Programs & Examples On #Indy 9

Indy 9 is a reference to a specific version of Indy.

Custom events in jQuery?

I think so.. it's possible to 'bind' custom events, like(from:

 $("p").bind("myCustomEvent", function(e, myName, myValue){
      $(this).text(myName + ", hi there!");
      $("span").stop().css("opacity", 1)
               .text("myName = " + myName)
    $("button").click(function () {
      $("p").trigger("myCustomEvent", [ "John" ]);

Why am I getting a NoClassDefFoundError in Java?

I have found that sometimes I get a NoClassDefFound error when code is compiled with an incompatible version of the class found at runtime. The specific instance I recall is with the apache axis library. There were actually 2 versions on my runtime classpath and it was picking up the out of date and incompatible version and not the correct one, causing a NoClassDefFound error. This was in a command line app where I was using a command similar to this.

set classpath=%classpath%;axis.jar

I was able to get it to pick up the proper version by using:

set classpath=axis.jar;%classpath%;

C# : assign data to properties via constructor vs. instantiating

Second approach is object initializer in C#

Object initializers let you assign values to any accessible fields or properties of an object at creation time without having to explicitly invoke a constructor.

The first approach

var albumData = new Album("Albumius", "Artistus", 2013);

explicitly calls the constructor, whereas in second approach constructor call is implicit. With object initializer you can leave out some properties as well. Like:

 var albumData = new Album
            Name = "Albumius",

Object initializer would translate into something like:

var albumData; 
var temp = new Album();
temp.Name = "Albumius";
temp.Artist = "Artistus";
temp.Year = 2013;
albumData = temp;

Why it uses a temporary object (in debug mode) is answered here by Jon Skeet.

As far as advantages for both approaches are concerned, IMO, object initializer would be easier to use specially if you don't want to initialize all the fields. As far as performance difference is concerned, I don't think there would any since object initializer calls the parameter less constructor and then assign the properties. Even if there is going to be performance difference it should be negligible.

How do I share variables between different .c files?

In 99.9% of all cases it is bad program design to share non-constant, global variables between files. There are very few cases when you actually need to do this: they are so rare that I cannot come up with any valid cases. Declarations of hardware registers perhaps.

In most of the cases, you should either use (possibly inlined) setter/getter functions ("public"), static variables at file scope ("private"), or incomplete type implementations ("private") instead.

In those few rare cases when you need to share a variable between files, do like this:

// file.h
extern int my_var;

// file.c
#include "file.h"
int my_var = something;

// main.c
#include "file.h"

Never put any form of variable definition in a h-file.

Uninstall mongoDB from ubuntu

Stop MongoDB

Stop the mongod process by issuing the following command:

sudo service mongod stop

Remove Packages

Remove any MongoDB packages that you had previously installed.

sudo apt-get purge mongodb-org*

Remove Data Directories.

Remove MongoDB databases and log files.

 sudo rm -r /var/log/mongodb /var/lib/mongodb

Allow only numbers and dot in script

Use Jquery instead. Add a decimal class to your textbox:

<input type="text" class="decimal" value="" />

Use this code in your JS. It checks for multiple decimals and also restrict users to type only numbers.

    var val = $(this).val();
         val = val.replace(/[^0-9\.]/g,'');
             val =val.replace(/\.+$/,"");

Check this fiddle:

Hope it helps.

Sending emails in Node.js?

node-email-templates is a much better option:

it has support for windows as well

How to Rotate a UIImage 90 degrees?

Minor change to the other answers that are based on Hardy Macia's code. There is no need to create a whole UIView object simply to calculate the bounding rectangle of the rotated image. Just apply a rotate transform to the image rectangle using CGRectApplyAffineTransform.

static CGFloat DegreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;}
static CGFloat RadiansToDegrees(CGFloat radians) {return radians * 180/M_PI;}

- (CGSize)rotatedImageSize:(CGFloat)degrees
    CGAffineTransform t = CGAffineTransformMakeRotation(DegreesToRadians(degrees));
    CGRect originalImageRect = CGRectMake(0, 0, self.size.width, self.size.height);
    CGRect rotatedImageRect = CGRectApplyAffineTransform(originalImageRect, t);
    CGSize rotatedSize = rotatedImageRect.size;

    return rotatedSize;

- (UIImage*)imageRotatedByDegrees:(CGFloat)degrees
    // calculate the size of the rotated view's containing box for our drawing space
    CGSize rotatedSize = [self rotatedImageSize:degrees];

    // Create the bitmap context
    CGContextRef bitmap = UIGraphicsGetCurrentContext();

    // Move the origin to the middle of the image so we will rotate and scale around the center.
    CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2);

    //   // Rotate the image context
    CGContextRotateCTM(bitmap, DegreesToRadians(degrees));

    // Now, draw the rotated/scaled image into the context
    CGContextScaleCTM(bitmap, 1.0, -1.0);
    CGContextDrawImage(bitmap, CGRectMake(-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), [self CGImage]);

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    return newImage;

Get all messages from Whatsapp


As WhatsApp put some effort into improving their encryption system, getting the data is not that easy anymore. With newer versions of WhatsApp it is no longer possible to use adb backup. Apps can deny backups and the WhatsApp client does that. If you happen to have a rooted phone, you can use a root shell to get the unencrypted database file.

If you do not have root, you can still decrypt the data if you have an old WhatsApp APK. Find a version that still allows backups. Then you can make a backup of the app's data folder, which will contain an encryption key named, well, key.

Now you'll need the encrypted database. Use a file explorer of your choice or, if you like the command line more, use adb:

adb pull /sdcard/WhatsApp/Databases/msgstore.db.crypt12

Using the two files, you could now use to get the plain text database. It is no longer possible to use Linux board tools like openssl because WhatsApp seems to use a modified version of the Spongy Castle API for cryptography that openssl does not understand.

Original Answer (only for the old crypt7)

As whatsapp is now using the crypt7 format, it is not that easy to get and decrypt the database anymore. There is a working approach using ADB and USB debugging.

You can either get the encryption keys via ADB and decrypt the message database stored on /sdcard, or you just get the plain version of the database via ADB backup, what seems to be the easier option.

To get the database, do the following:

Connect your Android phone to your computer. Now run

adb backup -f whatsapp_backup.ab -noapk com.whatsapp

to backup all files WhatsApp has created in its private folder.
You will get a zlib compressed file using tar format with some ADB headers. We need to get rid of those headers first as they confuse the decompression command:

dd if=whatsapp_backup.ab ibs=1 skip=24 of=whatsapp_backup.ab.nohdr

The file can now be decompressed:

cat whatsapp_backup.ab.nohdr | python -c "import zlib,sys;sys.stdout.write(zlib.decompress(" 1> whatsapp_backup.tar

This command runs Python and decompresses the file using zlib to whatsapp_backup.tar
Now we can unTAR the file:

tar xf whatsapp_backup.tar

The archive is now extracted to your current working directory and you can find the databases (msgstore.db and wa.db) in apps/com.whatsapp/db/

SQL variable to hold list of integers

Assuming the variable is something akin to:

[Value] [int] NOT NULL

And the Stored Procedure is using it in this form:

ALTER Procedure [dbo].[GetFooByIds]
    @Ids [IntList] ReadOnly

You can create the IntList and call the procedure like so:

Declare @IDs IntList;
Insert Into @IDs Select Id From dbo.{TableThatHasIds}
Where Id In (111, 222, 333, 444)
Exec [dbo].[GetFooByIds] @IDs

Or if you are providing the IntList yourself

DECLARE @listOfIDs dbo.IntList
INSERT INTO @listofIDs VALUES (1),(35),(118);

Subtract one day from datetime

To be honest I just use:

select convert(nvarchar(max), GETDATE(), 112)

which gives YYYYMMDD and minus one from it.

Or more correctly

select convert(nvarchar(max), GETDATE(), 112) - 1 

for yesterdays date.

Replace Getdate() with your value OrderDate

select convert(nvarchar (max),OrderDate,112)-1 AS SubtractDate FROM Orders

should do it.

jQuery UI DatePicker to show month year only

Use onSelect call back and remove the year portion manually and set the text in the field manually

How to test an SQL Update statement before running it?

Not a direct answer, but I've seen many borked prod data situations that could have been avoided by typing the WHERE clause first! Sometimes a WHERE 1 = 0 can help with putting a working statement together safely too. And looking at an estimated execution plan, which will estimate rows affected, can be useful. Beyond that, in a transaction that you roll back as others have said.

Converting BitmapImage to Bitmap and vice versa

If you just need to go from BitmapImage to Bitmap it's quite easy,

private Bitmap BitmapImage2Bitmap(BitmapImage bitmapImage)
        return new Bitmap(bitmapImage.StreamSource);

Set markers for individual points on a line in Matplotlib

Specify the keyword args linestyle and/or marker in your call to plot.

For example, using a dashed line and blue circle markers:

plt.plot(range(10), linestyle='--', marker='o', color='b')

A shortcut call for the same thing:

plt.plot(range(10), '--bo')


Here is a list of the possible line and marker styles:

================    ===============================
character           description
================    ===============================
   -                solid line style
   --               dashed line style
   -.               dash-dot line style
   :                dotted line style
   .                point marker
   ,                pixel marker
   o                circle marker
   v                triangle_down marker
   ^                triangle_up marker
   <                triangle_left marker
   >                triangle_right marker
   1                tri_down marker
   2                tri_up marker
   3                tri_left marker
   4                tri_right marker
   s                square marker
   p                pentagon marker
   *                star marker
   h                hexagon1 marker
   H                hexagon2 marker
   +                plus marker
   x                x marker
   D                diamond marker
   d                thin_diamond marker
   |                vline marker
   _                hline marker
================    ===============================

edit: with an example of marking an arbitrary subset of points, as requested in the comments:

import numpy as np
import matplotlib.pyplot as plt

xs = np.linspace(-np.pi, np.pi, 30)
ys = np.sin(xs)
markers_on = [12, 17, 18, 19]
plt.plot(xs, ys, '-gD', markevery=markers_on)


This last example using the markevery kwarg is possible in since 1.4+, due to the merge of this feature branch. If you are stuck on an older version of matplotlib, you can still achieve the result by overlaying a scatterplot on the line plot. See the edit history for more details.

How do you get the selected value of a Spinner?

This is another way:

spinner.setOnItemSelectedListener(new OnItemSelectedListener() {

        public void onItemSelected(AdapterView<?> arg0, View arg1,
                int pos, long arg3) {
            // TODO Auto-generated method stub


        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub


How to get Real IP from Visitor?

apply this code for get the ipaddress:

    if (getenv('HTTP_X_FORWARDED_FOR')) { $pipaddress = getenv('HTTP_X_FORWARDED_FOR');
 $ipaddress = getenv('REMOTE_ADDR'); 
    echo "Your Proxy IP address is : ".$pipaddress. "(via $ipaddress)" ; } 
    else { $ipaddress = getenv('REMOTE_ADDR'); echo "Your IP address is : $ipaddress"; }

A keyboard shortcut to comment/uncomment the select text in Android Studio

Windows 10 and Android Studio: Ctrl + / (on small num pad), don't use Ctrl + Shift-7!

Executing Batch File in C#

using System.Diagnostics;

private void ExecuteBatFile()
    Process proc = null;
        string targetDir = string.Format(@"D:\mydir");   //this is where mybatch.bat lies
        proc = new Process();
        proc.StartInfo.WorkingDirectory = targetDir;
        proc.StartInfo.FileName = "lorenzo.bat";
        proc.StartInfo.Arguments = string.Format("10");  //this is argument
        proc.StartInfo.CreateNoWindow = false;
        proc.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;  //this is for hiding the cmd execution will happen in back ground.
    catch (Exception ex)
        Console.WriteLine("Exception Occurred :{0},{1}", ex.Message, ex.StackTrace.ToString());

Use Awk to extract substring

You just want to set the field separator as . using the -F option and print the first field:

$ echo aaa0.bbb.ccc | awk -F'.' '{print $1}'

Same thing but using cut:

$ echo aaa0.bbb.ccc | cut -d'.' -f1

Or with sed:

$ echo aaa0.bbb.ccc | sed 's/[.].*//'

Even grep:

$ echo aaa0.bbb.ccc | grep -o '^[^.]*'

IntelliJ can't recognize JavaFX 11 with OpenJDK 11

Quick summary, you can do either:

  1. Include the JavaFX modules via --module-path and --add-modules like in José's answer.


  2. Once you have JavaFX libraries added to your project (either manually or via maven/gradle import), add the file similar to the one specified in this answer. (Note that this solution makes your app modular, so if you use other libraries, you will also need to add statements to require their modules inside the file).

This answer is a supplement to Jose's answer.

The situation is this:

  1. You are using a recent Java version, e.g. 13.
  2. You have a JavaFX application as a Maven project.
  3. In your Maven project you have the JavaFX plugin configured and JavaFX dependencies setup as per Jose's answer.
  4. You go to the source code of your main class which extends Application, you right-click on it and try to run it.
  5. You get an IllegalAccessError involving an "unnamed module" when trying to launch the app.

Excerpt for a stack trace generating an IllegalAccessError when trying to run a JavaFX app from Intellij Idea:

Exception in Application start method
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(
    at java.base/java.lang.reflect.Method.invoke(
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(
    at java.base/java.lang.reflect.Method.invoke(
    at java.base/sun.launcher.LauncherHelper$FXHelper.main(
Caused by: java.lang.RuntimeException: Exception in Application start method
    at java.base/
Caused by: java.lang.IllegalAccessError: class com.sun.javafx.fxml.FXMLLoaderHelper (in unnamed module @0x45069d0e) cannot access class com.sun.javafx.util.Utils (in module because module does not export com.sun.javafx.util to unnamed module @0x45069d0e
    at com.sun.javafx.fxml.FXMLLoaderHelper.<clinit>(
    at javafx.fxml.FXMLLoader.<clinit>(
    at org.jewelsea.demo.javafx.springboot.Main.start(
    at java.base/
Exception running application org.jewelsea.demo.javafx.springboot.Main

OK, now you are kind of stuck and have no clue what is going on.

What has actually happened is this:

  1. Maven has successfully downloaded the JavaFX dependencies for your application, so you don't need to separately download the dependencies or install a JavaFX SDK or module distribution or anything like that.
  2. Idea has successfully imported the modules as dependencies to your project, so everything compiles OK and all of the code completion and everything works fine.

So it seems everything should be OK. BUT, when you run your application, the code in the JavaFX modules is failing when trying to use reflection to instantiate instances of your application class (when you invoke launch) and your FXML controller classes (when you load FXML). Without some help, this use of reflection can fail in some cases, generating the obscure IllegalAccessError. This is due to a Java module system security feature which does not allow code from other modules to use reflection on your classes unless you explicitly allow it (and the JavaFX application launcher and FXMLLoader both require reflection in their current implementation in order for them to function correctly).

This is where some of the other answers to this question, which reference, come into the picture.

So let's take a crash course in Java modules:

The key part is this:

4.9. Opens

If we need to allow reflection of private types, but we don't want all of our code exposed, we can use the opens directive to expose specific packages.

But remember, this will open the package up to the entire world, so make sure that is what you want:

module my.module { opens; }

So, perhaps you don't want to open your package to the entire world, then you can do:

4.10. Opens … To

Okay, so reflection is great sometimes, but we still want as much security as we can get from encapsulation. We can selectively open our packages to a pre-approved list of modules, in this case, using the opens…to directive:

module my.module { opens to moduleOne, moduleTwo, etc.; }

So, you end up creating a src/main/java/ class which looks like this:

module org.jewelsea.demo.javafx.springboot {
    requires javafx.fxml;
    requires javafx.controls;
    opens org.jewelsea.demo.javafx.springboot to,javafx.fxml;

Where, org.jewelsea.demo.javafx.springboot is the name of the package which contains the JavaFX Application class and JavaFX Controller classes (replace this with the appropriate package name for your application). This tells the Java runtime that it is OK for classes in the and javafx.fxml to invoke reflection on the classes in your org.jewelsea.demo.javafx.springboot package. Once this is done, and the application is compiled and re-run things will work fine and the IllegalAccessError generated by JavaFX's use of reflection will no longer occur.

But what if you don't want to create a file

If instead of using the the Run button in the top toolbar of IDE to run your application class directly, you instead:

  1. Went to the Maven window in the side of the IDE.
  2. Chose the javafx maven plugin target
  3. Right-clicked on that and chose either Run Maven Build or Debug....

Then the app will run without the file. I guess this is because the maven plugin is smart enough to dynamically include some kind of settings which allows the app to be reflected on by the JavaFX classes even without a file, though I don't know how this is accomplished.

To get that setting transferred to the Run button in the top toolbar, right-click on the Maven target and choose the option to Create Run/Debug Configuration for the target. Then you can just choose Run from the top toolbar to execute the Maven target.

Dataframe to Excel sheet

Or you can do like this:

your_df.to_excel( r'C:\Users\full_path\excel_name.xlsx',
                  sheet_name= 'your_sheet_name'

Simple URL GET/POST function in Python


Here's a few common ways to use it:

import requests
url = 'https://...'
payload = {'key1': 'value1', 'key2': 'value2'}

r = requests.get(url)

# GET with params in URL
r = requests.get(url, params=payload)

# POST with form-encoded data
r =, data=payload)

# POST with JSON 
import json
r =, data=json.dumps(payload))

# Response, status etc


>>> from httplib2 import Http
>>> from urllib import urlencode
>>> h = Http()
>>> data = dict(name="Joe", comment="A test comment")
>>> resp, content = h.request("", "POST", urlencode(data))
>>> resp
{'status': '200', 'transfer-encoding': 'chunked', 'vary': 'Accept-Encoding,User-Agent',
 'server': 'Apache', 'connection': 'close', 'date': 'Tue, 31 Jul 2007 15:29:52 GMT', 
 'content-type': 'text/html'}

'No JUnit tests found' in Eclipse

In Eclipse Photon you may need to add JUnit 4 or 5 to the build path. Right click @Test and select 'Add JUnit 4 to build path'.

Python: Checking if a 'Dictionary' is empty doesn't seem to work

Simple ways to check an empty dict are below:

        a= {}

    1. if a == {}:
           print ('empty dict')
    2. if not a:
           print ('empty dict')

Although method 1st is more strict as when a = None, method 1 will provide correct result but method 2 will give an incorrect result.

Jquery Hide table rows

this might work for you...



<tr class="trhideclass1">

How to disable scientific notation?

format(99999999,scientific = F)



How to take MySQL database backup using MySQL Workbench?

  1. On ‘HOME’ page -- > select 'Manage Import / Export' under 'Server Administration'

  2. A box comes up... choose which server holds the data you want to back up.

  3. On the 'Export to Disk' tab, then select which databases you want to export.

  4. If you want all the tables, select option ‘Export to self-contained file’, otherwise choose the other option for a selective restore

  5. If you need advanced options, see other post, otherwise then click ‘Start Export’

How to get the data-id attribute?

using jQuery:

  $( ".myClass" ).load(function() {
    var myId = $(this).data("id");
    $('.myClass').attr('id', myId);

How to convert View Model into JSON object in ASP.NET MVC?

In mvc3 with razor @Html.Raw(Json.Encode(object)) seems to do the trick.

OPENSSL file_get_contents(): Failed to enable crypto

Ok I have found a solution. The problem is that the site uses SSLv3. And I know that there are some problems in the openssl module. Some time ago I had the same problem with the SSL versions.

function getSSLPage($url) {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_HEADER, false);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_SSLVERSION,3); 
    $result = curl_exec($ch);
    return $result;


When you set the SSL Version with curl to v3 then it works.


Another problem under Windows is that you don't have access to the certificates. So put the root certificates directly to curl.

here you can download the root certificates.

curl_setopt($ch, CURLOPT_CAINFO, __DIR__ . "/certs/cacert.pem");
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);

Then you can use the CURLOPT_SSL_VERIFYPEER option with true otherwise you get an error.

Git pull after forced update

This won't fix branches that already have the code you don't want in them (see below for how to do that), but if they had pulled some-branch and now want it to be clean (and not "ahead" of origin/some-branch) then you simply:

git checkout some-branch   # where some-branch can be replaced by any other branch
git branch base-branch -D  # where base-branch is the one with the squashed commits
git checkout -b base-branch origin/base-branch  # recreating branch with correct commits

Note: You can combine these all by putting && between them

Note2: Florian mentioned this in a comment, but who reads comments when looking for answers?

Note3: If you have contaminated branches, you can create new ones based off the new "dumb branch" and just cherry-pick commits over.


git checkout feature-old  # some branch with the extra commits
git log                   # gives commits (write down the id of the ones you want)
git checkout base-branch  # after you have already cleaned your local copy of it as above
git checkout -b feature-new # make a new branch for your feature
git cherry-pick asdfasd   # where asdfasd is one of the commit ids you want
# repeat previous step for each commit id
git branch feature-old -D # delete the old branch

Now feature-new is your branch without the extra (possibly bad) commits!

What's the difference between window.location and document.location in JavaScript?

It's rare to see the difference nowadays because html 5 don't support framesets anymore. But back at the time we have frameset, document.location would redirect only the frame in which code is being executed, and window.location would redirect the entire page.

Given a class, see if instance has method (Ruby)

The answer to "Given a class, see if instance has method (Ruby)" is better. Apparently Ruby has this built-in, and I somehow missed it. My answer is left for reference, regardless.

Ruby classes respond to the methods instance_methods and public_instance_methods. In Ruby 1.8, the first lists all instance method names in an array of strings, and the second restricts it to public methods. The second behavior is what you'd most likely want, since respond_to? restricts itself to public methods by default, as well.


In Ruby 1.9, though, those methods return arrays of symbols.


If you're planning on doing this often, you might want to extend Module to include a shortcut method. (It may seem odd to assign this to Module instead of Class, but since that's where the instance_methods methods live, it's best to keep in line with that pattern.)

class Module
  def instance_respond_to?(method_name)

If you want to support both Ruby 1.8 and Ruby 1.9, that would be a convenient place to add the logic to search for both strings and symbols, as well.

Make Div Draggable using CSS

You can do it now by using the CSS property -webkit-user-drag:

#drag_me {_x000D_
  -webkit-user-drag: element;_x000D_
<div draggable="true" id="drag_me">_x000D_
  Your draggable content here_x000D_

This property is only supported by webkit browsers, such as Safari or Chrome, but it is a nice approach to get it working using only CSS.

The HTML5 draggable attribute is only set to ensure dragging works for other browsers.

You can find more information here:

simple way to display data in a .txt file on a webpage?

I find that if I try things that others say do not work, it's how I learn the most.

<div id="list">
  <p><iframe src="README.txt" frameborder="0" height="400"

This worked for me. I used the yellow background-color that I set in the stylesheet.

#list  p {
    font: arial;
    font-size: 14px;
    background-color: yellow ;

If statement in aspx page

        if (true)
        Show true content
        Show false content

How to insert a line break in a SQL Server VARCHAR/NVARCHAR string

Following a Google...

Taking the code from the website:

        col1 VARCHAR(1000)

INSERT CRLF SELECT 'The quick brown@'
INSERT CRLF SELECT 'fox @jumped'



The quick brown@
fox @jumped
@over the

(4 row(s) affected)

SET col1 = REPLACE(col1, '@', CHAR(13))

Looks like it can be done by replacing a placeholder with CHAR(13)

Good question, never done it myself :)

How to declare an array of objects in C#

You are creating an array of null references. You should do something like:

for (int i = 0; i < houses.Count; i++)
    houses[i] = new GameObject();

Send File Attachment from Form Using phpMailer and PHP

This code help me in Attachment sending....

$mail->AddAttachment($_FILES['file']['tmp_name'], $_FILES['file']['name']);

Replace your AddAttachment(...) Code with above code

Confirmation dialog on ng-click - AngularJS

A clean directive approach.

Update: Old Answer (2014)

It basically intercepts the ng-click event, displays the message contained in the ng-confirm-click="message" directive and asks the user to confirm. If confirm is clicked the normal ng-click executes, if not the script terminates and ng-click is not run.

<!-- index.html -->
<button ng-click="publish()" ng-confirm-click="You are about to overwrite your PUBLISHED content!! Are you SURE you want to publish?">
// /app/directives/ng-confirm-click.js
Directives.directive('ngConfirmClick', [
    return {
      priority: -1,
      restrict: 'A',
      link: function(scope, element, attrs){
        element.bind('click', function(e){
          var message = attrs.ngConfirmClick;
          // confirm() requires jQuery
          if(message && !confirm(message)){

Code credit to Zach Snow:!/blog/2013/confirming-ng-click/

Update: New Answer (2016)

1) Changed prefix from 'ng' to 'mw' as the former ('ng') is reserved for native angular directives.

2) Modified directive to pass a function and message instead of intercepting ng-click event.

3) Added default "Are you sure?" message in the case that a custom message is not provided to mw-confirm-click-message="".

<!-- index.html -->
<button mw-confirm-click="publish()" mw-confirm-click-message="You are about to overwrite your PUBLISHED content!! Are you SURE you want to publish?">
// /app/directives/mw-confirm-click.js
"use strict";

var module = angular.module( "myApp" );
module.directive( "mwConfirmClick", [
  function( ) {
    return {
      priority: -1,
      restrict: 'A',
      scope: { confirmFunction: "&mwConfirmClick" },
      link: function( scope, element, attrs ){
        element.bind( 'click', function( e ){
          // message defaults to "Are you sure?"
          var message = attrs.mwConfirmClickMessage ? attrs.mwConfirmClickMessage : "Are you sure?";
          // confirm() requires jQuery
          if( confirm( message ) ) {

How do I create a new branch?

In the Repository Browser of TortoiseSVN, find the branch that you want to create the new branch from. Right-click, Copy To.... and enter the new branch path. Now you can "switch" your local WC to that branch.

Why is IoC / DI not common in Python?

Django makes great use of inversion of control. For instance, the database server is selected by the configuration file, then the framework provides appropriate database wrapper instances to database clients.

The difference is that Python has first-class types. Data types, including classes, are themselves objects. If you want something to use a particular class, simply name the class. For example:

if config_dbms_name == 'postgresql':
    import psycopg
    self.database_interface = psycopg
elif config_dbms_name == 'mysql':

Later code can then create a database interface by writing:

my_db_connection = self.database_interface()
# Do stuff with database.

Instead of the boilerplate factory functions that Java and C++ need, Python does it with one or two lines of ordinary code. This is the strength of functional versus imperative programming.

Not showing placeholder for input type="date" field

It works for me:

input[type='date']:after {
  content: attr(placeholder)

Remove all files except some from a directory

Rather than going for a direct command, please move required files to temp dir outside current dir. Then delete all files using rm * or rm -r *.

Then move required files to current dir.

Remote debugging Tomcat with Eclipse

See this answer for issues I had with Java 8 and Tomcat 9: Java remote debugging (JPDA) not working for me in Tomcat 9

This is similar to @DAB's warning, and his solution is likely more secure.

Clear screen in shell

Subprocess allows you to call "cls" for Shell.

import subprocess
cls ='cls',shell=True)

That's as simple as I can make it. Hope it works for you!

How to search images from private 1.0 registry in docker?

Modifying the answer from @mre to get the list just from one command (valid at least for Docker Registry v2).

docker exec -it <your_registry_container_id> ls -a /var/lib/registry/docker/registry/v2/repositories/

Python Math - TypeError: 'NoneType' object is not subscriptable

lista = list.sort(lista)

This should be


The .sort() method is in-place, and returns None. If you want something not in-place, which returns a value, you could use

sorted_list = sorted(lista)

Aside #1: please don't call your lists list. That clobbers the builtin list type.

Aside #2: I'm not sure what this line is meant to do:

print str("value 1a")+str(" + ")+str("value 2")+str(" = ")+str("value 3a ")+str("value 4")+str("\n")

is it simply

print "value 1a + value 2 = value 3a value 4"

? In other words, I don't know why you're calling str on things which are already str.

Aside #3: sometimes you use print("something") (Python 3 syntax) and sometimes you use print "something" (Python 2). The latter would give you a SyntaxError in py3, so you must be running 2.*, in which case you probably don't want to get in the habit or you'll wind up printing tuples, with extra parentheses. I admit that it'll work well enough here, because if there's only one element in the parentheses it's not interpreted as a tuple, but it looks strange to the pythonic eye..

The exception TypeError: 'NoneType' object is not subscriptable happens because the value of lista is actually None. You can reproduce TypeError that you get in your code if you try this at the Python command line:


The reason that lista gets set to None is because the return value of list.sort() is None... it does not return a sorted copy of the original list. Instead, as the documentation points out, the list gets sorted in-place instead of a copy being made (this is for efficiency reasons).

If you do not want to alter the original version you can use

other_list = sorted(lista)

Create an empty data.frame

By Using data.table we can specify data types for each column.

data=data.table(a=numeric(), b=numeric(), c=numeric())

Deleting rows from parent and child tables

Two possible approaches.

  1. If you have a foreign key, declare it as on-delete-cascade and delete the parent rows older than 30 days. All the child rows will be deleted automatically.

  2. Based on your description, it looks like you know the parent rows that you want to delete and need to delete the corresponding child rows. Have you tried SQL like this?

      delete from child_table
          where parent_id in (
               select parent_id from parent_table
                    where updd_tms != (sysdate-30)

    -- now delete the parent table records

    delete from parent_table
    where updd_tms != (sysdate-30);

---- Based on your requirement, it looks like you might have to use PL/SQL. I'll see if someone can post a pure SQL solution to this (in which case that would definitely be the way to go).

    v_sqlcode number;
    PRAGMA EXCEPTION_INIT(foreign_key_violated, -02291);
    for v_rec in (select parent_id, child id from child_table
                         where updd_tms != (sysdate-30) ) loop

    -- delete the children
    delete from child_table where child_id = v_rec.child_id;

    -- delete the parent. If we get foreign key violation, 
    -- stop this step and continue the loop
       delete from parent_table
          where parent_id = v_rec.parent_id;
       when foreign_key_violated
         then null;
 end loop;

Monad in plain English? (For the OOP programmer with no FP background)

Why do we need monads?

  1. We want to program only using functions. ("functional programming" after all -FP).
  2. Then, we have a first big problem. This is a program:

    f(x) = 2 * x

    g(x,y) = x / y

    How can we say what is to be executed first? How can we form an ordered sequence of functions (i.e. a program) using no more than functions?

    Solution: compose functions. If you want first g and then f, just write f(g(x,y)). OK, but ...

  3. More problems: some functions might fail (i.e. g(2,0), divide by 0). We have no "exceptions" in FP. How do we solve it?

    Solution: Let's allow functions to return two kind of things: instead of having g : Real,Real -> Real (function from two reals into a real), let's allow g : Real,Real -> Real | Nothing (function from two reals into (real or nothing)).

  4. But functions should (to be simpler) return only one thing.

    Solution: let's create a new type of data to be returned, a "boxing type" that encloses maybe a real or be simply nothing. Hence, we can have g : Real,Real -> Maybe Real. OK, but ...

  5. What happens now to f(g(x,y))? f is not ready to consume a Maybe Real. And, we don't want to change every function we could connect with g to consume a Maybe Real.

    Solution: let's have a special function to "connect"/"compose"/"link" functions. That way, we can, behind the scenes, adapt the output of one function to feed the following one.

    In our case: g >>= f (connect/compose g to f). We want >>= to get g's output, inspect it and, in case it is Nothing just don't call f and return Nothing; or on the contrary, extract the boxed Real and feed f with it. (This algorithm is just the implementation of >>= for the Maybe type).

  6. Many other problems arise which can be solved using this same pattern: 1. Use a "box" to codify/store different meanings/values, and have functions like g that return those "boxed values". 2. Have composers/linkers g >>= f to help connecting g's output to f's input, so we don't have to change f at all.

  7. Remarkable problems that can be solved using this technique are:

    • having a global state that every function in the sequence of functions ("the program") can share: solution StateMonad.

    • We don't like "impure functions": functions that yield different output for same input. Therefore, let's mark those functions, making them to return a tagged/boxed value: IO monad.

Total happiness !!!!

iPhone get SSID without private library

Here's the cleaned up ARC version, based on @elsurudo's code:

- (id)fetchSSIDInfo {
     NSArray *ifs = (__bridge_transfer NSArray *)CNCopySupportedInterfaces();
     NSLog(@"Supported interfaces: %@", ifs);
     NSDictionary *info;
     for (NSString *ifnam in ifs) {
         info = (__bridge_transfer NSDictionary *)CNCopyCurrentNetworkInfo((__bridge CFStringRef)ifnam);
         NSLog(@"%@ => %@", ifnam, info);
         if (info && [info count]) { break; }
     return info;

binning data in python with scipy/numpy

I would add, and also to answer the question find mean bin values using histogram2d python that the scipy also have a function specially designed to compute a bidimensional binned statistic for one or more sets of data

import numpy as np
from scipy.stats import binned_statistic_2d

x = np.random.rand(100)
y = np.random.rand(100)
values = np.random.rand(100)
bin_means = binned_statistic_2d(x, y, values, bins=10).statistic

the function scipy.stats.binned_statistic_dd is a generalization of this funcion for higher dimensions datasets

Difference between Hashing a Password and Encrypting it

Ideally you should do both.

First Hash the pass password for the one way security. Use a salt for extra security.

Then encrypt the hash to defend against dictionary attacks if your database of password hashes is compromised.

Can I force pip to reinstall the current version?

sudo pip3 install --upgrade --force-reinstall --no-deps --no-cache-dir <package-name>==<package-version>

Some relevant answers:

Difference between pip install options "ignore-installed" and "force-reinstall"

Start thread with member function

Here is a complete example

#include <thread>
#include <iostream>

class Wrapper {
      void member1() {
          std::cout << "i am member1" << std::endl;
      void member2(const char *arg1, unsigned arg2) {
          std::cout << "i am member2 and my first arg is (" << arg1 << ") and second arg is (" << arg2 << ")" << std::endl;
      std::thread member1Thread() {
          return std::thread([=] { member1(); });
      std::thread member2Thread(const char *arg1, unsigned arg2) {
          return std::thread([=] { member2(arg1, arg2); });
int main(int argc, char **argv) {
   Wrapper *w = new Wrapper();
   std::thread tw1 = w->member1Thread();
   std::thread tw2 = w->member2Thread("hello", 100);
   return 0;

Compiling with g++ produces the following result

g++ -Wall -std=c++11 -o hello -pthread

i am member1
i am member2 and my first arg is (hello) and second arg is (100)

How to read from a text file using VBScript?

Use first the method OpenTextFile, and then...

either read the file at once with the method ReadAll:

Set file = fso.OpenTextFile("C:\test.txt", 1)
content = file.ReadAll

or line by line with the method ReadLine:

Set dict = CreateObject("Scripting.Dictionary")
Set file = fso.OpenTextFile ("c:\test.txt", 1)
row = 0
Do Until file.AtEndOfStream
  line = file.Readline
  dict.Add row, line
  row = row + 1


'Loop over it
For Each line in dict.Items
  WScript.Echo line

How to split a string of space separated numbers into integers?

Use str.split():

>>> "42 0".split()  # or .split(" ")
['42', '0']

Note that str.split(" ") is identical in this case, but would behave differently if there were more than one space in a row. As well, .split() splits on all whitespace, not just spaces.

Using map usually looks cleaner than using list comprehensions when you want to convert the items of iterables to built-ins like int, float, str, etc. In Python 2:

>>> map(int, "42 0".split())
[42, 0]

In Python 3, map will return a lazy object. You can get it into a list with list():

>>> map(int, "42 0".split())
<map object at 0x7f92e07f8940>
>>> list(map(int, "42 0".split()))
[42, 0]

How to open CSV file in R when R says "no such file or directory"?

this work for me, accesing data from root. use double slash to access address.

dataset = read.csv('C:\\Users\\Desktop\\Machine Learning\\Data.csv')

Bootstrap 3 hidden-xs makes row narrower

.row {
    margin-right: 15px;

throw this in your CSS

How do I search for names with apostrophe in SQL Server?

Compare Names containing apostrophe in DB through Java code

String sql="select lastname  from employee where FirstName like '%"+firstName.trim().toLowerCase().replaceAll("'", "''")+"%'"

statement = conn.createStatement();

iterate the results.

Why does pycharm propose to change method to static

I can imagine following advantages of having a class method defined as static one:

  • you can call the method just using class name, no need to instantiate it.

remaining advantages are probably marginal if present at all:

  • might run a bit faster
  • save a bit of memory

What does a question mark represent in SQL queries?

I don't think that has any meaning in SQL. You might be looking at Prepared Statements in JDBC or something. In that case, the question marks are placeholders for parameters to the statement.

docker container ssl certificates

I am trying to do something similar to this. As commented above, I think you would want to build a new image with a custom Dockerfile (using the image you pulled as a base image), ADD your certificate, then RUN update-ca-certificates. This way you will have a consistent state each time you start a container from this new image.

# Dockerfile
FROM some-base-image:0.1
ADD you_certificate.crt:/container/cert/path
RUN update-ca-certificates

Let's say a docker build against that Dockerfile produced IMAGE_ID. On the next docker run -d [any other options] IMAGE_ID, the container started by that command will have your certificate info. Simple and reproducible.

Best way to define error codes/strings in Java?

enum for error code/message definition is still a nice solution though it has a i18n concerns. Actually we may have two situations: the code/message is displayed to the end user or to the system integrator. For the later case, I18N is not necessary. I think the web services is most likely the later case.

How can I delete an item from an array in VB.NET?

You can't. I would suggest that you put the array elements into a List, at least then you can remove items. An array can be extended, for example using ReDim but you cannot remove array elements once they have been created. You would have to rebuild the array from scratch to do that.

If you can avoid it, don't use arrays here, use a List.

Convert pandas timezone-aware DateTimeIndex to naive timestamp, but in certain timezone

The accepted solution does not work when there are multiple different timezones in a Series. It throws ValueError: Tz-aware datetime.datetime cannot be converted to datetime64 unless utc=True

The solution is to use the apply method.

Please see the examples below:

# Let's have a series `a` with different multiple timezones. 
> a
0    2019-10-04 16:30:00+02:00
1    2019-10-07 16:00:00-04:00
2    2019-09-24 08:30:00-07:00
Name: localized, dtype: object

> a.iloc[0]
Timestamp('2019-10-04 16:30:00+0200', tz='Europe/Amsterdam')

# trying the accepted solution
> a.dt.tz_localize(None)
ValueError: Tz-aware datetime.datetime cannot be converted to datetime64 unless utc=True

# Make it tz-naive. This is the solution:
> a.apply(lambda x:x.tz_localize(None))
0   2019-10-04 16:30:00
1   2019-10-07 16:00:00
2   2019-09-24 08:30:00
Name: localized, dtype: datetime64[ns]

# a.tz_convert() also does not work with multiple timezones, but this works:
> a.apply(lambda x:x.tz_convert('America/Los_Angeles'))
0   2019-10-04 07:30:00-07:00
1   2019-10-07 13:00:00-07:00
2   2019-09-24 08:30:00-07:00
Name: localized, dtype: datetime64[ns, America/Los_Angeles]

What is "Connect Timeout" in sql server connection string?

Connection Timeout=30 means that the database server has 30 seconds to establish a connection.

Connection Timeout specifies the time limit (in seconds), within which the connection to the specified server must be made, otherwise an exception is thrown i.e. It specifies how long you will allow your program to be held up while it establishes a database connection.

Connection Timeout=30

SqlConnection.ConnectionTimeout. specifies how many seconds the SQL Server service has to respond to a connection attempt. This is always set as part of the connection string.


  • The value is expressed in seconds, not milliseconds.

  • The default value is 30 seconds.

  • A value of 0 means to wait indefinitely and never time out.

In addition, SqlCommand.CommandTimeout specifies the timeout value of a specific query running on SQL Server, however this is set via the SqlConnection object/setting (depending on your programming language), and not in the connection string i.e. It specifies how long you will allow your program to be held up while the command is run.

How can I erase all inline styles with javascript and leave only the styles specified in the css style sheet?

I was using the $('div').attr('style', ''); technique and it wasn't working in IE8.

I outputted the style attribute using alert() and it was not stripping out inline styles.

.removeAttr ended up doing the trick in IE8.

How do you strip a character out of a column in SQL Server?

Use the "REPLACE" string function on the column in question:

UPDATE (yourTable)
SET YourColumn = REPLACE(YourColumn, '*', '')
WHERE (your conditions)

Replace the "*" with the character you want to strip out and specify your WHERE clause to match the rows you want to apply the update to.

Of course, the REPLACE function can also be used - as other answerer have shown - in a SELECT statement - from your question, I assumed you were trying to update a table.


How to create a fixed-size array of objects

If what you want is a fixed size array, and initialize it with nil values, you can use an UnsafeMutableBufferPointer, allocate memory for 64 nodes with it, and then read/write from/to the memory by subscripting the pointer type instance. This also has the benefit of avoiding checking if the memory must be reallocated, which Array does. I would however be surprised if the compiler doesn't optimize that away for arrays that don't have any more calls to methods that may require resizing, other than at the creation site.

let count = 64
let sprites = UnsafeMutableBufferPointer<SKSpriteNode>.allocate(capacity: count)

for i in 0..<count {
    sprites[i] = ...

for sprite in sprites {


This is however not very user friendly. So, let's make a wrapper!

class ConstantSizeArray<T>: ExpressibleByArrayLiteral {
    typealias ArrayLiteralElement = T
    private let memory: UnsafeMutableBufferPointer<T>
    public var count: Int {
        get {
            return memory.count
    private init(_ count: Int) {
        memory = UnsafeMutableBufferPointer.allocate(capacity: count)
    public convenience init(count: Int, repeating value: T) {
        memory.initialize(repeating: value)
    public required convenience init(arrayLiteral: ArrayLiteralElement...) {
        memory.initialize(from: arrayLiteral)
    deinit {
    public subscript(index: Int) -> T {
        set(value) {
            memory[index] = value;
        get {
            return memory[index]

extension ConstantSizeArray: MutableCollection {
    public var startIndex: Int {
        return 0
    public var endIndex: Int {
        return count - 1
    func index(after i: Int) -> Int {
        return i + 1;

Now, this is a class, and not a structure, so there's some reference counting overhead incurred here. You can change it to a struct instead, but because Swift doesn't provide you with an ability to use copy initializers and deinit on structures, you'll need a deallocation method (func release() { memory.deallocate() }), and all copied instances of the structure will reference the same memory.

Now, this class may just be good enough. Its use is simple:

let sprites = ConstantSizeArray<SKSpriteNode?>(count: 64, repeating: nil)

for i in 0..<sprites.count {
    sprite[i] = ...

for sprite in sprites {

For more protocols to implement conformance to, see the Array documentation (scroll to Relationships).

How do I get a file extension in PHP?

IMO, this is the best way if you have filenames like (ugly, but it sometimes happens):

$ext     = explode('.', $filename); // Explode the string
$my_ext  = end($ext); // Get the last entry of the array

echo $my_ext;

How can I style the border and title bar of a window in WPF?

If someone says you can't because only Windows can control the non-client area, they're wrong!

That's just a half-truth because Windows lets you specify the dimensions of the non-client area. The fact is, this is possible only throughout the Windows' kernel methods, and you're in .NET, not C/C++. Anyway, don't worry! P/Invoke was meant just for such things! Indeed, the whole of the Windows Form UI and Console application Std-I/O methods are offered using system calls. Hence, you'd have only to perform the right system calls to set the non-client area up, as documented in MSDN.

However, this is a really hard solution I came up with a lot of time ago. Luckily, as of .NET 4.5, you can use the WindowChrome class to adjust the non-client area like you want. Here you can get to start with.

In order to make things simpler and cleaner, I'll redirect you here, a guide to change the window border dimensions to whatever you want. By setting it to 0, you'll be able to implement your custom window border in place of the system's one.

I'm sorry for not posting a clear example, but later I will for sure.

Read int values from a text file in C

A simple solution using fscanf:

void read_ints (const char* file_name)
  FILE* file = fopen (file_name, "r");
  int i = 0;

  fscanf (file, "%d", &i);    
  while (!feof (file))
      printf ("%d ", i);
      fscanf (file, "%d", &i);      
  fclose (file);        

Uncaught syntaxerror: unexpected identifier?

There are errors here :

var formTag = document.getElementsByTagName("form"), // form tag is an array
selectListItem = $('select'),
makeSelect = document.createElement('select'),
makeSelect.setAttribute("id", "groups");

The code must change to:

var formTag = document.getElementsByTagName("form");
var selectListItem = $('select');
var makeSelect = document.createElement('select');
makeSelect.setAttribute("id", "groups");

By the way, there is another error at line 129 :

var createLi.appendChild(createSubList);

Replace it with:


How to iterate through an ArrayList of Objects of ArrayList of Objects?

int i = 0; // Counter used to determine when you're at the 3rd gun
for (Gun g : gunList) { // For each gun in your list
    System.out.println(g); // Print out the gun
    if (i == 2) { // If you're at the third gun
        ArrayList<Bullet> bullets = g.getBullet(); // Get the list of bullets in the gun
        for (Bullet b : bullets) { // Then print every bullet
    i++; // Don't forget to increment your counter so you know you're at the next gun

What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?

Dissatisfied with the other answers. The top voted answer as of 2019/3/13 is factually wrong.

The short terse version of what => means is it's a shortcut writing a function AND for binding it to the current this

const foo = a => a * 2;

Is effectively a shortcut for

const foo = function(a) { return a * 2; }.bind(this);

You can see all the things that got shortened. We didn't need function, nor return nor .bind(this) nor even braces or parentheses

A slightly longer example of an arrow function might be

const foo = (width, height) => {
  const area = width * height;
  return area;

Showing that if we want multiple arguments to the function we need parentheses and if we want write more than a single expression we need braces and an explicit return.

It's important to understand the .bind part and it's a big topic. It has to do with what this means in JavaScript.

ALL functions have an implicit parameter called this. How this is set when calling a function depends on how that function is called.


function foo() { console.log(this); }

If you call it normally

function foo() { console.log(this); }

this will be the global object.

If you're in strict mode

`use strict`;
function foo() { console.log(this); }

// or

function foo() {
   `use strict`;

It will be undefined

You can set this directly using call or apply

function foo(msg) { console.log(msg, this); }

const obj1 = {abc: 123}
const obj2 = {def: 456}, 'hello');  // prints Hello {abc: 123}
foo.apply(obj2, ['hi']);  // prints Hi {def: 456}

You can also set this implicitly using the dot operator .

function foo(msg) { console.log(msg, this); }
const obj = {
   abc: 123,
   bar: foo,
}'Hola');  // prints Hola {abc:123, bar: f}

A problem comes up when you want to use a function as a callback or a listener. You make class and want to assign a function as the callback that accesses an instance of the class.

class ShowName {
  constructor(name, elem) { = name;
    elem.addEventListener('click', function() {
       console.log(;  // won't work

The code above will not work because when the element fires the event and calls the function the this value will not be the instance of the class.

One common way to solve that problem is to use .bind

class ShowName {
  constructor(name, elem) { = name;
    elem.addEventListener('click', function() {
    }.bind(this); // <=========== ADDED! ===========

Because the arrow syntax does the same thing we can write

class ShowName {
  constructor(name, elem) { = name;
    elem.addEventListener('click',() => {

bind effectively makes a new function. If bind did not exist you could basically make your own like this

function bind(functionToBind, valueToUseForThis) {
  return function(...args) {, ...args);

In older JavaScript without the spread operator it would be

function bind(functionToBind, valueToUseForThis) {
  return function() {
    functionToBind.apply(valueToUseForThis, arguments);

Understanding that code requires an understanding of closures but the short version is bind makes a new function that always calls the original function with the this value that was bound to it. Arrow functions do the same thing since they are a shortcut for bind(this)

How to add element into ArrayList in HashMap

Typical code is to create an explicit method to add to the list, and create the ArrayList on the fly when adding. Note the synchronization so the list only gets created once!

public synchronized boolean addToList(String key, Item item) {
   Collection<Item> list = theMap.get(key);
   if (list == null)  {
      list = new ArrayList<Item>();  // or, if you prefer, some other List, a Set, etc...
      theMap.put(key, list );

   return list.add(item);

error: cast from 'void*' to 'int' loses precision

Safest way :

static_cast<int>(reinterpret_cast<long>(void * your_variable));

long guarantees a pointer size on Linux on any machine. Windows has 32 bit long only on 64 bit as well. Therefore, you need to change it to long long instead of long in windows for 64 bits. So reinterpret_cast has casted it to long type and then static_cast safely casts long to int, if you are ready do truncte the data.

Rotate label text in seaborn factorplot

This is still a matplotlib object. Try this:

# <your code here>
locs, labels = plt.xticks()
plt.setp(labels, rotation=45)

:: (double colon) operator in Java 8

:: is a new operator included in Java 8 that is used to refer a method of an existing class. You can refer static methods and non-static methods of a class.

For referring static methods, the syntax is:

ClassName :: methodName 

For referring non-static methods, the syntax is

objRef :: methodName


ClassName :: methodName

The only prerequisite for referring a method is that method exists in a functional interface, which must be compatible with the method reference.

Method references, when evaluated, create an instance of the functional interface.

Found on:

SimpleDateFormat parsing date with 'Z' literal

The 'X' only works if partial seconds are not present: i.e. SimpleDateFormat pattern of


Will correctly parse




Will NOT parse


Sad but true, a date-time with partial seconds does not appear to be a valid ISO date:

Where does git config --global get written to?

The global location is derived, on Windows MsysGit, using the HOMEDRIVE and HOMEPATH environment variables, unless you have defined a HOME environment variable. The is detailed in the 'profile' script.

In my corporate environment the HOMEDRIVE is H:, which is then mapped to a network URL \\share\$. The whole lot is then mapped to be "My Documents", which isn't where others would expect. There may have been some further problems with the drive to URL remapping. I don't even get to adjust the HOMEDRIVE or HOMEPATH variables anyway.

In my case I have defined a personal HOME environment variable and pointed it to D:\git\GitHOME and copied all those GIT files (which are without and extension) to the GitHOME directory for safe keeping.

The windows environment variables can be set via the Advanced tab in the My Computer properties dialog.

Difference between signature versions - V1 (Jar Signature) and V2 (Full APK Signature) while generating a signed APK in Android Studio?

It is a new signing mechanism introduced in Android 7.0, with additional features designed to make the APK signature more secure.

It is not mandatory. You should check BOTH of those checkboxes if possible, but if the new V2 signing mechanism gives you problems, you can omit it.

So you can just leave V2 unchecked if you encounter problems, but should have it checked if possible.

UPDATED: This is now mandatory when targeting Android 11.

excel VBA run macro automatically whenever a cell is changed

In an attempt to find a way to make the target cell for the intersect method a name table array, I stumbled across a simple way to run something when ANY cell or set of cells on a particular sheet changes. This code is placed in the worksheet module as well:

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Cells.Count > 0 Then
'mycode here
end if
end sub

How to make a launcher

Just develop a normal app and then add a couple of lines to the app's manifest file.

First you need to add the following attribute to your activity:


Then add two categories to the intent filter :

            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.HOME" />

The result could look something like this:

    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android=""
        android:versionName="1.0" >

            android:targetSdkVersion="19" />

            android:theme="@style/AppTheme" >
                android:label="@string/app_name" >
                    <action android:name="android.intent.action.MAIN" />
                    <category android:name="android.intent.category.LAUNCHER" />
                    <category android:name="android.intent.category.DEFAULT" />
                    <category android:name="android.intent.category.HOME" />


It's that simple!

mysql select from n last rows

Starting from the answer given by @chaos, but with a few modifications:

  • You should always use ORDER BY if you use LIMIT. There is no implicit order guaranteed for an RDBMS table. You may usually get rows in the order of the primary key, but you can't rely on this, nor is it portable.

  • If you order by in the descending order, you don't need to know the number of rows in the table beforehand.

  • You must give a correlation name (aka table alias) to a derived table.

Here's my version of the query:

    SELECT `id`, `val`
    FROM `big_table`
    ORDER BY `id` DESC
    LIMIT $n
) AS t
WHERE t.`val` = $certain_number;

Android M - check runtime permission - how to determine if the user checked "Never ask again"?

You can determine it by checking if permission rationale is to be shown inside the onRequestPermissionsResult() callback method. And if you find any permission set to never ask again, you can request users to grant permissions from the settings.

My full implementation would be like below. It works for both single or multiple permissions requests. Use the following or directly use my library.

public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if(permissions.length == 0){
    boolean allPermissionsGranted = true;
        for(int grantResult: grantResults){
            if(grantResult != PackageManager.PERMISSION_GRANTED){
                allPermissionsGranted = false;
        boolean somePermissionsForeverDenied = false;
        for(String permission: permissions){
            if(ActivityCompat.shouldShowRequestPermissionRationale(this, permission)){
                Log.e("denied", permission);
                if(ActivityCompat.checkSelfPermission(this, permission) == PackageManager.PERMISSION_GRANTED){
                    Log.e("allowed", permission);
                } else{
                    //set to never ask again
                    Log.e("set to never ask again", permission);
                    somePermissionsForeverDenied = true;
            final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
            alertDialogBuilder.setTitle("Permissions Required")
                    .setMessage("You have forcefully denied some of the required permissions " +
                            "for this action. Please open settings, go to permissions and allow them.")
                    .setPositiveButton("Settings", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
                            Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS,
                                    Uri.fromParts("package", getPackageName(), null));
                    .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
    } else {
        switch (requestCode) {
            //act according to the request code used while requesting the permission(s).

Python name 'os' is not defined

Just add:

import os

in the beginning, before:

from settings import PROJECT_ROOT

This will import the python's module os, which apparently is used later in the code of your module without being imported.

How to create a property for a List<T>

public class MyClass<T>
  private List<T> list;

  public List<T> MyList { get { return list; } set { list = value; } }

Then you can do something like

MyClass<int> instance1 = new MyClass<int>();
List<int> integers = instance1.MyList;

MyClass<Person> instance2 = new MyClass<Person>();
IEnumerable<Person> persons = instance2.MyList;

How to create strings containing double quotes in Excel formulas?

Have you tried escaping with a double-quote?

= "Maurice ""The Rocket"" Richard"

Cannot insert explicit value for identity column in table 'table' when IDENTITY_INSERT is set to OFF

In my CASE I was inserting more character than defined in table.

In My Table column was defined with nvarchar(3) and I was passing more than 3 characters and same ERROR message was coming .

Its not answer but may be in some case problem is similar

How to enable LogCat/Console in Eclipse for Android?

In Eclipse, Goto Window-> Show View -> Other -> Android-> Logcat.

Logcat is nothing but a console of your Emulator or Device.

System.out.println does not work in Android. So you have to handle every thing in Logcat. More Info Look out this Documentation.

Edit 1: System.out.println is working on Logcat. If you use that the Tag will be like System.out and Message will be your message.

Build not visible in itunes connect

You can see all of your activities (recently uploaded builds here). It will also provide current status of your build.

How does Subquery in select statement work in oracle

In the Oracle RDBMS, it is possible to use a multi-row subquery in the select clause as long as the (sub-)output is encapsulated as a collection. In particular, a multi-row select clause subquery can output each of its rows as an xmlelement that is encapsulated in an xmlforest.

How to detect if a browser is Chrome using jQuery?

$ = /chrom(e|ium)/.test(navigator.userAgent.toLowerCase()); 



UPDATE:(10x to @Mr. Bacciagalupe)

jQuery has removed $.browser from 1.9 and their latest release.

But you can still use $.browser as a standalone plugin, found here

Getting individual colors from a color map in matplotlib

For completeness these are the cmap choices I encountered so far:

Accent, Accent_r, Blues, Blues_r, BrBG, BrBG_r, BuGn, BuGn_r, BuPu, BuPu_r, CMRmap, CMRmap_r, Dark2, Dark2_r, GnBu, GnBu_r, Greens, Greens_r, Greys, Greys_r, OrRd, OrRd_r, Oranges, Oranges_r, PRGn, PRGn_r, Paired, Paired_r, Pastel1, Pastel1_r, Pastel2, Pastel2_r, PiYG, PiYG_r, PuBu, PuBuGn, PuBuGn_r, PuBu_r, PuOr, PuOr_r, PuRd, PuRd_r, Purples, Purples_r, RdBu, RdBu_r, RdGy, RdGy_r, RdPu, RdPu_r, RdYlBu, RdYlBu_r, RdYlGn, RdYlGn_r, Reds, Reds_r, Set1, Set1_r, Set2, Set2_r, Set3, Set3_r, Spectral, Spectral_r, Wistia, Wistia_r, YlGn, YlGnBu, YlGnBu_r, YlGn_r, YlOrBr, YlOrBr_r, YlOrRd, YlOrRd_r, afmhot, afmhot_r, autumn, autumn_r, binary, binary_r, bone, bone_r, brg, brg_r, bwr, bwr_r, cividis, cividis_r, cool, cool_r, coolwarm, coolwarm_r, copper, copper_r, cubehelix, cubehelix_r, flag, flag_r, gist_earth, gist_earth_r, gist_gray, gist_gray_r, gist_heat, gist_heat_r, gist_ncar, gist_ncar_r, gist_rainbow, gist_rainbow_r, gist_stern, gist_stern_r, gist_yarg, gist_yarg_r, gnuplot, gnuplot2, gnuplot2_r, gnuplot_r, gray, gray_r, hot, hot_r, hsv, hsv_r, inferno, inferno_r, jet, jet_r, magma, magma_r, nipy_spectral, nipy_spectral_r, ocean, ocean_r, pink, pink_r, plasma, plasma_r, prism, prism_r, rainbow, rainbow_r, seismic, seismic_r, spring, spring_r, summer, summer_r, tab10, tab10_r, tab20, tab20_r, tab20b, tab20b_r, tab20c, tab20c_r, terrain, terrain_r, twilight, twilight_r, twilight_shifted, twilight_shifted_r, viridis, viridis_r, winter, winter_r

Specify sudo password for Ansible

You can set the password for a group or for all servers at once:



How to uninstall Golang?

Use this command to uninstall Golang for Ubuntu.

This will remove just the golang-go package itself.

sudo apt-get remove golang-go

Uninstall golang-go and its dependencies:

sudo apt-get remove --auto-remove golang-go

jQuery - how can I find the element with a certain id?

As all html ids are unique in a valid html document why not search for the ID directly? If you're concerned if they type in an id that isn't a table then you can inspect the tag type that way?

Just an idea!


How to open warning/information/error dialog in Swing?

import javax.swing.JFrame;
import javax.swing.JOptionPane;

public class ErrorDialog {

  public static void main(String argv[]) {
    String message = "\"The Comedy of Errors\"\n"
        + "is considered by many scholars to be\n"
        + "the first play Shakespeare wrote";
    JOptionPane.showMessageDialog(new JFrame(), message, "Dialog",

VBA Count cells in column containing specified value

This isn't exactly what you are looking for but here is how I've approached this problem in the past;

You can enter a formula like;


...into a cell. This will count the Number of cells between A1 and A10 that contain the text "Green". You can then select this cell value in a VBA Macro and assign it to a variable as normal.

SQL search multiple values in same field

Try this


$sql = '';
$count = 0;
foreach($search as $text)
  if($count > 0)
     $sql = $sql."UNION Select name From myTable WHERE Name LIKE '%$text%'";
     $sql = $sql."Select name From myTable WHERE Name LIKE '%$text%'";



$comma_separated = "('" . implode("','", $search) . "')";  // ('1','2','3')
$sql = "Select name From myTable WHERE name IN ".$comma_separated ;

How can I split and parse a string in Python?

If it's always going to be an even LHS/RHS split, you can also use the partition method that's built into strings. It returns a 3-tuple as (LHS, separator, RHS) if the separator is found, and (original_string, '', '') if the separator wasn't present:

>>> "2.7.0_bf4fda703454".partition('_')
('2.7.0', '_', 'bf4fda703454')

>>> "shazam".partition("_")
('shazam', '', '')

What does the ^ (XOR) operator do?

One thing that other answers don't mention here is XOR with negative numbers -

 a  |  b  | a ^ b
 0  |  0  |  0
 0  |  1  |  1
 1  |  0  |  1
 1  |  1  |  0

While you could easily understand how XOR will work using the above functional table, it doesn't tell how it will work on negative numbers.

How XOR works with Negative Numbers :

Since this question is also tagged as python, I will be answering it with that in mind. The XOR ( ^ ) is an logical operator that will return 1 when the bits are different and 0 elsewhere.

A negative number is stored in binary as two's complement. In 2's complement, The leftmost bit position is reserved for the sign of the value (positive or negative) and doesn't contribute towards the value of number.

In, Python, negative numbers are written with a leading one instead of a leading zero. So if you are using only 8 bits for your two's-complement numbers, then you treat patterns from 00000000 to 01111111 as the whole numbers from 0 to 127, and reserve 1xxxxxxx for writing negative numbers.

With that in mind, lets understand how XOR works on negative number with an example. Lets consider the expression - ( -5 ^ -3 ) .

  • The binary representation of -5 can be considered as 1000...101 and
  • Binary representation of -3 can be considered as 1000...011.

Here, ... denotes all 0s, the number of which depends on bits used for representation (32-bit, 64-bit, etc). The 1 at the MSB ( Most Significant Bit ) denotes that the number represented by the binary representation is negative. The XOR operation will be done on all bits as usual.

XOR Operation :

      -5   :  10000101          |
     ^                          | 
      -3   :  10000011          |  
    ===================         |
    Result :  00000110  =  6    |

     ? -5 ^ -3 = 6

Since, the MSB becomes 0 after the XOR operation, so the resultant number we get is a positive number. Similarly, for all negative numbers, we consider their representation in binary format using 2's complement (one of most commonly used) and do simple XOR on their binary representation.

The MSB bit of result will denote the sign and the rest of the bits will denote the value of the final result.

The following table could be useful in determining the sign of result.

  a   |   b   | a ^ b
  +   |   +   |   +
  +   |   -   |   -
  -   |   +   |   -
  -   |   -   |   +

The basic rules of XOR remains same for negative XOR operations as well, but how the operation really works in negative numbers could be useful for someone someday .

How to display .svg image using swift

As I know there are 2 different graphic formats:

  1. Raster graphics (uses bitmaps) and is used in JPEG, PNG, APNG, GIF, and MPEG4 file format.
  2. Vector graphics (uses points, lines, curves and other shapes). Vector graphics are used in the SVG, EPS, PDF or AI graphic file formats.

So if you need to use an image stored in SVG File in your Xcode I would suggest:

  1. Convert SVG file to PDF. I used

  2. Use Xcode to manage you PDF file.


INNER JOIN is ANSI syntax that you should use.

It is generally considered more readable, especially when you join lots of tables.

It can also be easily replaced with an OUTER JOIN whenever a need arises.

The WHERE syntax is more relational model oriented.

A result of two tables JOINed is a cartesian product of the tables to which a filter is applied which selects only those rows with joining columns matching.

It's easier to see this with the WHERE syntax.

As for your example, in MySQL (and in SQL generally) these two queries are synonyms.

Also, note that MySQL also has a STRAIGHT_JOIN clause.

Using this clause, you can control the JOIN order: which table is scanned in the outer loop and which one is in the inner loop.

You cannot control this in MySQL using WHERE syntax.

ASP.NET MVC: No parameterless constructor defined for this object

This error started for me when I added a new way to instantiate a class.


    public class myClass
         public string id{ get; set; }
         public List<string> myList{get; set;}

         // error happened after I added this
         public myClass(string id, List<string> lst)
             this.myList= lst;

The error was resolved when I added when I made this change, adding a parameterless constructor. I believe the compiler creates a parameterless constuctor by default but if you add your own then you must explicitly create it.

    public class myClass
         public string id{ get; set; }
         public List<string> myList{get; set;}

         // error doesn't happen when I add this
         public myClass() { }

         // error happened after I added this, but no longer happens after adding above
         public myClass(string id, List<string> lst)
             this.myList= lst;

How to get a list of user accounts using the command line in MySQL?

A user account comprises the username and the host level access.

Therefore, this is the query that gives all user accounts

SELECT CONCAT(QUOTE(user),'@',QUOTE(host)) UserAccount FROM mysql.user;

Get max and min value from array in JavaScript

arr = [9,4,2,93,6,2,4,61,1];
ArrMax = Math.max.apply(Math, arr);

How to remove empty lines with or without whitespace in Python

Same as what @NullUserException said, this is how I write it:

removedWhitespce = re.sub(r'^\s*$', '', line)

How to view unallocated free space on a hard disk through terminal

I had just the same trouble with fedora 26 and LVM partitions, it seems I forgot check something during the installation, So, my 15G root directory has been increased to 227G like I needed.

I posted the steps I followed here:

resize2fs: Bad magic number in super-block while trying to open

0) #df -h

Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G     0  1.9G   0% /dev/shm
tmpfs                    1.9G  824K  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/mapper/fedora-root   15G  2.1G   13G  14% /
tmpfs                    1.9G     0  1.9G   0% /tmp
/dev/md126p1             976M  119M  790M  14% /boot
tmpfs                    388M     0  388M   0% /run/user/0

1) # vgs

  VG     #PV #LV #SN Attr   VSize   VFree   
  fedora   1   2   0 wz--n- 231.88g 212.96g

2) # vgdisplay

  --- Volume group ---
  VG Name               fedora
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               231.88 GiB
  PE Size               4.00 MiB
  Total PE              59361
  Alloc PE / Size       4844 / 18.92 GiB
  Free  PE / Size       54517 / 212.96 GiB
  VG UUID               9htamV-DveQ-Jiht-Yfth-OZp7-XUDC-tWh5Lv

3) # lvextend -l +100%FREE /dev/mapper/fedora-root

  Size of logical volume fedora/root changed from 15.00 GiB (3840 extents) to 227.96 GiB (58357 extents).
  Logical volume fedora/root successfully resized.

4) #lvdisplay

5) #fd -h

6) # xfs_growfs /dev/mapper/fedora-root

meta-data=/dev/mapper/fedora-root isize=512    agcount=4, agsize=983040 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1 spinodes=0 rmapbt=0
         =                       reflink=0
data     =                       bsize=4096   blocks=3932160, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 3932160 to 59757568

7) #df -h

Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G     0  1.9G   0% /dev/shm
tmpfs                    1.9G  828K  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/mapper/fedora-root  228G  2.3G  226G   2% /
tmpfs                    1.9G     0  1.9G   0% /tmp
/dev/md126p1             976M  119M  790M  14% /boot
tmpfs                    388M     0  388M   0% /run/user/0

Best regards,

What does iterator->second mean?

I'm sure you know that a std::vector<X> stores a whole bunch of X objects, right? But if you have a std::map<X, Y>, what it actually stores is a whole bunch of std::pair<const X, Y>s. That's exactly what a map is - it pairs together the keys and the associated values.

When you iterate over a std::map, you're iterating over all of these std::pairs. When you dereference one of these iterators, you get a std::pair containing the key and its associated value.

std::map<std::string, int> m = /* fill it */;
auto it = m.begin();

Here, if you now do *it, you will get the the std::pair for the first element in the map.

Now the type std::pair gives you access to its elements through two members: first and second. So if you have a std::pair<X, Y> called p, p.first is an X object and p.second is a Y object.

So now you know that dereferencing a std::map iterator gives you a std::pair, you can then access its elements with first and second. For example, (*it).first will give you the key and (*it).second will give you the value. These are equivalent to it->first and it->second.

Having links relative to root?

Use this code "./" as root on the server as it works for me

<a href="./fruits/index.html">Back to Fruits List</a>

but when you are on a local machine use the following code "../" as the root relative path

<a href="../fruits/index.html">Back to Fruits List</a>

How do I include a file over 2 directories back?

include dirname(__FILE__).'/../../index.php';

is your best bet here, and it will avoid most of the relative path bugs you can encounter with other solutions.

Indeed, it will force the include to always be relative to the position of the current script where this code is placed (which location is most likely stable, since you define the architecture of your application). This is different from just doing include '../../index.php' which will include relatively to the executing (also named "calling") script and then relatively to the current working directory, which will point to the parent script that includes your script, instead of resolving from your included script's path.

From the PHP documentation:

Files are included based on the file path given or, if none is given, the include_path specified. If the file isn't found in the include_path, include will finally check in the calling script's own directory and the current working directory before failing.

And the oldest post I've found citing this trick dates back to 2003, by Tapken.

You can test with the following setup:

Create a layout like this:

¦   parent.php
¦   goal.php
    ¦   included.php
    ¦   goal.php

In parent.php, put:

include dirname(__FILE__).'/sub/included.php';

In sub/included.php, put:

print("WRONG : " . realpath('goal.php'));
print("GOOD : " . realpath(dirname(__FILE__).'/goal.php'));

Result when accessing parent.php:

WRONG : X:\htdocs\goal.php
GOOD : X:\htdocs\sub\goal.php

As we can see, in the first case, the path is resolved from the calling script parent.php, while by using the dirname(__FILE__).'/path' trick, the include is done from the script included.php where the code is placed in.

Beware, the following NOT equivalent to the trick above contrary to what can be read elsewhere:

include '/../../index.php';

Indeed, prepending / will work, but it will resolve just like include ../../index.php from the calling script (the difference is that include_path won't be looked afterwards if it fails). From PHP doc:

If a path is defined — whether absolute (starting with a drive letter or \ on Windows, or / on Unix/Linux systems) or relative to the current directory (starting with . or ..) — the include_path will be ignored altogether.

How to return history of validation loss in Keras

Thanks to Alloush,

Following parameter must be included in

validation_data = (x_test, y_test)

If it is not defined, val_acc and val_loss will not be exist at output.

How to set up a Web API controller for multipart/form-data

Here's another answer for the ASP.Net Core solution to this problem...

On the Angular side, I took this code example...

... and modified it to call an HTTP Post endpoint:

  prepareFilesList(files: Array<any>) {

    const formData = new FormData();
    for (var i = 0; i < files.length; i++) { 
      formData.append("file[]", files[i]);

    let URL = "https://localhost:44353/api/Users";, formData).subscribe(
      data => { console.log(data); },
      error => { console.log(error); }

With this in place, here's the code I needed in the ASP.Net Core WebAPI controller:

public ActionResult Post()
    var files = Request.Form.Files;

    foreach (IFormFile file in files)
        if (file.Length == 0)
        string tempFilename = Path.Combine(Path.GetTempPath(), file.FileName);
        System.Diagnostics.Trace.WriteLine($"Saved file to: {tempFilename}");

        using (var fileStream = new FileStream(tempFilename, FileMode.Create))
    return new OkObjectResult("Yes");
  catch (Exception ex)
    return new BadRequestObjectResult(ex.Message);

Shockingly simple, but I had to piece together examples from several (almost-correct) sources to get this to work properly.

How to use jQuery to call an ASP.NET web service?

I don't know about that specific SharePoint web service, but you can decorate a page method or a web service with <WebMethod()> (in VB.NET) to ensure that it serializes to JSON. You can probably just wrap the method that webservice.asmx uses internally, in your own web service.

Dave Ward has a nice walkthrough on this.

Install Chrome extension form outside the Chrome Web Store

For Windows, you can also whitelist your extension through Windows policies. The full steps are details in this answer, but there are quicker steps:

  1. Create the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallWhitelist.
  2. For each extension you want to whitelist, add a string value whose name should be a sequence number (starting at 1) and value is the extension ID.

For instance, in order to whitelist 2 extensions with ID aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa and bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb, create a string value with name 1 and value aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, and a second value with name 2 and value bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb. This can be sum up by this registry file:

Windows Registry Editor Version 5.00



EDIT: actually, Chromium docs also indicate how to do it for other OS.

Integer value in TextView

Alternative approach:

 TextView tv = new TextView(this);

Unable to create/open lock file: /data/mongod.lock errno:13 Permission denied

In my case (AWS EC2 instance, Ubuntu) helped:

$ sudo mkdir -p /data/db/
$ sudo chown `USERNAME` /data/db

And after that everything worked fine.

How to convert strings into integers in Python?

Yet another functional solution for Python 2:

from functools import partial

map(partial(map, int), T1)

Python 3 will be a little bit messy though:

list(map(list, map(partial(map, int), T1)))

we can fix this with a wrapper

def oldmap(f, iterable):
    return list(map(f, iterable))

oldmap(partial(oldmap, int), T1)

Modelling an elevator using Object-Oriented Analysis and Design

I've seen many variants of this problem. One of the main differences (that determines the difficulty) is whether there is some centralized attempt to have a "smart and efficient system" that would have load balancing (e.g., send more idle elevators to lobby in morning). If that is the case, the design will include a whole subsystem with really fun design.

A full design is obviously too much to present here and there are many altenatives. The breadth is also not clear. In an interview, they'll try to figure out how you would think. However, these are some of the things you would need:

  1. Representation of the central controller (assuming there is one).

  2. Representations of elevators

  3. Representations of the interface units of the elevator (these may be different from elevator to elevator). Obviously also call buttons on every floor, etc.

  4. Representations of the arrows or indicators on each floor (almost a "view" of the elevator model).

  5. Representation of a human and cargo (may be important for factoring in maximal loads)

  6. Representation of the building (in some cases, as certain floors may be blocked at times, etc.)

Excel compare two columns and highlight duplicates

A simple formula to use is


Formula specified is for cell A1. Simply copy and paste special - format to the whole of column A

Simple If/Else Razor Syntax

I would just go with

<tr @(if (count++ % 2 == 0){<text>class="alt-row"</text>})>

Or even better

<tr class="alt-row@(count++ % 2)">

this will give you lines like

<tr class="alt-row0">
<tr class="alt-row1">
<tr class="alt-row0">
<tr class="alt-row1">

Change font-weight of FontAwesome icons?

.star-light::after {
    content: "\f005";
    font-family: "FontAwesome";
    font-size: 3.2rem;
    color: #fff;
    font-weight: 900;
    background-color: red;

How to pass complex object to ASP.NET WebApi GET from jQuery ajax call?

After finding this StackOverflow question/answer

Complex type is getting null in a ApiController parameter

the [FromBody] attribute on the controller method needs to be [FromUri] since a GET does not have a body. After this change the "filter" complex object is passed correctly.

SQL Server - In clause with a declared variable

I think problem is in

3 + ', ' + 4

change it to

'3' + ', ' + '4'


SET @ExcludedList = '3' + ', ' + '4' + ' ,' + '22'


SET @ExcludedListe such that your query should become


SELECT * FROM A WHERE Id NOT IN ('3', '4', '22')



How do I find a list of Homebrew's installable packages?

brew help will show you the list of commands that are available.

brew list will show you the list of installed packages. You can also append formulae, for example brew list postgres will tell you of files installed by postgres (providing it is indeed installed).

brew search <search term> will list the possible packages that you can install. brew search post will return multiple packages that are available to install that have post in their name.

brew info <package name> will display some basic information about the package in question.

You can also search or (both sites do basically the same thing)

'console' is undefined error for Internet Explorer

You can use console.log(...) directly in Firefox but not in IEs. In IEs you have to use window.console.

$(document).ready shorthand

The shorthand is:

$(function() {
    // Code here

How do I make a matrix from a list of vectors in R?

simplify2array is a base function that is fairly intuitive. However, since R's default is to fill in data by columns first, you will need to transpose the output. (sapply uses simplify2array, as documented in help(sapply).)

> t(simplify2array(a))
      [,1] [,2] [,3] [,4] [,5] [,6]
 [1,]    1    1    2    3    4    5
 [2,]    2    1    2    3    4    5
 [3,]    3    1    2    3    4    5
 [4,]    4    1    2    3    4    5
 [5,]    5    1    2    3    4    5
 [6,]    6    1    2    3    4    5
 [7,]    7    1    2    3    4    5
 [8,]    8    1    2    3    4    5
 [9,]    9    1    2    3    4    5
[10,]   10    1    2    3    4    5

How to write multiple line string using Bash with variables?

The syntax (<<<) and the command used (echo) is wrong.

Correct would be:


cat >/etc/myconfig.conf <<EOL
line 1, ${kernel}
line 2, 
line 3, ${distro}
line 4 line

cat /etc/myconfig.conf

This construction is referred to as a Here Document and can be found in the Bash man pages under man --pager='less -p "\s*Here Documents"' bash.

IE11 meta element Breaks SVG

After trying the other suggestions to no avail I discovered that this issue was related to styling for me. I don't know a lot about the why but I found that my SVGs were not visible because they were not holding their place in the DOM.

In essence, the containers around my SVGs were at width: 0 and overflow: hidden.

I fixed this by setting a width on the containers but it is possible that there is a more direct solution to that particular issue.

How to open google chrome from terminal?

I'm not sure how extensively you've searched, but this seems to be similar to what you're searching for:

(I just assumed you're using Mac since you used the word "terminal")

Add regression line equation and R^2 on graph

Here is one solution

# SOURCE:!topic/ggplot2/1TgH-kG5XMA

lm_eqn <- function(df){
    m <- lm(y ~ x, df);
    eq <- substitute(italic(y) == a + b %.% italic(x)*","~~italic(r)^2~"="~r2, 
         list(a = format(unname(coef(m)[1]), digits = 2),
              b = format(unname(coef(m)[2]), digits = 2),
             r2 = format(summary(m)$r.squared, digits = 3)))

p1 <- p + geom_text(x = 25, y = 300, label = lm_eqn(df), parse = TRUE)

EDIT. I figured out the source from where I picked this code. Here is the link to the original post in the ggplot2 google groups


Rollback transaction after @Test

Just add @Transactional annotation on top of your test:

@ContextConfiguration(locations = {"testContext.xml"})
public class StudentSystemTest {

By default Spring will start a new transaction surrounding your test method and @Before/@After callbacks, rolling back at the end. It works by default, it's enough to have some transaction manager in the context.

From: Transaction management (bold mine):

In the TestContext framework, transactions are managed by the TransactionalTestExecutionListener. Note that TransactionalTestExecutionListener is configured by default, even if you do not explicitly declare @TestExecutionListeners on your test class. To enable support for transactions, however, you must provide a PlatformTransactionManager bean in the application context loaded by @ContextConfiguration semantics. In addition, you must declare @Transactional either at the class or method level for your tests.

Inserting line breaks into PDF

I have simply replaced the "\n" with "<br>" tag. Worked fine. It seems TCPDF render the text as HTML

$strText = str_replace("\n","<br>",$strText);
$pdf->MultiCell($width, $height,$strText, 0, 'J', 0, 1, '', '', true, null, true);

Store boolean value in SQLite

You could simplify the above equations using the following:

boolean flag = sqlInt != 0;

If the int representation (sqlInt) of the boolean is 0 (false), the boolean (flag) will be false, otherwise it will be true.

Concise code is always nicer to work with :)

Inline <style> tags vs. inline css properties

Style rules can be attached using:

  • External Files
  • In-page Style Tags
  • Inline Style Attribute

Generally, I prefer to use linked style sheets because they:

  • can be cached by browsers for performance; and
  • are a lot easier to maintain for a development perspective.

However, your question is asking specifically about the style tag versus inline styles. Prefer to use the style tag, in this case, because it:

  • provides a clear separation of markup from styling;
  • produces cleaner HTML markup; and
  • is more efficient with selectors to apply rules to multiple elements on a page improving management as well as making your page size smaller.

Inline elements only affect their respective element.

An important difference between the style tag and the inline attribute is specificity. Specificity determines when one style overrides another. Generally, inline styles have a higher specificity.

Read CSS: Specificity Wars for an entertaining look at this subject.

I hope that helps!

How do I force Internet Explorer to render in Standards Mode and NOT in Quirks?

It's possible that the HTML5 Doctype is causing you problems with those older browsers. It could also be down to something funky related to the HTML5 shiv.

You could try switching to one of the XHTML doctypes and changing your markup accordingly, at least temporarily. This might allow you to narrow the problem down.

Is your design breaking when those IEs switch to quirks mode? If it's your CSS causing things to display strangely, it might be worth working on the CSS so the site looks the same even when the browsers switch modes.

What is a Maven artifact?

To maven, the build process is arranged as a set of artifacts. Artifacts include:

  1. The plugins that make up Maven itself.
  2. Dependencies that your code depends on.
  3. Anything that your build produces that can, in turn be consumed by something else.

Artifacts live in repositories.

How to split and modify a string in NodeJS?

Use split and map function:

var str = "123, 124, 234,252";
var arr = str.split(",");
arr = (val) { return +val + 1; });

Notice +val - string is casted to a number.

Or shorter:

var str = "123, 124, 234,252";
var arr = str.split(",").map(function (val) { return +val + 1; });

edit 2015.07.29

Today I'd advise against using + operator to cast variable to a number. Instead I'd go with a more explicit but also more readable Number call:

var str = "123, 124, 234,252";_x000D_
var arr = str.split(",").map(function (val) {_x000D_
  return Number(val) + 1;_x000D_

edit 2017.03.09

ECMAScript 2015 introduced arrow function so it could be used instead to make the code more concise:

var str = "123, 124, 234,252";_x000D_
var arr = str.split(",").map(val => Number(val) + 1);_x000D_

How do I get the output of a shell command executed using into a variable from Jenkinsfile (groovy)?

For those who need to use the output in subsequent shell commands, rather than groovy, something like this example could be done:

    stage('Show Files') {
        environment {
          MY_FILES = sh(script: 'cd mydir && ls -l', returnStdout: true)
        steps {
          sh '''
            echo "$MY_FILES"

I found the examples on code maven to be quite useful.

JPA With Hibernate Error: [PersistenceUnit: JPA] Unable to build EntityManagerFactory

It worked for me after adding the following dependency in pom,


How to create a byte array in C++?

Byte is not a standard type in C/C++, so it is represented by char.

An advantage of this is that you can treat a basic_string as a byte array allowing for safe storage and function passing. This will help you avoid the memory leaks and segmentation faults you might encounter when using the various forms of char[] and char*.

For example, this creates a string as a byte array of null values:

typedef basic_string<unsigned char> u_string;

u_string bytes = u_string(16,'\0');

This allows for standard bitwise operations with other char values, including those stored in other string variables. For example, to XOR the char values of another u_string across bytes:

u_string otherBytes = "some more chars, which are just bytes";
for(int i = 0; i < otherBytes.length(); i++)
    bytes[i%16] ^= (int)otherBytes[i];

Undefined Reference to

Another way to get this error is by accidentally writing the definition of something in an anonymous namespace:


namespace foo {
    void bar();

namespace foo {
    namespace {  // wrong
        void bar() { cout << "hello"; };
} file:

#include "foo.h"

void baz() {

Sizing elements to percentage of screen width/height

There is many way to do this.

1. Using MediaQuery : Its return fullscreen of your device including appbar,toolbar

        width: MediaQuery.of(context).size.width * 0.50,
        height: MediaQuery.of(context).size.height*0.50, 
        color: Colors.blueAccent[400],

enter image description here

2. Using Expanded : You can set width/height in ratio

        height: MediaQuery.of(context).size.height * 0.50,
        child: Row(
          children: <Widget>[
              flex: 70,
              child: Container(
                color: Colors.lightBlue[400],
              flex: 30,
              child: Container(
                color: Colors.deepPurple[800],

enter image description here

3. Others Like Flexible and AspectRatio and FractionallySizedBox

T-SQL and the WHERE LIKE %Parameter% clause

you may try this one, used CONCAT

WHERE LastName LIKE Concat('%',@LastName,'%')

Display html text in uitextview

Use following block of code for ios 7+.

NSString *htmlString = @"<h1>Header</h1><h2>Subheader</h2><p>Some <em>text</em></p><img src='' width=70 height=100 />";
NSAttributedString *attributedString = [[NSAttributedString alloc]
          initWithData: [htmlString dataUsingEncoding:NSUnicodeStringEncoding]
               options: @{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType }
    documentAttributes: nil
                 error: nil
textView.attributedText = attributedString;

When are you supposed to use escape instead of encodeURI / encodeURIComponent?

Inspired by Johann's table, I've decided to extend the table. I wanted to see which ASCII characters get encoded.

screenshot of console.table

var ascii = " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~";_x000D_
var encoded = [];_x000D_
ascii.split("").forEach(function (char) {_x000D_
    var obj = { char };_x000D_
    if (char != encodeURI(char))_x000D_
        obj.encodeURI = encodeURI(char);_x000D_
    if (char != encodeURIComponent(char))_x000D_
        obj.encodeURIComponent = encodeURIComponent(char);_x000D_
    if (obj.encodeURI || obj.encodeURIComponent)_x000D_

Table shows only the encoded characters. Empty cells mean that the original and the encoded characters are the same.

Just to be extra, I'm adding another table for urlencode() vs rawurlencode(). The only difference seems to be the encoding of space character.

screenshot of console.table

$ascii = str_split(" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~", 1);
$encoded = [];
foreach ($ascii as $char) {
    $obj = ["char" => $char];
    if ($char != urlencode($char))
        $obj["urlencode"] = urlencode($char);
    if ($char != rawurlencode($char))
        $obj["rawurlencode"] = rawurlencode($char);
    if (isset($obj["rawurlencode"]) || isset($obj["rawurlencode"]))
        $encoded[] = $obj;
echo "var encoded = " . json_encode($encoded) . ";";

How to put two divs on the same line with CSS in simple_form in rails?

why not use flexbox ? so wrap them into another div like that

.flexContainer { _x000D_
  margin: 2px 10px;_x000D_
  display: flex;_x000D_
} _x000D_
.left {_x000D_
  flex-basis : 30%;_x000D_
.right {_x000D_
  flex-basis : 30%;_x000D_
<form id="new_production" class="simple_form new_production" novalidate="novalidate" method="post" action="/projects/1/productions" accept-charset="UTF-8">_x000D_
    <div style="margin:0;padding:0;display:inline">_x000D_
        <input type="hidden" value="?" name="utf8">_x000D_
        <input type="hidden" value="2UQCUU+tKiKKtEiDtLLNeDrfBDoHTUmz5Sl9+JRVjALat3hFM=" name="authenticity_token">_x000D_
    <div class="flexContainer">_x000D_
      <div class="left">Proj Name:</div>_x000D_
      <div class="right">must have a name</div>_x000D_
    <div class="input string required"> </div>_x000D_

feel free to play with flex-basis percentage to get more customized space.

How to use glOrtho() in OpenGL?

Have a look at this picture: Graphical Projections enter image description here

The glOrtho command produces an "Oblique" projection that you see in the bottom row. No matter how far away vertexes are in the z direction, they will not recede into the distance.

I use glOrtho every time I need to do 2D graphics in OpenGL (such as health bars, menus etc) using the following code every time the window is resized:

glOrtho(0.0f, windowWidth, windowHeight, 0.0f, 0.0f, 1.0f);

This will remap the OpenGL coordinates into the equivalent pixel values (X going from 0 to windowWidth and Y going from 0 to windowHeight). Note that I've flipped the Y values because OpenGL coordinates start from the bottom left corner of the window. So by flipping, I get a more conventional (0,0) starting at the top left corner of the window rather.

Note that the Z values are clipped from 0 to 1. So be careful when you specify a Z value for your vertex's position, it will be clipped if it falls outside that range. Otherwise if it's inside that range, it will appear to have no effect on the position except for Z tests.

Finding what branch a Git commit came from

khichar.anil covered most of this in his answer.

I am just adding the flag that will remove the tags from the revision names list. This gives us:

git name-rev --name-only --exclude=tags/* $SHA

How can I check if a string represents an int, without using try/except?

If you're really just annoyed at using try/excepts all over the place, please just write a helper function:

def RepresentsInt(s):
        return True
    except ValueError:
        return False

>>> print RepresentsInt("+123")
>>> print RepresentsInt("10.0")

It's going to be WAY more code to exactly cover all the strings that Python considers integers. I say just be pythonic on this one.

Escaping ampersand character in SQL string

You can use

set define off

Using this it won't prompt for the input

JavaScript replace/regex

Your regex pattern should have the g modifier:

var pattern = /[somepattern]+/g;

notice the g at the end. it tells the replacer to do a global replace.

Also you dont need to use the RegExp object you can construct your pattern as above. Example pattern:

var pattern = /[0-9a-zA-Z]+/g;

a pattern is always surrounded by / on either side - with modifiers after the final /, the g modifier being the global.

EDIT: Why does it matter if pattern is a variable? In your case it would function like this (notice that pattern is still a variable):

var pattern = /[0-9a-zA-Z]+/g;
repeater.replace(pattern, "1234abc");

But you would need to change your replace function to this:

this.markup = this.markup.replace(pattern, value);

how to fix stream_socket_enable_crypto(): SSL operation failed with code 1

Reading app/config/mailphp

Supported : "smtp", "mail", "sendmail"

Depending on your mail utilities installed on your machine, fill in the value of the driver key. I would do

'driver' => 'sendmail',

How can I add a box-shadow on one side of an element?

div {
 border: 1px solid #666;
    width: 50px;
    height: 50px;
    -webkit-box-shadow: inset 10px 0px 5px -1px #888 ;

Invalid application path

I had a similar issue today. It was caused by skype! A recent update to skype had re-enabled port 80 and 443 as alternatives to incoming connections.

H/T :

To disable, go to skype > options > Advanced > Connections and uncheck "Use port 80 and 443 as alternatives to incoming connections"

Alert after page load

Another option to resolve issue described in OP which I encountered on recent bootcamp training is using window.setTimeout to wrap around the code which is bothersome. My understanding is that it delays the execution of the function for the specified time period (500ms in this case), allowing enough time for the page to load. So, for example:

<script type = "text/javascript">
                alert("Hello World!");
            }, 500); 

When to choose mouseover() and hover() function?

As you can read at

The mouseenter JavaScript event is proprietary to Internet Explorer. Because of the event's general utility, jQuery simulates this event so that it can be used regardless of browser. This event is sent to an element when the mouse pointer enters the element. Any HTML element can receive this event.

Ascending and Descending Number Order in java

package pack2;

import java.util.Scanner;

public class group {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    Scanner data= new Scanner(;
    int value[]= new int[5];
    int temp=0,i=0,j=0;
    System.out.println("Enter 5 element of array");

      System.out.println("Increasing Order:");

How do I read a text file of about 2 GB?

Try Vim, emacs (has a low maximum buffer size limit if compiled in 32-bit mode), hex tools

Android: How to overlay a bitmap and draw over a bitmap?

I can't believe no one has answered this yet! A rare occurrence on SO!


The question doesn't quite make sense to me. But I'll give it a stab. If you're asking about direct drawing to a canvas (polygons, shading, text etc...) vs. loading a bitmap and blitting it onto the canvas that would depend on the complexity of your drawing. As the drawing gets more complex the CPU time required will increase accordingly. However, blitting a bitmap onto a canvas will always be a constant time which is proportional to the size of the bitmap.


Without knowing what "something" is how can I show you how to do it? You should be able to figure out #2 from the answer for #3.



  • bmp1 is larger than bmp2.
  • You want them both overlaid from the top left corner.

        private Bitmap overlay(Bitmap bmp1, Bitmap bmp2) {
            Bitmap bmOverlay = Bitmap.createBitmap(bmp1.getWidth(), bmp1.getHeight(), bmp1.getConfig());
            Canvas canvas = new Canvas(bmOverlay);
            canvas.drawBitmap(bmp1, new Matrix(), null);
            canvas.drawBitmap(bmp2, new Matrix(), null);
            return bmOverlay;

iPhone 5 CSS media query

/* iPad */
@media screen and (min-device-width: 768px) {
    /* ipad-portrait */
    @media screen and (max-width: 896px) { 
            display: none !important;
    /* ipad-landscape */
    @media screen and (min-width: 897px) { 

/* iPhone */
@media screen and (max-device-width: 480px) {
    /* iphone-portrait */
    @media screen and (max-width: 400px) { 

    /* iphone-landscape */
    @media screen and (min-width: 401px) { 


How to Reload ReCaptcha using JavaScript?

For AngularJS users:


C dynamically growing array

Building on Matteo Furlans design, when he said "most dynamic array implementations work by starting off with an array of some (small) default size, then whenever you run out of space when adding a new element, double the size of the array". The difference in the "work in progress" below is that it doesn't double in size, it aims at using only what is required. I have also omitted safety checks for simplicity...Also building on brimboriums idea, I have tried to add a delete function to the code...

The storage.h file looks like this...

#ifndef STORAGE_H
#define STORAGE_H

#ifdef __cplusplus
extern "C" {

    typedef struct 
        int *array;
        size_t size;
    } Array;

    void Array_Init(Array *array);
    void Array_Add(Array *array, int item);
    void Array_Delete(Array *array, int index);
    void Array_Free(Array *array);

#ifdef __cplusplus

#endif /* STORAGE_H */

The storage.c file looks like this...

#include <stdio.h>
#include <stdlib.h>
#include "storage.h"

/* Initialise an empty array */
void Array_Init(Array *array) 
    int *int_pointer;

    int_pointer = (int *)malloc(sizeof(int));

    if (int_pointer == NULL)
        printf("Unable to allocate memory, exiting.\n");
        array->array = int_pointer; 
        array->size = 0;

/* Dynamically add to end of an array */
void Array_Add(Array *array, int item) 
    int *int_pointer;

    array->size += 1;

    int_pointer = (int *)realloc(array->array, array->size * sizeof(int));

    if (int_pointer == NULL)
        printf("Unable to reallocate memory, exiting.\n");
        array->array = int_pointer;
        array->array[array->size-1] = item;

/* Delete from a dynamic array */
void Array_Delete(Array *array, int index) 
    int i;
    Array temp;
    int *int_pointer;


    for(i=index; i<array->size; i++)
        array->array[i] = array->array[i + 1];

    array->size -= 1;

    for (i = 0; i < array->size; i++)
        Array_Add(&temp, array->array[i]);

    int_pointer = (int *)realloc(temp.array, temp.size * sizeof(int));

    if (int_pointer == NULL)
        printf("Unable to reallocate memory, exiting.\n");
        array->array = int_pointer; 

/* Free an array */
void Array_Free(Array *array) 
  array->array = NULL;
  array->size = 0;  

The main.c looks like this...

#include <stdio.h>
#include <stdlib.h>
#include "storage.h"

int main(int argc, char** argv) 
    Array pointers;
    int i;


    for (i = 0; i < 60; i++)
        Array_Add(&pointers, i);        

    Array_Delete(&pointers, 3);

    Array_Delete(&pointers, 6);

    Array_Delete(&pointers, 30);

    for (i = 0; i < pointers.size; i++)
        printf("Value: %d Size:%d \n", pointers.array[i], pointers.size);


    return (EXIT_SUCCESS);

Look forward to the constructive criticism to follow...

How to align 3 divs (left/center/right) inside another div?

You've done it correctly, you only need to clear your floats. Simply add

overflow: auto; 

to your container class.

How do I get the current username in .NET using C#?

If you are in a network of users, then the username will be different:

- Will Display format : 'Username'

rather than

- Will Display format : 'NetworkName\Username'

Choose the format you want.

Ajax passing data to php script

Try sending the data like this:

var data = {};
data.album = this.title;

Then you can access it like


Notice not a 'GET'

How to download all dependencies and packages to directory

The marked answer has the problem that the available packages on the machine that is doing the downloads might be different from the target machine, and thus the package set might be incomplete.

To avoid this and get all dependencies, use the following:

apt-get download $(apt-rdepends <package>|grep -v "^ ")

Some packages returned from apt-rdepends don't exist with the exact name for apt-get download to download (for example, libc-dev). In those cases, filter out those exact names (be sure to use ^<NAME>$ so that other related names, for example libc-dev-bin, that do exist are not skipped).

apt-get download $(apt-rdepends <package>|grep -v "^ " |grep -v "^libc-dev$")

Once downloaded, you can move the .deb files to a machine without Internet and install them:

sudo dpkg -i *.deb

How to reenable event.preventDefault?

I had a similar problem recently. I had a form and PHP function that to be run once the form is submitted. However, I needed to run a javascript first.

        // This variable is used in order to determine if we already did our js fun
        var window.alreadyClicked = "NO"
        $("form:not('#press')").bind("submit", function(e){
            // Check if we already run js part
            if(window.alreadyClicked == "NO"){
                // Prevent page refresh
                // Change variable value so next time we submit the form the js wont run
                window.alreadyClicked = "YES"
                // Here is your actual js you need to run before doing the php part

                // Submit the form again but since we changed the value of our variable js wont be run and page can reload (and php can do whatever you told it to)

Most efficient way to remove special characters from string

public static string RemoveSpecialCharacters(string str){
    return str.replaceAll("[^A-Za-z0-9_\\\\.]", "");

How to get year/month/day from a date object?

var dt = new Date();

dt.getFullYear() + "/" + (dt.getMonth() + 1) + "/" + dt.getDate();

Since month index are 0 based you have to increment it by 1.


For a complete list of date object functions see



Returns the month (0-11) in the specified date according to local time.


Returns the month (0-11) in the specified date according to universal time.

LINQ query to return a Dictionary<string, string>

Use the ToDictionary method directly.

var result = 
  // as Jon Skeet pointed out, OrderBy is useless here, I just leave it 
  // show how to use OrderBy in a LINQ query
  myClassCollection.OrderBy(mc => mc.SomePropToSortOn)
                   .ToDictionary(mc => mc.KeyProp.ToString(), 
                                 mc => mc.ValueProp.ToString(), 

How to add a hook to the application context initialization event?

Spring has some standard events which you can handle.

To do that, you must create and register a bean that implements the ApplicationListener interface, something like this:

package test.pack.age;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextRefreshedEvent;

public class ApplicationListenerBean implements ApplicationListener {

    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ContextRefreshedEvent) {
            ApplicationContext applicationContext = ((ContextRefreshedEvent) event).getApplicationContext();
            // now you can do applicationContext.getBean(...)
            // ...

You then register this bean within your servlet.xml or applicationContext.xml file:

<bean id="eventListenerBean" class="test.pack.age.ApplicationListenerBean" />

and Spring will notify it when the application context is initialized.

In Spring 3 (if you are using this version), the ApplicationListener class is generic and you can declare the event type that you are interested in, and the event will be filtered accordingly. You can simplify a bit your bean code like this:

public class ApplicationListenerBean implements ApplicationListener<ContextRefreshedEvent> {

    public void onApplicationEvent(ContextRefreshedEvent event) {
        ApplicationContext applicationContext = event.getApplicationContext();
        // now you can do applicationContext.getBean(...)
        // ...

Apache: Restrict access to specific source IP inside virtual host

In Apache 2.4, the authorization configuration syntax has changed, and the Order, Deny or Allow directives should no longer be used.

The new way to do this would be:

<VirtualHost *:8080>
    <Location />
        Require ip

Further examples using the new syntax can be found in the Apache documentation: Upgrading to 2.4 from 2.2

How to pass data in the ajax DELETE request other than headers

I was able to successfully pass through the data attribute in the ajax method. Here is my code

     url: "/api/Gigs/Cancel",
     type: "DELETE",
     data: {
             "GigId": link.attr('data-gig-id')


The link.attr method simply returned the value of 'data-gig-id' .

Conversion failed when converting from a character string to uniqueidentifier

this fails:

 SET @vPortalUID='2A66057D-F4E5-4E2B-B2F1-38C51A96D385'
 SET @nPortalUID = CAST(@vPortalUID AS uniqueidentifier)
 PRINT @nPortalUID

this works

 SET @vPortalUID='2A66057D-F4E5-4E2B-B2F1-38C51A96D385'
 PRINT @nPortalUID

the difference is NVARCHAR(36), your input parameter is too small!

how to refresh my datagridview after I add new data

This reloads the datagridview:


Hope this helps

SQLAlchemy IN clause

How about


edit: Without the ORM, it would be

        [,],, 456))

select() takes two parameters, the first one is a list of fields to retrieve, the second one is the where condition. You can access all fields on a table object via the c (or columns) property.

Switch android x86 screen resolution

Based on my experience, it's enough to use the following additional boot options:

UVESA_MODE=320x480 DPI=160

No need to add vga definition. Watch out for DPI value! As bigger one makes your icons bigger.

To add the previous boot options, go to debug mode (during grub menu selection)

mount -o remount,rw /mnt
vi /mnt/grub/menu.lst

Now edit on this line:

kernel /android-2.3-RC1/kernel quiet root=/dev/ram0 androidboot_hardware=eeepc acpi_sleep=s3_bios,s3_mode SRC=/android-2.3-RC1 SDCARD=/data/sdcard.img UVESA_MODE=320x480 DPI=160


How to initialize a struct in accordance with C programming language standards

void function(void) {
  MY_TYPE a;
  a.flag = true;
  a.value = 15;
  a.stuff = 0.123;

jQuery: How to detect window width on the fly?

Changing a variable doesn't magically execute code within the if-block. Place the common code in a function, then bind the event, and call the function:

$(document).ready(function() {
    // Optimalisation: Store the references outside the event handler:
    var $window = $(window);
    var $pane = $('#pane1');

    function checkWidth() {
        var windowsize = $window.width();
        if (windowsize > 440) {
            //if the window is greater than 440px wide then turn on jScrollPane..
    // Execute on load
    // Bind event listener

How to check a radio button with jQuery?

Short and easy to read option:


It returns true or false, so you can use it in "if" statement.

Remove menubar from Electron app

According to the official documentation @ the proper way to do this now since 7.1.2 and I have tested it on 8.0 as well is to :

const { app, Menu } = require('electron')


html5 input for money/currency

Using javascript's Number.prototype.toLocaleString:

var currencyInput = document.querySelector('input[type="currency"]')
var currency = 'GBP' //

 // format inital value

// bind event listeners
currencyInput.addEventListener('focus', onFocus)
currencyInput.addEventListener('blur', onBlur)

function localStringToNumber( s ){
  return Number(String(s).replace(/[^0-9.-]+/g,""))

function onFocus(e){
  var value =; = value ? localStringToNumber(value) : ''

function onBlur(e){
  var value =

  var options = {
      maximumFractionDigits : 2,
      currency              : currency,
      style                 : "currency",
      currencyDisplay       : "symbol"
  } = (value || value === 0) 
    ? localStringToNumber(value).toLocaleString(undefined, options)
    : ''
  padding: 10px;
  font: 20px Arial;
  width: 70%;
<input type='currency' value="123" placeholder='Type a number & click outside' />

Here's a very simple demo illustrating the above method (HTML-only)

I've made a tiny React component if anyone's interested

VLook-Up Match first 3 characters of one column with another column

=VLOOKUP(LEFT(A1,3),LEFT(B$2:B$22,3), 1,FALSE)

LEFT() truncates the first n character of a string, and you need to do it in both columns. The third parameter of VLOOKUP is the number of the column to return with. So if your range is not only B$2:B$22 but B$2:C$22 you can choose to return with column B value (1) or column C value (2)

Method List in Visual Studio Code

There's no such feature today, the CTRL+SHIFT+O == CTRL+P @ doesn't work for all languages.

As a last resort you can use the search panel - although it is not so fast an easy to use as you'd like - you can enter this regex in the search panel to find all functions:


How to escape double quotes in JSON

Try this:

"maingame": {
  "day1": {
    "text1": "Tag 1",
     "text2": "Heute startet unsere Rundreise \" Example text\". Jeden Tag wird ein neues Reiseziel angesteuert bis wir.</strong> "

(just one backslash (\) in front of quotes).

install / uninstall APKs programmatically (PackageManager vs Intents)

If you're using Kotlin, API 14+, and just wish to show uninstall dialog for your app:

startActivity(Intent(Intent.ACTION_UNINSTALL_PACKAGE).apply {
    data = Uri.parse("package:$packageName")

You can change packageName to any other package name if you want to prompt the user to uninstall another app on the device

pandas read_csv and filter columns with usecols

import csv first and use csv.DictReader its easy to process...

Array vs ArrayList in performance

When deciding to use Array or ArrayList, your first instinct really shouldn't be worrying about performance, though they do perform differently. You first concern should be whether or not you know the size of the Array before hand. If you don't, naturally you would go with an array list, just for functionality.