and attempted to set the certificate manually, but Safari did not present the options to trust the certificate.

Ultimately, I had to Reset Safari (Safari->Reset Safari... menu). Then afterward visit github.com and select the certificate, and "Always trust" This feels wrong and deletes the history and stored passwords, but it resolved my SSL verification issues. A bittersweet victory.

How do I fix a merge conflict due to removal of a file in a branch?

I normally just run git mergetool and it will prompt me if I want to keep the modified file or keep it deleted. This is the quickest way IMHO since it's one command instead of several per file.

If you have a bunch of deleted files in a specific subdirectory and you want all of them to be resolved by deleting the files, you can do this:

yes d | git mergetool -- the/subdirectory

The d is provided to choose deleting each file. You can also use m to keep the modified file. Taken from the prompt you see when you run mergetool:

Use (m)odified or (d)eleted file, or (a)bort?

Error inflating when extending a class

Another possible cause of the "Error inflating class" message could be misspelling the full package name where it's specified in XML:

<com.alpenglow.androcap.GhostSurfaceCameraView android:id="@+id/ghostview_cameraview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"/>

Opening your layout XML file in the Eclipse XML editor should highlight this problem.

How do I move an existing Git submodule within a Git repository?

The string in quotes after "[submodule" doesn't matter. You can change it to "foobar" if you want. It's used to find the matching entry in ".git/config".

Therefore, if you make the change before you run "git submodule init", it'll work fine. If you make the change (or pick up the change through a merge), you'll need to either manually edit .git/config or run "git submodule init" again. If you do the latter, you'll be left with a harmless "stranded" entry with the old name in .git/config.

How to implement debounce in Vue2?

I had the same problem and here is a solution that works without plugins.

Since <input v-model="xxxx"> is exactly the same as

<input
   v-bind:value="xxxx"
   v-on:input="xxxx = $event.target.value"
>

(source)

I figured I could set a debounce function on the assigning of xxxx in xxxx = $event.target.value

like this

<input
   v-bind:value="xxxx"
   v-on:input="debounceSearch($event.target.value)"
>

methods:

debounceSearch(val){
  if(search_timeout) clearTimeout(search_timeout);
  var that=this;
  search_timeout = setTimeout(function() {
    that.xxxx = val; 
  }, 400);
},

How to install a .ipa file into my iPhone?

You need to install the provisioning profile (drag and drop it into iTunes). Then drag and drop the .ipa. Ensure you device is set to sync apps, and try again.

C++, What does the colon after a constructor mean?

You are calling the constructor of its base class, demo.

Read a javascript cookie by name

The point of Stack Overflow is to provide a database of good quality answers, so I am going to reference some standard source code and an article that gives examples:

http://www.codelib.net/javascript/cookies.html

Note: The code is regular-expression free for greatly enhanced efficiency.

Using the source code provided, you would use cookies like this:

makeCookie('color', 'silver');

This saves a cookie indicating that the color is silver. The cookie would expire after the current session (as soon as the user quits the browser).

makeCookie('color', 'green', { domain: 'gardens.home.com' });

This saves the color green for gardens.home.com.

makeCookie('color', 'white', { domain: '.home.com', path: '/invoices' });
makeCookie('invoiceno', '0259876', { path: '/invoices', secure: true });

saves the color white for invoices viewed anywhere at home.com. The second cookie is a secure cookie, and records an invoice number. This cookie will be sent only to pages that are viewed through secure HTTPS connections, and scripts within secure pages are the only scripts allowed to access the cookie.

One HTTP host is not allowed to store or read cookies for another HTTP host. Thus, a cookie domain must be stored with at least two periods. By default, the domain is the same as the domain of the web address which created the cookie.

The path of an HTTP cookie restricts it to certain files on the HTTP host. Some browsers use a default path of /, so the cookie will be available on the whole host. Other browsers use the whole filename. In this case, if /invoices/overdue.cgi creates a cookie, only /invoices/overdue.cgi is going to get the cookie back.

When setting paths and other parameters, they are usually based on data obtained from variables like location.href, etc. These strings are already escaped, so when the cookie is created, the cookie function does not escape these values again. Only the name and value of the cookie are escaped, so we can conveniently use arbitrary names or values. Some browsers limit the total size of a cookie, or the total number of cookies which one domain is allowed to keep.

makeCookie('rememberemail', 'yes', { expires: 7 });
makeCookie('rememberlogin', 'yes', { expires: 1 });
makeCookie('allowentergrades', 'yes', { expires: 1/24 });

these cookies would remember the user's email for 7 days, the user's login for 1 day, and allow the user to enter grades without a password for 1 hour (a twenty-fourth of a day). These time limits are obeyed even if they quit the browser, and even if they don't quit the browser. Users are free to use a different browser program, or to delete cookies. If they do this, the cookies will have no effect, regardless of the expiration date.

makeCookie('rememberlogin', 'yes', { expires: -1 });

deletes the cookie. The cookie value is superfluous, and the return value false means that deletion was successful. (A expiration of -1 is used instead of 0. If we had used 0, the cookie might be undeleted until one second past the current time. In this case we would think that deletion was unsuccessful.)

Obviously, since a cookie can be deleted in this way, a new cookie will also overwrite any value of an old cookie which has the same name, including the expiration date, etc. However, cookies for completely non-overlapping paths or domains are stored separately, and the same names do not interfere with each other. But in general, any path or domain which has access to a cookie can overwrite the cookie, no matter whether or not it changes the path or domain of the new cookie.

rmCookie('rememberlogin');

also deletes the cookie, by doing makeCookie('rememberlogin', '', { expires: -1 }). This makes the cookie code longer, but saves code for people who use it, which one might think saves more code in the long run.

JQuery - Call the jquery button click event based on name property

$('element[name="element_name"]').click(function(){
    //do stuff
});

in your case:

$('input[name="btnName"]').click(function(){
    //do stuff
});

How to install a specific JDK on Mac OS X?

Compiling with -source 1.5 -target 1.5 (in a JDK 6 environment) will honor only language elements that were in 1.5 and prior. Great. But there were no language changes in 6 anyway. Problem with this approach (on Mac with 1.6) is that using classes that came AFTER 1.5 will still compile because they exist in the rt.jar. So one could run in a 1.5 env and get a class not found exception with no prior warning when compiling. I found this out the hard way with javax.swing.event.RowSorterEvent/Listener. Both entered "Since 1.6" but are not caught with -source 1.5

Getting a union of two arrays in JavaScript

_x000D_
_x000D_
function unique(arrayName)_x000D_
{_x000D_
  var newArray=new Array();_x000D_
  label: for(var i=0; i<arrayName.length;i++ )_x000D_
  {  _x000D_
    for(var j=0; j<newArray.length;j++ )_x000D_
    {_x000D_
      if(newArray[j]==arrayName[i]) _x000D_
        continue label;_x000D_
    }_x000D_
    newArray[newArray.length] = arrayName[i];_x000D_
  }_x000D_
  return newArray;_x000D_
}_x000D_
_x000D_
var arr1 = new Array(0,2,4,4,4,4,4,5,5,6,6,6,7,7,8,9,5,1,2,3,0);_x000D_
var arr2= new Array(3,5,8,1,2,32,1,2,1,2,4,7,8,9,1,2,1,2,3,4,5);_x000D_
var union = unique(arr1.concat(arr2));_x000D_
console.log(union);
_x000D_
_x000D_
_x000D_

Should composer.lock be committed to version control?

Yes obviously.

That’s because a locally installed composer will give first preference to composer.lock file over composer.json.

If lock file is not available in vcs the composer will point to composer.json file to install latest dependencies or versions.

The file composer.lock maintains dependency in more depth i.e it points to the actual commit of the version of the package we include in our software, hence this is one of the most important files which handles the dependency more finely.

How to convert char to integer in C?

The standard function atoi() will likely do what you want.

A simple example using "atoi":

#include <unistd.h>

int main(int argc, char *argv[])
{
    int useconds = atoi(argv[1]); 
    usleep(useconds);
}

When should I use Lazy<T>?

Just to point onto the example posted by Mathew

public sealed class Singleton
{
    // Because Singleton's constructor is private, we must explicitly
    // give the Lazy<Singleton> a delegate for creating the Singleton.
    private static readonly Lazy<Singleton> instanceHolder =
        new Lazy<Singleton>(() => new Singleton());

    private Singleton()
    {
        ...
    }

    public static Singleton Instance
    {
        get { return instanceHolder.Value; }
    }
}

before the Lazy was born we would have done it this way:

private static object lockingObject = new object();
public static LazySample InstanceCreation()
{
    if(lazilyInitObject == null)
    {
         lock (lockingObject)
         {
              if(lazilyInitObject == null)
              {
                   lazilyInitObject = new LazySample ();
              }
         }
    }
    return lazilyInitObject ;
}

How to convert JSON object to an Typescript array?

That's correct, your response is an object with fields:

{
    "page": 1,
    "results": [ ... ]
}

So you in fact want to iterate the results field only:

this.data = res.json()['results'];

... or even easier:

this.data = res.json().results;

Xcode 10.2.1 Command PhaseScriptExecution failed with a nonzero exit code

I tried most of above. I was developing in Flutter so what worked for me was pub cache repair.

Encoding an image file with base64

import base64
from PIL import Image
from io import BytesIO

with open("image.jpg", "rb") as image_file:
    data = base64.b64encode(image_file.read())

im = Image.open(BytesIO(base64.b64decode(data)))
im.save('image1.png', 'PNG')

How to view file history in Git?

TortoiseGit also provides a command line tool to do see the history of a file. Using PowerShell:

C:\Program` Files\TortoiseGit\bin\TortoiseGitProc.exe /command:log /path:"c:\path\to\your\file.txt"

How do I pass data between Activities in Android application?

You can try Shared Preference, it may be a good alternative for sharing data between the activities

To save session id -

SharedPreferences pref = myContexy.getSharedPreferences("Session 
Data",MODE_PRIVATE);
SharedPreferences.Editor edit = pref.edit();
edit.putInt("Session ID", session_id);
edit.commit();

To get them -

SharedPreferences pref = myContexy.getSharedPreferences("Session Data", MODE_PRIVATE);
session_id = pref.getInt("Session ID", 0);

How to use If Statement in Where Clause in SQL?

SELECT *
  FROM Customer
 WHERE (I.IsClose=@ISClose OR @ISClose is NULL)  
   AND (C.FirstName like '%'+@ClientName+'%' or @ClientName is NULL )    
   AND (isnull(@Value,1) <> 2
        OR I.RecurringCharge = @Total
        OR @Total is NULL )    
   AND (isnull(@Value,2) <> 3
        OR I.RecurringCharge like '%'+cast(@Total as varchar(50))+'%'
        OR @Total is NULL )

Basically, your condition was

if (@Value=2)
   TEST FOR => (I.RecurringCharge=@Total  or @Total is NULL )    

flipped around,

AND (isnull(@Value,1) <> 2                -- A
        OR I.RecurringCharge = @Total    -- B
        OR @Total is NULL )              -- C

When (A) is true, i.e. @Value is not 2, [A or B or C] will become TRUE regardless of B and C results. B and C are in reality only checked when @Value = 2, which is the original intention.

How to automatically update your docker containers, if base-images are updated

Premise to my answer:

  1. Containers are run with tags.
  2. The same tag can be pointed to different image UUID as we please/ feel appropriate.
  3. Updates done to an image can be committed to a new image layer

Approach

  1. Build all the containers in the first place with a security-patch update script
  2. Build an automated process for the following
    • Run an existing image to new container with security patch script as the command
    • Commit changes to the image as
      • existing tag -> followed by restarting the containers one by one
      • new version tag -> replace few containers with new tag -> validate -> move all containers to new tag

Additionally, the base image can be upgraded/ the container with a complete new base image can be built at regular intervals, as the maintainer feels necessary

Advantages

  1. We are preserving the old version of the image while creating the new security patched image, hence we can rollback to previous running image if necessary
  2. We are preserving the docker cache, hence less network transfer (only the changed layer gets on the wire)
  3. The upgrade process can be validated in staging before moving to prod
  4. This can be a controlled process, hence the security patches only when necessary/ deemed important can be pushed.

Is it possible to return empty in react render function?

Yes you can return an empty value from a React render method.

You can return any of the following: false, null, undefined, or true

According to the docs:

false, null, undefined, and true are valid children. They simply don’t render.

You could write

return null; or
return false; or
return true; or
return <div>{undefined}</div>; 

However return null is the most preferred as it signifies that nothing is returned

Bootstrap get div to align in the center

When I align elements in center I use the bootstrap class text-center:

<div class="text-center">Centered content goes here</div>

PDO get the last ID inserted

That's because that's an SQL function, not PHP. You can use PDO::lastInsertId().

Like:

$stmt = $db->prepare("...");
$stmt->execute();
$id = $db->lastInsertId();

If you want to do it with SQL instead of the PDO API, you would do it like a normal select query:

$stmt = $db->query("SELECT LAST_INSERT_ID()");
$lastId = $stmt->fetchColumn();

How to set python variables to true or false?

Python boolean keywords are True and False, notice the capital letters. So like this:

a = True;
b = True;
match_var = True if a == b else False
print match_var;

When compiled and run, this prints:

True

How to perform a sum of an int[] array

When you declare a variable, you need to declare its type - in this case: int. Also you've put a random comma in the while loop. It probably worth looking up the syntax for Java and consider using a IDE that picks up on these kind of mistakes. You probably want something like this:

int [] numbers = { 1, 2, 3, 4, 5 ,6, 7, 8, 9 , 10 };
int sum = 0;
for(int i = 0; i < numbers.length; i++){
    sum += numbers[i];
}
System.out.println("The sum is: " + sum);

How to run a shell script in OS X by double-clicking?

Have you tried using the .command filename extension?

How can I install pip on Windows?

Simple CMD way

Use CURL to download get-pip.py:

curl --http1.1 https://bootstrap.pypa.io/get-pip.py --output get-pip.py

Execute the downloaded Python file

python get-pip.py

Then add C:\Python37\Scripts path to your environment variable. It assumes that there is a Python37 folder in your C drive. That folder name may vary according to the installed Python version

Now you can install Python packages by running

pip install awesome_package_name

java.lang.UnsupportedClassVersionError: Unsupported major.minor version 51.0 (unable to load class frontend.listener.StartupListener)

What is your output when you do java -version? This will tell you what version the running JVM is.

The Unsupported major.minor version 51.0 error could mean:

  • Your server is running a lower Java version then the one used to compile your Servlet and vice versa

Either way, uninstall all JVM runtimes including JDK and download latest and re-install. That should fix any Unsupported major.minor error as you will have the lastest JRE and JDK (Maybe even newer then the one used to compile the Servlet)

See: http://www.java.com/en/download/manual.jsp (7 Update 25 )

and here: http://www.oracle.com/technetwork/java/javase/downloads/index.html (Java Platform (JDK) 7u25)

for the latest version of the JRE and JDK respectively.

EDIT:

Most likely your code was written in Java7 however maybe it was done using Java7update4 and your system is running Java7update3. Thus they both are effectively the same major version but the minor versions differ. Only the larger minor version is backward compatible with the lower minor version.

Edit 2 : If you have more than one jdk installed on your pc. you should check that Apache Tomcat is using the same one (jre) you are compiling your programs with. If you installed a new jdk after installing apache it normally won't select the new version.

Create XML file using java

You can use a DOM XML parser to create an XML file using Java. A good example can be found on this site:

try {
    DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

    //root elements
    Document doc = docBuilder.newDocument();

    Element rootElement = doc.createElement("company");
    doc.appendChild(rootElement);

    //staff elements
    Element staff = doc.createElement("Staff");
    rootElement.appendChild(staff);

    //set attribute to staff element
    Attr attr = doc.createAttribute("id");
    attr.setValue("1");
    staff.setAttributeNode(attr);

    //shorten way
    //staff.setAttribute("id", "1");

    //firstname elements
    Element firstname = doc.createElement("firstname");
    firstname.appendChild(doc.createTextNode("yong"));
    staff.appendChild(firstname);

    //lastname elements
    Element lastname = doc.createElement("lastname");
    lastname.appendChild(doc.createTextNode("mook kim"));
    staff.appendChild(lastname);

    //nickname elements
    Element nickname = doc.createElement("nickname");
    nickname.appendChild(doc.createTextNode("mkyong"));
    staff.appendChild(nickname);

    //salary elements
    Element salary = doc.createElement("salary");
    salary.appendChild(doc.createTextNode("100000"));
    staff.appendChild(salary);

    //write the content into xml file
    TransformerFactory transformerFactory =  TransformerFactory.newInstance();
    Transformer transformer = transformerFactory.newTransformer();
    DOMSource source = new DOMSource(doc);

    StreamResult result =  new StreamResult(new File("C:\\testing.xml"));
    transformer.transform(source, result);

    System.out.println("Done");

}catch(ParserConfigurationException pce){
    pce.printStackTrace();
}catch(TransformerException tfe){
    tfe.printStackTrace();
}

How to use target in location.href

You could try this:

        <script type="text/javascript">
         function newWindow(url){
                window.open(url);
            }
        </script>

And call the function

You should not use <Link> outside a <Router>

I kinda come up with this code :

import React from 'react';
import { render } from 'react-dom';

// import componentns
import Main from './components/Main';
import PhotoGrid from './components/PhotoGrid';
import Single from './components/Single';

// import react router
import { Router, Route, IndexRoute, BrowserRouter, browserHistory} from 'react-router-dom'

class MainComponent extends React.Component {
  render() {
    return (
      <div>
        <BrowserRouter history={browserHistory}>
          <Route path="/" component={Main} >
            <IndexRoute component={PhotoGrid}></IndexRoute>
            <Route path="/view/:postId" component={Single}></Route>
          </Route>
        </BrowserRouter>
      </div>
    );
  }
}

render(<MainComponent />, document.getElementById('root'));

I think the error was because you were rendering the Main component, and the Main component didn't know anything about Router, so you have to render its father component.

How npm start runs a server on port 8000

To change the port

npm start --port 8000

How to print to console when using Qt

Well, after studying several examples on the Internet describing how to output messages from a GUI in Qt to stdout, I have refined a working stand-alone example on redirecting messages to a console, via qDebug() and installing qInstallMessageHandler(). The console will be showed at the same time as the GUI and can be hidden if deemed necessary. The code is easy to integrate with existing code in your project. Here is the full sample and feel free to use it in any way as you like, as long as you adhere to the License GNU GPL v2. You have to use a form of some sort and a MainWindow I think - otherwise the sample will run, but probably crash when forced to quit. Note: there is no way to quit via a close button or a menu close because I have tested those alternatives and the application will crash eventually every now and then. Without the close button the application will be stable and you can close it down from the main window. Enjoy!

#include "mainwindow.h"
#include <QApplication>

//GNU GPL V2, 2015-02-07
#include <QMessageBox>
#include <windows.h>
#define CONSOLE_COLUMNS 80
#define CONSOLE_ROWS    5000
#define YOURCONSOLETITLE "Your_Console_Title"

typedef struct{

    CONSOLE_SCREEN_BUFFER_INFOEX conScreenBuffInfoEX;

    HANDLE con_screenbuf;
    HWND hwndConsole;
    HMENU consoleMenu ;
    QString consoleTitle;

    QMessageBox mBox;
    QString localMsg;
    QString errorMessage;
    WINBOOL errorCode;

} consoleT;

static consoleT *console;

BOOL WINAPI catchCTRL( DWORD ctrlMsg ){

        if( ctrlMsg == CTRL_C_EVENT ){

            HWND hwndWin = GetConsoleWindow();
               ShowWindow(hwndWin,SW_FORCEMINIMIZE);
        }

    return TRUE;
}

void removeCloseMenu(){

    int i;

    for( i = 0; i < 10; i++){

        console->hwndConsole = FindWindowW( NULL, console->consoleTitle.toStdWString().data());

        if(console->hwndConsole != NULL)
            break;
    }

    if( !(console->errorCode = 0) && (console->hwndConsole == NULL))
            console->errorMessage += QString("\nFindWindowW error: %1 \n").arg(console->errorCode);

    if( !(console->errorCode = 0) &&  !(console->consoleMenu = GetSystemMenu( console->hwndConsole, FALSE )) )
        console->errorMessage += QString("GetSystemMenu error: %1 \n").arg(console->errorCode);

    if(!(console->errorCode = DeleteMenu( console->consoleMenu, SC_CLOSE, MF_BYCOMMAND )))
           console->errorMessage += QString("DeleteMenu error: %1 \n").arg(console->errorCode);
}

void initialiseConsole(){

    console->conScreenBuffInfoEX.cbSize = sizeof(CONSOLE_SCREEN_BUFFER_INFOEX);
    console->consoleMenu = NULL;
    console->consoleTitle = YOURCONSOLETITLE;
    console->con_screenbuf = INVALID_HANDLE_VALUE;
    console->errorCode = 0;
    console->errorMessage = "";
    console->hwndConsole = NULL;
    console->localMsg = "";

    if(!(console->errorCode = FreeConsole()))
        console->errorMessage += QString("\nFreeConsole error: %1 \n").arg(console->errorCode);

    if(!(console->errorCode = AllocConsole()))
        console->errorMessage += QString("\nAllocConsole error: %1 \n").arg(console->errorCode);

    if( (console->errorCode = -1) && (INVALID_HANDLE_VALUE ==(console->con_screenbuf = CreateConsoleScreenBuffer( GENERIC_WRITE | GENERIC_READ,0, NULL, CONSOLE_TEXTMODE_BUFFER, NULL))))
        console->errorMessage += QString("\nCreateConsoleScreenBuffer error: %1 \n").arg(console->errorCode);

    if(!(console->errorCode = SetConsoleActiveScreenBuffer(console->con_screenbuf)))
        console->errorMessage += QString("\nSetConsoleActiveScreenBuffer error: %1 \n").arg(console->errorCode);

    if(!(console->errorCode = GetConsoleScreenBufferInfoEx(console->con_screenbuf, &console->conScreenBuffInfoEX)))
        console->errorMessage += QString("\nGetConsoleScreenBufferInfoEx error: %1 \n").arg(console->errorCode);

    console->conScreenBuffInfoEX.dwSize.X = CONSOLE_COLUMNS;
    console->conScreenBuffInfoEX.dwSize.Y = CONSOLE_ROWS;

    if(!(console->errorCode = SetConsoleScreenBufferInfoEx(console->con_screenbuf, &console->conScreenBuffInfoEX)))
       console->errorMessage += QString("\nSetConsoleScreenBufferInfoEx error: %1 \n").arg(console->errorCode);

    if(!(console->errorCode = SetConsoleTitleW(console->consoleTitle.toStdWString().data())))
        console->errorMessage += QString("SetConsoleTitle error: %1 \n").arg(console->errorCode);

    SetConsoleCtrlHandler(NULL, FALSE);
    SetConsoleCtrlHandler(catchCTRL, TRUE);

    removeCloseMenu();

    if(console->errorMessage.length() > 0){
        console->mBox.setText(console->errorMessage);
        console->mBox.show();
    }

}

void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg){


    if((console->con_screenbuf != INVALID_HANDLE_VALUE)){

        switch (type) {

        case QtDebugMsg:
            console->localMsg = console->errorMessage + "Debug: " + msg;
            WriteConsoleW(console->con_screenbuf, console->localMsg.toStdWString().data(), console->localMsg.toStdWString().length(), NULL, NULL );
            WriteConsoleA(console->con_screenbuf, "\n--\n", 4, NULL, NULL );
            break;

        case QtWarningMsg:
            console->localMsg = console->errorMessage + "Warning: " + msg;
            WriteConsoleW(console->con_screenbuf, console->localMsg.toStdWString().data(), console->localMsg.toStdWString().length() , NULL, NULL );
            WriteConsoleA(console->con_screenbuf, "\n--\n", 4, NULL, NULL );
            break;

        case QtCriticalMsg:
            console->localMsg = console->errorMessage + "Critical: " + msg;
            WriteConsoleW(console->con_screenbuf, console->localMsg.toStdWString().data(), console->localMsg.toStdWString().length(), NULL, NULL );
            WriteConsoleA(console->con_screenbuf, "\n--\n", 4, NULL, NULL );
            break;

        case QtFatalMsg:
            console->localMsg = console->errorMessage + "Fatal: " + msg;
            WriteConsoleW(console->con_screenbuf, console->localMsg.toStdWString().data(), console->localMsg.toStdWString().length(), NULL, NULL );
            WriteConsoleA(console->con_screenbuf, "\n--\n", 4, NULL, NULL );
            abort();
        }
    }
}



int main(int argc, char *argv[])
{

    qInstallMessageHandler(messageHandler);

    QApplication a(argc, argv);

    console = new consoleT();
    initialiseConsole();

    qDebug() << "Hello World!";

    MainWindow w;
    w.show();

    return a.exec();
}

How to install JDBC driver in Eclipse web project without facing java.lang.ClassNotFoundexception

The only solution worked for me is putting the .jar file under WEB-INF/lib . Hope this will help.

Return multiple values from a function in swift

Also:

func getTime() -> (hour: Int, minute: Int,second: Int) {
    let hour = 1
    let minute = 2
    let second = 3
    return ( hour, minute, second)
}

Then it's invoked as:

let time = getTime()
print("hour: \(time.hour), minute: \(time.minute), second: \(time.second)")

This is the standard way how to use it in the book The Swift Programming Language written by Apple.

or just like:

let time = getTime()
print("hour: \(time.0), minute: \(time.1), second: \(time.2)")

it's the same but less clearly.

moment.js, how to get day of week number

From the docs page, notice they have these helpful headers

http://momentjs.com/docs/#/get-set/weekday/
(I didn't see them at first)

With header sections for:

  • Date of Month
  • Day of Week
  • etc

.

  var now = moment();
  var day  = now.day();
  var date = now.date(); // Number

Data truncation: Data too long for column 'logo' at row 1

You are trying to insert data that is larger than allowed for the column logo.

Use following data types as per your need

TINYBLOB   :     maximum length of 255 bytes  
BLOB       :     maximum length of 65,535 bytes  
MEDIUMBLOB :     maximum length of 16,777,215 bytes  
LONGBLOB   :     maximum length of 4,294,967,295 bytes  

Use LONGBLOB to avoid this exception.

What is the difference between 'java', 'javaw', and 'javaws'?

java.exe is associated with the console, whereas javaw.exe doesn't have any such association. So, when java.exe is run, it automatically opens a command prompt window where output and error streams are shown.

CRC32 C or C++ implementation

The crc code in zlib (http://zlib.net/) is among the fastest there is, and has a very liberal open source license.

And you should not use adler-32 except for special applications where speed is more important than error detection performance.

How to change the timeout on a .NET WebClient object

I had to fight with this issue yesterday and I've also ended up to write my custom extension class.

As you can see by looking at the code below and comparing it with the accepted answer, I tried to tweak the suggestion a little bit more in order to have a more versatile class: this way you can set a precise timeout either upon instancing the object or right before using a method that uses the internal WebRequest handler.

using System;
using System.Net;

namespace Ryadel.Components.Web
{
    /// <summary>
    /// An extension of the standard System.Net.WebClient
    /// featuring a customizable constructor and [Timeout] property.
    /// </summary>
    public class RyadelWebClient : WebClient
    {
        /// <summary>
        /// Default constructor (30000 ms timeout)
        /// NOTE: timeout can be changed later on using the [Timeout] property.
        /// </summary>
        public RyadelWebClient() : this(30000) { }

        /// <summary>
        /// Constructor with customizable timeout
        /// </summary>
        /// <param name="timeout">
        /// Web request timeout (in milliseconds)
        /// </param>
        public RyadelWebClient(int timeout)
        {
            Timeout = timeout;
        }

        #region Methods
        protected override WebRequest GetWebRequest(Uri uri)
        {
            WebRequest w = base.GetWebRequest(uri);
            w.Timeout = Timeout;
            ((HttpWebRequest)w).ReadWriteTimeout = Timeout;
            return w;
        }
        #endregion

        /// <summary>
        /// Web request timeout (in milliseconds)
        /// </summary>
        public int Timeout { get; set; }
    }
}

While I was there, I also took the chance to lower the default Timeout value to 30 seconds, as 100 seemed way too much for me.

In case you need additional info regarding this class or how to use it, check out this post I wrote on my blog.

Python: TypeError: cannot concatenate 'str' and 'int' objects

Apart from other answers, one could also use format()

print("a + b as integers: {}".format(c))

For example -

hours = 13
minutes = 32
print("Time elapsed - {} hours and {} minutes".format(hours, minutes))

will result in output - Time elapsed - 13 hours and 32 minutes

Check out docs for more information.

How can I check if two segments intersect?

The answer by Georgy is the cleanest to implement, by far. Had to chase this down, since the brycboe example, while simple as well, had issues with colinearity.

Code for testing:

#!/usr/bin/python
#
# Notes on intersection:
#
# https://bryceboe.com/2006/10/23/line-segment-intersection-algorithm/
#
# https://stackoverflow.com/questions/3838329/how-can-i-check-if-two-segments-intersect

from shapely.geometry import LineString

class Point:
    def __init__(self,x,y):
        self.x = x
        self.y = y

def ccw(A,B,C):
    return (C.y-A.y)*(B.x-A.x) > (B.y-A.y)*(C.x-A.x)

def intersect(A,B,C,D):
    return ccw(A,C,D) != ccw(B,C,D) and ccw(A,B,C) != ccw(A,B,D)


def ShapelyIntersect(A,B,C,D):
    return LineString([(A.x,A.y),(B.x,B.y)]).intersects(LineString([(C.x,C.y),(D.x,D.y)]))


a = Point(0,0)
b = Point(0,1)
c = Point(1,1)
d = Point(1,0)

'''
Test points:

b(0,1)   c(1,1)




a(0,0)   d(1,0)
'''

# F
print(intersect(a,b,c,d))

# T
print(intersect(a,c,b,d))
print(intersect(b,d,a,c))
print(intersect(d,b,a,c))

# F
print(intersect(a,d,b,c))

# same end point cases:
print("same end points")
# F - not intersected
print(intersect(a,b,a,d))
# T - This shows as intersected
print(intersect(b,a,a,d))
# F - this does not
print(intersect(b,a,d,a))
# F - this does not
print(intersect(a,b,d,a))

print("same end points, using shapely")
# T
print(ShapelyIntersect(a,b,a,d))
# T
print(ShapelyIntersect(b,a,a,d))
# T
print(ShapelyIntersect(b,a,d,a))
# T
print(ShapelyIntersect(a,b,d,a))

How to create JSON string in JavaScript?

Javascript doesn't handle Strings over multiple lines.

You will need to concatenate those:

var obj = '{'
       +'"name" : "Raj",'
       +'"age"  : 32,'
       +'"married" : false'
       +'}';

You can also use template literals in ES6 and above: (See here for the documentation)

var obj = `{
           "name" : "Raj",
           "age" : 32,
           "married" : false,
           }`;

Troubleshooting "program does not contain a static 'Main' method" when it clearly does...?

That's odd. Does your program compile and run successfully and only fail on 'Publish' or does it fail on every compile now?

Also, have you perhaps changed the file's properties' Build Action to something other than Compile?

How best to determine if an argument is not sent to the JavaScript function

function example(arg) {
  var argumentID = '0'; //1,2,3,4...whatever
  if (argumentID in arguments === false) {
    console.log(`the argument with id ${argumentID} was not passed to the function`);
  }
}

Because arrays inherit from Object.prototype. Consider ? to make the world better.

File changed listener in Java

I use the VFS API from Apache Commons, here is an example of how to monitor a file without much impact in performance:

DefaultFileMonitor

Weblogic Transaction Timeout : how to set in admin console in WebLogic AS 8.1

The link above is rather outdated. For WebLogic 12c you may define the transaction timout in a transaction-descriptor for each EJB in the WebLogic deployment descriptor weblogic-ejb-jar.xml, see weblogic-ejb-jar.xml Deployment Descriptor Reference.

For a message driven been it looks like this:

<weblogic-enterprise-bean>
    <ejb-name>TestMessageBeanLow</ejb-name>
    <message-driven-descriptor>
        <pool>
            <max-beans-in-free-pool>1</max-beans-in-free-pool>
        </pool>
        <destination-jndi-name>jms/ActiveMQ/TestRequestQueue_LOW</destination-jndi-name>
        <connection-factory-jndi-name>jms/ActiveMQ/TestConnectionFactory</connection-factory-jndi-name>
    </message-driven-descriptor>
    <transaction-descriptor>
        <trans-timeout-seconds>60</trans-timeout-seconds>
    </transaction-descriptor>
    <resource-description>
        <res-ref-name>jms/ConnectionFactory</res-ref-name>
        <jndi-name>jms/ActiveMQ/TestConnectionFactory</jndi-name>
    </resource-description>
</weblogic-enterprise-bean>

Stored procedure - return identity as output parameter or scalar

Its all depend on your client data access-layer. Many ORM frameworks rely on explicitly querying the SCOPE_IDENTITY during the insert operation.

If you are in complete control over the data access layer then is arguably better to return SCOPE_IDENTITY() as an output parameter. Wrapping the return in a result set adds unnecessary meta data overhead to describe the result set, and complicates the code to process the requests result.

If you prefer a result set return, then again is arguable better to use the OUTPUT clause:

INSERT INTO  MyTable (col1, col2, col3)
OUTPUT INSERTED.id, col1, col2, col3
VALUES (@col1, @col2, @col3);

This way you can get the entire inserted row back, including default and computed columns, and you get a result set containing one row for each row inserted, this working correctly with set oriented batch inserts.

Overall, I can't see a single case when returning SCOPE_IDENTITY() as a result set would be a good practice.

How to parse/read a YAML file into a Python object?

If your YAML file looks like this:

# tree format
treeroot:
    branch1:
        name: Node 1
        branch1-1:
            name: Node 1-1
    branch2:
        name: Node 2
        branch2-1:
            name: Node 2-1

And you've installed PyYAML like this:

pip install PyYAML

And the Python code looks like this:

import yaml
with open('tree.yaml') as f:
    # use safe_load instead load
    dataMap = yaml.safe_load(f)

The variable dataMap now contains a dictionary with the tree data. If you print dataMap using PrettyPrint, you will get something like:

{
    'treeroot': {
        'branch1': {
            'branch1-1': {
                'name': 'Node 1-1'
            },
            'name': 'Node 1'
        },
        'branch2': {
            'branch2-1': {
                'name': 'Node 2-1'
            },
            'name': 'Node 2'
        }
    }
}

So, now we have seen how to get data into our Python program. Saving data is just as easy:

with open('newtree.yaml', "w") as f:
    yaml.dump(dataMap, f)

You have a dictionary, and now you have to convert it to a Python object:

class Struct:
    def __init__(self, **entries): 
        self.__dict__.update(entries)

Then you can use:

>>> args = your YAML dictionary
>>> s = Struct(**args)
>>> s
<__main__.Struct instance at 0x01D6A738>
>>> s...

and follow "Convert Python dict to object".

For more information you can look at pyyaml.org and this.

How to alter a column's data type in a PostgreSQL table?

See documentation here: http://www.postgresql.org/docs/current/interactive/sql-altertable.html

ALTER TABLE tbl_name ALTER COLUMN col_name TYPE varchar (11);

How to count number of unique values of a field in a tab-delimited text file?

# COLUMN is integer column number
# INPUT_FILE is input file name

cut -f ${COLUMN} < ${INPUT_FILE} | sort -u | wc -l

Accessing a resource via codebehind in WPF

You should use System.Windows.Controls.UserControl's FindResource() or TryFindResource() methods.

Also, a good practice is to create a string constant which maps the name of your key in the resource dictionary (so that you can change it at only one place).

Does a foreign key automatically create an index?

Foreign keys do not create indexes. Only alternate key constraints(UNIQUE) and primary key constraints create indexes. This is true in Oracle and SQL Server.

In Gradle, is there a better way to get Environment Variables?

Well; this works as well:

home = "$System.env.HOME"

It's not clear what you're aiming for.

count number of rows in a data frame in R based on group

library(plyr)
ddply(data, .(MONTH-YEAR), nrow)

This will give you the answer, if "MONTH-YEAR" is a variable. First, try unique(data$MONTH-YEAR) and see if it returns unique values (no duplicates).

Then above simple split-apply-combine will return what you are looking for.

Django values_list vs values

values()

Returns a QuerySet that returns dictionaries, rather than model instances, when used as an iterable.

values_list()

Returns a QuerySet that returns list of tuples, rather than model instances, when used as an iterable.

distinct()

distinct are used to eliminate the duplicate elements.

Example:

>>> list(Article.objects.values_list('id', flat=True)) # flat=True will remove the tuples and return the list   
[1, 2, 3, 4, 5, 6]

>>> list(Article.objects.values('id'))
[{'id':1}, {'id':2}, {'id':3}, {'id':4}, {'id':5}, {'id':6}]

Can we call the function written in one JavaScript in another JS file?

yes you can . you need to refer both JS file to the .aspx page

<script language="javascript" type="text/javascript" src="JScript1.js">
 </script>

    <script language="javascript" type="text/javascript" src="JScript2.js">
    </script>

JScript1.js

function ani1() {
    alert("1");
    ani2();
}
JScript2.js
function ani2() {
    alert("2");
}

Why does Math.Round(2.5) return 2 instead of 3?

From MSDN, Math.Round(double a) returns:

The integer nearest a. If the fractional component of a is halfway between two integers, one of which is even and the other odd, then the even number is returned.

... and so 2.5, being halfway between 2 and 3, is rounded down to the even number (2). this is called Banker's Rounding (or round-to-even), and is a commonly-used rounding standard.

Same MSDN article:

The behavior of this method follows IEEE Standard 754, section 4. This kind of rounding is sometimes called rounding to nearest, or banker's rounding. It minimizes rounding errors that result from consistently rounding a midpoint value in a single direction.

You can specify a different rounding behavior by calling the overloads of Math.Round that take a MidpointRounding mode.

The thread has exited with code 0 (0x0) with no unhandled exception

I have also faced this problem and the solution is:

  1. open Solution Explore
  2. double click on Program.cs file

I added this code again and my program ran accurately:

Application.Run(new PayrollSystem()); 
//File name this code removed by me accidentally.

T-SQL split string

I had to write something like this recently. Here's the solution I came up with. It's generalized for any delimiter string and I think it would perform slightly better:

CREATE FUNCTION [dbo].[SplitString] 
    ( @string nvarchar(4000)
    , @delim nvarchar(100) )
RETURNS
    @result TABLE 
        ( [Value] nvarchar(4000) NOT NULL
        , [Index] int NOT NULL )
AS
BEGIN
    DECLARE @str nvarchar(4000)
          , @pos int 
          , @prv int = 1

    SELECT @pos = CHARINDEX(@delim, @string)
    WHILE @pos > 0
    BEGIN
        SELECT @str = SUBSTRING(@string, @prv, @pos - @prv)
        INSERT INTO @result SELECT @str, @prv

        SELECT @prv = @pos + LEN(@delim)
             , @pos = CHARINDEX(@delim, @string, @pos + 1)
    END

    INSERT INTO @result SELECT SUBSTRING(@string, @prv, 4000), @prv
    RETURN
END

Cannot add a project to a Tomcat server in Eclipse

  1. Right-click on project
  2. Go to properties => project factes
  3. Click on runtime tab
  4. Check the box of the server
  5. Then ok

Close the eclipse and start the server you will able to see and run the project.

Writing a dict to txt file and reading it back?

To store Python objects in files, use the pickle module:

import pickle

a = {
  'a': 1,
  'b': 2
}

with open('file.txt', 'wb') as handle:
  pickle.dump(a, handle)

with open('file.txt', 'rb') as handle:
  b = pickle.loads(handle.read())

print a == b # True

Notice that I never set b = a, but instead pickled a to a file and then unpickled it into b.

As for your error:

self.whip = open('deed.txt', 'r').read()

self.whip was a dictionary object. deed.txt contains text, so when you load the contents of deed.txt into self.whip, self.whip becomes the string representation of itself.

You'd probably want to evaluate the string back into a Python object:

self.whip = eval(open('deed.txt', 'r').read())

Notice how eval sounds like evil. That's intentional. Use the pickle module instead.

How to get device make and model on iOS?

I've made the plist file to help you to get the complete name for each device (source code right at the end of my answer)

Based on OhhMee's answer, you can use it like this:

Swift 4.0

static func deviceName() -> String {

        var systemInfo = utsname()
        uname(&systemInfo)

        guard let iOSDeviceModelsPath = Bundle.main.path(forResource: "iOSDeviceModelMapping", ofType: "plist") else { return "" }
        guard let iOSDevices = NSDictionary(contentsOfFile: iOSDeviceModelsPath) else { return "" }

        let machineMirror = Mirror(reflecting: systemInfo.machine)
        let identifier = machineMirror.children.reduce("") { identifier, element in
            guard let value = element.value as? Int8, value != 0 else { return identifier }
            return identifier + String(UnicodeScalar(UInt8(value)))
        }

        return iOSDevices.value(forKey: identifier) as! String
    }

Don't forget to add #import <sys/utsname.h> in your Bridging Header.

Objective C

#import <sys/utsname.h>

NSString *machineName()
{
    struct utsname systemInfo;
    uname(&systemInfo);

    NSString *iOSDeviceModelsPath = [[NSBundle mainBundle] pathForResource:@"iOSDeviceModelMapping" ofType:@"plist"];
    NSDictionary *iOSDevices = [NSDictionary dictionaryWithContentsOfFile:iOSDeviceModelsPath];

    NSString* deviceModel = [NSString stringWithCString:systemInfo.machine
                                               encoding:NSUTF8StringEncoding];

    return [iOSDevices valueForKey:deviceModel];
}

The plist file :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>x86_64</key>
    <string>Simulator</string>
    <key>i386</key>
    <string>Simulator</string>
    <key>iPod1,1</key>
    <string>iPod Touch 1st Gen</string>
    <key>iPod2,1</key>
    <string>iPod Touch 2nd Gen</string>
    <key>iPod3,1</key>
    <string>iPod Touch 3rd Gen</string>
    <key>iPod4,1</key>
    <string>iPod Touch 4th Gen</string>
    <key>iPod5,1</key>
    <string>iPod Touch 5th Gen</string>
    <key>iPod7,1</key>
    <string>iPod Touch 6th Gen</string>
    <key>iPhone1,1</key>
    <string>iPhone</string>
    <key>iPhone1,2</key>
    <string>iPhone 3G</string>
    <key>iPhone2,1</key>
    <string>iPhone 3GS</string>
    <key>iPhone3,1</key>
    <string>iPhone 4</string>
    <key>iPhone3,2</key>
    <string>iPhone 4</string>
    <key>iPhone3,3</key>
    <string>iPhone 4</string>
    <key>iPhone4,1</key>
    <string>iPhone 4S</string>
    <key>iPhone5,1</key>
    <string>iPhone 5 model A1428</string>
    <key>iPhone5,2</key>
    <string>iPhone 5 model A1429</string>
    <key>iPhone5,3</key>
    <string>iPhone 5C</string>
    <key>iPhone5,4</key>
    <string>iPhone 5C</string>
    <key>iPhone6,1</key>
    <string>iPhone 5S</string>
    <key>iPhone6,2</key>
    <string>iPhone 5S</string>
    <key>iPhone7,2</key>
    <string>iPhone 6</string>
    <key>iPhone7,1</key>
    <string>iPhone 6 Plus</string>
    <key>iPhone8,1</key>
    <string>iPhone 6S</string>
    <key>iPhone8,2</key>
    <string>iPhone 6S Plus</string>
    <key>iPhone8,4</key>
    <string>iPhone SE</string>
    <key>iPhone9,1</key>
    <string>iPhone 7</string>
    <key>iPhone9,2</key>
    <string>iPhone 7 Plus</string>
    <key>iPhone9,3</key>
    <string>iPhone 7</string>
    <key>iPhone9,4</key>
    <string>iPhone 7 Plus</string>
    <key>iPhone10,1</key>
    <string>iPhone 8</string>
    <key>iPhone10,4</key>
    <string>iPhone 8</string>
    <key>iPhone10,2</key>
    <string>iPhone 8 Plus</string>
    <key>iPhone10,5</key>
    <string>iPhone 8 Plus</string>
    <key>iPhone10,3</key>
    <string>iPhone X</string>
    <key>iPhone10,6</key>
    <string>iPhone X</string>
    <key>iPhone11,2</key>
    <string>iPhone XS</string>
    <key>iPhone11,4</key>
    <string>iPhone XS Max</string>
    <key>iPhone11,6</key>
    <string>iPhone XS Max</string>
    <key>iPhone11,8</key>
    <string>iPhone XR</string>
    <key>iPad1,1</key>
    <string>iPad</string>
    <key>iPad2,1</key>
    <string>iPad 2</string>
    <key>iPad2,2</key>
    <string>iPad 2</string>
    <key>iPad2,3</key>
    <string>iPad 2</string>
    <key>iPad2,4</key>
    <string>iPad 2</string>
    <key>iPad3,1</key>
    <string>iPad 3rd Gen</string>
    <key>iPad3,2</key>
    <string>iPad 3rd Gen</string>
    <key>iPad3,3</key>
    <string>iPad 3rd Gen</string>
    <key>iPad3,4</key>
    <string>iPad 4th Gen</string>
    <key>iPad3,5</key>
    <string>iPad 4th Gen</string>
    <key>iPad3,6</key>
    <string>iPad 4th Gen</string>
    <key>iPad4,1</key>
    <string>iPad Air</string>
    <key>iPad4,2</key>
    <string>iPad Air</string>
    <key>iPad4,3</key>
    <string>iPad Air</string>
    <key>iPad2,5</key>
    <string>iPad Mini 1st Gen</string>
    <key>iPad2,6</key>
    <string>iPad Mini 1st Gen</string>
    <key>iPad2,7</key>
    <string>iPad Mini 1st Gen</string>
    <key>iPad4,4</key>
    <string>iPad Mini 2nd Gen</string>
    <key>iPad4,5</key>
    <string>iPad Mini 2nd Gen</string>
    <key>iPad4,6</key>
    <string>iPad Mini 2nd Gen</string>
    <key>iPad4,7</key>
    <string>iPad Mini 3rd Gen</string>
    <key>iPad4,8</key>
    <string>iPad Mini 3rd Gen</string>
    <key>iPad4,9</key>
    <string>iPad Mini 3rd Gen</string>
    <key>iPad5,1</key>
    <string>iPad Mini 4</string>
    <key>iPad5,2</key>
    <string>iPad Mini 4</string>
    <key>iPad5,3</key>
    <string>iPad Air 2</string>
    <key>iPad5,4</key>
    <string>iPad Air 2</string>
    <key>iPad6,3</key>
    <string>iPad Pro 9.7 inch</string>
    <key>iPad6,4</key>
    <string>iPad Pro 9.7 inch</string>
    <key>iPad6,7</key>
    <string>iPad Pro 12.9 inch</string>
    <key>iPad6,8</key>
    <string>iPad Pro 12.9 inch</string>
    <key>iPad7,1</key>
    <string>iPad Pro 12.9 inch 2nd Gen</string>
    <key>iPad7,2</key>
    <string>iPad Pro 12.9 inch 2nd Gen</string>
    <key>iPad7,3</key>
    <string>iPad Pro 10.5 inch</string>
    <key>iPad7,4</key>
    <string>iPad Pro 10.5 inch</string>
    <key>iPad8,1</key>
    <string>iPad Pro 11 inch</string>
    <key>iPad8,2</key>
    <string>iPad Pro 11 inch</string>
    <key>iPad8,3</key>
    <string>iPad Pro 11 inch</string>
    <key>iPad8,4</key>
    <string>iPad Pro 11 inch</string>
    <key>iPad8,5</key>
    <string>iPad Pro 12.9 inch 3rd Gen</string>
    <key>iPad8,6</key>
    <string>iPad Pro 12.9 inch 3rd Gen</string>
    <key>iPad8,7</key>
    <string>iPad Pro 12.9 inch 3rd Gen</string>
    <key>iPad8,8</key>
    <string>iPad Pro 12.9 inch 3rd Gen</string>
</dict>
</plist>

CSS table td width - fixed, not flexible

It's not the prettiest CSS, but I got this to work:

table td {
    width: 30px;
    overflow: hidden;
    display: inline-block;
    white-space: nowrap;
}

Examples, with and without ellipses:

_x000D_
_x000D_
body {_x000D_
    font-size: 12px;_x000D_
    font-family: Tahoma, Helvetica, sans-serif;_x000D_
}_x000D_
_x000D_
table {_x000D_
    border: 1px solid #555;_x000D_
    border-width: 0 0 1px 1px;_x000D_
}_x000D_
table td {_x000D_
    border: 1px solid #555;_x000D_
    border-width: 1px 1px 0 0;_x000D_
}_x000D_
_x000D_
/* What you need: */_x000D_
table td {_x000D_
    width: 30px;_x000D_
    overflow: hidden;_x000D_
    display: inline-block;_x000D_
    white-space: nowrap;_x000D_
}_x000D_
_x000D_
table.with-ellipsis td {   _x000D_
    text-overflow: ellipsis;_x000D_
}
_x000D_
<table cellpadding="2" cellspacing="0">_x000D_
    <tr>_x000D_
        <td>first</td><td>second</td><td>third</td><td>forth</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td>first</td><td>this is really long</td><td>third</td><td>forth</td>_x000D_
    </tr>_x000D_
</table>_x000D_
_x000D_
<br />_x000D_
_x000D_
<table class="with-ellipsis" cellpadding="2" cellspacing="0">_x000D_
    <tr>_x000D_
        <td>first</td><td>second</td><td>third</td><td>forth</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td>first</td><td>this is really long</td><td>third</td><td>forth</td>_x000D_
    </tr>_x000D_
</table>
_x000D_
_x000D_
_x000D_

Oracle SQL escape character (for a '&')

the & is the default value for DEFINE, which allows you to use substitution variables. I like to turn it off using

SET DEFINE OFF

then you won't have to worry about escaping or CHR(38).

Can two Java methods have same name with different return types?

According the JLS, you cannot however due to a feature/bug in the Java 6/7 compiler (Oracle's JDK, OpenJDK, IBM's JDK) you can have different return types for the same method signature if you use generics.

public class Main {
    public static void main(String... args) {
        Main.<Integer>print();
        Main.<Short>print();
        Main.<Byte>print();
        Main.<Void>print();
    }

    public static <T extends Integer> int print() {
        System.out.println("here - Integer");
        return 0;
    }
    public static <T extends Short> short print() {
        System.out.println("here - Short");
        return 0;
    }
    public static <T extends Byte> byte print() {
        System.out.println("here - Byte");
        return 0;
    }
    public static <T extends Void> void print() {
        System.out.println("here - Void");
    }
}

Prints

here - Integer
here - Short
here - Byte
here - Void

For more details, read my article here

What is the ultimate postal code and zip regex?

  1. Every postal code system uses only A-Z and/or 0-9 and sometimes space/dash

  2. Not every country uses postal codes (ex. Ireland outside of Dublin), but we'll ignore that here.

  3. The shortest postal code format is Sierra Leone with NN

  4. The longest is American Samoa with NNNNN-NNNNNN

  5. You should allow one space or dash.

  6. Should not begin or end with space or dash

This should cover the above:

(?i)^[a-z0-9][a-z0-9\- ]{0,10}[a-z0-9]$

Remove duplicate values from JS array

Apart from being a simpler, more terse solution than the current answers (minus the future-looking ES6 ones), I perf tested this and it was much faster as well:

var uniqueArray = dupeArray.filter(function(item, i, self){
  return self.lastIndexOf(item) == i;
});

One caveat: Array.lastIndexOf() was added in IE9, so if you need to go lower than that, you'll need to look elsewhere.

Recommended SQL database design for tags or tagging

I would suggest following design : Item Table: Itemid, taglist1, taglist2
this will be fast and make easy saving and retrieving the data at item level.

In parallel build another table: Tags tag do not make tag unique identifier and if you run out of space in 2nd column which contains lets say 100 items create another row.

Now while searching for items for a tag it will be super fast.

How do I check the difference, in seconds, between two dates?

Here's the one that is working for me.

from datetime import datetime

date_format = "%H:%M:%S"

# You could also pass datetime.time object in this part and convert it to string.
time_start = str('09:00:00') 
time_end = str('18:00:00')

# Then get the difference here.    
diff = datetime.strptime(time_end, date_format) - datetime.strptime(time_start, date_format)

# Get the time in hours i.e. 9.60, 8.5
result = diff.seconds / 3600;

Hope this helps!

How to filter a dictionary according to an arbitrary condition function?

>>> points = {'a': (3, 4), 'c': (5, 5), 'b': (1, 2), 'd': (3, 3)}
>>> dict(filter(lambda x: (x[1][0], x[1][1]) < (5, 5), points.items()))

{'a': (3, 4), 'b': (1, 2), 'd': (3, 3)}

np.mean() vs np.average() in Python NumPy?

In some version of numpy there is another imporant difference that you must be aware:

average do not take in account masks, so compute the average over the whole set of data.

mean takes in account masks, so compute the mean only over unmasked values.

g = [1,2,3,55,66,77]
f = np.ma.masked_greater(g,5)

np.average(f)
Out: 34.0

np.mean(f)
Out: 2.0

Currently running queries in SQL Server

The tool is called the SQL Server Profiler, it's still part of the standard toolset.

Eclipse: Java was started but returned error code=13

This is caused when java is updated. You have to delete in environement path : C:**ProgramData\Oracle\Java\javapath**

Rails: Using greater than/less than with a where statement

Another fancy possibility is...

User.where("id > :id", id: 100)

This feature allows you to create more comprehensible queries if you want to replace in multiple places, for example...

User.where("id > :id OR number > :number AND employee_id = :employee", id: 100, number: 102, employee: 1205)

This has more meaning than having a lot of ? on the query...

User.where("id > ? OR number > ? AND employee_id = ?", 100, 102, 1205)

How to pass parameters to a Script tag?

Put the values you need someplace where the other script can retrieve them, like a hidden input, and then pull those values from their container when you initialize your new script. You could even put all your params as a JSON string into one hidden field.

WordPress is giving me 404 page not found for all pages except the homepage

after 2 long days, the solution was to add options +FollowSymLinks to the top of my .htaccess file.

Catch KeyError in Python

If it's raising a KeyError with no message, then it won't print anything. If you do...

try:
    connection = manager.connect("I2Cx")
except Exception as e:
    print repr(e)

...you'll at least get the exception class name.

A better alternative is to use multiple except blocks, and only 'catch' the exceptions you intend to handle...

try:
    connection = manager.connect("I2Cx")
except KeyError as e:
    print 'I got a KeyError - reason "%s"' % str(e)
except IndexError as e:
    print 'I got an IndexError - reason "%s"' % str(e)

There are valid reasons to catch all exceptions, but you should almost always re-raise them if you do...

try:
    connection = manager.connect("I2Cx")
except KeyError as e:
    print 'I got a KeyError - reason "%s"' % str(e)
except:
    print 'I got another exception, but I should re-raise'
    raise

...because you probably don't want to handle KeyboardInterrupt if the user presses CTRL-C, nor SystemExit if the try-block calls sys.exit().

SQL How to replace values of select return?

You can use casting in the select clause like:

SELECT id, name, CAST(hide AS BOOLEAN) FROM table_name;

How to change app default theme to a different app theme?

Or try to check your mainActivity.xml you make sure that this one
xmlns:app="http://schemas.android.com/apk/res-auto"hereis included

Using Regular Expressions to Extract a Value in Java

Allain basically has the java code, so you can use that. However, his expression only matches if your numbers are only preceded by a stream of word characters.

"(\\d+)"

should be able to find the first string of digits. You don't need to specify what's before it, if you're sure that it's going to be the first string of digits. Likewise, there is no use to specify what's after it, unless you want that. If you just want the number, and are sure that it will be the first string of one or more digits then that's all you need.

If you expect it to be offset by spaces, it will make it even more distinct to specify

"\\s+(\\d+)\\s+"

might be better.

If you need all three parts, this will do:

"(\\D+)(\\d+)(.*)"

EDIT The Expressions given by Allain and Jack suggest that you need to specify some subset of non-digits in order to capture digits. If you tell the regex engine you're looking for \d then it's going to ignore everything before the digits. If J or A's expression fits your pattern, then the whole match equals the input string. And there's no reason to specify it. It probably slows a clean match down, if it isn't totally ignored.

Git: add vs push vs commit

Very nice pdf about many GIT secrets.

Add is same as svn's add (how ever sometimes it is used to mark file resolved).

Commit also is same as svn's , but it commit change into your local repository.

What is Unicode, UTF-8, UTF-16?

Unicode is a fairly complex standard. Don’t be too afraid, but be prepared for some work! [2]

Because a credible resource is always needed, but the official report is massive, I suggest reading the following:

  1. The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!) An introduction by Joel Spolsky, Stack Exchange CEO.
  2. To the BMP and beyond! A tutorial by Eric Muller, Technical Director then, Vice President later, at The Unicode Consortium. (first 20 slides and you are done)

A brief explanation:

Computers read bytes and people read characters, so we use encoding standards to map characters to bytes. ASCII was the first widely used standard, but covers only Latin (7 bits/character can represent 128 different characters). Unicode is a standard with the goal to cover all possible characters in the world (can hold up to 1,114,112 characters, meaning 21 bits/character max. Current Unicode 8.0 specifies 120,737 characters in total, and that's all).

The main difference is that an ASCII character can fit to a byte (8 bits), but most Unicode characters cannot. So encoding forms/schemes (like UTF-8 and UTF-16) are used, and the character model goes like this:

Every character holds an enumerated position from 0 to 1,114,111 (hex: 0-10FFFF) called code point.
An encoding form maps a code point to a code unit sequence. A code unit is the way you want characters to be organized in memory, 8-bit units, 16-bit units and so on. UTF-8 uses 1 to 4 units of 8 bits, and UTF-16 uses 1 or 2 units of 16 bits, to cover the entire Unicode of 21 bits max. Units use prefixes so that character boundaries can be spotted, and more units mean more prefixes that occupy bits. So, although UTF-8 uses 1 byte for the Latin script it needs 3 bytes for later scripts inside Basic Multilingual Plane, while UTF-16 uses 2 bytes for all these. And that's their main difference.
Lastly, an encoding scheme (like UTF-16BE or UTF-16LE) maps (serializes) a code unit sequence to a byte sequence.

character: p
code point: U+03C0
encoding forms (code units):
      UTF-8: CF 80
      UTF-16: 03C0
encoding schemes (bytes):
      UTF-8: CF 80
      UTF-16BE: 03 C0
      UTF-16LE: C0 03

Tip: a hex digit represents 4 bits, so a two-digit hex number represents a byte
Also take a look at Plane maps in Wikipedia to get a feeling of the character set layout

Delaying function in swift

 NSTimer.scheduledTimerWithTimeInterval(NSTimeInterval(3), target: self, selector: "functionHere", userInfo: nil, repeats: false)

This would call the function functionHere() with a 3 seconds delay

PHP code is not being executed, instead code shows on the page

i had similar problem but in my case solution was different. my file that held php code was called "somename.html" changed it to "somename.php" worked fine

Radio button checked event handling

$("#expires1").click(function(){
     if (this.checked)
        alert("testing....");
});

How to compile a 64-bit application using Visual C++ 2010 Express?

And make sure you download the Windows7.1 SDK, not just the Windows 7 one. That caused me a lot of head pounding.

What is the regex pattern for datetime (2008-09-01 12:35:45 )?

I have modified the regex pattern from http://regexlib.com/REDetails.aspx?regexp_id=610. The following pattern should match your case.

^(?=\d)(?:(?:1[6-9]|[2-9]\d)?\d\d([-.\/])(?:1[012]|0?[1-9])\1(?:31(?<!.(?:0[2469]|11))|(?:30|29)(?<!.02)|29(?=.0?2.(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))(?:\x20|$))|(?:2[0-8]|1\d|0?[1-9]))(?:(?=\x20\d)\x20|$))?(((0?[1-9]|1[012])(:[0-5]\d){0,2}(\x20[AP]M))|([01]\d|2[0-3])(:[0-5]\d){1,2})?$

YYYY-MM-DD HH:MM:SS

What's the syntax to import a class in a default package in Java?

You can't import classes from the default package. You should avoid using the default package except for very small example programs.

From the Java language specification:

It is a compile time error to import a type from the unnamed package.

How do I hide the bullets on my list for the sidebar?

You have a selector ul on line 252 which is setting list-style: square outside none (a square bullet). You'll have to change it to list-style: none or just remove the line.

If you only want to remove the bullets from that specific instance, you can use the specific selector for that list and its items as follows:

ul#groups-list.items-list { list-style: none }

Clearing coverage highlighting in Eclipse

I have used the Open Clover Tool for the code coverage, I have also been searching this for a long time. Its pretty straightforward, in the Coverage Explorer tab, you can find three square buttons which says the code lines you wanted to display, click on hide the coverage square box and its gone. Last button in the image below: enter image description here

How to remove "disabled" attribute using jQuery?

for removing the disabled properties

 $('#inputDisabled').removeAttr('Disabled');

for adding the disabled properties

 $('#inputDisabled').attr('disabled', 'disabled' );

iOS how to set app icon and launch images

I've tried most of the above and a few others and have found https://appicon.co to be the easiest, fastest, and provides the most comprehensive set.

  1. Drag your image onto the screen
  2. Click Generate
  3. Open the file just downloaded to your Downloads folder

Here, you may be able to drag this entire folder into Xcode. If not:

  1. Double-click the Assets.xcassets folder
  2. Select all files
  3. Drag them to Assets.xcassets
  4. Rename it to Appicon

Getting reference to the top-most view/window in iOS application

Actually there could be more than one UIWindow in your application. For example, if a keyboard is on screen then [[UIApplication sharedApplication] windows] will contain at least two windows (your key-window and the keyboard window).

So if you want your view to appear ontop of both of them then you gotta do something like:

[[[[UIApplication sharedApplication] windows] lastObject] addSubview:view];

(Assuming lastObject contains the window with the highest windowLevel priority).

What is the use of GO in SQL Server Management Studio & Transact SQL?

Since Management Studio 2005 it seems that you can use GO with an int parameter, like:

INSERT INTO mytable DEFAULT VALUES
GO 10

The above will insert 10 rows into mytable. Generally speaking, GO will execute the related sql commands n times.

How to extract text from a PDF file?

How to extract text from a PDF file?

The first thing to understand is the PDF format. It has a public specification written in English, see ISO 32000-2:2017 and read the more than 700 pages of PDF 1.7 specification. You certainly at least need to read the wikipedia page about PDF

Once you understood the details of the PDF format, extracting text is more or less easy (but what about text appearing in figures or images; its figure 1)? Don't expect writing a perfect software text extractor alone in a few weeks....

On Linux, you might also use pdf2text which you could popen from your Python code.

In general, extracting text from a PDF file is an ill defined problem. For a human reader some text could be made (as a figure) from different dots, or a photo, etc...

The Google search engine is capable of extracting text from PDF, but is rumored to need more than half a billion lines of source code. Do you have the necessary resources (in man power, in budget) to develop a competitor?

A possibility might be to print the PDF to some virtual printer (e.g. using GhostScript or Firefox), then to use OCR techniques to extract text.

I would recommend instead to work on the data representation which has generated that PDF file, for example on the original LaTeX code (or Lout code) or on OOXML code.

In all cases, you need to budget at least several person years of software development.

Populating a database in a Laravel migration file

Here is a very good explanation of why using Laravel's Database Seeder is preferable to using Migrations: https://web.archive.org/web/20171018135835/http://laravelbook.com/laravel-database-seeding/

Although, following the instructions on the official documentation is a much better idea because the implementation described at the above link doesn't seem to work and is incomplete. http://laravel.com/docs/migrations#database-seeding

How to save the output of a console.log(object) to a file?

In case you have an object logged:

  • Right click on the object in console and click Store as a global variable
  • the output will be something like temp1
  • type in console copy(temp1)
  • paste to your favorite text editor

Getting Exception(org.apache.poi.openxml4j.exception - no content type [M1.13]) when reading xlsx file using Apache POI?

Cleaned up the code (commented out the logger mostly) to make it run in my Eclipse environment.

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;

import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.*;

public class ReadXLSX {
private String filepath;
private XSSFWorkbook workbook;
// private static Logger logger=null;
private InputStream resourceAsStream;

public ReadXLSX(String filePath) {
    // logger=LoggerFactory.getLogger("ReadXLSX");
    this.filepath = filePath;
    resourceAsStream = ClassLoader.getSystemResourceAsStream(filepath);
}

public ReadXLSX(InputStream fileStream) {
    // logger=LoggerFactory.getLogger("ReadXLSX");
    this.resourceAsStream = fileStream;
}

private void loadFile() throws FileNotFoundException,
        NullObjectFoundException {

    if (resourceAsStream == null)
        throw new FileNotFoundException("Unable to locate give file..");
    else {
        try {
            workbook = new XSSFWorkbook(resourceAsStream);

        } catch (IOException ex) {

        }

    }
}// end loadxlsFile

public String[] getSheetsName() {
    int totalsheet = 0;
    int i = 0;
    String[] sheetName = null;

    try {
        loadFile();
        totalsheet = workbook.getNumberOfSheets();
        sheetName = new String[totalsheet];
        while (i < totalsheet) {
            sheetName[i] = workbook.getSheetName(i);
            i++;
        }

    } catch (FileNotFoundException ex) {
        // logger.error(ex);
    } catch (NullObjectFoundException ex) {
        // logger.error(ex);
    }

    return sheetName;
}

public int[] getSheetsIndex() {
    int totalsheet = 0;
    int i = 0;
    int[] sheetIndex = null;
    String[] sheetname = getSheetsName();
    try {
        loadFile();
        totalsheet = workbook.getNumberOfSheets();
        sheetIndex = new int[totalsheet];
        while (i < totalsheet) {
            sheetIndex[i] = workbook.getSheetIndex(sheetname[i]);
            i++;
        }

    } catch (FileNotFoundException ex) {
        // logger.error(ex);
    } catch (NullObjectFoundException ex) {
        // logger.error(ex);
    }

    return sheetIndex;
}

private boolean validateIndex(int index) {
    if (index < getSheetsIndex().length && index >= 0)
        return true;
    else
        return false;
}

public int getNumberOfSheet() {
    int totalsheet = 0;
    try {
        loadFile();
        totalsheet = workbook.getNumberOfSheets();

    } catch (FileNotFoundException ex) {
        // logger.error(ex.getMessage());
    } catch (NullObjectFoundException ex) {
        // logger.error(ex.getMessage());
    }

    return totalsheet;
}

public int getNumberOfColumns(int SheetIndex) {
    int NO_OF_Column = 0;
    @SuppressWarnings("unused")
    XSSFCell cell = null;
    XSSFSheet sheet = null;
    try {
        loadFile(); // load give Excel
        if (validateIndex(SheetIndex)) {
            sheet = workbook.getSheetAt(SheetIndex);
            Iterator<Row> rowIter = sheet.rowIterator();
            XSSFRow firstRow = (XSSFRow) rowIter.next();
            Iterator<Cell> cellIter = firstRow.cellIterator();
            while (cellIter.hasNext()) {
                cell = (XSSFCell) cellIter.next();
                NO_OF_Column++;
            }
        } else
            throw new InvalidSheetIndexException("Invalid sheet index.");
    } catch (Exception ex) {
        // logger.error(ex.getMessage());

    }

    return NO_OF_Column;
}

public int getNumberOfRows(int SheetIndex) {
    int NO_OF_ROW = 0;
    XSSFSheet sheet = null;

    try {
        loadFile(); // load give Excel
        if (validateIndex(SheetIndex)) {
            sheet = workbook.getSheetAt(SheetIndex);
            NO_OF_ROW = sheet.getLastRowNum();
        } else
            throw new InvalidSheetIndexException("Invalid sheet index.");
    } catch (Exception ex) {
        // logger.error(ex);
    }

    return NO_OF_ROW;
}

public String[] getSheetHeader(int SheetIndex) {
    int noOfColumns = 0;
    XSSFCell cell = null;
    int i = 0;
    String columns[] = null;
    XSSFSheet sheet = null;

    try {
        loadFile(); // load give Excel
        if (validateIndex(SheetIndex)) {
            sheet = workbook.getSheetAt(SheetIndex);
            noOfColumns = getNumberOfColumns(SheetIndex);
            columns = new String[noOfColumns];
            Iterator<Row> rowIter = sheet.rowIterator();
            XSSFRow Row = (XSSFRow) rowIter.next();
            Iterator<Cell> cellIter = Row.cellIterator();

            while (cellIter.hasNext()) {
                cell = (XSSFCell) cellIter.next();
                columns[i] = cell.getStringCellValue();
                i++;
            }
        } else
            throw new InvalidSheetIndexException("Invalid sheet index.");
    }

    catch (Exception ex) {
        // logger.error(ex);
    }

    return columns;
}// end of method

public String[][] getSheetData(int SheetIndex) {
    int noOfColumns = 0;
    XSSFRow row = null;
    XSSFCell cell = null;
    int i = 0;
    int noOfRows = 0;
    int j = 0;
    String[][] data = null;
    XSSFSheet sheet = null;

    try {
        loadFile(); // load give Excel
        if (validateIndex(SheetIndex)) {
            sheet = workbook.getSheetAt(SheetIndex);
            noOfColumns = getNumberOfColumns(SheetIndex);
            noOfRows = getNumberOfRows(SheetIndex) + 1;
            data = new String[noOfRows][noOfColumns];
            Iterator<Row> rowIter = sheet.rowIterator();
            while (rowIter.hasNext()) {
                row = (XSSFRow) rowIter.next();
                Iterator<Cell> cellIter = row.cellIterator();
                j = 0;
                while (cellIter.hasNext()) {
                    cell = (XSSFCell) cellIter.next();
                    if (cell.getCellType() == Cell.CELL_TYPE_STRING) {
                        data[i][j] = cell.getStringCellValue();
                    } else if (cell.getCellType() == Cell.CELL_TYPE_NUMERIC) {
                        if (HSSFDateUtil.isCellDateFormatted(cell)) {
                            String formatCellValue = new DataFormatter()
                                    .formatCellValue(cell);
                            data[i][j] = formatCellValue;
                        } else {
                            data[i][j] = Double.toString(cell
                                    .getNumericCellValue());
                        }

                    } else if (cell.getCellType() == Cell.CELL_TYPE_BOOLEAN) {
                        data[i][j] = Boolean.toString(cell
                                .getBooleanCellValue());
                    }

                    else if (cell.getCellType() == Cell.CELL_TYPE_FORMULA) {
                        data[i][j] = cell.getCellFormula().toString();
                    }

                    j++;
                }

                i++;
            } // outer while

        } else
            throw new InvalidSheetIndexException("Invalid sheet index.");

    } catch (Exception ex) {
        // logger.error(ex);
    }
    return data;
}

public String[][] getSheetData(int SheetIndex, int noOfRows) {
    int noOfColumns = 0;
    XSSFRow row = null;
    XSSFCell cell = null;
    int i = 0;
    int j = 0;
    String[][] data = null;
    XSSFSheet sheet = null;

    try {
        loadFile(); // load give Excel

        if (validateIndex(SheetIndex)) {
            sheet = workbook.getSheetAt(SheetIndex);
            noOfColumns = getNumberOfColumns(SheetIndex);
            data = new String[noOfRows][noOfColumns];
            Iterator<Row> rowIter = sheet.rowIterator();
            while (i < noOfRows) {

                row = (XSSFRow) rowIter.next();
                Iterator<Cell> cellIter = row.cellIterator();
                j = 0;
                while (cellIter.hasNext()) {
                    cell = (XSSFCell) cellIter.next();
                    if (cell.getCellType() == Cell.CELL_TYPE_STRING) {
                        data[i][j] = cell.getStringCellValue();
                    } else if (cell.getCellType() == Cell.CELL_TYPE_NUMERIC) {
                        if (HSSFDateUtil.isCellDateFormatted(cell)) {
                            String formatCellValue = new DataFormatter()
                                    .formatCellValue(cell);
                            data[i][j] = formatCellValue;
                        } else {
                            data[i][j] = Double.toString(cell
                                    .getNumericCellValue());
                        }
                    }

                    j++;
                }

                i++;
            } // outer while
        } else
            throw new InvalidSheetIndexException("Invalid sheet index.");
    } catch (Exception ex) {
        // logger.error(ex);
    }

    return data;
}
}

Created this little testcode:

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;


public class ReadXLSXTest {

/**
 * @param args
 * @throws FileNotFoundException 
 */
public static void main(String[] args) throws FileNotFoundException {
    // TODO Auto-generated method stub


    ReadXLSX test = new ReadXLSX(new FileInputStream(new File("./sample.xlsx")));

    System.out.println(test.getSheetsName());
    System.out.println(test.getNumberOfSheet());


}

}

All this ran like a charm, so my guess is you have an XLSX file that is 'corrupt' in one way or another. Try testing with other data.

Cheers, Wim

How to make an anchor tag refer to nothing?

I know this is tagged as a jQuery question, but you can answer this with AngularJS, also.

in your element, add the ng-click directive and use the $event variable which is the click event... prevent its default behavior:

<a href="#" ng-click="$event.preventDefault()">

You can even pass the $event variable into a function:

<a href="#" ng-click="doSomething($event)">

in that function, you do whatever you want with the click event.

'const int' vs. 'int const' as function parameters in C++ and C

const int is identical to int const, as is true with all scalar types in C. In general, declaring a scalar function parameter as const is not needed, since C's call-by-value semantics mean that any changes to the variable are local to its enclosing function.

How to add a default include path for GCC in Linux?

Try setting C_INCLUDE_PATH (for C header files) or CPLUS_INCLUDE_PATH (for C++ header files).

As Ciro mentioned, CPATH will set the path for both C and C++ (and any other language).

More details in GCC's documentation.

How to check if text fields are empty on form submit using jQuery?

A simple solution would be something like this

$( "form" ).on( "submit", function() { 

   var has_empty = false;

   $(this).find( 'input[type!="hidden"]' ).each(function () {

      if ( ! $(this).val() ) { has_empty = true; return false; }
   });

   if ( has_empty ) { return false; }
});

Note: The jQuery.on() method is only available in jQuery version 1.7+, but it is now the preferred method of attaching event handlers.

This code loops through all of the inputs in the form and prevents form submission by returning false if any of them have no value. Note that it doesn't display any kind of message to the user about why the form failed to submit (I would strongly recommend adding one).

Or, you could look at the jQuery validate plugin. It does this and a lot more.

NB: This type of technique should always be used in conjunction with server side validation.

set height of imageview as matchparent programmatically

imageView.getLayoutParams().height= ViewGroup.LayoutParams.MATCH_PARENT;

How to compare two JSON objects with the same elements in a different order equal?

Another way could be to use json.dumps(X, sort_keys=True) option:

import json
a, b = json.dumps(a, sort_keys=True), json.dumps(b, sort_keys=True)
a == b # a normal string comparison

This works for nested dictionaries and lists.

MassAssignmentException in Laravel

To make all fields fillable, just declare on your class:

protected $guarded = array();

This will enable you to call fill method without declare each field.

How to make child element higher z-index than parent?

Nothing is impossible. Use the force.

.parent {
    position: relative;
}

.child {
    position: absolute;
    top:0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 100;
}

How to use Console.WriteLine in ASP.NET (C#) during debug?

Console.Write will not work in ASP.NET as it is called using the browser. Use Response.Write instead.

See Stack Overflow question Where does Console.WriteLine go in ASP.NET?.

If you want to write something to Output window during debugging, you can use

System.Diagnostics.Debug.WriteLine("SomeText");

but this will work only during debug.

See Stack Overflow question Debug.WriteLine not working.

Converting a vector<int> to string

I usually do it this way...

#include <string>
#include <vector>

int main( int argc, char* argv[] )
{
    std::vector<char> vec;
    //... do something with vec
    std::string str(vec.begin(), vec.end());
    //... do something with str
    return 0;
}

DateTimePicker time picker in 24 hour but displaying in 12hr?

Perfectly worked for me

jQuery('#datetimepicker1').datetimepicker({
    use24hours: true,   
    format: "YYYY-MM-DD HH:mm ",
    defaultDate: new Date(),
    });

"No resource identifier found for attribute 'showAsAction' in package 'android'"

Check your compileSdkVersion on app build.gradle. Set it to 21:

compileSdkVersion 21

npm can't find package.json

Follwing the below steps you well get package.json file.

npm --version
npm install express
npm init -y

Server.MapPath - Physical path given, virtual path expected

var files = Directory.GetFiles(@"E:\ftproot\sales");

'Access denied for user 'root'@'localhost' (using password: NO)'

1) You can set root password by invoking MySQL console. It is located in

C:\wamp\bin\mysql\mysql5.1.53\bin by default.

Get to the directory and type MySQL. then set the password as follows..

    > SET PASSWORD FOR root@localhost = PASSWORD('new-password');

2) You can configure wamp's phpmyadmin application for root user by editing

C:\wamp\apps\phpmyadmin3.3.9\config.inc.php 

Note :- if you are using xampp then , file will be located at

C:\xampp\phpMyadmin\config.inc.php

It looks like this:

        $cfg['Servers'][$i]['verbose'] = 'localhost';
        $cfg['Servers'][$i]['host'] = 'localhost';
        $cfg['Servers'][$i]['port'] = '';
        $cfg['Servers'][$i]['socket'] = '';
        $cfg['Servers'][$i]['connect_type'] = 'tcp';
        $cfg['Servers'][$i]['extension'] = 'mysqli';
        $cfg['Servers'][$i]['auth_type'] = 'config';
        $cfg['Servers'][$i]['user'] = 'root';
        $cfg['Servers'][$i]['password'] = 'YOURPASSWORD';
        $cfg['Servers'][$i]['AllowNoPassword'] = false;

The error "Access denied for user 'root@localhost' (using password:NO)" will be resolved when you set $cfg['Servers'][$i]['AllowNoPassword'] to false

If you priviously changed the password for 'root@localhost', then you have to do 2 things to solve the error "Access denided for user 'root@localhost'":

  1. if ['password'] have a empty quotes like ' ' then put your password between quotes.
  2. change the (using password:NO) to (using password:YES)

This will resolve the error.

Note: phpmyadmin is a separate tool which comes with wamp. It just provide a interface to MySQL. if you change my sql root's password, then you should change the phpmyadmin configurations. Usually phpmyadmin is configured to root user.

How to include file in a bash shell script

Yes, use source or the short form which is just .:

. other_script.sh

IF statement: how to leave cell blank if condition is false ("" does not work)

The easiest solution is to use conditional formatting if the IF Statement comes back false to change the font of the results cell to whatever color background is. Yes, technically the cell isn't blank, but you won't be able to see it's contents.

How do I fix a NoSuchMethodError?

I've had the same problem. This is also caused when there is an ambiguity in classes. My program was trying to invoke a method which was present in two JAR files present in the same location / class path. Delete one JAR file or execute your code such that only one JAR file is used. Check that you are not using same JAR or different versions of the same JAR that contain the same class.

DISP_E_EXCEPTION [step] [] [Z-JAVA-105 Java exception java.lang.NoSuchMethodError(com.example.yourmethod)]

Unable to import path from django.urls

For those who are using python 2.7, python2.7 don't support django 2 so you can't install django.urls. If you are already using python 3.6 so you need to upgrade django to latest version which is greater than 2.

  • On PowerShell

    pip install -U django

  • Verification

>

PS C:\Users\xyz> python
Python 3.6.6 |Anaconda, Inc.| (default, Jul 25 2018, 15:27:00) [MSC v.1910 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.

>>> from django.urls import path
>>>

As next prompt came, it means it is installed now and ready to use.

How to remove last n characters from every element in the R vector

Similar to @Matthew_Plourde using gsub

However, using a pattern that will trim to zero characters i.e. return "" if the original string is shorter than the number of characters to cut:

cs <- c("foo_bar","bar_foo","apple","beer","so","a")
gsub('.{0,3}$', '', cs)
# [1] "foo_" "bar_" "ap"   "b"    ""    ""

Difference is, {0,3} quantifier indicates 0 to 3 matches, whereas {3} requires exactly 3 matches otherwise no match is found in which case gsub returns the original, unmodified string.

N.B. using {,3} would be equivalent to {0,3}, I simply prefer the latter notation.

See here for more information on regex quantifiers: https://www.regular-expressions.info/refrepeat.html

How to make the corners of a button round?

Create an XML file like below one. Set it as background for the button. Change the radius attribute to your wish, if you need more curve for the button.

button_background.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <solid android:color="@color/primary" />
    <corners android:radius="5dp" />
</shape>

Set background to your button:

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/button_background"/>

Call PHP function from Twig template

I am surprised the code answer is not posted already, it's a one liner.

You could just {{ categeory_id | getVariations }}

It's a one-liner:

$twig->addFilter('getVariations', new Twig_Filter_Function('getVariations'));

How to add a touch event to a UIView?

Create a gesture recognizer (subclass), that will implement touch events, like touchesBegan. You can add it to the view after that.

This way you'll use composition instead subclassing (which was the request).

Replace X-axis with own values

Not sure if it's what you mean, but you can do this:

plot(1:10, xaxt = "n", xlab='Some Letters')
axis(1, at=1:10, labels=letters[1:10])

which then gives you the graph:

enter image description here

Is there an easy way to add a border to the top and bottom of an Android View?

Just to enforce @phreakhead ´s and user1051892 ´s answers, <item android:bottom|android:left|android:right|android:top> if negative, must to be greater than <stroke android:width>. If not, item´s painting will be mixed with stroke´s painting and you may think these values are not working.

Is it possible to import a whole directory in sass using @import?

The accepted answer by Dennis Best states that "Otherwise, load order is and should be irrelevant... if we are doing things properly." This is simply incorrect. If you are doing things properly, you make use of the css order to help you reduce specificity and keeping you css simple and clean.

What I do to organize imports is adding an _all.scss file in a directory, where I import all the relevant files in it, in the correct order. This way, my main import file will be simple and clean, like this:

// Import all scss in the project

// Utilities, mixins and placeholders
@import 'utils/_all';

// Styles
@import 'components/_all';
@import 'modules/_all';
@import 'templates/_all';

You could do this for sub-directories as well, if you need, but I don't think the structure of your css files should be too deep.

Though I use this approach, I still think a glob import should exist in sass, for situations where order does not matter, like a directory of mixins or even animations.

How to programmatically log out from Facebook SDK 3.0 without using Facebook login/logout button?

Since Facebook's Android SDK v4.0 (see changelog) you need to execute the following:

LoginManager.getInstance().logOut();

How to mock void methods with Mockito

I think I've found a simpler answer to that question, to call the real method for just one method (even if it has a void return) you can do this:

Mockito.doCallRealMethod().when(<objectInstance>).<method>();
<objectInstance>.<method>();

Or, you could call the real method for all methods of that class, doing this:

<Object> <objectInstance> = mock(<Object>.class, Mockito.CALLS_REAL_METHODS);

Bash: Syntax error: redirection unexpected

do it the simpler way,

direc=$(basename `pwd`)

Or use the shell

$ direc=${PWD##*/}

How to use nan and inf in C?

I usually use

#define INFINITY (1e999)

or

const double INFINITY = 1e999

which works at least in IEEE 754 contexts because the highest representable double value is roughly 1e308. 1e309 would work just as well, as would 1e99999, but three nines is sufficient and memorable. Since this is either a double literal (in the #define case) or an actual Inf value, it will remain infinite even if you're using 128-bit (“long double”) floats.

print arraylist element?

You should override toString() method in your Dog class. which will be called when you use this object in sysout.

In Perl, what is the difference between a .pm (Perl module) and .pl (Perl script) file?

At the very core, the file extension you use makes no difference as to how perl interprets those files.

However, putting modules in .pm files following a certain directory structure that follows the package name provides a convenience. So, if you have a module Example::Plot::FourD and you put it in a directory Example/Plot/FourD.pm in a path in your @INC, then use and require will do the right thing when given the package name as in use Example::Plot::FourD.

The file must return true as the last statement to indicate successful execution of any initialization code, so it's customary to end such a file with 1; unless you're sure it'll return true otherwise. But it's better just to put the 1;, in case you add more statements.

If EXPR is a bareword, the require assumes a ".pm" extension and replaces "::" with "/" in the filename for you, to make it easy to load standard modules. This form of loading of modules does not risk altering your namespace.

All use does is to figure out the filename from the package name provided, require it in a BEGIN block and invoke import on the package. There is nothing preventing you from not using use but taking those steps manually.

For example, below I put the Example::Plot::FourD package in a file called t.pl, loaded it in a script in file s.pl.

C:\Temp> cat t.pl
package Example::Plot::FourD;

use strict; use warnings;

sub new { bless {} => shift }

sub something { print "something\n" }

"Example::Plot::FourD"

C:\Temp> cat s.pl
#!/usr/bin/perl
use strict; use warnings;

BEGIN {
    require 't.pl';
}

my $p = Example::Plot::FourD->new;
$p->something;


C:\Temp> s
something

This example shows that module files do not have to end in 1, any true value will do.

How to clear an EditText on click?

((EditText) findViewById(R.id.User)).setText("");
((EditText) findViewById(R.id.Password)).setText("");

How to resolve "git pull,fatal: unable to access 'https://github.com...\': Empty reply from server"

I tried a few of the tricks listed here without any luck. Looks like something was getting cached by my terminal emulator (iTerm2) or session. The issue went away when I ran the command from a fresh terminal tab.

CSS: Auto resize div to fit container width

You can overflow:hidden to your #content. Write like this:

#content
{
    min-width:700px;
    margin-left:10px;
    overflow:hidden;
    background-color:AppWorkspace;
}

Check this http://jsfiddle.net/Zvt2j/1/

How to default to other directory instead of home directory

I use ConEmu (strongly recommended on Windows) where I have a task for starting Git Bash like

enter image description here

Note the button "Startup dir..." in the bottom. It adds a -new_console:d:<path> to the startup command of the Git Bash. Make it point to wherever you like

how to use concatenate a fixed string and a variable in Python

I'm guessing that you meant to do this:

msg['Subject'] = "Auto Hella Restart Report " + sys.argv[1]
# To concatenate strings in python, use       ^ 

Copy all files with a certain extension from all subdirectories

From all of the above, I came up with this version. This version also works for me in the mac recovery terminal.

find ./ -name '*.xsl' -exec cp -prv '{}' '/path/to/targetDir/' ';'

It will look in the current directory and recursively in all of the sub directories for files with the xsl extension. It will copy them all to the target directory.

cp flags are:

  • p - preserve attributes of the file
  • r - recursive
  • v - verbose (shows you whats being copied)

How to check if array is not empty?

if self.table:
    print 'It is not empty'

Is fine too

How do I scroll a row of a table into view (element.scrollintoView) using jQuery?

I found a case (overflow div > table > tr > td) in which scrolling to the relative position of the tr does not work. Instead, I had to scroll the overflow container (div) using scrollTop to <tr>.offset().top - <table>.offset().top. Eg:

$('#container').scrollTop( $('#tr').offset().top - $('#td').offset().top )

How to use a typescript enum value in an Angular2 ngSwitch statement

You can create a custom decorator to add to your component to make it aware of enums.

myenum.enum.ts:

export enum MyEnum {
    FirstValue,
    SecondValue
}

myenumaware.decorator.ts

import { MyEnum } from './myenum.enum';

export function MyEnumAware(constructor: Function) {
    constructor.prototype.MyEnum = MyEnum;
}

enum-aware.component.ts

import { Component } from '@angular2/core';
import { MyEnum } from './myenum.enum';
import { MyEnumAware } from './myenumaware.decorator';

@Component({
  selector: 'enum-aware',
  template: `
    <div [ngSwitch]="myEnumValue">
      <div *ngSwitchCase="MyEnum.FirstValue">
        First Value
      </div>
      <div *ngSwitchCase="MyEnum.SecondValue">
        Second Value
      </div>
    </div>
    <button (click)="toggleValue()">Toggle Value</button>
  `,
})
@MyEnumAware // <---------------!!!
export default class EnumAwareComponent {
  myEnumValue: MyEnum = MyEnum.FirstValue;

  toggleValue() {
    this.myEnumValue = this.myEnumValue === MyEnum.FirstValue
        ? MyEnum.SecondValue : MyEnum.FirstValue;
  }
}

Get a list of resources from classpath directory

Neither of answers worked for me even though I had my resources put in resources folders and followed the above answers. What did make a trick was:

@Value("file:*/**/resources/**/schema/*.json")
private Resource[] resources;

CSS: fixed to bottom and centered

I ran into a problem where the typical position: fixed and bottom: 0 didn't work. Discovered a neat functionality with position: sticky. Note it's "relatively" new so it won't with IE/Edge 15 and earlier.

Here's an example for w3schools.

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_x000D_
<!DOCTYPE html>
<html>
<head>
<style>
div.sticky {
  position: sticky;
  bottom: 0;
  background-color: yellow;
  padding: 30px;
  font-size: 20px;
}
</style>
</head>
<body>

<p>Lorem ipsum dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas nisl est,  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dlerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dlerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dlerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dlerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas  dolor nteger frinegestas odio, vitae scelerisque enim ligula venenatis dolor. Maecenas </p>

<div class="sticky">I will stick to the screen when you reach my scroll position</div>

</body>
</html>
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PHP: How do you determine every Nth iteration of a loop?

every 3 posts?

if($counter % 3 == 0){
    echo IMAGE;
}

How to specify preference of library path?

This is an old question, but no one seems to have mentioned this.

You were getting lucky that the thing was linking at all.

You needed to change

g++ -g -Wall -o my_binary -L/my/dir -lfoo bar.cpp

to this:

g++ -g -Wall -o my_binary -L/my/dir bar.cpp -lfoo

Your linker keeps track of symbols it needs to resolve. If it reads the library first, it doesn't have any needed symbols, so it ignores the symbols in it. Specify the libraries after the things that need to link to them so that your linker has symbols to find in them.

Also, -lfoo makes it search specifically for a file named libfoo.a or libfoo.so as needed. Not libfoo.so.0. So either ln the name or rename the library as appopriate.

To quote the gcc man page:

-l library
   ...
   It makes a difference where in the command you 
   write this option; the linker searches and processes 
   libraries and object files in the order they are 
   specified.  Thus, foo.o -lz bar.o searches library z 
   after file foo.o but before bar.o.  If bar.o refers 
   to functions in z, those functions may not be loaded.

Adding the file directly to g++'s command line should have worked, unless of course, you put it prior to bar.cpp, causing the linker to ignore it for lacking any needed symbols, because no symbols were needed yet.

How to remove the default arrow icon from a dropdown list (select element)?

Try This:

HTML:

<div class="customselect">
    <select>
    <option>2000</option>
    <option>2001</option>
    <option>2002</option>
    </select>
</div>

CSS:

.customselect {
    width: 70px;
    overflow: hidden;
}

.customselect select {
   width: 100px;
   -moz-appearance: none;
   -webkit-appearance: none;
   appearance: none;
}

Creating files in C++

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

string filename = "/tmp/filename.txt";

int main() {
  std::ofstream o(filename.c_str());

  o << "Hello, World\n" << std::endl;

  return 0;
}

This is what I had to do in order to use a variable for the filename instead of a regular string.

Javascript Uncaught Reference error Function is not defined

Change the wrapping from "onload" to "No wrap - in <body>"

The function defined has a different scope.

What exactly is Python's file.flush() doing?

There's typically two levels of buffering involved:

  1. Internal buffers
  2. Operating system buffers

The internal buffers are buffers created by the runtime/library/language that you're programming against and is meant to speed things up by avoiding system calls for every write. Instead, when you write to a file object, you write into its buffer, and whenever the buffer fills up, the data is written to the actual file using system calls.

However, due to the operating system buffers, this might not mean that the data is written to disk. It may just mean that the data is copied from the buffers maintained by your runtime into the buffers maintained by the operating system.

If you write something, and it ends up in the buffer (only), and the power is cut to your machine, that data is not on disk when the machine turns off.

So, in order to help with that you have the flush and fsync methods, on their respective objects.

The first, flush, will simply write out any data that lingers in a program buffer to the actual file. Typically this means that the data will be copied from the program buffer to the operating system buffer.

Specifically what this means is that if another process has that same file open for reading, it will be able to access the data you just flushed to the file. However, it does not necessarily mean it has been "permanently" stored on disk.

To do that, you need to call the os.fsync method which ensures all operating system buffers are synchronized with the storage devices they're for, in other words, that method will copy data from the operating system buffers to the disk.

Typically you don't need to bother with either method, but if you're in a scenario where paranoia about what actually ends up on disk is a good thing, you should make both calls as instructed.


Addendum in 2018.

Note that disks with cache mechanisms is now much more common than back in 2013, so now there are even more levels of caching and buffers involved. I assume these buffers will be handled by the sync/flush calls as well, but I don't really know.

CentOS 7 and Puppet unable to install nc

Nc is a link to nmap-ncat.

It would be nice to use nmap-ncat in your puppet, because NC is a virtual name of nmap-ncat.

Puppet cannot understand the links/virtualnames

your puppet should be:

package {
  'nmap-ncat':
    ensure => installed;
}

MySQL Cannot Add Foreign Key Constraint

My solution is maybe a little embarrassing and tells the tale of why you should sometimes look at what you have in front of you instead of these posts :)

I had ran a forward engineer before, which failed, so that meant that my database already had a few tables, then i have been sitting trying to fix foreign key contraints failures trying to make sure that everything was perfect, but it ran up against the tables previously created, so it was to no prevail.

Char array declaration and initialization in C

This is another C example of where the same syntax has different meanings (in different places). While one might be able to argue that the syntax should be different for these two cases, it is what it is. The idea is that not that it is "not allowed" but that the second thing means something different (it means "pointer assignment").

Can't operator == be applied to generic types in C#?

In general, EqualityComparer<T>.Default.Equals should do the job with anything that implements IEquatable<T>, or that has a sensible Equals implementation.

If, however, == and Equals are implemented differently for some reason, then my work on generic operators should be useful; it supports the operator versions of (among others):

  • Equal(T value1, T value2)
  • NotEqual(T value1, T value2)
  • GreaterThan(T value1, T value2)
  • LessThan(T value1, T value2)
  • GreaterThanOrEqual(T value1, T value2)
  • LessThanOrEqual(T value1, T value2)

How to load a jar file at runtime

I was asked to build a java system that will have the ability to load new code while running

You might want to base your system on OSGi (or at least take a lot at it), which was made for exactly this situation.

Messing with classloaders is really tricky business, mostly because of how class visibility works, and you do not want to run into hard-to-debug problems later on. For example, Class.forName(), which is widely used in many libraries does not work too well on a fragmented classloader space.

How can a query multiply 2 cell for each row MySQL?

Use this:

SELECT 
    Pieces, Price, 
    Pieces * Price as 'Total' 
FROM myTable

Replace console output in Python

For anyone who stumbles upon this years later (like I did), I tweaked 6502's methods a little bit to allow the progress bar to decrease as well as increase. Useful in slightly more cases. Thanks 6502 for a great tool!

Basically, the only difference is that the whole line of #s and -s is written each time progress(x) is called, and the cursor is always returned to the start of the bar.

def startprogress(title):
    """Creates a progress bar 40 chars long on the console
    and moves cursor back to beginning with BS character"""
    global progress_x
    sys.stdout.write(title + ": [" + "-" * 40 + "]" + chr(8) * 41)
    sys.stdout.flush()
    progress_x = 0


def progress(x):
    """Sets progress bar to a certain percentage x.
    Progress is given as whole percentage, i.e. 50% done
    is given by x = 50"""
    global progress_x
    x = int(x * 40 // 100)                      
    sys.stdout.write("#" * x + "-" * (40 - x) + "]" + chr(8) * 41)
    sys.stdout.flush()
    progress_x = x


def endprogress():
    """End of progress bar;
    Write full bar, then move to next line"""
    sys.stdout.write("#" * 40 + "]\n")
    sys.stdout.flush()

The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'NTLM'

I have upgraded my older version of WCF to WCF 4 with below changes, hope you can also make the similar changes.

1. Web.config:

<system.serviceModel>
      <bindings>
        <basicHttpBinding>
          <binding name="Demo_BasicHttp">
            <security mode="TransportCredentialOnly">
              <transport clientCredentialType="InheritedFromHost"/>
            </security>
          </binding>
        </basicHttpBinding>
      </bindings>
      <services>
        <service name="DemoServices.CalculatorService.ServiceImplementation.CalculatorService" behaviorConfiguration="Demo_ServiceBehavior">
          <endpoint address="" binding="basicHttpBinding"
              bindingConfiguration="Demo_BasicHttp" contract="DemoServices.CalculatorService.ServiceContracts.ICalculatorServiceContract">
            <identity>
              <dns value="localhost"/>
            </identity>
          </endpoint>
          <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
        </service>
      </services>
      <behaviors>
        <serviceBehaviors>
          <behavior name="Demo_ServiceBehavior">
            <!-- To avoid disclosing metadata information, set the values below to false before deployment -->
            <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true"/>
            <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
            <serviceDebug includeExceptionDetailInFaults="false"/>
          </behavior>
        </serviceBehaviors>
      </behaviors>
      <protocolMapping>
        <add scheme="http" binding="basicHttpBinding" bindingConfiguration="Demo_BasicHttp"/>
      </protocolMapping>
      <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" />
    </system.serviceModel>

2. App.config:

    <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="BasicHttpBinding_ICalculatorServiceContract" maxBufferSize="2147483647" maxBufferPoolSize="33554432" maxReceivedMessageSize="2147483647" closeTimeout="00:10:00" sendTimeout="00:10:00" receiveTimeout="00:10:00">
          <readerQuotas maxArrayLength="2147483647" maxBytesPerRead="4096" />
          <security mode="TransportCredentialOnly">
            <transport clientCredentialType="Ntlm" proxyCredentialType="None" realm="" />
          </security>
        </binding>
      </basicHttpBinding>
    </bindings>
    <client>
      <endpoint address="http://localhost:24357/CalculatorService.svc" binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_ICalculatorServiceContract" contract="ICalculatorServiceContract" name="Demo_BasicHttp" />
    </client>
  </system.serviceModel>

Scala best way of turning a Collection into a Map-by-key?

Another solution (might not work for all types)

import scala.collection.breakOut
val m:Map[P, T] = c.map(t => (t.getP, t))(breakOut)

this avoids the creation of the intermediary list, more info here: Scala 2.8 breakOut

Git on Bitbucket: Always asked for password, even after uploading my public SSH key

I was having other weirdness around logging in. I came across something that seemed totally dumb but worked in my case. Simply go to MacOS's keychain. Find the login lock icon in the sidebar. Click it to logout and then click to login. Sounds dumb but it solved my issues. Worth a shot.

java.sql.SQLException: No suitable driver found for jdbc:microsoft:sqlserver

Following is a simple code to read from SQL database. Database names is "database1". Table name is "table1". It contain two columns "uname" and "pass". Dont forget to add "sqljdbc4.jar" to your project. Download sqljdbc4.jar

public class NewClass {

    public static void main(String[] args) {

        Connection conn = null;
        String dbName = "database1";
        String serverip="192.168.100.100";
        String serverport="1433";
        String url = "jdbc:sqlserver://"+serverip+"\\SQLEXPRESS:"+serverport+";databaseName="+dbName+"";
        Statement stmt = null;
        ResultSet result = null;
        String driver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
        String databaseUserName = "admin";
        String databasePassword = "root";
        try {
            Class.forName(driver).newInstance();
            conn = DriverManager.getConnection(url, databaseUserName, databasePassword);
            stmt = conn.createStatement();
            result = null;
            String pa,us;
            result = stmt.executeQuery("select * from table1 ");

            while (result.next()) {
                us=result.getString("uname");
                pa = result.getString("pass");              
                System.out.println(us+"  "+pa);
            }

            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

How to show current time in JavaScript in the format HH:MM:SS?

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function realtime() {_x000D_
  _x000D_
  let time = moment().format('h:mm:ss a');_x000D_
  document.getElementById('time').innerHTML = time;_x000D_
  _x000D_
  setInterval(() => {_x000D_
    time = moment().format('h:mm:ss a');_x000D_
    document.getElementById('time').innerHTML = time;_x000D_
  }, 1000)_x000D_
}_x000D_
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realtime();
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<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.1/moment.min.js"></script>_x000D_
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<div id="time"></div>
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A very simple way using moment.js and setInterval.

setInterval(() => {
  moment().format('h:mm:ss a');
}, 1000)

Sample output

Using setInterval() set to 1000ms or 1 second, the output will refresh every 1 second.

3:25:50 pm

This is how I use this method on one of my side projects.

setInterval(() => {
  this.time = this.shared.time;
}, 1000)

Maybe you're wondering if using setInterval() would cause some performance issues.

Is setInterval CPU intensive?

I don't think setInterval is inherently going to cause you significant performance problems. I suspect the reputation may come from an earlier era, when CPUs were less powerful. ... - lonesomeday

No, setInterval is not CPU intensive in and of itself. If you have a lot of intervals running on very short cycles (or a very complex operation running on a moderately long interval), then that can easily become CPU intensive, depending upon exactly what your intervals are doing and how frequently they are doing it. ... - aroth

But in general, using setInterval really like a lot on your site may slow down things. 20 simultaneously running intervals with more or less heavy work will affect the show. And then again.. you really can mess up any part I guess that is not a problem of setInterval. ... - jAndy

How to use PHP OPCache?

I encountered this when setting up moodle. I added the following lines in the php.ini file.

zend_extension=C:\xampp\php\ext\php_opcache.dll

[opcache]
opcache.enable = 1
opcache.memory_consumption = 128
opcache.max_accelerated_files = 4000
opcache.revalidate_freq = 60

; Required for Moodle
opcache.use_cwd = 1
opcache.validate_timestamps = 1
opcache.save_comments = 1
opcache.enable_file_override = 0

; If something does not work in Moodle
;opcache.revalidate_path = 1 ; May fix problems with include paths
;opcache.mmap_base = 0x20000000 ; (Windows only) fix OPcache crashes with event id 487

; Experimental for Moodle 2.6 and later
;opcache.fast_shutdown = 1
;opcache.enable_cli = 1 ; Speeds up CLI cron
;opcache.load_comments = 0 ; May lower memory use, might not be compatible with add-ons and other apps

extension=C:\xampp\php\ext\php_intl.dll

[intl]
intl.default_locale = en_utf8
intl.error_level = E_WARNING

intl -> http://php.net/manual/en/book.intl.php

What is the difference between a JavaBean and a POJO?

A JavaBean follows certain conventions. Getter/setter naming, having a public default constructor, being serialisable etc. See JavaBeans Conventions for more details.

A POJO (plain-old-Java-object) isn't rigorously defined. It's a Java object that doesn't have a requirement to implement a particular interface or derive from a particular base class, or make use of particular annotations in order to be compatible with a given framework, and can be any arbitrary (often relatively simple) Java object.

Remove directory which is not empty

Async version of @SharpCoder's answer using fs.promises:

const fs = require('fs');
const afs = fs.promises;

const deleteFolderRecursive = async path =>  {
    if (fs.existsSync(path)) {
        for (let entry of await afs.readdir(path)) {
            const curPath = path + "/" + entry;
            if ((await afs.lstat(curPath)).isDirectory())
                await deleteFolderRecursive(curPath);
            else await afs.unlink(curPath);
        }
        await afs.rmdir(path);
    }
};

Get month name from number

This is not so helpful if you need to just know the month name for a given number (1 - 12), as the current day doesn't matter.

calendar.month_name[i]

or

calendar.month_abbr[i]

are more useful here.

Here is an example:

import calendar

for month_idx in range(1, 13):
    print (calendar.month_name[month_idx])
    print (calendar.month_abbr[month_idx])
    print ("")

Sample output:

January
Jan

February
Feb

March
Mar

...

Store select query's output in one array in postgres

I had exactly the same problem. Just one more working modification of the solution given by Denis (the type must be specified):

SELECT ARRAY(
SELECT column_name::text
FROM information_schema.columns
WHERE table_name='aean'
)

Angular.js vs Knockout.js vs Backbone.js

It depends on the nature of your application. And, since you did not describe it in great detail, it is an impossible question to answer. I find Backbone to be the easiest, but I work in Angular all day. Performance is more up to the coder than the framework, in my opinion.

Are you doing heavy DOM manipulation? I would use jQuery and Backbone.

Very data driven app? Angular with its nice data binding.

Game programming? None - direct to canvas; maybe a game engine.

How to skip over an element in .map()?

I think the most simple way to skip some elements from an array is by using the filter() method.

By using this method (ES5) and the ES6 syntax you can write your code in one line, and this will return what you want:

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_x000D_
let images = [{src: 'img.png'}, {src: 'j1.json'}, {src: 'img.png'}, {src: 'j2.json'}];_x000D_
_x000D_
let sources = images.filter(img => img.src.slice(-4) != 'json').map(img => img.src);_x000D_
_x000D_
console.log(sources);
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_x000D_
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Apache VirtualHost 403 Forbidden

If you did everything right, just give the permission home directory like:

sudo chmod o+x $HOME

then

sudo systemctl restart apache2

Auto detect mobile browser (via user-agent?)

You can check the User-Agent string. In JavaScript, that's really easy, it's just a property of the navigator object.

var useragent = navigator.userAgent;

You can check if the device if iPhone or Blackberry in JS with something like

var isIphone = !!agent.match(/iPhone/i),
    isBlackberry = !!agent.match(/blackberry/i);

if isIphone is true you are accessing the site from an Iphone, if isBlackBerry you are accessing the site from a Blackberry.

You can use "UserAgent Switcher" plugin for firefox to test that.

If you are also interested, it may be worth it checking out my script "redirection_mobile.js" hosted on github here https://github.com/sebarmeli/JS-Redirection-Mobile-Site and you can read more details in one of my article here:

http://blog.sebarmeli.com/2010/11/02/how-to-redirect-your-site-to-a-mobile-version-through-javascript/

Count rows with not empty value

Solved using a solution i found googling by Yogi Anand: https://productforums.google.com/d/msg/docs/3qsR2m-1Xx8/sSU6Z6NYLOcJ

The example below counts the number of non-empty rows in the range A3:C, remember to update both ranges in the formula with your range of interest.

=ArrayFormula(SUM(SIGN(MMULT(LEN(A3:C), TRANSPOSE(SIGN(COLUMN(A3:C)))))))

Also make sure to avoid circular dependencies, it will happen if you for example count the number of non-empty rows in A:C and place this formula in the A or C column.

Environment variables in Jenkins

What ultimately worked for me was the following steps:

  1. Configure the Environment Injector Plugin: https://wiki.jenkins-ci.org/display/JENKINS/EnvInject+Plugin
  2. Goto to the /job//configure screen
  3. In Build Environment section check "Inject environment variables to the build process"
  4. In "Properties Content" specified: TZ=America/New_York

MSIE and addEventListener Problem in Javascript?

The problem is that IE does not have the standard addEventListener method. IE uses its own attachEvent which does pretty much the same.

Good explanation of the differences, and also about the 3rd parameter can be found at quirksmode.

How to turn on front flash light programmatically in Android?

For this problem you should:

  1. Check whether the flashlight is available or not?

  2. If so then Turn Off/On

  3. If not then you can do whatever, according to your app needs.

For Checking availability of flash in the device:

You can use the following:

 context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);

which will return true if a flash is available, false if not.

See:
http://developer.android.com/reference/android/content/pm/PackageManager.html for more information.

For turning on/off flashlight:

I googled out and got this about android.permission.FLASHLIGHT. Android manifests' permission looks promising:

 <!-- Allows access to the flashlight -->
 <permission android:name="android.permission.FLASHLIGHT"
             android:permissionGroup="android.permission-group.HARDWARE_CONTROLS"
             android:protectionLevel="normal"
             android:label="@string/permlab_flashlight"
             android:description="@string/permdesc_flashlight" />

Then make use of Camera and set Camera.Parameters. The main parameter used here is FLASH_MODE_TORCH.

eg.

Code Snippet to turn on camera flashlight.

Camera cam = Camera.open();     
Parameters p = cam.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
cam.setParameters(p);
cam.startPreview();

Code snippet to turn off camera led light.

  cam.stopPreview();
  cam.release();

I just found a project that uses this permission. Check quick-settings' src code. here http://code.google.com/p/quick-settings/ (Note: This link is now broken)

For Flashlight directly look http://code.google.com/p/quick-settings/source/browse/trunk/quick-settings/#quick-settings/src/com/bwx/bequick/flashlight (Note: This link is now broken)

Update6 You could also try to add a SurfaceView as described in this answer LED flashlight on Galaxy Nexus controllable by what API? This seems to be a solution that works on many phones.

Update 5 Major Update

I have found an alternative Link (for the broken links above): http://www.java2s.com/Open-Source/Android/Tools/quick-settings/com.bwx.bequick.flashlight.htm You can now use this link. [Update: 14/9/2012 This link is now broken]

Update 1

Another OpenSource Code : http://code.google.com/p/torch/source/browse/

Update 2

Example showing how to enable the LED on a Motorola Droid: http://code.google.com/p/droidled/

Another Open Source Code :

http://code.google.com/p/covedesigndev/
http://code.google.com/p/search-light/

Update 3 (Widget for turning on/off camera led)

If you want to develop a widget that turns on/off your camera led, then you must refer my answer Widget for turning on/off camera flashlight in android..

Update 4

If you want to set the intensity of light emerging from camera LED you can refer Can I change the LED intensity of an Android device? full post. Note that only rooted HTC devices support this feature.

** Issues:**

There are also some problems while turning On/Off flashlight. eg. for the devices not having FLASH_MODE_TORCH or even if it has, then flashlight does not turn ON etc.

Typically Samsung creates a lot of problems.

You can refer to problems in the given below list:

Use camera flashlight in Android

Turn ON/OFF Camera LED/flash light in Samsung Galaxy Ace 2.2.1 & Galaxy Tab

Entity Framework Queryable async

The problem seems to be that you have misunderstood how async/await work with Entity Framework.

About Entity Framework

So, let's look at this code:

public IQueryable<URL> GetAllUrls()
{
    return context.Urls.AsQueryable();
}

and example of it usage:

repo.GetAllUrls().Where(u => <condition>).Take(10).ToList()

What happens there?

  1. We are getting IQueryable object (not accessing database yet) using repo.GetAllUrls()
  2. We create a new IQueryable object with specified condition using .Where(u => <condition>
  3. We create a new IQueryable object with specified paging limit using .Take(10)
  4. We retrieve results from database using .ToList(). Our IQueryable object is compiled to sql (like select top 10 * from Urls where <condition>). And database can use indexes, sql server send you only 10 objects from your database (not all billion urls stored in database)

Okay, let's look at first code:

public async Task<IQueryable<URL>> GetAllUrlsAsync()
{
    var urls = await context.Urls.ToListAsync();
    return urls.AsQueryable();
}

With the same example of usage we got:

  1. We are loading in memory all billion urls stored in your database using await context.Urls.ToListAsync();.
  2. We got memory overflow. Right way to kill your server

About async/await

Why async/await is preferred to use? Let's look at this code:

var stuff1 = repo.GetStuff1ForUser(userId);
var stuff2 = repo.GetStuff2ForUser(userId);
return View(new Model(stuff1, stuff2));

What happens here?

  1. Starting on line 1 var stuff1 = ...
  2. We send request to sql server that we want to get some stuff1 for userId
  3. We wait (current thread is blocked)
  4. We wait (current thread is blocked)
  5. .....
  6. Sql server send to us response
  7. We move to line 2 var stuff2 = ...
  8. We send request to sql server that we want to get some stuff2 for userId
  9. We wait (current thread is blocked)
  10. And again
  11. .....
  12. Sql server send to us response
  13. We render view

So let's look to an async version of it:

var stuff1Task = repo.GetStuff1ForUserAsync(userId);
var stuff2Task = repo.GetStuff2ForUserAsync(userId);
await Task.WhenAll(stuff1Task, stuff2Task);
return View(new Model(stuff1Task.Result, stuff2Task.Result));

What happens here?

  1. We send request to sql server to get stuff1 (line 1)
  2. We send request to sql server to get stuff2 (line 2)
  3. We wait for responses from sql server, but current thread isn't blocked, he can handle queries from another users
  4. We render view

Right way to do it

So good code here:

using System.Data.Entity;

public IQueryable<URL> GetAllUrls()
{
   return context.Urls.AsQueryable();
}

public async Task<List<URL>> GetAllUrlsByUser(int userId) {
   return await GetAllUrls().Where(u => u.User.Id == userId).ToListAsync();
}

Note, than you must add using System.Data.Entity in order to use method ToListAsync() for IQueryable.

Note, that if you don't need filtering and paging and stuff, you don't need to work with IQueryable. You can just use await context.Urls.ToListAsync() and work with materialized List<Url>.

Iterating Over Dictionary Key Values Corresponding to List in Python

Dictionary objects allow you to iterate over their items. Also, with pattern matching and the division from __future__ you can do simplify things a bit.

Finally, you can separate your logic from your printing to make things a bit easier to refactor/debug later.

from __future__ import division

def Pythag(league):
    def win_percentages():
        for team, (runs_scored, runs_allowed) in league.iteritems():
            win_percentage = round((runs_scored**2) / ((runs_scored**2)+(runs_allowed**2))*1000)
            yield win_percentage

    for win_percentage in win_percentages():
        print win_percentage

How to bind a List<string> to a DataGridView control?

Try this:

IList<String> list_string= new List<String>();
DataGridView.DataSource = list_string.Select(x => new { Value = x }).ToList();
dgvSelectedNode.Show();

I hope this helps.

Changing the position of Bootstrap popovers based on the popover's X position in relation to window edge?

Based on the documentation you should be able to use auto in combination with the preferred placement e.g. auto left

http://getbootstrap.com/javascript/#popovers: "When "auto" is specified, it will dynamically reorient the popover. For example, if placement is "auto left", the tooltip will display to the left when possible, otherwise it will display right."

I was trying to do the same thing and then realised that this functionality already existed.

Is it possible to make an HTML anchor tag not clickable/linkable using CSS?

The answer is:

<a href="page.html" onclick="return false">page link</a>

Python creating a dictionary of lists

You can use defaultdict:

>>> from collections import defaultdict
>>> d = defaultdict(list)
>>> a = ['1', '2']
>>> for i in a:
...   for j in range(int(i), int(i) + 2):
...     d[j].append(i)
...
>>> d
defaultdict(<type 'list'>, {1: ['1'], 2: ['1', '2'], 3: ['2']})
>>> d.items()
[(1, ['1']), (2, ['1', '2']), (3, ['2'])]

jQuery Ajax PUT with parameters

You can use the PUT method and pass data that will be included in the body of the request:

let data = {"key":"value"}

$.ajax({
    type: 'PUT',
    url: 'http://example.com/api',
    contentType: 'application/json',
    data: JSON.stringify(data), // access in body
}).done(function () {
    console.log('SUCCESS');
}).fail(function (msg) {
    console.log('FAIL');
}).always(function (msg) {
    console.log('ALWAYS');
});

What is the keyguard in Android?

In a nutshell, it is your lockscreen.

PIN, pattern, face, password locks or the default lock (slide to unlock), but it is your lock screen.

AssertNull should be used or AssertNotNull

assertNotNull asserts that the object is not null. If it is null the test fails, so you want that.

String to decimal conversion: dot separation instead of comma

Thanks for all reply.

Because I have to write a decimal number in a xml file I have find out the problem. In this discussion I have learned that xml file standard use dot for decimal value and this is culture independent. So my solution is write dot decimal number in a xml file and convert the readed string from the same xml file mystring.Replace(".", ","); Thanks Agat for suggestion to research the problem in xml context and ? ? ? ? ? ? because I didn't know visual studio doesn't respect the culture settings I have in my code.