Programs & Examples On #Otp

OTP is a set of useful middle-ware, libraries and tools written in Erlang. It is an integral part of the open source distribution of Erlang. (For the one-time passwords, use [tag:one-time-password])

DeprecationWarning: Buffer() is deprecated due to security and usability issues when I move my script to another server

var userPasswordString = new Buffer(baseAuth, 'base64').toString('ascii');

Change this line from your code to this -

var userPasswordString = Buffer.from(baseAuth, 'base64').toString('ascii');

or in my case, I gave the encoding in reverse order

var userPasswordString = Buffer.from(baseAuth, 'utf-8').toString('base64');

Error : Program type already present:$Behavior

This can happens when one library is loaded into gradle several times. Most often through other connected libraries.

Remove a implementation this library in build.gradle

Then Build -> Clear project

and you can run the assembly)

ReferenceError: fetch is not defined

For those also using typescript on node-js and are getting a ReferenceError: fetch is not defined error

npm install these packages:

    "amazon-cognito-identity-js": "3.0.11"
    "node-fetch": "^2.3.0"

Then include:

import Global = NodeJS.Global;
export interface GlobalWithCognitoFix extends Global {
    fetch: any
declare const global: GlobalWithCognitoFix;
global.fetch = require('node-fetch');

Could not resolve in Android Studio new project

this work for me. add configurations.all in app/build.gradle

android {
    configurations.all {
        resolutionStrategy.force ''

No provider for HttpClient

I found slimier problem. Please import the HttpClientModule in your app.module.ts file as follow:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';

  declarations: [

imports: [
  providers: [],
  bootstrap: [AppComponent]
export class AppModule { }

Unable to merge dex

android {
    defaultConfig {
        minSdkVersion 15 
        targetSdkVersion 26
        multiDexEnabled true

dependencies {
  compile ''

Kubernetes Pod fails with CrashLoopBackOff

I faced similar issue "CrashLoopBackOff" when I debugged getting pods and logs of pod. Found out that my command arguments are wrong

Hide header in stack navigator React navigation

    options={{ headerShown: false }}

options={{ headerShown: false }} works for me.

** "@react-navigation/native": "^5.0.7", "@react-navigation/stack": "^5.0.8",

Could not find in circle ci

mtrakal's solution worked fine.

Added to

buildscript {
    repositories {
        maven { url '' }
    dependencies {
        classpath ''

        // NOTE: Do not place your application dependencies here; 
        // they belong in the individual module build.gradle files

allprojects {
    repositories {

Then it automatically upgraded to alpha2.

Invalidate the caches and restarted all is fine.

File | Invalidate Caches / Restart

choose 'Invalidate & Restart'

Error:Execution failed for task ':app:compileDebugKotlin'. > Compilation error. See log for more details

in my case I accidentally changed version="1.0" to xml version="1.0" in my XML file.

I only had to change it back.

if you have the same problem and the solutions above didn't work for you. open Gradle Console and scroll to Run with --debug option click it and it will show you more useful info about your error.

some notes:

this error doesn't appear directly after I make the change in XML it appear only after I change some java code. I think it has something to do with the instant run and build cash.

Android: Getting "Manifest merger failed" error after updating to a new version of gradle

I have updated old android project for the Wear OS. I have got this error message while build the project:

Manifest merger failed : Attribute value=(26.0.2) from [] AndroidManifest.xml:25:13-35
is also present at [] AndroidManifest.xml:28:13-35 value=(26.1.0).
Suggestion: add 'tools:replace="android:value"' to <meta-data> element at AndroidManifest.xml:23:9-25:38 to override.

My build.gradle for Wear app contains these dependencies:

dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation ''
implementation ''
compileOnly ''}


Adding implementation '' into the dependencies solved my problem.

REST API - Use the "Accept: application/json" HTTP Header

Well Curl could be a better option for json representation but in that case it would be difficult to understand the structure of json because its in command line. if you want to get your json on browser you simply remove all the XML Annotations like -


from your model class and than run the same url, you have used for xml representation.

Make sure that you have jacson-databind dependency in your pom.xml


Gradle error: Minimum supported Gradle version is 3.3. Current version is 3.2

Error Message: Gradle sync failed: Minimum supported Gradle version is 4.9. Current version is 4.1-milestone-1. If using the gradle wrapper, try editing the distributionUrl in SampleProj/app/gradle/wrapper/ to

I am using Android studio IDE version 3.2 beta 2.

Solution: When we open file in IDE it shows correct distributionUrl. but originally it has not been updated. So change the distributionUrl property manually.

Example : open a file in notepad or any other editor. /Project/app/gradle/wrapper/ and change distributionUrl property to like this


Error:Cause: unable to find valid certification path to requested target

Like a noob!

I was getting a nightmare with this and forgot that i've recently installed a new AV (Kaspersky)

So another solution is: Disable your AV or add exclusions to your AV firewall or proxy

hope it helps to save some time.

Laravel 5.4 redirection to custom url after login

  1. Go to Providers->RouteServiceProvider.php

  2. There change the route, given below:

    class RouteServiceProvider extends ServiceProvider
     protected $namespace = 'App\Http\Controllers';
      * The path to the "home" route for your application.
      * @var string
     public const HOME = '/dashboard';

Didn't find class ""?

I had the same error and I solved it with MultiDex, like described on this link :

Sometimes it is not enough just to enable MultiDex.

If any class that's required during startup is not provided in the primary DEX file, then your app crashes with the error java.lang.NoClassDefFoundError.

FirebaseInitProvider is required during startup.

So you must manually specify FirebaseInitProvider as required in the primary DEX file.

build.gradle file

android {
    buildTypes {
        release {
            multiDexKeepFile file('multidex-config.txt')

multidex-config.txt (in the same directory as the build.gradle file)


How do I access Configuration in any class in ASP.NET Core?

The right way to do it:

In .NET Core you can inject the IConfiguration as a parameter into your Class constructor, and it will be available.

public class MyClass 
    private IConfiguration configuration;
    public MyClass(IConfiguration configuration)
        ConnectionString = new configuration.GetValue<string>("ConnectionString");

Now, when you want to create an instance of your class, since your class gets injected the IConfiguration, you won't be able to just do new MyClass(), because it needs a IConfiguration parameter injected into the constructor, so, you will need to inject your class as well to the injecting chain, which means two simple steps:

1) Add your Class/es - where you want to use the IConfiguration, to the IServiceCollection at the ConfigureServices() method in Startup.cs


2) Define an instance - let's say in the Controller, and inject it using the constructor:

public class MyController : ControllerBase
    private MyClass _myClass;
    public MyController(MyClass myClass)
        _myClass = myClass;

Now you should be able to enjoy your _myClass.configuration freely...

Another option:

If you are still looking for a way to have it available without having to inject the classes into the controller, then you can store it in a static class, which you will configure in the Startup.cs, something like:

public static class MyAppData
    public static IConfiguration Configuration;

And your Startup constructor should look like this:

public Startup(IConfiguration configuration)
    Configuration = configuration;
    MyAppData.Configuration = configuration;

Then use MyAppData.Configuration anywhere in your program.

Don't confront me why the first option is the right way, I can just see experienced developers always avoid garbage data along their way, and it's well understood that it's not the best practice to have loads of data available in memory all the time, neither is it good for performance and nor for development, and perhaps it's also more secure to only have with you what you need.

How to upload a file and JSON data in Postman?

I needed to pass both: a file and an integer. I did it this way:

  1. needed to pass a file to upload: did it as per Sumit's answer.

    Request type : POST

    Body -> form-data

    under the heading KEY, entered the name of the variable ('file' in my backend code).

    in the backend:

    file = request.files['file']

    Next to 'file', there's a drop-down box which allows you to choose between 'File' or 'Text'. Chose 'File' and under the heading VALUE, 'Select files' appeared. Clicked on this which opened a window to select the file.

2. needed to pass an integer:

went to:


entered variable name (e.g.: id) under KEY and its value (e.g.: 1) under VALUE

in the backend:

id = request.args.get('id')


Could not find method android() for arguments

My issue was inside of my app.gradle. I ran into this issue when I moved

apply plugin: ""

from the top line to below a line with

apply from:

I switched the plugin back to the top and violá

My exact error was

Could not find method android() for arguments [dotenv_wke4apph61tdae6bfodqe7sj$_run_closure1@5d9d91a5] on project ':app' of type org.gradle.api.Project.

The top of my app.gradle now looks like this

project.ext.envConfigFiles = [
        debug: ".env",
        release: ".env",
        anothercustombuild: ".env",

apply from: project(':react-native-config').projectDir.getPath() + "/dotenv.gradle"
apply plugin: ""

Install pip in docker

This command worked fine for me:

RUN apt-get -y install python3-pip

Error: No toolchains found in the NDK toolchains folder for ABI with prefix: llvm

After looking around, the solution was to remove the NDK designation from my preferences.

Android Studio ? Preferences ? System Settings ? Android SDK ? SDK Tools ? Unselect NDK ? Apply button.

Project and Gradle compiled fine after that and I was able to move on with my project work.

As far as why this is happening, I do not know but for more info on NDK check out:

File URL "Not allowed to load local resource" in the Internet Browser

For people do not like to modify chrome's security options, we can simply start a python http server from directory which contains your local file:

python -m SimpleHTTPServer

and for python 3:

python3 -m http.server

Now you can reach any local file directly from your js code or externally with

OTP (token) should be automatically read from the message

I will recommend you not to use any third party libraries for auto fetch OTP from SMS Inbox. This can be done easily if you have basic understanding of Broadcast Receiver and how it works. Just Try following approach :

Step 1) Create single interface i.e SmsListner

package com.wnrcorp.reba;
public interface SmsListener{
public void messageReceived(String messageText);}

Step 2) Create single Broadcast Receiver i.e SmsReceiver

package com.wnrcorp.reba;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsMessage;
public class SmsReceiver extends BroadcastReceiver {
private static SmsListener mListener;
Boolean b;
String abcd,xyz;
public void onReceive(Context context, Intent intent) {
Bundle data  = intent.getExtras();
Object[] pdus = (Object[]) data.get("pdus");
    for(int i=0;i<pdus.length;i++){
        SmsMessage smsMessage = SmsMessage.createFromPdu((byte[]) pdus[i]);
        String sender = smsMessage.getDisplayOriginatingAddress();
       // b=sender.endsWith("WNRCRP");  //Just to fetch otp sent from WNRCRP
        String messageBody = smsMessage.getMessageBody();
       abcd=messageBody.replaceAll("[^0-9]","");   // here abcd contains otp 
        which is in number format
        //Pass on the text to our listener.
        if(b==true) {
            mListener.messageReceived(abcd);  // attach value to interface 
public static void bindListener(SmsListener listener) {
    mListener = listener;

Step 3) Add Listener i.e broadcast receiver in android manifest file

<receiver android:name=".SmsReceiver">    
            <action android:name="android.provider.Telephony.SMS_RECEIVED"/>

and add permission

<uses-permission android:name="android.permission.RECEIVE_SMS"/>

Final Step 4) The activity where you going to auto fetch otp when it is received in inbox. In my case I'm fetching otp and setting on edittext field.

public class OtpVerificationActivity extends AppCompatActivity {
EditText ed;
TextView tv;
String otp_generated,contactNo,id1;
GlobalData gd = new GlobalData();
protected void onCreate(Bundle savedInstanceState) {
    tv=(TextView) findViewById(; 
    /*This is important because this will be called every time you receive 
     any sms */            
 SmsReceiver.bindListener(new SmsListener() {
        public void messageReceived(String messageText) {
    tv.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
                InputMethodManager imm=
            catch(Exception e)
            if (ed.getText().toString().equals(otp_generated))
                Toast.makeText(OtpVerificationActivity.this, "OTP Verified 
       Successfully !", Toast.LENGTH_SHORT).show();           

Layout File for OtpVerificationActivity

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android=""
            android:text="OTP Confirmation"
            android:hint="OTP Here"

Screenshots for OTP Verification Activity where you fetch OTP as soons as messages received enter image description here

Graphviz's executables are not found (Python 3.4)

Please note that I am using windows 10. some of the following may or may not applicable for other versions of windows or operating systems:

** Note 2: **
"the Graphviz bin file address on your system" can be C:\Program Files (x86)\Graphviz2.38\bin or any other path you installed Graphviz there.

We have problem not only with Graphviz but also with other external EXE files we want to use in Jupyter.
The reason is when jupyter wants to import a package it looks in working directory to find it and when it fails to find the package it returns such errors.
What we can do is tackle this is as follows:
1) check if the Graphviz is installed on your system and if not you can download and install it from:
and then install it. When you installing Graphviz, keep in mind where (in which folder) you are installing it. If you see the above error when you use

import graphviz

then you have several options:

2) you can call the .exe file in the ipynb via

import os
os.environ["PATH"] += os.pathsep + r'the Graphviz bin file address on your system'

It is my experience that it is only works for the same ipynb that I am working with and every time that I open the notebook I need to call this lines of code.

3) If you want the Jupyter where to find the exe file, you need to set environmenal path.
In windows 10 you can do this going to:
Control Panel > System and Security > System > Advanced System Settings > Environment Variables > Path > Edit > New
and then add the "the Graphviz bin file address on your system" In windows 8 or lower go to :
Control Panel > System and Security > System > Advanced System Settings > Environment Variables
and then add the ;(semicolon) + "the Graphviz bin file address on your system" to the end of path string
Note: remember to restart your machine.

4) and even this does not work, define a variable going to:
Control Panel > System and Security > System > Advanced System Settings > Environment Variables and then:

Start to define an environmental variable

Then define a variable as this: Remember to name the variable Graphviz

Remember to name the variable Graphviz. At last restart your PC and hope it works.

How to give spacing between buttons using bootstrap

Depends on how much space you want. I'm not sure I agree with the logic of adding a "col-XX-1" in between each one, because you are then defining an entire "column" in between each one.

If you just want "a little spacing" in between each button, I like to add padding to the encompassing row. That way, I can still use all 12 columns, while including a "space" in between each button.


Bootstrap 3: How do you align column content to bottom of row

Vertical align bottom and remove the float seems to work. I then had a margin issue, but the -2px keeps them from getting pushed down (and they still don't overlap)

.profile-header > div {
  display: inline-block;
  vertical-align: bottom;
  float: none;
  margin: -2px;
.profile-header {
  border:2px solid green;
  display: table-cell;
.profile-pic {
  border:2px solid red;
.profile-about {
  border:2px solid blue;
.profile-about2 {
  border:2px solid pink;

Example here:

multiple plot in one figure in Python

Since I don't have a high enough reputation to comment I'll answer liang question on Feb 20 at 10:01 as an answer to the original question.

In order for the for the line labels to show you need to add plt.legend to your code. to build on the previous example above that also includes title, ylabel and xlabel:

import matplotlib.pyplot as plt

plt.plot(<X AXIS VALUES HERE>, <Y AXIS VALUES HERE>, 'line type', label='label here')
plt.plot(<X AXIS VALUES HERE>, <Y AXIS VALUES HERE>, 'line type', label='label here')

Transparent color of Bootstrap-3 Navbar

The class is .navbar-default. You need to create a class on your custom css .navbar-default.And follow the css code. Also if you don’t want box-shadow on your menu, you can put on the same class.

 .navbar-default {
      background-color:transparent !important;

enter image description here

To change font navbar color, the class is to change – .navbar-default .navbar-nav>li>a see the code bellow:

  .navbar-default .navbar-nav>li>a {

ref :

AngularJS- Login and Authentication in each route and controller

I feel like this way is easiest, but perhaps it's just personal preference.

When you specify your login route (and any other anonymous routes; ex: /register, /logout, /refreshToken, etc.), add:

allowAnonymous: true

So, something like this:

$stateProvider.state('login', {
    url: '/login',
    allowAnonymous: true, //if you move this, don't forget to update
                          //variable path in the force-page check.
    views: {
        root: {
            templateUrl: "app/auth/login/login.html",
            controller: 'LoginCtrl'
    //Any other config

You don't ever need to specify "allowAnonymous: false", if not present, it is assumed false, in the check. In an app where most URLs are force authenticated, this is less work. And safer; if you forget to add it to a new URL, the worst that can happen is an anonymous URL is protected. If you do it the other way, specifying "requireAuthentication: true", and you forget to add it to a URL, you are leaking a sensitive page to the public.

Then run this wherever you feel fits your code design best.

//I put it right after the main app module config. I.e. This thing:
angular.module('app', [ /* your dependencies*/ ])
       .config(function (/* you injections */) { /* your config */ })

//Make sure there's no ';' ending the previous line. We're chaining. (or just use a variable)
//Then force the logon page
.run(function ($rootScope, $state, $location, User /* My custom session obj */) {
    $rootScope.$on('$stateChangeStart', function(event, newState) {
        if (!User.authenticated && newState.allowAnonymous != true) {
            //Don't use: $state.go('login');
            //Apparently you can't set the $state while in a $state event.
            //It doesn't work properly. So we use the other way.

CSS property to pad text inside of div

I see a lot of answers here that have you subtracting from the width of the div and/or using box-sizing, but all you need to do is apply the padding the child elements of the div in question. So, for example, if you have some markup like this:

<div id="container">
    <p id="text">Find Agents</p>

All you need to do is apply this CSS:

#text {
    padding: 10px;

Here is a fiddle showing the difference:

Or, better yet, if you have multiple elements and don't feel like giving them all the same class, you can do something like this:

.container * {
    padding: 5px 10px;

Which will select all of the child elements and assign them the padding you want. Here is a fiddle of that in action:

Bootstrap 3 Styled Select dropdown looks ugly in Firefox on OS X

Building on the excellent answers by rafx and Sina, here is a snippet that only targets Firefox and replaces the default button with a down-caret copied from Bootstrap's icon theme.


default select


styled select

@-moz-document url-prefix() {
  select.form-control {
    padding-right: 25px;
    background-image: url("data:image/svg+xml,\
      <svg version='1.1' xmlns='' width='14px'\
           height='14px' viewBox='0 0 1200 1000' fill='rgb(51,51,51)'>\
        <path d='M1100 411l-198 -199l-353 353l-353 -353l-197 199l551 551z'/>\
    background-repeat: no-repeat;
    background-position: calc(100% - 7px) 50%;
    -moz-appearance: none;
    appearance: none;

(The inline SVG has backslashes and newlines for readability. Remove them if they cause trouble in your asset pipeline.)

Here is the JSFiddle

Bootstrap 3 collapse accordion: collapse all works but then cannot expand all while maintaining data-parent

To keep the accordion nature intact when wanting to also use 'hide' and 'show' functions like .collapse( 'hide' ), you must initialize the collapsible panels with the parent property set in the object with toggle: false before making any calls to 'hide' or 'show'

// initialize collapsible panels
$('#accordion .collapse').collapse({
  toggle: false,
  parent: '#accordion'

// show panel one (will collapse others in accordion)
$( '#collapseOne' ).collapse( 'show' );

// show panel two (will collapse others in accordion)
$( '#collapseTwo' ).collapse( 'show' );

// hide panel two (will not collapse/expand others in accordion)
$( '#collapseTwo' ).collapse( 'hide' );

PowerShell script to check the status of a URL

You can try this:

function Get-UrlStatusCode([string] $Url)
        (Invoke-WebRequest -Uri $Url -UseBasicParsing -DisableKeepAlive).StatusCode
    catch [Net.WebException]

$statusCode = Get-UrlStatusCode ''

Twitter Bootstrap 3, vertically center content

Option 1 is to use display:table-cell. You need to unfloat the Bootstrap col-* using float:none..

.center {

Option 2 is display:flex to vertical align the row with flexbox: {
   display: flex;
   align-items: center;

Vertical centering is very different in Bootstrap 4. See this answer for Bootstrap 4

Bootstrap 3 select input form inline

I know this is a bit old, but I had the same problem and my search brought me here. I wanted two select elements and a button all inline, which worked in 2 but not 3. I ended up wrapping the three elements in <form class="form-inline">...</form>. This actually worked perfectly for me.

Bootstrap 3 Multi-column within a single ul not floating properly

You should try using the Grid Template.

Here's what I've used for a two Column Layout of a <ul>

<ul class="list-group row">
     <li class="list-group-item col-xs-6">Row1</li>
     <li class="list-group-item col-xs-6">Row2</li>
     <li class="list-group-item col-xs-6">Row3</li>
     <li class="list-group-item col-xs-6">Row4</li>
     <li class="list-group-item col-xs-6">Row5</li>

This worked for me.

Bootstrap 3 - How to load content in modal body via AJAX?

A simple way to use modals is with eModal!

Ex from github:

  1. Link to eModal.js <script src="//"></script>
  2. use eModal to display a modal for alert, ajax, prompt or confirm

    // Display an alert modal with default title (Attention)

$(document).ready(function () {/* activate scroll spy menu */_x000D_
    var iconPrefix = '.glyphicon-';_x000D_
    $(iconPrefix + 'cloud').click(ajaxDemo);_x000D_
    $(iconPrefix + 'comment').click(alertDemo);_x000D_
    $(iconPrefix + 'ok').click(confirmDemo);_x000D_
    $(iconPrefix + 'pencil').click(promptDemo);_x000D_
    $(iconPrefix + 'screenshot').click(iframeDemo);_x000D_
    ///////////////////* Implementation *///////////////////_x000D_
    // Demos_x000D_
    function ajaxDemo() {_x000D_
        var title = 'Ajax modal';_x000D_
        var params = {_x000D_
            buttons: [_x000D_
               { text: 'Close', close: true, style: 'danger' },_x000D_
               { text: 'New content', close: false, style: 'success', click: ajaxDemo }_x000D_
            size: eModal.size.lg,_x000D_
            title: title,_x000D_
            url: '' + Math.floor((Math.random() * 7) + 1) + '/short/ul/bq/prude/code/decorete'_x000D_
        return eModal_x000D_
            .then(function () { alert('Ajax Request complete!!!!', title) });_x000D_
    function alertDemo() {_x000D_
        var title = 'Alert modal';_x000D_
        return eModal_x000D_
            .alert('You welcome! Want clean code ?', title)_x000D_
            .then(function () { alert('Alert modal is visible.', title); });_x000D_
    function confirmDemo() {_x000D_
        var title = 'Confirm modal callback feedback';_x000D_
        return eModal_x000D_
            .confirm('It is simple enough?', 'Confirm modal')_x000D_
            .then(function (/* DOM */) { alert('Thank you for your OK pressed!', title); })_x000D_
            .fail(function (/*null*/) { alert('Thank you for your Cancel pressed!', title) });_x000D_
    function iframeDemo() {_x000D_
        var title = 'Insiders';_x000D_
        return eModal_x000D_
            .iframe('', title)_x000D_
            .then(function () { alert('iFrame loaded!!!!', title) });_x000D_
    function promptDemo() {_x000D_
        var title = 'Prompt modal callback feedback';_x000D_
        return eModal_x000D_
            .prompt({ size:, message: 'What\'s your name?', title: title })_x000D_
            .then(function (input) { alert({ message: 'Hi ' + input + '!', title: title, imgURI: '' }) })_x000D_
            .fail(function (/**/) { alert('Why don\'t you tell me your name?', title); });_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<link href="" rel="stylesheet" >_x000D_
<link href="http//" rel="stylesheet">_x000D_
<div class="row" itemprop="about">_x000D_
 <div class="col-sm-1 text-center"></div>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10 text-center">_x000D_
    <p>You must get the message from a remote server? No problem!</p>_x000D_
    <i class="glyphicon glyphicon-cloud fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10 text-center">_x000D_
    <p>Traditional alert box. Using only text or a lot of magic!?</p>_x000D_
    <i class="glyphicon glyphicon-comment fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10 text-center">_x000D_
    <p>Get an okay from user, has never been so simple and clean!</p>_x000D_
    <i class="glyphicon glyphicon-ok fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10  text-center">_x000D_
    <p>Do you have a question for the user? We take care of it...</p>_x000D_
    <i class="glyphicon glyphicon-pencil fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-2 text-center">_x000D_
  <div class="row">_x000D_
   <div class="col-sm-10  text-center">_x000D_
    <p>IFrames are hard to deal with it? We don't think so!</p>_x000D_
    <i class="glyphicon glyphicon-screenshot fa-5x pointer" title="Try me!"></i>_x000D_
 <div class="col-sm-1 text-center"></div>_x000D_

Bootstrap radio button "checked" flag

Use active class with label to make it auto select and use checked="" .

   <label class="btn btn-primary  active" value="regular"  style="width:47%">
   <input  type="radio" name="service" checked=""  > Regular </label>
   <label class="btn btn-primary " value="express" style="width:46%">
   <input type="radio" name="service"> Express </label>

Bootstrap 3 panel header with buttons wrong position

In this case you should add .clearfix at the end of container with floated elements.

<div class="panel-heading">
    <h4>Panel header</h4>
    <div class="btn-group pull-right">
        <a href="#" class="btn btn-default btn-sm">## Lock</a>
        <a href="#" class="btn btn-default btn-sm">## Delete</a>
        <a href="#" class="btn btn-default btn-sm">## Move</a>
    <span class="clearfix"></span>

Carousel with Thumbnails in Bootstrap 3.0

Bootstrap 4 (update 2019)

A multi-item carousel can be accomplished in several ways as explained here. Another option is to use separate thumbnails to navigate the carousel slides.

Bootstrap 3 (original answer)

This can be done using the grid inside each carousel item.

       <div id="myCarousel" class="carousel slide">
                <div class="carousel-inner">
                    <div class="item active">
                        <div class="row">
                            <div class="col-sm-3">..
                            <div class="col-sm-3">..
                            <div class="col-sm-3">..
                            <div class="col-sm-3">..
                    ...add more item(s)

Demo example thumbnail slider using the carousel:

Another example with carousel indicators as thumbnails:

How to simulate POST request?

Simple way is to use curl from command-line, for example:

curl --data "$DATA" --request POST --header "Content-Type:application/x-www-form-urlencoded" | python -m json.tool

or here is example how to send raw POST request using Bash shell (JSON request):

exec 3<> /dev/tcp/

DATA='{"email": "[email protected]"}'
LEN=$(printf "$DATA" | wc -c)

cat >&3 << EOF
POST /api/retrieveInfo HTTP/1.1
User-Agent: Bash
Accept: */*
Content-Length: $LEN
Connection: close


# Read response.
while read line <&3; do
   echo $line

How to make bootstrap 3 fluid layout without horizontal scrollbar

You can add a 10px padding on the sides to your body element if all it's children are rows

body {
  padding: 0 10px;

if your HTML markup looks something like this:

    <div class="row"></div>
    <div class="row"></div>
    <div class="row"></div>

The rows have a 10 px negative margin. That's what's causing the overflow. If you add 10px padding to the body, they will cancel each other out.

Bootstrap 3 unable to display glyphicon properly

the icons and the css are now seperated out from bootstrap. here is a fiddle that is from another stackoverflow answer

@import url("//");

Bootstrap 3 Glyphicons CDN

How to use vertical align in bootstrap

Maybe an old topic but if someone needs further help with this do the following for example (this puts the text in middle line of image if it has larger height then the text).


<div class="row display-table">
    <div class="col-xs-12 col-sm-4 display-cell">
    <div class="col-xs-12 col-sm-8 display-cell">


    display: table;
    table-layout: fixed;

    display: table-cell;
    vertical-align: middle;
    float: none;

The important thing that I missed out on was "float: none;" since it got float left from bootstrap col attributes.


Options for embedding Chromium instead of IE WebBrowser control with WPF/C#

You've already listed the most notable solutions for embedding Chromium (CEF, Chrome Frame, Awesomium). There aren't any more projects that matter.

There is still the Berkelium project (see Berkelium Sharp and Berkelium Managed), but it emebeds an old version of Chromium.

CEF is your best bet - it's fully open source and frequently updated. It's the only option that allows you to embed the latest version of Chromium. Now that Per Lundberg is actively working on porting CEF 3 to CefSharp, this is the best option for the future. There is also Xilium.CefGlue, but this one provides a low level API for CEF, it binds to the C API of CEF. CefSharp on the other hand binds to the C++ API of CEF.

Adobe is not the only major player using CEF, see other notable applications using CEF on the CEF wikipedia page.

Updating Chrome Frame is pointless since the project has been retired.

DataTables warning: Requested unknown parameter '0' from the data source for row '0'

If someone is using the new DataTables (which is awesome btw) and want to use array of objects then you can do so easily with the columns option. Refer to the following link for an excellent example on this.

DataTables with Array of Objects

I was struggling with this for the past 2 days and this solved it. I didn't wanted to switch to multi-dimensional arrays for other code reasons so was looking for a solution like this.

Reading a text file using OpenFileDialog in windows forms

for this approach, you will need to add system.IO to your references by adding the next line of code below the other references near the top of the c# file(where the other using ****.** stand).

using System.IO;

this next code contains 2 methods of reading the text, the first will read single lines and stores them in a string variable, the second one reads the whole text and saves it in a string variable(including "\n" (enters))

both should be quite easy to understand and use.

    string pathToFile = "";//to save the location of the selected object
    private void openToolStripMenuItem_Click(object sender, EventArgs e)
        OpenFileDialog theDialog = new OpenFileDialog();
        theDialog.Title = "Open Text File";
        theDialog.Filter = "TXT files|*.txt";
        theDialog.InitialDirectory = @"C:\";
        if (theDialog.ShowDialog() == DialogResult.OK)
            pathToFile = theDialog.FileName;//doesn't need .tostring because .filename returns a string// saves the location of the selected object


        if (File.Exists(pathToFile))// only executes if the file at pathtofile exists//you need to add the using System.IO reference at the top of te code to use this
            string firstLine = File.ReadAllLines(pathToFile).Skip(0).Take(1).First();//selects first line of the file
            string secondLine = File.ReadAllLines(pathToFile).Skip(1).Take(1).First();

            string text = "";
            using(StreamReader sr =new StreamReader(pathToFile))
                text = sr.ReadToEnd();//all text wil be saved in text enters are also saved

To split the text you can use .Split(" ") and use a loop to put the name back into one string. if you don't want to use .Split() then you could also use foreach and ad an if statement to split it where needed.

to add the data to your class you can use the constructor to add the data like:

  public Employee(int EMPLOYEENUM, string NAME, string ADRESS, double WAGE, double HOURS)
            EmployeeNum = EMPLOYEENUM;
            Name = NAME;
            Address = ADRESS;
            Wage = WAGE;
            Hours = HOURS;

or you can add it using the set by typing .variablename after the name of the instance(if they are public and have a set this will work). to read the data you can use the get by typing .variablename after the name of the instance(if they are public and have a get this will work).

Getting Python error "from: can't read /var/mail/Bio"

No, it's not the script, it's the fact that your script is not executed by Python at all. If your script is stored in a file named, you have to execute it as python, otherwise the default shell will execute it and it will bail out at the from keyword. (Incidentally, from is the name of a command line utility which prints names of those who have sent mail to the given username, so that's why it tries to access the mailboxes).

Another possibility is to add the following line to the top of the script:

#!/usr/bin/env python

This will instruct your shell to execute the script via python instead of trying to interpret it on its own.

Spring,Request method 'POST' not supported

In Jsp:


In Controller

@RequestMapping(value = "proffessional", method = RequestMethod.POST)

Spelling MisMatch !

ldap_bind: Invalid Credentials (49)

I don't see an obvious problem with the above.

It's possible your ldap.conf is being overridden, but the command-line options will take precedence, ldapsearch will ignore BINDDN in the main ldap.conf, so the only parameter that could be wrong is the URI. (The order is ETCDIR/ldap.conf then ~/ldaprc or ~/.ldaprc and then ldaprc in the current directory, though there environment variables which can influence this too, see man ldapconf.)

Try an explicit URI:

ldapsearch -x -W -D 'cn=Manager,dc=example,dc=com' -b "" -s base -H ldap://localhost

or prevent defaults with:

LDAPNOINIT=1 ldapsearch -x -W -D 'cn=Manager,dc=example,dc=com' -b "" -s base

If that doesn't work, then some troubleshooting (you'll probably need the full path to the slapd binary for these):

  • make sure your slapd.conf is being used and is correct (as root)

    slapd -T test -f slapd.conf -d 65535

    You may have a left-over or default slapd.d configuration directory which takes preference over your slapd.conf (unless you specify your config explicitly with -f, slapd.conf is officially deprecated in OpenLDAP-2.4). If you don't get several pages of output then your binaries were built without debug support.

  • stop OpenLDAP, then manually start slapd in a separate terminal/console with debug enabled (as root, ^C to quit)

    slapd -h ldap://localhost -d 481

    then retry the search and see if you can spot the problem (there will be a lot of schema noise in the start of the output unfortunately). (Note: running slapd without the -u/-g options can change file ownerships which can cause problems, you should usually use those options, probably -u ldap -g ldap )

  • if debug is enabled, then try also

    ldapsearch -v -d 63 -W -D 'cn=Manager,dc=example,dc=com' -b "" -s base

java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)

As you are creating a database from scratch, you could use:

Connection connection = DriverManager.getConnection("jdbc:mysql://localhost/?user=root&password=rootpassword"); 
PreparedStatement ps = connection.prepareStatement("CREATE DATABASE databasename");
int result = ps.executeUpdate();

Here is an identical scenario.

Android Image View Pinch Zooming

Custom zoom view in Kotlin

 import android.content.Context
 import android.util.AttributeSet
 import android.util.Log
 import android.view.MotionEvent
 import android.view.ScaleGestureDetector
 import android.view.ScaleGestureDetector.SimpleOnScaleGestureListener
 import androidx.appcompat.widget.AppCompatImageView

 class ZoomImageview : AppCompatImageView {
var matri: Matrix? = null
var mode = NONE

// Remember some things for zooming
var last = PointF()
var start = PointF()
var minScale = 1f
var maxScale = 3f
lateinit var m: FloatArray
var viewWidth = 0
var viewHeight = 0
var saveScale = 1f
protected var origWidth = 0f
protected var origHeight = 0f
var oldMeasuredWidth = 0
var oldMeasuredHeight = 0
var mScaleDetector: ScaleGestureDetector? = null
var contex: Context? = null

constructor(context: Context) : super(context) {

constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {

private fun sharedConstructing(context: Context) {
    this.contex= context
    mScaleDetector = ScaleGestureDetector(context, ScaleListener())
    matri = Matrix()
    m = FloatArray(9)
    imageMatrix = matri
    scaleType = ScaleType.MATRIX
    setOnTouchListener { v, event ->
        val curr = PointF(event.x, event.y)
        when (event.action) {
            MotionEvent.ACTION_DOWN -> {
                mode = DRAG
            MotionEvent.ACTION_MOVE -> if (mode == DRAG) {
                val deltaX = curr.x - last.x
                val deltaY = curr.y - last.y
                val fixTransX = getFixDragTrans(deltaX, viewWidth.toFloat(), origWidth * saveScale)
                val fixTransY = getFixDragTrans(deltaY, viewHeight.toFloat(), origHeight * saveScale)
                matri!!.postTranslate(fixTransX, fixTransY)
                last[curr.x] = curr.y
            MotionEvent.ACTION_UP -> {
                mode = NONE
                val xDiff = Math.abs(curr.x - start.x).toInt()
                val yDiff = Math.abs(curr.y - start.y).toInt()
                if (xDiff < CLICK && yDiff < CLICK) performClick()
            MotionEvent.ACTION_POINTER_UP -> mode = NONE
        imageMatrix = matri
        true // indicate event was handled

fun setMaxZoom(x: Float) {
    maxScale = x

private inner class ScaleListener : SimpleOnScaleGestureListener() {
    override fun onScaleBegin(detector: ScaleGestureDetector): Boolean {
        mode = ZOOM
        return true

    override fun onScale(detector: ScaleGestureDetector): Boolean {
        var mScaleFactor = detector.scaleFactor
        val origScale = saveScale
        saveScale *= mScaleFactor
        if (saveScale > maxScale) {
            saveScale = maxScale
            mScaleFactor = maxScale / origScale
        } else if (saveScale < minScale) {
            saveScale = minScale
            mScaleFactor = minScale / origScale
        if (origWidth * saveScale <= viewWidth || origHeight * saveScale <= viewHeight) matri!!.postScale(mScaleFactor, mScaleFactor, viewWidth / 2.toFloat(), viewHeight / 2.toFloat()) else matri!!.postScale(mScaleFactor, mScaleFactor, detector.focusX, detector.focusY)
        return true

fun fixTrans() {
    val transX = m[Matrix.MTRANS_X]
    val transY = m[Matrix.MTRANS_Y]
    val fixTransX = getFixTrans(transX, viewWidth.toFloat(), origWidth * saveScale)
    val fixTransY = getFixTrans(transY, viewHeight.toFloat(), origHeight * saveScale)
    if (fixTransX != 0f || fixTransY != 0f) matri!!.postTranslate(fixTransX, fixTransY)

fun getFixTrans(trans: Float, viewSize: Float, contentSize: Float): Float {
    val minTrans: Float
    val maxTrans: Float
    if (contentSize <= viewSize) {
        minTrans = 0f
        maxTrans = viewSize - contentSize
    } else {
        minTrans = viewSize - contentSize
        maxTrans = 0f
    if (trans < minTrans) return -trans + minTrans
    if (trans > maxTrans) return -trans + maxTrans
    return 0f

fun getFixDragTrans(delta: Float, viewSize: Float, contentSize: Float): Float {
    if (contentSize <= viewSize) {
        return 0f
    } else {
        return delta

override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec)
    viewWidth = MeasureSpec.getSize(widthMeasureSpec)
    viewHeight = MeasureSpec.getSize(heightMeasureSpec)
    // Rescales image on rotation
    if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight || viewWidth == 0 || viewHeight == 0) return
    oldMeasuredHeight = viewHeight
    oldMeasuredWidth = viewWidth
    if (saveScale == 1f) {
        //Fit to screen.
        val scale: Float
        val drawable = drawable
        if (drawable == null || drawable.intrinsicWidth == 0 || drawable.intrinsicHeight == 0) return
        val bmWidth = drawable.intrinsicWidth
        val bmHeight = drawable.intrinsicHeight
        Log.d("bmSize", "bmWidth: $bmWidth bmHeight : $bmHeight")
        val scaleX = viewWidth.toFloat() / bmWidth.toFloat()
        val scaleY = viewHeight.toFloat() / bmHeight.toFloat()
        scale = Math.min(scaleX, scaleY)
        matri!!.setScale(scale, scale)
        // Center the image
        var redundantYSpace = viewHeight.toFloat() - scale * bmHeight.toFloat()
        var redundantXSpace = viewWidth.toFloat() - scale * bmWidth.toFloat()
        redundantYSpace /= 2.toFloat()
        redundantXSpace /= 2.toFloat()
        matri!!.postTranslate(redundantXSpace, redundantYSpace)
        origWidth = viewWidth - 2 * redundantXSpace
        origHeight = viewHeight - 2 * redundantYSpace
        imageMatrix = matri

companion object {
    // We can be in one of these 3 states
    const val NONE = 0
    const val DRAG = 1
    const val ZOOM = 2
    const val CLICK = 3

How to get the Parent's parent directory in Powershell?

Version for a directory

get-item is your friendly helping hand here.

(get-item $scriptPath ).parent.parent

If you Want the string only

(get-item $scriptPath ).parent.parent.FullName

Version for a file

If $scriptPath points to a file then you have to call Directory property on it first, so the call would look like this

(get-item $scriptPath).Directory.Parent.Parent.FullName

This will only work if $scriptPath exists. Otherwise you have to use Split-Path cmdlet.

Non-resolvable parent POM using Maven 3.0.3 and relativePath notation

For me, it works when I double checked the parent´s "group ID" and "artifact ID" that in my case were the wrong ones and that was the problem.

C# Iterate through Class properties

You could possibly use Reflection to do this. As far as I understand it, you could enumerate the properties of your class and set the values. You would have to try this out and make sure you understand the order of the properties though. Refer to this MSDN Documentation for more information on this approach.

For a hint, you could possibly do something like:

Record record = new Record();

PropertyInfo[] properties = typeof(Record).GetProperties();
foreach (PropertyInfo property in properties)
    property.SetValue(record, value);

Where value is the value you're wanting to write in (so from your resultItems array).

ORA-01008: not all variables bound. They are bound

I found how to run the query without error, but I hesitate to call it a "solution" without really understanding the underlying cause.

This more closely resembles the beginning of my actual query:

-- Comment
-- More comment
SELECT rf.flowrow, rf.stage, rf.process,
rf.instr instnum, rf.procedure_id, rtd_history.runtime, rtd_history.waittime
    -- Comment at beginning of subquery
    -- These two comment lines are the problem
    SELECT sub2.flowrow, sub2.stage, sub2.process, sub2.instr,
    FROM ( ...

The second set of comments above, at the beginning of the subquery, were the problem. When removed, the query executes. Other comments are fine. This is not a matter of some rogue or missing newline causing the following line to be commented, because the following line is a SELECT. A missing select would yield a different error than "not all variables bound."

I asked around and found one co-worker who has run into this -- comments causing query failures -- several times. Does anyone know how this can be the cause? It is my understanding that the very first thing a DBMS would do with comments is see if they contain hints, and if not, remove them during parsing. How can an ordinary comment containing no unusual characters (just letters and a period) cause an error? Bizarre.

Does Git Add have a verbose switch

I was debugging an issue with git and needed some very verbose output to figure out what was going wrong. I ended up setting the GIT_TRACE environment variable:

export GIT_TRACE=1
git add *.txt

You can also use these on the same line:

GIT_TRACE=1 git add *.txt


14:06:05.508517 git.c:415               trace: built-in: git add test.txt test2.txt
14:06:05.544890 git.c:415               trace: built-in: git config --get oh-my-zsh.hide-dirty

Passing parameters to a Bash function

There are two typical ways of declaring a function. I prefer the second approach.

function function_name {


function_name () {

To call a function with arguments:

function_name "$arg1" "$arg2"

The function refers to passed arguments by their position (not by name), that is $1, $2, and so forth. $0 is the name of the script itself.


function_name () {
   echo "Parameter #1 is $1"

Also, you need to call your function after it is declared.

#!/usr/bin/env sh

foo 1  # this will fail because foo has not been declared yet.

foo() {
    echo "Parameter #1 is $1"

foo 2 # this will work.


./ line 2: foo: command not found
Parameter #1 is 2

Reference: Advanced Bash-Scripting Guide.

matching query does not exist Error in Django

I also had this problem. It was caused by the development server not deleting the django session after a debug abort in Aptana, with subsequent database deletion. (Meaning the id of a non-existent database record was still present in the session the next time the development server started)

To resolve this during development, I used


Javascript Drag and drop for touch devices

Thanks for the above codes! - I tried several options and this was the ticket. I had problems in that preventDefault was preventing scrolling on the ipad - I am now testing for draggable items and it works great so far.

if ( == 'draggable_item' ) {

How to remove lines in a Matplotlib plot

I'm showing that a combination of lines.pop(0) l.remove() and del l does the trick.

from matplotlib import pyplot
import numpy, weakref
a = numpy.arange(int(1e3))
fig = pyplot.Figure()
ax  = fig.add_subplot(1, 1, 1)
lines = ax.plot(a)

l = lines.pop(0)
wl = weakref.ref(l)  # create a weak reference to see if references still exist
#                      to this object
print wl  # not dead
print wl  # not dead
del l
print wl  # dead  (remove either of the steps above and this is still live)

I checked your large dataset and the release of the memory is confirmed on the system monitor as well.

Of course the simpler way (when not trouble-shooting) would be to pop it from the list and call remove on the line object without creating a hard reference to it:


Mysql SELECT CASE WHEN something then return field

You are mixing the 2 different CASE syntaxes inappropriately.

Use this style (Searched)

  WHEN u.nnmu ='0' THEN mu.naziv_mesta
  WHEN u.nnmu ='1' THEN m.naziv_mesta
 END as mesto_utovara,

Or this style (Simple)

  CASE u.nnmu 
  WHEN '0' THEN mu.naziv_mesta
  WHEN '1' THEN m.naziv_mesta
 END as mesto_utovara,

Not This (Simple but with boolean search predicates)

  CASE u.nnmu 
  WHEN u.nnmu ='0' THEN mu.naziv_mesta
  WHEN u.nnmu ='1' THEN m.naziv_mesta
 END as mesto_utovara,

In MySQL this will end up testing whether u.nnmu is equal to the value of the boolean expression u.nnmu ='0' itself. Regardless of whether u.nnmu is 1 or 0 the result of the case expression itself will be 1

For example if nmu = '0' then (nnmu ='0') evaluates as true (1) and (nnmu ='1') evaluates as false (0). Substituting these into the case expression gives

  WHEN 1 THEN '0'
  WHEN 0 THEN '1'
 END as mesto_utovara

if nmu = '1' then (nnmu ='0') evaluates as false (0) and (nnmu ='1') evaluates as true (1). Substituting these into the case expression gives

  WHEN 0 THEN '0'
  WHEN 1 THEN '1'
 END as mesto_utovara

Address already in use: JVM_Bind

I notice you are using windows, which is particularly bad about using low port numbers for outgoing sockets. See here for how to reserve the port number that you want to rely on using for glassfish.

Assert that a WebElement is not present using Selenium WebDriver with java

For node.js I've found the following to be effective way to wait for an element to no longer be present:

// variable to hold loop limit
    var limit = 5;
// variable to hold the loop count
    var tries = 0;
        var retry = driver.findElements(By.xpath(selector));
            while(retry.size > 0 && tries < limit){
                driver.sleep(timeout / 10)
                retry = driver.findElements(By.xpath(selector))

Clang vs GCC - which produces faster binaries?

Basically speaking, the answer is: it depends. There are many many benchmarks focusing on different kinds of application.

My benchmark on my app is: gcc > icc > clang.

There are rare IO, but many CPU float and data structure operations.

compile flags is -Wall -g -DNDEBUG -O3.

Something better than .NET Reflector?

Instead of using the autoupdater, we just set the properties of the EXE file to read-only. That way it doesn’t delete the file.

Static linking vs dynamic linking

On Unix-like systems, dynamic linking can make life difficult for 'root' to use an application with the shared libraries installed in out-of-the-way locations. This is because the dynamic linker generally won't pay attention to LD_LIBRARY_PATH or its equivalent for processes with root privileges. Sometimes, then, static linking saves the day.

Alternatively, the installation process has to locate the libraries, but that can make it difficult for multiple versions of the software to coexist on the machine.

How to decrypt an encrypted Apple iTunes iPhone backup?

Security researchers Jean-Baptiste Bédrune and Jean Sigwald presented how to do this at Hack-in-the-box Amsterdam 2011.

Since then, Apple has released an iOS Security Whitepaper with more details about keys and algorithms, and Charlie Miller et al. have released the iOS Hacker’s Handbook, which covers some of the same ground in a how-to fashion. When iOS 10 first came out there were changes to the backup format which Apple did not publicize at first, but various people reverse-engineered the format changes.

Encrypted backups are great

The great thing about encrypted iPhone backups is that they contain things like WiFi passwords that aren’t in regular unencrypted backups. As discussed in the iOS Security Whitepaper, encrypted backups are considered more “secure,” so Apple considers it ok to include more sensitive information in them.

An important warning: obviously, decrypting your iOS device’s backup removes its encryption. To protect your privacy and security, you should only run these scripts on a machine with full-disk encryption. While it is possible for a security expert to write software that protects keys in memory, e.g. by using functions like VirtualLock() and SecureZeroMemory() among many other things, these Python scripts will store your encryption keys and passwords in strings to be garbage-collected by Python. This means your secret keys and passwords will live in RAM for a while, from whence they will leak into your swap file and onto your disk, where an adversary can recover them. This completely defeats the point of having an encrypted backup.

How to decrypt backups: in theory

The iOS Security Whitepaper explains the fundamental concepts of per-file keys, protection classes, protection class keys, and keybags better than I can. If you’re not already familiar with these, take a few minutes to read the relevant parts.

Now you know that every file in iOS is encrypted with its own random per-file encryption key, belongs to a protection class, and the per-file encryption keys are stored in the filesystem metadata, wrapped in the protection class key.

To decrypt:

  1. Decode the keybag stored in the BackupKeyBag entry of Manifest.plist. A high-level overview of this structure is given in the whitepaper. The iPhone Wiki describes the binary format: a 4-byte string type field, a 4-byte big-endian length field, and then the value itself.

    The important values are the PBKDF2 ITERations and SALT, the double protection salt DPSL and iteration count DPIC, and then for each protection CLS, the WPKY wrapped key.

  2. Using the backup password derive a 32-byte key using the correct PBKDF2 salt and number of iterations. First use a SHA256 round with DPSL and DPIC, then a SHA1 round with ITER and SALT.

    Unwrap each wrapped key according to RFC 3394.

  3. Decrypt the manifest database by pulling the 4-byte protection class and longer key from the ManifestKey in Manifest.plist, and unwrapping it. You now have a SQLite database with all file metadata.

  4. For each file of interest, get the class-encrypted per-file encryption key and protection class code by looking in the Files.file database column for a binary plist containing EncryptionKey and ProtectionClass entries. Strip the initial four-byte length tag from EncryptionKey before using.

    Then, derive the final decryption key by unwrapping it with the class key that was unwrapped with the backup password. Then decrypt the file using AES in CBC mode with a zero IV.

How to decrypt backups: in practice

First you’ll need some library dependencies. If you’re on a mac using a homebrew-installed Python 2.7 or 3.7, you can install the dependencies with:

CFLAGS="-I$(brew --prefix)/opt/openssl/include" \
LDFLAGS="-L$(brew --prefix)/opt/openssl/lib" \    
    pip install biplist fastpbkdf2 pycrypto

In runnable source code form, here is how to decrypt a single preferences file from an encrypted iPhone backup:

#!/usr/bin/env python3.7
# coding: UTF-8

from __future__ import print_function
from __future__ import division

import argparse
import getpass
import os.path
import pprint
import random
import shutil
import sqlite3
import string
import struct
import tempfile
from binascii import hexlify

import Crypto.Cipher.AES #
import biplist
import fastpbkdf2
from biplist import InvalidPlistException

def main():
    ## Parse options
    parser = argparse.ArgumentParser()
    parser.add_argument('--backup-directory', dest='backup_directory',
    parser.add_argument('--password-pipe', dest='password_pipe',
Keeps password from being visible in system process list.
Typical use: --password-pipe=<(echo -n foo)
    parser.add_argument('--no-anonymize-output', dest='anonymize',
    args = parser.parse_args()
    ANONYMIZE_OUTPUT = args.anonymize
        print('Warning: All output keys are FAKE to protect your privacy')

    manifest_file = os.path.join(args.backup_directory, 'Manifest.plist')
    with open(manifest_file, 'rb') as infile:
        manifest_plist = biplist.readPlist(infile)
    keybag = Keybag(manifest_plist['BackupKeyBag'])
    # the actual keys are unknown, but the wrapped keys are known

    if args.password_pipe:
        password = readpipe(args.password_pipe)
        if password.endswith(b'\n'):
            password = password[:-1]
        password = getpass.getpass('Backup password: ').encode('utf-8')

    ## Unlock keybag with password
    if not keybag.unlockWithPasscode(password):
        raise Exception('Could not unlock keybag; bad password?')
    # now the keys are known too

    ## Decrypt metadata DB
    manifest_key = manifest_plist['ManifestKey'][4:]
    with open(os.path.join(args.backup_directory, 'Manifest.db'), 'rb') as db:
        encrypted_db =

    manifest_class = struct.unpack('<l', manifest_plist['ManifestKey'][:4])[0]
    key = keybag.unwrapKeyForClass(manifest_class, manifest_key)
    decrypted_data = AESdecryptCBC(encrypted_db, key)

    temp_dir = tempfile.mkdtemp()
        # Does anyone know how to get Python’s SQLite module to open some
        # bytes in memory as a database?
        db_filename = os.path.join(temp_dir, 'db.sqlite3')
        with open(db_filename, 'wb') as db_file:
        conn = sqlite3.connect(db_filename)
        conn.row_factory = sqlite3.Row
        c = conn.cursor()
        # c.execute("select * from Files limit 1");
        # r = c.fetchone()
            SELECT fileID, domain, relativePath, file
            FROM Files
            WHERE relativePath LIKE 'Media/PhotoData/MISC/DCIM_APPLE.plist'
            ORDER BY domain, relativePath""")
        results = c.fetchall()

    for item in results:
        fileID, domain, relativePath, file_bplist = item

        plist = biplist.readPlistFromString(file_bplist)
        file_data = plist['$objects'][plist['$top']['root'].integer]
        size = file_data['Size']

        protection_class = file_data['ProtectionClass']
        encryption_key = plist['$objects'][

        backup_filename = os.path.join(args.backup_directory,
                                    fileID[:2], fileID)
        with open(backup_filename, 'rb') as infile:
            data =
            key = keybag.unwrapKeyForClass(protection_class, encryption_key)
            # truncate to actual length, as encryption may introduce padding
            decrypted_data = AESdecryptCBC(data, key)[:size]

        print('== decrypted data:')

        print('== pretty-printed plist')

# this section is mostly copied from parts of iphone-dataprotection

KEYBAG_TYPES = ["System", "Backup", "Escrow", "OTA (icloud)"]
KEY_TYPES = ["AES", "Curve25519"]

    6: "kSecAttrAccessibleWhenUnlocked",
    7: "kSecAttrAccessibleAfterFirstUnlock",
    8: "kSecAttrAccessibleAlways",
    9: "kSecAttrAccessibleWhenUnlockedThisDeviceOnly",
    10: "kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly",
    11: "kSecAttrAccessibleAlwaysThisDeviceOnly"

class Keybag(object):
    def __init__(self, data):
        self.type = None
        self.uuid = None
        self.wrap = None
        self.deviceKey = None
        self.attrs = {}
        self.classKeys = {}
        self.KeyBagKeys = None #DATASIGN blob

    def parseBinaryBlob(self, data):
        currentClassKey = None

        for tag, data in loopTLVBlocks(data):
            if len(data) == 4:
                data = struct.unpack(">L", data)[0]
            if tag == b"TYPE":
                self.type = data
                if self.type > 3:
                    print("FAIL: keybag type > 3 : %d" % self.type)
            elif tag == b"UUID" and self.uuid is None:
                self.uuid = data
            elif tag == b"WRAP" and self.wrap is None:
                self.wrap = data
            elif tag == b"UUID":
                if currentClassKey:
                    self.classKeys[currentClassKey[b"CLAS"]] = currentClassKey
                currentClassKey = {b"UUID": data}
            elif tag in CLASSKEY_TAGS:
                currentClassKey[tag] = data
                self.attrs[tag] = data
        if currentClassKey:
            self.classKeys[currentClassKey[b"CLAS"]] = currentClassKey

    def unlockWithPasscode(self, passcode):
        passcode1 = fastpbkdf2.pbkdf2_hmac('sha256', passcode,
                                        self.attrs[b"DPIC"], 32)
        passcode_key = fastpbkdf2.pbkdf2_hmac('sha1', passcode1,
                                            self.attrs[b"ITER"], 32)
        print('== Passcode key')
        for classkey in self.classKeys.values():
            if b"WPKY" not in classkey:
            k = classkey[b"WPKY"]
            if classkey[b"WRAP"] & WRAP_PASSCODE:
                k = AESUnwrap(passcode_key, classkey[b"WPKY"])
                if not k:
                    return False
                classkey[b"KEY"] = k
        return True

    def unwrapKeyForClass(self, protection_class, persistent_key):
        ck = self.classKeys[protection_class][b"KEY"]
        if len(persistent_key) != 0x28:
            raise Exception("Invalid key length")
        return AESUnwrap(ck, persistent_key)

    def printClassKeys(self):
        print("== Keybag")
        print("Keybag type: %s keybag (%d)" % (KEYBAG_TYPES[self.type], self.type))
        print("Keybag version: %d" % self.attrs[b"VERS"])
        print("Keybag UUID: %s" % anonymize(hexlify(self.uuid)))
                    "Public key"]))
        for k, ck in self.classKeys.items():
            if k == 6:print("")

                anonymize(hexlify(ck.get(b"KEY", b""))).ljust(65),
                anonymize(hexlify(ck.get(b"WPKY", b""))).ljust(65),

def loopTLVBlocks(blob):
    i = 0
    while i + 8 <= len(blob):
        tag = blob[i:i+4]
        length = struct.unpack(">L",blob[i+4:i+8])[0]
        data = blob[i+8:i+8+length]
        yield (tag,data)
        i += 8 + length

def unpack64bit(s):
    return struct.unpack(">Q",s)[0]
def pack64bit(s):
    return struct.pack(">Q",s)

def AESUnwrap(kek, wrapped):
    C = []
    for i in range(len(wrapped)//8):
    n = len(C) - 1
    R = [0] * (n+1)
    A = C[0]

    for i in range(1,n+1):
        R[i] = C[i]

    for j in reversed(range(0,6)):
        for i in reversed(range(1,n+1)):
            todec = pack64bit(A ^ (n*j+i))
            todec += pack64bit(R[i])
            B =
            A = unpack64bit(B[:8])
            R[i] = unpack64bit(B[8:])

    if A != 0xa6a6a6a6a6a6a6a6:
        return None
    res = b"".join(map(pack64bit, R[1:]))
    return res

ZEROIV = "\x00"*16
def AESdecryptCBC(data, key, iv=ZEROIV, padding=False):
    if len(data) % 16:
        print("AESdecryptCBC: data length not /16, truncating")
        data = data[0:(len(data)/16) * 16]
    data =, Crypto.Cipher.AES.MODE_CBC, iv).decrypt(data)
    if padding:
        return removePadding(16, data)
    return data

# here are some utility functions, one making sure I don’t leak my
# secret keys when posting the output on Stack Exchange

anon_random = random.Random(0)
memo = {}
def anonymize(s):
    if type(s) == str:
        s = s.encode('utf-8')
    global anon_random, memo
        if s in memo:
            return memo[s]
        possible_alphabets = [
            string.digits + 'abcdef',
            "".join(chr(x) for x in range(0, 256)),
        for a in possible_alphabets:
            if all((chr(c) if type(c) == int else c) in a for c in s):
                alphabet = a
        ret = "".join([anon_random.choice(alphabet) for i in range(len(s))])
        memo[s] = ret
        return ret
        return s

def wrap(s, width=78):
    "Return a width-wrapped repr(s)-like string without breaking on \’s"
    s = repr(s)
    quote = s[0]
    s = s[1:-1]
    ret = []
    while len(s):
        i = s.rfind('\\', 0, width)
        if i <= width - 4: # "\x??" is four characters
            i = width
        s = s[i:]
    return '\n'.join("%s%s%s" % (quote, line ,quote) for line in ret)

def readpipe(path):
    if stat.S_ISFIFO(os.stat(path).st_mode):
        with open(path, 'rb') as pipe:
        raise Exception("Not a pipe: {!r}".format(path))

if __name__ == '__main__':

Which then prints this output:

Warning: All output keys are FAKE to protect your privacy
== Keybag
Keybag type: Backup keybag (1)
Keybag version: 3
Keybag UUID: dc6486c479e84c94efce4bea7169ef7d
Class                                                WRAP Type       Key                                                              WPKY                                                             Public key
NSFileProtectionComplete                             2    AES                                                                         4c80b6da07d35d393fc7158e18b8d8f9979694329a71ceedee86b4cde9f97afec197ad3b13c5d12b
NSFileProtectionCompleteUnlessOpen                   2    AES                                                                         09e8a0a9965f00f213ce06143a52801f35bde2af0ad54972769845d480b5043f545fa9b66a0353a6
NSFileProtectionCompleteUntilFirstUserAuthentication 2    AES                                                                         e966b6a0742878ce747cec3fa1bf6a53b0d811ad4f1d6147cd28a5d400a8ffe0bbabea5839025cb5
NSFileProtectionNone                                 2    AES                                                                         902f46847302816561e7df57b64beea6fa11b0068779a65f4c651dbe7a1630f323682ff26ae7e577
NSFileProtectionRecovery?                            3    AES                                                                         a3935fed024cd9bc11d0300d522af8e89accfbe389d7c69dca02841df46c0a24d0067dba2f696072

kSecAttrAccessibleWhenUnlocked                       2    AES                                                                         09a1856c7e97a51a9c2ecedac8c3c7c7c10e7efa931decb64169ee61cb07a0efb115050fd1e33af1
kSecAttrAccessibleAfterFirstUnlock                   2    AES                                                                         0509d215f2f574efa2f192efc53c460201168b26a175f066b5347fc48bc76c637e27a730b904ca82
kSecAttrAccessibleAlways                             2    AES                                                                         b7ac3c4f1e04896144ce90c4583e26489a86a6cc45a2b692a5767b5a04b0907e081daba009fdbb3c
kSecAttrAccessibleWhenUnlockedThisDeviceOnly         3    AES                                                                         417526e67b82e7c6c633f9063120a299b84e57a8ffee97b34020a2caf6e751ec5750053833ab4d45
kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly     3    AES                                                                         b0e17b0cf7111c6e716cd0272de5684834798431c1b34bab8d1a1b5aba3d38a3a42c859026f81ccc
kSecAttrAccessibleAlwaysThisDeviceOnly               3    AES                                                                         9b3bdc59ae1d85703aa7f75d49bdc600bf57ba4a458b20a003a10f6e36525fb6648ba70e6602d8b2

== Passcode key

== Keybag
Keybag type: Backup keybag (1)
Keybag version: 3
Keybag UUID: dc6486c479e84c94efce4bea7169ef7d
Class                                                WRAP Type       Key                                                              WPKY                                                             Public key
NSFileProtectionComplete                             2    AES        64e8fc94a7b670b0a9c4a385ff395fe9ba5ee5b0d9f5a5c9f0202ef7fdcb386f 4c80b6da07d35d393fc7158e18b8d8f9979694329a71ceedee86b4cde9f97afec197ad3b13c5d12b
NSFileProtectionCompleteUnlessOpen                   2    AES        22a218c9c446fbf88f3ccdc2ae95f869c308faaa7b3e4fe17b78cbf2eeaf4ec9 09e8a0a9965f00f213ce06143a52801f35bde2af0ad54972769845d480b5043f545fa9b66a0353a6
NSFileProtectionCompleteUntilFirstUserAuthentication 2    AES        1004c6ca6e07d2b507809503180edf5efc4a9640227ac0d08baf5918d34b44ef e966b6a0742878ce747cec3fa1bf6a53b0d811ad4f1d6147cd28a5d400a8ffe0bbabea5839025cb5
NSFileProtectionNone                                 2    AES        2e809a0cd1a73725a788d5d1657d8fd150b0e360460cb5d105eca9c60c365152 902f46847302816561e7df57b64beea6fa11b0068779a65f4c651dbe7a1630f323682ff26ae7e577
NSFileProtectionRecovery?                            3    AES        9a078d710dcd4a1d5f70ea4062822ea3e9f7ea034233e7e290e06cf0d80c19ca a3935fed024cd9bc11d0300d522af8e89accfbe389d7c69dca02841df46c0a24d0067dba2f696072

kSecAttrAccessibleWhenUnlocked                       2    AES        606e5328816af66736a69dfe5097305cf1e0b06d6eb92569f48e5acac3f294a4 09a1856c7e97a51a9c2ecedac8c3c7c7c10e7efa931decb64169ee61cb07a0efb115050fd1e33af1
kSecAttrAccessibleAfterFirstUnlock                   2    AES        6a4b5292661bac882338d5ebb51fd6de585befb4ef5f8ffda209be8ba3af1b96 0509d215f2f574efa2f192efc53c460201168b26a175f066b5347fc48bc76c637e27a730b904ca82
kSecAttrAccessibleAlways                             2    AES        c0ed717947ce8d1de2dde893b6026e9ee1958771d7a7282dd2116f84312c2dd2 b7ac3c4f1e04896144ce90c4583e26489a86a6cc45a2b692a5767b5a04b0907e081daba009fdbb3c
kSecAttrAccessibleWhenUnlockedThisDeviceOnly         3    AES        80d8c7be8d5103d437f8519356c3eb7e562c687a5e656cfd747532f71668ff99 417526e67b82e7c6c633f9063120a299b84e57a8ffee97b34020a2caf6e751ec5750053833ab4d45
kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly     3    AES        a875a15e3ff901351c5306019e3b30ed123e6c66c949bdaa91fb4b9a69a3811e b0e17b0cf7111c6e716cd0272de5684834798431c1b34bab8d1a1b5aba3d38a3a42c859026f81ccc
kSecAttrAccessibleAlwaysThisDeviceOnly               3    AES        1e7756695d337e0b06c764734a9ef8148af20dcc7a636ccfea8b2eb96a9e9373 9b3bdc59ae1d85703aa7f75d49bdc600bf57ba4a458b20a003a10f6e36525fb6648ba70e6602d8b2

== decrypted data:
'<?xml version="1.0" encoding="UTF-8"?>\n<!DOCTYPE plist PUBLIC "-//Apple//DTD '
'PLIST 1.0//EN" "">\n<plist versi'

== pretty-printed plist
{'DCIMLastDirectoryNumber': 100, 'DCIMLastFileNumber': 3}

Extra credit

The iphone-dataprotection code posted by Bédrune and Sigwald can decrypt the keychain from a backup, including fun things like saved wifi and website passwords:

$ python iphone-dataprotection/python_scripts/ ...

|                              Passwords                                             |
|Service           |Account          |Data           |Access group  |Protection class|
|AirPort           |Ed’s Coffee Shop |<3FrenchRoast  |apple         |AfterFirstUnlock|

That code no longer works on backups from phones using the latest iOS, but there are some golang ports that have been kept up to date allowing access to the keychain.

How can I programmatically check whether a keyboard is present in iOS app?

Swift implementation:

class KeyboardStateListener: NSObject
  static var shared = KeyboardStateListener()
  var isVisible = false

  func start() {
    let nc = NSNotificationCenter.defaultCenter()
    nc.addObserver(self, selector: #selector(didShow), name: UIKeyboardDidShowNotification, object: nil)
    nc.addObserver(self, selector: #selector(didHide), name: UIKeyboardDidHideNotification, object: nil)

  func didShow()
    isVisible = true

  func didHide()
    isVisible = false

Because swift doesn't execute class load method on startup it is important to start this service on app launch:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject : AnyObject]?) -> Bool

Java Swing - how to show a panel on top of another panel?

JOptionPane.showInternalInputDialog probably does what you want. If not, it would be helpful to understand what it is missing.

SQL Server Text type vs. varchar data type

There has been some major changes in ms 2008 -> Might be worth considering the following article when making a decisions on what data type to use.

Bytes per

  1. varchar(max), varbinary(max), xml, text, or image column 2^31-1 2^31-1
  2. nvarchar(max) column 2^30-1 2^30-1

When should I use a struct rather than a class in C#?

The C# struct is a lightweight alternative to a class. It can do almost the same as a class, but it's less "expensive" to use a struct rather than a class. The reason for this is a bit technical, but to sum up, new instances of a class is placed on the heap, where newly instantiated structs are placed on the stack. Furthermore, you are not dealing with references to structs, like with classes, but instead you are working directly with the struct instance. This also means that when you pass a struct to a function, it is by value, instead of as a reference. There is more about this in the chapter about function parameters.

So, you should use structs when you wish to represent more simple data structures, and especially if you know that you will be instantiating lots of them. There are lots of examples in the .NET framework, where Microsoft has used structs instead of classes, for instance the Point, Rectangle and Color struct.

Local file access with JavaScript

If the user selects a file via <input type="file">, you can read and process that file using the File API.

Reading or writing arbitrary files is not allowed by design. It's a violation of the sandbox. From Wikipedia -> Javascript -> Security:

JavaScript and the DOM provide the potential for malicious authors to deliver scripts to run on a client computer via the web. Browser authors contain this risk using two restrictions. First, scripts run in a sandbox in which they can only perform web-related actions, not general-purpose programming tasks like creating files.

2016 UPDATE: Accessing the filesystem directly is possible via the Filesystem API, which is only supported by Chrome and Opera and may end up not being implemented by other browsers (with the exception of Edge). For details see Kevin's answer.

.NET data structures: ArrayList, List, HashTable, Dictionary, SortedList, SortedDictionary -- Speed, memory, and when to use each?

First, all collections in .NET implement IEnumerable.

Second, a lot of the collections are duplicates because generics were added in version 2.0 of the framework.

So, although the generic collections likely add features, for the most part:

  • List is a generic implementation of ArrayList.
  • Dictionary is a generic implementation of Hashtable

Arrays are a fixed size collection that you can change the value stored at a given index.

SortedDictionary is an IDictionary that is sorted based on the keys. SortedList is an IDictionary that is sorted based on a required IComparer.

So, the IDictionary implementations (those supporting KeyValuePairs) are: * Hashtable * Dictionary * SortedList * SortedDictionary

Another collection that was added in .NET 3.5 is the Hashset. It is a collection that supports set operations.

Also, the LinkedList is a standard linked-list implementation (the List is an array-list for faster retrieval).

Good Free Alternative To MS Access

I'd the same problem of you. I had a MS access application but I wanted to go to a web application accessible to everybody and without paying money to MS. So I decided to use MySql and Wavemaker (open source) to get the scope..I'm very happy of this decision. and that's the result

how to query for a list<String> in jdbctemplate

Is there a way to have placeholders, like ? for column names? For example SELECT ? FROM TABLEA GROUP BY ?

Use dynamic query as below:

String queryString = "SELECT "+ colName+ " FROM TABLEA GROUP BY "+ colName;

If I want to simply run the above query and get a List what is the best way?

List<String> data = getJdbcTemplate().query(query, new RowMapper<String>(){
                            public String mapRow(ResultSet rs, int rowNum) 
                                                         throws SQLException {
                                    return rs.getString(1);

EDIT: To Stop SQL Injection, check for non word characters in the colName as :

          Pattern pattern = Pattern.compile("\\W");
               //throw exception as invalid column name

Removing spaces from a variable input using PowerShell 4.0

You can use:

$answer.replace(' ' , '')


$answer -replace " ", ""

if you want to remove all whitespace you can use:

$answer -replace "\s", ""

Indent multiple lines quickly in vi

Go to the start of the text

  • press v for visual mode.
  • use up/down arrow to highlight text.
  • press = to indent all the lines you highlighted.

JUnit assertEquals(double expected, double actual, double epsilon)

Epsilon is your "fuzz factor," since doubles may not be exactly equal. Epsilon lets you describe how close they have to be.

If you were expecting 3.14159 but would take anywhere from 3.14059 to 3.14259 (that is, within 0.001), then you should write something like

double myPi = 22.0d / 7.0d; //Don't use this in real life!
assertEquals(3.14159, myPi, 0.001);

(By the way, 22/7 comes out to 3.1428+, and would fail the assertion. This is a good thing.)

Android: Proper Way to use onBackPressed() with Toast

You may also need to reset counter in onPause to prevent cases when user presses home or navigates away by some other means after first back press. Otherwise, I don't see an issue.

What exactly does a jar file contain?

A .jar file is akin to a .exe file. In essence, they are both executable zip files (different zip algorithms).

In a jar file, you will see folders and class files. Each class file is similar to your .o file, and is a compiled java archive.

If you wanted to see the code in a jar file, download a java decompiler (located here: and a .jar extractor (7zip works fine).

How to filter an array from all elements of another array

All the above solutions "work", but are less than optimal for performance and are all approach the problem in the same way which is linearly searching all entries at each point using Array.prototype.indexOf or Array.prototype.includes. A far faster solution (far faster even than a binary search for most cases) would be to sort the arrays and skip ahead as you go along as seen below. However, one downside is that this requires all entries in the array to be numbers or strings. Also however, binary search may in some rare cases be faster than the progressive linear search. These cases arise from the fact that my progressive linear search has a complexity of O(2n1+n2) (only O(n1+n2) in the faster C/C++ version) (where n1 is the searched array and n2 is the filter array), whereas the binary search has a complexity of O(n1ceil(log2n2)) (ceil = round up -- to the ceiling), and, lastly, the indexOf search has a highly variable complexity between O(n1) and O(n1n2), averaging out to O(n1ceil(n2÷2)). Thus, indexOf will only be the fastest, on average, in the cases of (n1,n2) equaling {1,2}, {1,3}, or {x,1|x?N}. However, this is still not a perfect representation of modern hardware. IndexOf is natively optimized to the fullest extent imaginable in most modern browsers, making it very subject to the laws of branch prediction. Thus, if we make the same assumption on indexOf as we do with progressive linear and binary search -- that the array is presorted -- then, according to the stats listed in the link, we can expect roughly a 6x speed up for IndexOf, shifting its complexity to between O(n1÷6) and O(n1n2), averaging out to O(n1ceil(n27÷12)). Finally, take note that the below solution will never work with objects because objects in JavaScript cannot be compared by pointers in JavaScript.

function sortAnyArray(a,b) { return a>b ? 1 : (a===b ? 0 : -1); }
function sortIntArray(a,b) { return (a|0) - (b|0) |0; }
function fastFilter(array, handle) {
    var out=[], value=0;
    for (var i=0,  len=array.length|0; i < len; i=i+1|0)
        if (handle(value = array[i])) 
            out.push( value );
    return out;

const Math_clz32 = Math.clz32 || (function(log, LN2){
  return function(x) {
    return 31 - log(x >>> 0) / LN2 | 0; // the "| 0" acts like math.floor
})(Math.log, Math.LN2);

  ) yields [1, 5], and it can work with strings too
function filterArrayByAnotherArray(searchArray, filterArray) {
    if (
        // NOTE: This does not check the whole array. But, if you know
        //        that there are only strings or numbers (not a mix of
        //        both) in the array, then this is a safe assumption.
        // Always use `==` with `typeof` because browsers can optimize
        //  the `==` into `===` (ONLY IN THIS CIRCUMSTANCE)
        typeof searchArray[0] == "number" &&
        typeof filterArray[0] == "number" &&
        (searchArray[0]|0) === searchArray[0] &&
        (filterArray[0]|0) === filterArray[0]
    ) {filterArray
        // if all entries in both arrays are integers
    } else {
    var searchArrayLen = searchArray.length, filterArrayLen = filterArray.length;
    var progressiveLinearComplexity = ((searchArrayLen<<1) + filterArrayLen)>>>0
    var binarySearchComplexity= (searchArrayLen * (32-Math_clz32(filterArrayLen-1)))>>>0;
    // After computing the complexity, we can predict which algorithm will be the fastest
    var i = 0;
    if (progressiveLinearComplexity < binarySearchComplexity) {
        // Progressive Linear Search
        return fastFilter(searchArray, function(currentValue){
            while (filterArray[i] < currentValue) i=i+1|0;
            // +undefined = NaN, which is always false for <, avoiding an infinite loop
            return filterArray[i] !== currentValue;
    } else {
        // Binary Search
        return fastFilter(

// see for implementation
//  details about this binary search algorithm

function fastestBinarySearch(array){
  var initLen = (array.length|0) - 1 |0;
  const compGoto = Math_clz32(initLen) & 31;
  return function(sValue) {
    var len = initLen |0;
    switch (compGoto) {
      case 0:
        if (len & 0x80000000) {
          const nCB = len & 0x80000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 1:
        if (len & 0x40000000) {
          const nCB = len & 0xc0000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 2:
        if (len & 0x20000000) {
          const nCB = len & 0xe0000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 3:
        if (len & 0x10000000) {
          const nCB = len & 0xf0000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 4:
        if (len & 0x8000000) {
          const nCB = len & 0xf8000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 5:
        if (len & 0x4000000) {
          const nCB = len & 0xfc000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 6:
        if (len & 0x2000000) {
          const nCB = len & 0xfe000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 7:
        if (len & 0x1000000) {
          const nCB = len & 0xff000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 8:
        if (len & 0x800000) {
          const nCB = len & 0xff800000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 9:
        if (len & 0x400000) {
          const nCB = len & 0xffc00000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 10:
        if (len & 0x200000) {
          const nCB = len & 0xffe00000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 11:
        if (len & 0x100000) {
          const nCB = len & 0xfff00000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 12:
        if (len & 0x80000) {
          const nCB = len & 0xfff80000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 13:
        if (len & 0x40000) {
          const nCB = len & 0xfffc0000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 14:
        if (len & 0x20000) {
          const nCB = len & 0xfffe0000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 15:
        if (len & 0x10000) {
          const nCB = len & 0xffff0000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 16:
        if (len & 0x8000) {
          const nCB = len & 0xffff8000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 17:
        if (len & 0x4000) {
          const nCB = len & 0xffffc000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 18:
        if (len & 0x2000) {
          const nCB = len & 0xffffe000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 19:
        if (len & 0x1000) {
          const nCB = len & 0xfffff000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 20:
        if (len & 0x800) {
          const nCB = len & 0xfffff800;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 21:
        if (len & 0x400) {
          const nCB = len & 0xfffffc00;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 22:
        if (len & 0x200) {
          const nCB = len & 0xfffffe00;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 23:
        if (len & 0x100) {
          const nCB = len & 0xffffff00;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 24:
        if (len & 0x80) {
          const nCB = len & 0xffffff80;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 25:
        if (len & 0x40) {
          const nCB = len & 0xffffffc0;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 26:
        if (len & 0x20) {
          const nCB = len & 0xffffffe0;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 27:
        if (len & 0x10) {
          const nCB = len & 0xfffffff0;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 28:
        if (len & 0x8) {
          const nCB = len & 0xfffffff8;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 29:
        if (len & 0x4) {
          const nCB = len & 0xfffffffc;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 30:
        if (len & 0x2) {
          const nCB = len & 0xfffffffe;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 31:
        if (len & 0x1) {
          const nCB = len & 0xffffffff;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
    // MODIFICATION: Instead of returning the index, this binary search
    //                instead returns whether something was found or not.
    if (array[len|0] !== sValue) {
       return true; // preserve the value at this index
    } else {
       return false; // eliminate the value at this index

Please see my other post here for more details on the binary search algorithm used

If you are squeamish about file size (which I respect), then you can sacrifice a little performance in order to greatly reduce the file size and increase maintainability.

function sortAnyArray(a,b) { return a>b ? 1 : (a===b ? 0 : -1); }
function sortIntArray(a,b) { return (a|0) - (b|0) |0; }
function fastFilter(array, handle) {
    var out=[], value=0;
    for (var i=0,  len=array.length|0; i < len; i=i+1|0)
        if (handle(value = array[i])) 
            out.push( value );
    return out;

  ) yields [1, 5], and it can work with strings too
function filterArrayByAnotherArray(searchArray, filterArray) {
    if (
        // NOTE: This does not check the whole array. But, if you know
        //        that there are only strings or numbers (not a mix of
        //        both) in the array, then this is a safe assumption.
        typeof searchArray[0] == "number" &&
        typeof filterArray[0] == "number" &&
        (searchArray[0]|0) === searchArray[0] &&
        (filterArray[0]|0) === filterArray[0]
    ) {
        // if all entries in both arrays are integers
    } else {
    // Progressive Linear Search
    var i = 0;
    return fastFilter(searchArray, function(currentValue){
        while (filterArray[i] < currentValue) i=i+1|0;
        // +undefined = NaN, which is always false for <, avoiding an infinite loop
        return filterArray[i] !== currentValue;

To prove the difference in speed, let us examine some JSPerfs. For filtering an array of 16 elements, binary search is roughly 17% faster than indexOf while filterArrayByAnotherArray is roughly 93% faster than indexOf. For filtering an array of 256 elements, binary search is roughly 291% faster than indexOf while filterArrayByAnotherArray is roughly 353% faster than indexOf. For filtering an array of 4096 elements, binary search is roughly 2655% faster than indexOf while filterArrayByAnotherArray is roughly 4627% faster than indexOf.

Reverse-filtering (like an AND gate)

The previous section provided code to take array A and array B, and remove all elements from A that exist in B:

// yields [1, 5]

This next section will provide code for reverse-filtering, where we remove all elements from A that DO NOT exist in B. This process is functionally equivalent to only retaining the elements common to both A and B, like an AND gate:

// yields [3]

Here is the code for reverse filtering:

function sortAnyArray(a,b) { return a>b ? 1 : (a===b ? 0 : -1); }
function sortIntArray(a,b) { return (a|0) - (b|0) |0; }
function fastFilter(array, handle) {
    var out=[], value=0;
    for (var i=0,  len=array.length|0; i < len; i=i+1|0)
        if (handle(value = array[i])) 
            out.push( value );
    return out;

const Math_clz32 = Math.clz32 || (function(log, LN2){
  return function(x) {
    return 31 - log(x >>> 0) / LN2 | 0; // the "| 0" acts like math.floor
})(Math.log, Math.LN2);

  ) yields [3], and it can work with strings too
function reverseFilterArrayByAnotherArray(searchArray, filterArray) {
    if (
        // NOTE: This does not check the whole array. But, if you know
        //        that there are only strings or numbers (not a mix of
        //        both) in the array, then this is a safe assumption.
        // Always use `==` with `typeof` because browsers can optimize
        //  the `==` into `===` (ONLY IN THIS CIRCUMSTANCE)
        typeof searchArray[0] == "number" &&
        typeof filterArray[0] == "number" &&
        (searchArray[0]|0) === searchArray[0] &&
        (filterArray[0]|0) === filterArray[0]
    ) {
        // if all entries in both arrays are integers
    } else {
    var searchArrayLen = searchArray.length, filterArrayLen = filterArray.length;
    var progressiveLinearComplexity = ((searchArrayLen<<1) + filterArrayLen)>>>0
    var binarySearchComplexity= (searchArrayLen * (32-Math_clz32(filterArrayLen-1)))>>>0;
    // After computing the complexity, we can predict which algorithm will be the fastest
    var i = 0;
    if (progressiveLinearComplexity < binarySearchComplexity) {
        // Progressive Linear Search
        return fastFilter(searchArray, function(currentValue){
            while (filterArray[i] < currentValue) i=i+1|0;
            // +undefined = NaN, which is always false for <, avoiding an infinite loop
            // For reverse filterning, I changed !== to ===
            return filterArray[i] === currentValue;
    } else {
        // Binary Search
        return fastFilter(

// see for implementation
//  details about this binary search algorithim

function inverseFastestBinarySearch(array){
  var initLen = (array.length|0) - 1 |0;
  const compGoto = Math_clz32(initLen) & 31;
  return function(sValue) {
    var len = initLen |0;
    switch (compGoto) {
      case 0:
        if (len & 0x80000000) {
          const nCB = len & 0x80000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 1:
        if (len & 0x40000000) {
          const nCB = len & 0xc0000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 2:
        if (len & 0x20000000) {
          const nCB = len & 0xe0000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 3:
        if (len & 0x10000000) {
          const nCB = len & 0xf0000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 4:
        if (len & 0x8000000) {
          const nCB = len & 0xf8000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 5:
        if (len & 0x4000000) {
          const nCB = len & 0xfc000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 6:
        if (len & 0x2000000) {
          const nCB = len & 0xfe000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 7:
        if (len & 0x1000000) {
          const nCB = len & 0xff000000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 8:
        if (len & 0x800000) {
          const nCB = len & 0xff800000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 9:
        if (len & 0x400000) {
          const nCB = len & 0xffc00000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 10:
        if (len & 0x200000) {
          const nCB = len & 0xffe00000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 11:
        if (len & 0x100000) {
          const nCB = len & 0xfff00000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 12:
        if (len & 0x80000) {
          const nCB = len & 0xfff80000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 13:
        if (len & 0x40000) {
          const nCB = len & 0xfffc0000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 14:
        if (len & 0x20000) {
          const nCB = len & 0xfffe0000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 15:
        if (len & 0x10000) {
          const nCB = len & 0xffff0000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 16:
        if (len & 0x8000) {
          const nCB = len & 0xffff8000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 17:
        if (len & 0x4000) {
          const nCB = len & 0xffffc000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 18:
        if (len & 0x2000) {
          const nCB = len & 0xffffe000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 19:
        if (len & 0x1000) {
          const nCB = len & 0xfffff000;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 20:
        if (len & 0x800) {
          const nCB = len & 0xfffff800;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 21:
        if (len & 0x400) {
          const nCB = len & 0xfffffc00;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 22:
        if (len & 0x200) {
          const nCB = len & 0xfffffe00;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 23:
        if (len & 0x100) {
          const nCB = len & 0xffffff00;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 24:
        if (len & 0x80) {
          const nCB = len & 0xffffff80;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 25:
        if (len & 0x40) {
          const nCB = len & 0xffffffc0;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 26:
        if (len & 0x20) {
          const nCB = len & 0xffffffe0;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 27:
        if (len & 0x10) {
          const nCB = len & 0xfffffff0;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 28:
        if (len & 0x8) {
          const nCB = len & 0xfffffff8;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 29:
        if (len & 0x4) {
          const nCB = len & 0xfffffffc;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 30:
        if (len & 0x2) {
          const nCB = len & 0xfffffffe;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
      case 31:
        if (len & 0x1) {
          const nCB = len & 0xffffffff;
          len ^= (len ^ (nCB-1)) & ((array[nCB] <= sValue |0) - 1 >>>0);
    // MODIFICATION: Instead of returning the index, this binary search
    //                instead returns whether something was found or not.
    // For reverse filterning, I swapped true with false and vice-versa
    if (array[len|0] !== sValue) {
       return false; // preserve the value at this index
    } else {
       return true; // eliminate the value at this index

For the slower smaller version of the reverse filtering code, see below.

function sortAnyArray(a,b) { return a>b ? 1 : (a===b ? 0 : -1); }
function sortIntArray(a,b) { return (a|0) - (b|0) |0; }
function fastFilter(array, handle) {
    var out=[], value=0;
    for (var i=0,  len=array.length|0; i < len; i=i+1|0)
        if (handle(value = array[i])) 
            out.push( value );
    return out;

  ) yields [3], and it can work with strings too
function reverseFilterArrayByAnotherArray(searchArray, filterArray) {
    if (
        // NOTE: This does not check the whole array. But, if you know
        //        that there are only strings or numbers (not a mix of
        //        both) in the array, then this is a safe assumption.
        typeof searchArray[0] == "number" &&
        typeof filterArray[0] == "number" &&
        (searchArray[0]|0) === searchArray[0] &&
        (filterArray[0]|0) === filterArray[0]
    ) {
        // if all entries in both arrays are integers
    } else {
    // Progressive Linear Search
    var i = 0;
    return fastFilter(searchArray, function(currentValue){
        while (filterArray[i] < currentValue) i=i+1|0;
        // +undefined = NaN, which is always false for <, avoiding an infinite loop
        // For reverse filter, I changed !== to ===
        return filterArray[i] === currentValue;

What is difference between cacerts and keystore?

Check your JAVA_HOME path. As systems looks for a java.policy file which is located in JAVA_HOME/jre/lib/security. Your JAVA_HOME should always be ../JAVA/JDK.

How do I replace text inside a div element?

If you really want us to just continue where you left off, you could do:

if (fieldNameElement)
    fieldNameElement.innerHTML = 'some HTML';

How to use BufferedReader in Java

As far as i understand fr is the object of your FileReadExample class. So it is obvious it will not have any method like fr.readLine() if you dont create one yourself.

secondly, i think a correct constructor of the BufferedReader class will help you do your task.

String str;
BufferedReader buffread = new BufferedReader(new FileReader(new File("file.dat")));
str = buffread.readLine();

this should help you.

How can I check if a value is a json object?

If you have jQuery, use isPlainObject.

if ($.isPlainObject(my_var)) {}

How to send an HTTP request with a header parameter?

With your own Code and a Slight Change withou jQuery,

function testingAPI(){ 
    var key = "8a1c6a354c884c658ff29a8636fd7c18"; 
    var url = "";

function httpGet(url,key){
    var xmlHttp = new XMLHttpRequest(); "GET", url, false );
    return xmlHttp.responseText;

Thank You

Avoid trailing zeroes in printf()

Hit the same issue, double precision is 15 decimal, and float precision is 6 decimal, so I wrote to 2 functions for them separately

#include <stdio.h>
#include <math.h>
#include <string>
#include <string.h>

std::string doublecompactstring(double d)
    char buf[128] = {0};
    if (isnan(d))
        return "NAN";
    sprintf(buf, "%.15f", d);
    // try to remove the trailing zeros
    size_t ccLen = strlen(buf);
    for(int i=(int)(ccLen -1);i>=0;i--)
        if (buf[i] == '0')
            buf[i] = '\0';

    return buf;

std::string floatcompactstring(float d)
    char buf[128] = {0};
    if (isnan(d))
        return "NAN";
    sprintf(buf, "%.6f", d);
    // try to remove the trailing zeros
    size_t ccLen = strlen(buf);
    for(int i=(int)(ccLen -1);i>=0;i--)
        if (buf[i] == '0')
            buf[i] = '\0';

    return buf;

int main(int argc, const char* argv[])
    double a = 0.000000000000001;
    float  b = 0.000001f;

    printf("a: %s\n", doublecompactstring(a).c_str());
    printf("b: %s\n", floatcompactstring(b).c_str());
    return 0;

output is

a: 0.000000000000001
b: 0.000001

Encapsulation vs Abstraction?

Encapsulation is a strategy used as part of abstraction. Encapsulation refers to the state of objects - objects encapsulate their state and hide it from the outside; outside users of the class interact with it through its methods, but cannot access the classes state directly. So the class abstracts away the implementation details related to its state.

Abstraction is a more generic term, it can also be achieved by (amongst others) subclassing. For example, the interface List in the standard library is an abstraction for a sequence of items, indexed by their position, concrete examples of a List are an ArrayList or a LinkedList. Code that interacts with a List abstracts over the detail of which kind of a list it is using.

Abstraction is often not possible without hiding underlying state by encapsulation - if a class exposes its internal state, it can't change its inner workings, and thus cannot be abstracted.

fast way to copy formatting in excel

Remember that when you write:

MyArray = Range("A1:A5000")

you are really writing

MyArray = Range("A1:A5000").Value

You can also use names:

MyArray = Names("MyWSTable").RefersToRange.Value

But Value is not the only property of Range. I have used:

MyArray = Range("A1:A5000").NumberFormat

I doubt

MyArray = Range("A1:A5000").Font

would work but I would expect

MyArray = Range("A1:A5000").Font.Bold

to work.

I do not know what formats you want to copy so you will have to try.

However, I must add that when you copy and paste a large range, it is not as much slower than doing it via an array as we all thought.

Post Edit information

Having posted the above I tried by own advice. My experiments with copying Font.Color and Font.Bold to an array have failed.

Of the following statements, the second would fail with a type mismatch:

  ValueArray = .Range("A1:T5000").Value
  ColourArray = .Range("A1:T5000").Font.Color

ValueArray must be of type variant. I tried both variant and long for ColourArray without success.

I filled ColourArray with values and tried the following statement:

  .Range("A1:T5000").Font.Color = ColourArray

The entire range would be coloured according to the first element of ColourArray and then Excel looped consuming about 45% of the processor time until I terminated it with the Task Manager.

There is a time penalty associated with switching between worksheets but recent questions about macro duration have caused everyone to review our belief that working via arrays was substantially quicker.

I constructed an experiment that broadly reflects your requirement. I filled worksheet Time1 with 5000 rows of 20 cells which were selectively formatted as: bold, italic, underline, subscript, bordered, red, green, blue, brown, yellow and gray-80%.

With version 1, I copied every 7th cells from worksheet "Time1" to worksheet "Time2" using copy.

With version 2, I copied every 7th cells from worksheet "Time1" to worksheet "Time2" by copying the value and the colour via an array.

With version 3, I copied every 7th cells from worksheet "Time1" to worksheet "Time2" by copying the formula and the colour via an array.

Version 1 took an average of 12.43 seconds, version 2 took an average of 1.47 seconds while version 3 took an average of 1.83 seconds. Version 1 copied formulae and all formatting, version 2 copied values and colour while version 3 copied formulae and colour. With versions 1 and 2 you could add bold and italic, say, and still have some time in hand. However, I am not sure it would be worth the bother given that copying 21,300 values only takes 12 seconds.

** Code for Version 1**

I do not think this code includes anything that needs an explanation. Respond with a comment if I am wrong and I will fix.

Sub SelectionCopyAndPaste()

  Dim ColDestCrnt As Integer
  Dim ColSrcCrnt As Integer
  Dim NumSelect As Long
  Dim RowDestCrnt As Integer
  Dim RowSrcCrnt As Integer
  Dim StartTime As Single

  Application.ScreenUpdating = False
  Application.Calculation = xlCalculationManual
  NumSelect = 1
  ColDestCrnt = 1
  RowDestCrnt = 1
  With Sheets("Time2")
  End With
  StartTime = Timer
  Do While True
    ColSrcCrnt = (NumSelect Mod 20) + 1
    RowSrcCrnt = (NumSelect - ColSrcCrnt) / 20 + 1
    If RowSrcCrnt > 5000 Then
      Exit Do
    End If
    Sheets("Time1").Cells(RowSrcCrnt, ColSrcCrnt).Copy _
                 Destination:=Sheets("Time2").Cells(RowDestCrnt, ColDestCrnt)
    If ColDestCrnt = 20 Then
      ColDestCrnt = 1
      RowDestCrnt = RowDestCrnt + 1
     ColDestCrnt = ColDestCrnt + 1
    End If
    NumSelect = NumSelect + 7
  Debug.Print Timer - StartTime
  ' Average 12.43 secs
  Application.Calculation = xlCalculationAutomatic

End Sub

** Code for Versions 2 and 3**

The User type definition must be placed before any subroutine in the module. The code works through the source worksheet copying values or formulae and colours to the next element of the array. Once selection has been completed, it copies the collected information to the destination worksheet. This avoids switching between worksheets more than is essential.

Type ValueDtl
  Value As String
  Colour As Long
End Type

Sub SelectionViaArray()

  Dim ColDestCrnt As Integer
  Dim ColSrcCrnt As Integer
  Dim InxVLCrnt As Integer
  Dim InxVLCrntMax As Integer
  Dim NumSelect As Long
  Dim RowDestCrnt As Integer
  Dim RowSrcCrnt As Integer
  Dim StartTime As Single
  Dim ValueList() As ValueDtl

  Application.ScreenUpdating = False
  Application.Calculation = xlCalculationManual

  ' I have sized the array to more than I expect to require because ReDim
  ' Preserve is expensive.  However, I will resize if I fill the array.
  ' For my experiment I know exactly how many elements I need but that
  ' might not be true for you.
  ReDim ValueList(1 To 25000)

  NumSelect = 1
  ColDestCrnt = 1
  RowDestCrnt = 1
  InxVLCrntMax = 0      ' Last used element in ValueList.
  With Sheets("Time2")
  End With
  StartTime = Timer
  With Sheets("Time1")
    Do While True
      ColSrcCrnt = (NumSelect Mod 20) + 1
      RowSrcCrnt = (NumSelect - ColSrcCrnt) / 20 + 1
      If RowSrcCrnt > 5000 Then
        Exit Do
      End If
      InxVLCrntMax = InxVLCrntMax + 1
      If InxVLCrntMax > UBound(ValueList) Then
        ' Resize array if it has been filled 
        ReDim Preserve ValueList(1 To UBound(ValueList) + 1000)
      End If
      With .Cells(RowSrcCrnt, ColSrcCrnt)
        ValueList(InxVLCrntMax).Value = .Value              ' Version 2
        ValueList(InxVLCrntMax).Value = .Formula            ' Version 3
        ValueList(InxVLCrntMax).Colour = .Font.Color
      End With
      NumSelect = NumSelect + 7
  End With
  With Sheets("Time2")
    For InxVLCrnt = 1 To InxVLCrntMax
      With .Cells(RowDestCrnt, ColDestCrnt)
        .Value = ValueList(InxVLCrnt).Value                 ' Version 2
        .Formula = ValueList(InxVLCrnt).Value               ' Version 3
        .Font.Color = ValueList(InxVLCrnt).Colour
      End With
      If ColDestCrnt = 20 Then
        ColDestCrnt = 1
        RowDestCrnt = RowDestCrnt + 1
       ColDestCrnt = ColDestCrnt + 1
      End If
  End With
  Debug.Print Timer - StartTime
  ' Version 2 average 1.47 secs
  ' Version 3 average 1.83 secs
  Application.Calculation = xlCalculationAutomatic

End Sub

How to change css property using javascript

Use document.getElementsByClassName('className').style = your_style.

var d = document.getElementsByClassName("left1");
d.className = d.className + " otherclass";

Use single quotes for JS strings contained within an html attribute's double quotes


<div class="somelclass"></div>

then document.getElementsByClassName('someclass').style = "NewclassName";

<div class='someclass'></div>

then document.getElementsByClassName("someclass").style = "NewclassName";

This is personal experience.

append multiple values for one key in a dictionary

It's easier if you get these values into a list of tuples. To do this, you can use list slicing and the zip function.

data_in = [2010,2,2009,4,1989,8,2009,7]
data_pairs = zip(data_in[::2],data_in[1::2])

Zip takes an arbitrary number of lists, in this case the even and odd entries of data_in, and puts them together into a tuple.

Now we can use the setdefault method.

data_dict = {}
for x in data_pairs:

setdefault takes a key and a default value, and returns either associated value, or if there is no current value, the default value. In this case, we will either get an empty or populated list, which we then append the current value to.

Numpy: Creating a complex array from 2 real ones?

I am python novice so this may not be the most efficient method but, if I understand the intent of the question correctly, steps listed below worked for me.

>>> import numpy as np
>>> Data = np.random.random((100, 100, 1000, 2))
>>> result = np.empty(Data.shape[:-1], dtype=complex)
>>> result.real = Data[...,0]; result.imag = Data[...,1]
>>> print Data[0,0,0,0], Data[0,0,0,1], result[0,0,0]
0.0782889873474 0.156087854837 (0.0782889873474+0.156087854837j)

Calling @Html.Partial to display a partial view belonging to a different controller

As GvS said, but I also find it useful to use strongly typed views so that I can write something like

@Html.Partial(MVC.Student.Index(), model)

without magic strings.

How do I Sort a Multidimensional Array in PHP

Multiple row sorting using a closure

Here's another approach using uasort() and an anonymous callback function (closure). I've used that function regularly. PHP 5.3 required – no more dependencies!

 * Sorting array of associative arrays - multiple row sorting using a closure.
 * See also:
 * @param array $data input-array
 * @param string|array $fields array-keys
 * @license Public Domain
 * @return array
function sortArray( $data, $field ) {
    $field = (array) $field;
    uasort( $data, function($a, $b) use($field) {
        $retval = 0;
        foreach( $field as $fieldname ) {
            if( $retval == 0 ) $retval = strnatcmp( $a[$fieldname], $b[$fieldname] );
        return $retval;
    } );
    return $data;

/* example */
$data = array(
    array( "firstname" => "Mary", "lastname" => "Johnson", "age" => 25 ),
    array( "firstname" => "Amanda", "lastname" => "Miller", "age" => 18 ),
    array( "firstname" => "James", "lastname" => "Brown", "age" => 31 ),
    array( "firstname" => "Patricia", "lastname" => "Williams", "age" => 7 ),
    array( "firstname" => "Michael", "lastname" => "Davis", "age" => 43 ),
    array( "firstname" => "Sarah", "lastname" => "Miller", "age" => 24 ),
    array( "firstname" => "Patrick", "lastname" => "Miller", "age" => 27 )

$data = sortArray( $data, 'age' );
$data = sortArray( $data, array( 'lastname', 'firstname' ) );

How to wait for all threads to finish, using ExecutorService?

Clean way with ExecutorService

 List<Future<Void>> results = null;
 try {
     List<Callable<Void>> tasks = new ArrayList<>();
     ExecutorService executorService = Executors.newFixedThreadPool(4);
     results = executorService.invokeAll(tasks);
 } catch (InterruptedException ex) {
 } catch (Exception ex) {

How Do I Insert a Byte[] Into an SQL Server VARBINARY Column

You can do something like this, very simple and efficient solution: What i did was actually use a parameter instead of basic placeholder, created a SqlParameter object and used another existing execution method. For e.g in your scenario:

string sql = "INSERT INTO mssqltable (varbinarycolumn) VALUES (@img)";
SqlParameter param = new SqlParameter("img", arraytoinsert); //where img is your parameter name in the query
ExecuteStoreCommand(sql, param);

This should work like a charm, provided you have an open sql connection established.

Submit form on pressing Enter with AngularJS

Angular supports this out of the box. Have you tried ngSubmit on your form element?

<form ng-submit="myFunc()" ng-controller="mycontroller">
   <input type="text" ng-model="name" />
    <br />
    <input type="text" ng-model="email" />

EDIT: Per the comment regarding the submit button, see Submitting a form by pressing enter without a submit button which gives the solution of:

<input type="submit" style="position: absolute; left: -9999px; width: 1px; height: 1px;"/>

If you don't like the hidden submit button solution, you'll need to bind a controller function to the Enter keypress or keyup event. This normally requires a custom directive, but the AngularUI library has a nice keypress solution set up already. See

After adding the angularUI lib, your code would be something like:

<form ui-keypress="{13:'myFunc($event)'}">
  ... input fields ...

or you can bind the enter keypress to each individual field.

Also, see this SO questions for creating a simple keypres directive: How can I detect onKeyUp in AngularJS?

EDIT (2014-08-28): At the time this answer was written, ng-keypress/ng-keyup/ng-keydown did not exist as native directives in AngularJS. In the comments below @darlan-alves has a pretty good solution with:

<input ng-keyup="$event.keyCode == 13 && myFunc()"... />

Servlet returns "HTTP Status 404 The requested resource (/servlet) is not available"


This can have a lot of causes which are broken down in following sections:

  • Put servlet class in a package
  • Set servlet URL in url-pattern
  • @WebServlet works only on Servlet 3.0 or newer
  • javax.servlet.* doesn't work anymore in Servlet 5.0 or newer
  • Make sure compiled *.class file is present in built WAR
  • Test the servlet individually without any JSP/HTML page
  • Use domain-relative URL to reference servlet from HTML
  • Use straight quotes in HTML attributes

Put servlet class in a package

First of all, put the servlet class in a Java package. You should always put publicly reuseable Java classes in a package, otherwise they are invisible to classes which are in a package, such as the server itself. This way you eliminiate potential environment-specific problems. Packageless servlets work only in specific Tomcat+JDK combinations and this should never be relied upon.

In case of a "plain" IDE project, the class needs to be placed in its package structure inside "Java Resources" folder and thus not "WebContent", this is for web files such as JSP. Below is an example of the folder structure of a default Eclipse Dynamic Web Project as seen in Navigator view:

 |-- src
 |    `-- com
 |         `-- example
 |              `--
 |-- WebContent
 |    |-- WEB-INF
 |    |    `-- web.xml
 |    `-- jsps
 |         `-- page.jsp

In case of a Maven project, the class needs to be placed in its package structure inside main/java and thus not main/resources, this is for non-class files and absolutely also not main/webapp, this is for web files. Below is an example of the folder structure of a default Maven webapp project as seen in Eclipse's Navigator view:

 |-- src
 |    `-- main
 |         |-- java
 |         |    `-- com
 |         |         `-- example
 |         |              `--
 |         |-- resources
 |         `-- webapp
 |              |-- WEB-INF
 |              |    `-- web.xml
 |              `-- jsps
 |                   `-- page.jsp

Note that the /jsps subfolder is not strictly necessary. You can even do without it and put the JSP file directly in webcontent/webapp root, but I'm just taking over this from your question.

Set servlet URL in url-pattern

The servlet URL is specified as the "URL pattern" of the servlet mapping. It's absolutely not per definition the classname/filename of the servlet class. The URL pattern is to be specified as value of @WebServlet annotation.

package com.example; // Use a package!

@WebServlet("/servlet") // This is the URL of the servlet.
public class YourServlet extends HttpServlet { // Must be public and extend HttpServlet.
    // ...

In case you want to support path parameters like /servlet/foo/bar, then use an URL pattern of /servlet/* instead. See also Servlet and path parameters like /xyz/{value}/test, how to map in web.xml?

@WebServlet works only on Servlet 3.0 or newer

In order to use @WebServlet, you only need to make sure that your web.xml file, if any (it's optional since Servlet 3.0), is declared conform Servlet 3.0+ version and thus not conform e.g. 2.5 version or lower. Below is a Servlet 4.0 compatible one (which matches Tomcat 9+, WildFly 11+, Payara 5+, etc).

<?xml version="1.0" encoding="UTF-8"?>
    <!-- Config here. -->

Or, in case you're not on Servlet 3.0+ yet (e.g. Tomcat 6 or older), then remove the @WebServlet annotation.

package com.example;

public class YourServlet extends HttpServlet {
    // ...

And register the servlet instead in web.xml like this:

    <url-pattern>/servlet</url-pattern>  <!-- This is the URL of the servlet. -->

Note thus that you should not use both ways. Use either annotation based configuarion or XML based configuration. When you have both, then XML based configuration will override annotation based configuration.

javax.servlet.* doesn't work anymore in Servlet 5.0 or newer

Since Jakarta EE 9 / Servlet 5.0 (Tomcat 10, TomEE 9, WildFly 22 Preview, GlassFish 6, Payara 6, Liberty 22, etc), the javax.* package has been renamed to jakarta.* package.

In other words, please make absolutely sure that you don't randomly put JAR files of a different server in your WAR project such as tomcat-servlet-api-9.x.x.jar merely in order to get the javax.* package to compile. This will only cause trouble. Remove it altogether and edit the imports of your servlet class from

import javax.servlet.*;
import javax.servlet.http.*;


import jakarta.servlet.*;
import jakarta.servlet.http.*;

In case you're using Maven, you can find examples of proper pom.xml declarations for Tomcat 10+, Tomcat 9-, JEE 9+ and JEE 8- in this answer: Tomcat 9 casting servlets to javax.servlet.Servlet instead of jakarta.servlet.http.HttpServlet

Make sure compiled *.class file is present in built WAR

In case you're using a build tool such as Eclipse and/or Maven, then you need to make absolutely sure that the compiled servlet class file resides in its package structure in /WEB-INF/classes folder of the produced WAR file. In case of package com.example; public class YourServlet, it must be located in /WEB-INF/classes/com/example/YourServlet.class. Otherwise you will face in case of @WebServlet also a 404 error, or in case of <servlet> a HTTP 500 error like below:

HTTP Status 500

Error instantiating servlet class com.example.YourServlet

And find in the server log a java.lang.ClassNotFoundException: com.example.YourServlet, followed by a java.lang.NoClassDefFoundError: com.example.YourServlet, in turn followed by javax.servlet.ServletException: Error instantiating servlet class com.example.YourServlet.

An easy way to verify if the servlet is correctly compiled and placed in classpath is to let the build tool produce a WAR file (e.g. rightclick project, Export > WAR file in Eclipse) and then inspect its contents with a ZIP tool. If the servlet class is missing in /WEB-INF/classes, or if the export causes an error, then the project is badly configured or some IDE/project configuration defaults have been mistakenly reverted (e.g. Project > Build Automatically has been disabled in Eclipse).

You also need to make sure that the project icon has no red cross indicating a build error. You can find the exact error in Problems view (Window > Show View > Other...). Usually the error message is fine Googlable. In case you have no clue, best is to restart from scratch and do not touch any IDE/project configuration defaults. In case you're using Eclipse, you can find instructions in How do I import the javax.servlet API in my Eclipse project?

Test the servlet individually without any JSP/HTML page

Provided that the server runs on localhost:8080, and that the WAR is successfully deployed on a context path of /contextname (which defaults to the IDE project name, case sensitive!), and the servlet hasn't failed its initialization (read server logs for any deploy/servlet success/fail messages and the actual context path and servlet mapping), then a servlet with URL pattern of /servlet is available at http://localhost:8080/contextname/servlet.

You can just enter it straight in browser's address bar to test it invidivually. If its doGet() is properly overriden and implemented, then you will see its output in browser. Or if you don't have any doGet() or if it incorrectly calls super.doGet(), then a "HTTP 405: HTTP method GET is not supported by this URL" error will be shown (which is still better than a 404 as a 405 is evidence that the servlet itself is actually found).

Overriding service() is a bad practice, unless you're reinventing a MVC framework — which is very unlikely if you're just starting out with servlets and are clueless as to the problem described in the current question ;) See also Design Patterns web based applications.

Regardless, if the servlet already returns 404 when tested invidivually, then it's entirely pointless to try with a HTML form instead. Logically, it's therefore also entirely pointless to include any HTML form in questions about 404 errors from a servlet.

Use domain-relative URL to reference servlet from HTML

Once you've verified that the servlet works fine when invoked individually, then you can advance to HTML. As to your concrete problem with the HTML form, the <form action> value needs to be a valid URL. The same applies to <a href>. You need to understand how absolute/relative URLs work. You know, an URL is a web address as you can enter/see in the webbrowser's address bar. If you're specifying a relative URL as form action, i.e. without the http:// scheme, then it becomes relative to the current URL as you see in your webbrowser's address bar. It's thus absolutely not relative to the JSP/HTML file location in server's WAR folder structure as many starters seem to think.

So, assuming that the JSP page with the HTML form is opened by http://localhost:8080/contextname/jsps/page.jsp, and you need to submit to a servlet located in http://localhost:8080/contextname/servlet, here are several cases (note that you can safely substitute <form action> with <a href> here):

  • Form action submits to an URL with a leading slash.

      <form action="/servlet">

    The leading slash / makes the URL relative to the domain, thus the form will submit to


    But this will likely result in a 404 as it's in the wrong context.

  • Form action submits to an URL without a leading slash.

      <form action="servlet">

    This makes the URL relative to the current folder of the current URL, thus the form will submit to


    But this will likely result in a 404 as it's in the wrong folder.

  • Form action submits to an URL which goes one folder up.

      <form action="../servlet">

    This will go one folder up (exactly like as in local disk file system paths!), thus the form will submit to


    This one must work!

  • The canonical approach, however, is to make the URL domain-relative so that you don't need to fix the URLs once again when you happen to move the JSP files around into another folder.

      <form action="${pageContext.request.contextPath}/servlet">

    This will generate

      <form action="/contextname/servlet">

    Which will thus always submit to the right URL.

Use straight quotes in HTML attributes

You need to make absolutely sure you're using straight quotes in HTML attributes like action="..." or action='...' and thus not curly quotes like action=”...” or action=’...’. Curly quotes are not supported in HTML and they will simply become part of the value. Watch out when copy-pasting code snippets from blogs! Some blog engines, notably Wordpress, are known to by default use so-called "smart quotes" which thus also corrupts the quotes in code snippets this way. On the other hand, instead of copy-pasting code, try simply typing over the code yourself. Additional advantage of actually getting the code through your brain and fingers is that it will make you to remember and understand the code much better in long term and also make you a better developer.

See also:

Other cases of HTTP Status 404 error:

When or Why to use a "SET DEFINE OFF" in Oracle Database

Here is the example:

SQL> set define off;
SQL> select * from dual where dummy='&var';

no rows selected

SQL> set define on
SQL> /
Enter value for var: X
old   1: select * from dual where dummy='&var'
new   1: select * from dual where dummy='X'


With set define off, it took a row with &var value, prompted a user to enter a value for it and replaced &var with the entered value (in this case, X).

Better way to convert an int to a boolean

int i = 0;
bool b = Convert.ToBoolean(i);

Generating UML from C++ code?

I have used Rational Rose and Rational Rhapsody for reverse engineering large projects. I would prefer Rational Rhapsody for getting the UML class files for C++ !

Chrome javascript debugger breakpoints don't do anything?

make sure that you have opened javascript console(or sources) in your chrome window. otherwise it will never hit the breakpoint. you can open javascript console by option button in right upper corner-->tools-->javascript console.

SQL How to correctly set a date variable value and use it?

Your syntax is fine, it will return rows where LastAdDate lies within the last 6 months;

select cast('01-jan-1970' as datetime) as LastAdDate into #PubAdvTransData 
    union select GETDATE()
    union select NULL
    union select '01-feb-2010'

DECLARE @sp_Date DATETIME = DateAdd(m, -6, GETDATE())

SELECT * FROM #PubAdvTransData pat
     WHERE (pat.LastAdDate > @sp_Date)

>2010-02-01 00:00:00.000
>2010-04-29 21:12:29.920

Are you sure LastAdDate is of type DATETIME?

Check whether a request is GET or POST


    // …

Detected both log4j-over-slf4j.jar AND slf4j-log4j12.jar on the class path, preempting StackOverflowError.

For gradle

    exclude module: 'log4j'
    exclude module: 'slf4j-log4j12'

Property 'catch' does not exist on type 'Observable<any>'

Warning: This solution is deprecated since Angular 5.5, please refer to Trent's answer below


Yes, you need to import the operator:

import 'rxjs/add/operator/catch';

Or import Observable this way:

import {Observable} from 'rxjs/Rx';

But in this case, you import all operators.

See this question for more details:

Using LINQ to group by multiple properties and sum

Use the .Select() after grouping:

var agencyContracts = _agencyContractsRepository.AgencyContracts
    .GroupBy(ac => new
                       ac.AgencyContractID, // required by your view model. should be omited
                                            // in most cases because group by primary key
                                            // makes no sense.
    .Select(ac => new AgencyContractViewModel
                       AgencyContractID = ac.Key.AgencyContractID,
                       AgencyId = ac.Key.AgencyID,
                       VendorId = ac.Key.VendorID,
                       RegionId = ac.Key.RegionID,
                       Amount = ac.Sum(acs => acs.Amount),
                       Fee = ac.Sum(acs => acs.Fee)

how to log in to mysql and query the database from linux terminal

  1. you should use mysql command. It's a command line client for mysql RDBMS, and comes with most mysql installations:

  2. To stop or start mysql database (you rarely should need doing that 'by hand'), use proper init script with stop or start parameter, usually /etc/init.d/mysql stop. This, however depends on your linux distribution. Some new distributions encourage service mysql start style.

  3. You're logging in by using mysql sql shell.

  4. The error comes probably because double '-p' parameter. You can provide -ppassword or just -p and you'll be asked for password interactively. Also note, that some instalations might use mysql (not root) user as an administrative user. Check your sqlyog configuration to obtain working connection parameters.

JAX-WS client : what's the correct path to access the local WSDL?

For those of you using Spring, you can simply reference any classpath-resource using the classpath-protocol. So in case of the wsdlLocation, this becomes:


Note that is not standard Java behavior. See also:

Global javascript variable inside document.ready

like this: put intro outside your document ready, Good discussion here: @thecodeparadox is awesomely fast :P anyways!

 var intro;

$(document).ready(function() {

    if ($('.intro_check').is(':checked')) {
        intro = true;
        $('.intro').wrap('<div class="disabled"></div>');

        if(this.checked) {
            intro = false;
        } else {
            intro = true;
            if($('.intro').exists()) {
            } else {
                $('.intro').wrap('<div class="disabled"></div>');

windows batch file rename

@echo off
pushd "pathToYourFolder" || exit /b
for /f "eol=: delims=" %%F in ('dir /b /a-d *_*.jpg') do (
  for /f "tokens=1* eol=_ delims=_" %%A in ("%%~nF") do ren "%%F" "%%~nB_%%A%%~xF"

Note: The name is split at the first occurrence of _. If a file is named "part1_part2_part3.jpg", then it will be renamed to "part2_part3_part1.jpg"

MySQL error: key specification without a key length

MySQL disallows indexing a full value of BLOB, TEXT and long VARCHAR columns because data they contain can be huge, and implicitly DB index will be big, meaning no benefit from index.

MySQL requires that you define first N characters to be indexed, and the trick is to choose a number N that’s long enough to give good selectivity, but short enough to save space. The prefix should be long enough to make the index nearly as useful as it would be if you’d indexed the whole column.

Before we go further let us define some important terms. Index selectivity is ratio of the total distinct indexed values and total number of rows. Here is one example for test table:

| id  | value     |
| 1   | abc       |
| 2   | abd       |
| 3   | adg       |

If we index only the first character (N=1), then index table will look like the following table:

| indexedValue  | rows      |
| a             | 1,2,3     |

In this case, index selectivity is equal to IS=1/3 = 0.33.

Let us now see what will happen if we increase number of indexed characters to two (N=2).

| indexedValue  | rows      |
| ab             | 1,2      |
| ad             | 3        |

In this scenario IS=2/3=0.66 which means we increased index selectivity, but we have also increased the size of index. Trick is to find the minimal number N which will result to maximal index selectivity.

There are two approaches you can do calculations for your database table. I will make demonstration on the this database dump.

Let's say we want to add column last_name in table employees to the index, and we want to define the smallest number N which will produce the best index selectivity.

First let us identify the most frequent last names:

select count(*) as cnt, last_name 
from employees 
group by employees.last_name 
order by cnt

| cnt | last_name   |
| 226 | Baba        |
| 223 | Coorg       |
| 223 | Gelosh      |
| 222 | Farris      |
| 222 | Sudbeck     |
| 221 | Adachi      |
| 220 | Osgood      |
| 218 | Neiman      |
| 218 | Mandell     |
| 218 | Masada      |
| 217 | Boudaillier |
| 217 | Wendorf     |
| 216 | Pettis      |
| 216 | Solares     |
| 216 | Mahnke      |
15 rows in set (0.64 sec)

As you can see, the last name Baba is the most frequent one. Now we are going to find the most frequently occurring last_name prefixes, beginning with five-letter prefixes.

| cnt | prefix |
| 794 | Schaa  |
| 758 | Mande  |
| 711 | Schwa  |
| 562 | Angel  |
| 561 | Gecse  |
| 555 | Delgr  |
| 550 | Berna  |
| 547 | Peter  |
| 543 | Cappe  |
| 539 | Stran  |
| 534 | Canna  |
| 485 | Georg  |
| 417 | Neima  |
| 398 | Petti  |
| 398 | Duclo  |
15 rows in set (0.55 sec)

There are much more occurrences of every prefix, which means we have to increase number N until the values are almost the same as in the previous example.

Here are results for N=9

select count(*) as cnt, left(last_name,9) as prefix 
from employees 
group by prefix 
order by cnt desc 
limit 0,15;

| cnt | prefix    |
| 336 | Schwartzb |
| 226 | Baba      |
| 223 | Coorg     |
| 223 | Gelosh    |
| 222 | Sudbeck   |
| 222 | Farris    |
| 221 | Adachi    |
| 220 | Osgood    |
| 218 | Mandell   |
| 218 | Neiman    |
| 218 | Masada    |
| 217 | Wendorf   |
| 217 | Boudailli |
| 216 | Cummings  |
| 216 | Pettis    |

Here are results for N=10.

| cnt | prefix     |
| 226 | Baba       |
| 223 | Coorg      |
| 223 | Gelosh     |
| 222 | Sudbeck    |
| 222 | Farris     |
| 221 | Adachi     |
| 220 | Osgood     |
| 218 | Mandell    |
| 218 | Neiman     |
| 218 | Masada     |
| 217 | Wendorf    |
| 217 | Boudaillie |
| 216 | Cummings   |
| 216 | Pettis     |
| 216 | Solares    |
15 rows in set (0.56 sec)

This are very good results. This means that we can make index on column last_name with indexing only first 10 characters. In table definition column last_name is defined as VARCHAR(16), and this means we have saved 6 bytes (or more if there are UTF8 characters in the last name) per entry. In this table there are 1637 distinct values multiplied by 6 bytes is about 9KB, and imagine how this number would grow if our table contains million of rows.

You can read other ways of calculating number of N in my post Prefixed indexes in MySQL.

How can I use regex to get all the characters after a specific character, e.g. comma (",")

You don't need regex to do this. Here's an example :

var str = "'SELECT___100E___7',24";
var afterComma = str.substr(str.indexOf(",") + 1); // Contains 24 //

OPENSSL file_get_contents(): Failed to enable crypto

Had same problem - it was somewhere in the ca certificate, so I used the ca bundle used for curl, and it worked. You can download the curl ca bundle here:

For encryption and security issues see this helpful article:

Here is the example:

    $url = '';
    $cn_match = '';

    $data = array (     
        'apikey' => '[example api key here]',               
        'limit' => intval($limit),
        'offset' => intval($offset)

    // use key 'http' even if you send the request to https://...
    $options = array(
        'http' => array(
            'header'  => "Content-type: application/x-www-form-urlencoded\r\n",
            'method'  => 'POST',                
            'content' => http_build_query($data)                
        , 'ssl' => array(
            'verify_peer' => true,
            'cafile' => [path to file] . "cacert.pem",
            'ciphers' => 'HIGH:TLSv1.2:TLSv1.1:TLSv1.0:!SSLv3:!SSLv2',
            'CN_match' => $cn_match,
            'disable_compression' => true,

    $context  = stream_context_create($options);
    $response = file_get_contents($url, false, $context);

Hope that helps

API Gateway CORS: no 'Access-Control-Allow-Origin' header

1) I needed to do the same as @riseres and some other changes.This are my response headers:

headers: {
            'Access-Control-Allow-Origin' : '*',
            'Access-Control-Allow-Credentials' : true,
            'Content-Type': 'application/json'

2) And

According to this documentation:

When you use proxy for lambda functions on API Gateway config, the post or get methods have no added headers, only the options does. You must do it manually in the response(server or lambda response).

3) And

Beside that, I needed to disable the 'API Key Required' option in my API gateway post method.

How to center a WPF app on screen?

I prefer to put it in the WPF code.

In [WindowName].xaml file:

<Window x:Class=...
WindowStartupLocation ="CenterScreen">

Failed to connect to camera service

I know this question has been answered long time ago, but I would like to add a small thing.

To everyone having the same error, make sure to add this permission in you manifest file:

<uses-permission android:name="android.permission.CAMERA" />

IMPORTANT to use the CAPITAL letters for CAMERA, as I had the permission with small letters and it didn't work.

Use HTML5 to resize an image before upload

if any interested I've made a typescript version:

interface IResizeImageOptions {
  maxSize: number;
  file: File;
const resizeImage = (settings: IResizeImageOptions) => {
  const file = settings.file;
  const maxSize = settings.maxSize;
  const reader = new FileReader();
  const image = new Image();
  const canvas = document.createElement('canvas');
  const dataURItoBlob = (dataURI: string) => {
    const bytes = dataURI.split(',')[0].indexOf('base64') >= 0 ?
        atob(dataURI.split(',')[1]) :
    const mime = dataURI.split(',')[0].split(':')[1].split(';')[0];
    const max = bytes.length;
    const ia = new Uint8Array(max);
    for (var i = 0; i < max; i++) ia[i] = bytes.charCodeAt(i);
    return new Blob([ia], {type:mime});
  const resize = () => {
    let width = image.width;
    let height = image.height;

    if (width > height) {
        if (width > maxSize) {
            height *= maxSize / width;
            width = maxSize;
    } else {
        if (height > maxSize) {
            width *= maxSize / height;
            height = maxSize;

    canvas.width = width;
    canvas.height = height;
    canvas.getContext('2d').drawImage(image, 0, 0, width, height);
    let dataUrl = canvas.toDataURL('image/jpeg');
    return dataURItoBlob(dataUrl);

  return new Promise((ok, no) => {
      if (!file.type.match(/image.*/)) {
        no(new Error("Not an image"));

      reader.onload = (readerEvent: any) => {
        image.onload = () => ok(resize());
        image.src =;

and here's the javascript result:

var resizeImage = function (settings) {
    var file = settings.file;
    var maxSize = settings.maxSize;
    var reader = new FileReader();
    var image = new Image();
    var canvas = document.createElement('canvas');
    var dataURItoBlob = function (dataURI) {
        var bytes = dataURI.split(',')[0].indexOf('base64') >= 0 ?
            atob(dataURI.split(',')[1]) :
        var mime = dataURI.split(',')[0].split(':')[1].split(';')[0];
        var max = bytes.length;
        var ia = new Uint8Array(max);
        for (var i = 0; i < max; i++)
            ia[i] = bytes.charCodeAt(i);
        return new Blob([ia], { type: mime });
    var resize = function () {
        var width = image.width;
        var height = image.height;
        if (width > height) {
            if (width > maxSize) {
                height *= maxSize / width;
                width = maxSize;
        } else {
            if (height > maxSize) {
                width *= maxSize / height;
                height = maxSize;
        canvas.width = width;
        canvas.height = height;
        canvas.getContext('2d').drawImage(image, 0, 0, width, height);
        var dataUrl = canvas.toDataURL('image/jpeg');
        return dataURItoBlob(dataUrl);
    return new Promise(function (ok, no) {
        if (!file.type.match(/image.*/)) {
            no(new Error("Not an image"));
        reader.onload = function (readerEvent) {
            image.onload = function () { return ok(resize()); };
            image.src =;

usage is like:

    file: $image.files[0],
    maxSize: 500
}).then(function (resizedImage) {
    console.log("upload resized image")
}).catch(function (err) {

or (async/await):

const config = {
    file: $image.files[0],
    maxSize: 500
const resizedImage = await resizeImage(config)
console.log("upload resized image")

How do I make a composite key with SQL Server Management Studio?

create table myTable 
    Column1 int not null,
    Column2 int not null

    ADD  PRIMARY KEY (Column1,Column2)

How to find Google's IP address?

Google maintains a server infrastructure that grows dynamically with the ever increasing internet demands. This link by google describes the method to remain up to date with their IP address ranges.

When you need the literal IP addresses for Google Apps mail servers, start by using one of the common DNS lookup commands (nslookup, dig, host) to retrieve the SPF records for the domain, like so:

nslookup -q=TXT

This returns a list of the domains included in Google's SPF record, such as:,,

Now look up the DNS records associated with those domains, one at a time, like so:

nslookup -q=TXT
nslookup -q=TXT
nslookup -q=TXT

The results of these commands contain the current range of addresses.

How to get error information when HttpWebRequest.GetResponse() fails

I faced a similar situation:

I was trying to read raw response in case of an HTTP error consuming a SOAP service, using BasicHTTPBinding.

However, when reading the response using GetResponseStream(), got the error:

Stream not readable

So, this code worked for me:

    response = basicHTTPBindingClient.CallOperation(request);
catch (ProtocolException exception)
    var webException = exception.InnerException as WebException;
    var rawResponse = string.Empty;

    var alreadyClosedStream = webException.Response.GetResponseStream() as MemoryStream;
    using (var brandNewStream = new MemoryStream(alreadyClosedStream.ToArray()))
    using (var reader = new StreamReader(brandNewStream))
        rawResponse = reader.ReadToEnd();

How do I add multiple conditions to "ng-disabled"?

There is maybe a bit of a gotcha in the phrasing of the original question:

I need to check that two conditions are both true before enabling a button

The first thing to remember that the ng-disabled directive is evaluating a condition under which the button should be, well, disabled, but the original question is referring to the conditions under which it should en enabled. It will be enabled under any circumstances where the ng-disabled expression is not "truthy".

So, the first consideration is how to rephrase the logic of the question to be closer to the logical requirements of ng-disabled. The logical inverse of checking that two conditions are true in order to enable a button is that if either condition is false then the button should be disabled.

Thus, in the case of the original question, the pseudo-expression for ng-disabled is "disable the button if condition1 is false or condition2 is false". Translating into the Javascript-like code snippet required by Angular (, we get:

!condition1 || !condition2

Zoomlar has it right!

What use is find_package() if you need to specify CMAKE_MODULE_PATH anyway?

How is this usually done? Should I copy the cmake/ directory of SomeLib into my project and set the CMAKE_MODULE_PATH relatively?

If you don't trust CMake to have that module, then - yes, do that - sort of: Copy the find_SomeLib.cmake and its dependencies into your cmake/ directory. That's what I do as a fallback. It's an ugly solution though.

Note that the FindFoo.cmake modules are each a sort of a bridge between platform-dependence and platform-independence - they look in various platform-specific places to obtain paths in variables whose names is platform-independent.

HTML Entity Decode

Inspired by Robert K's solution, strips html tags and prevents executing scripts and eventhandlers like: <img src=fake onerror="prompt(1)"> Tested on latest Chrome, FF, IE (should work from IE9, but haven't tested).

var decodeEntities = (function () {
        //create a new html document (doesn't execute script tags in child elements)
        var doc = document.implementation.createHTMLDocument("");
        var element = doc.createElement('div');

        function getText(str) {
            element.innerHTML = str;
            str = element.textContent;
            element.textContent = '';
            return str;

        function decodeHTMLEntities(str) {
            if (str && typeof str === 'string') {
                var x = getText(str);
                while (str !== x) {
                    str = x;
                    x = getText(x);
                return x;
        return decodeHTMLEntities;

Simply call:

decodeEntities('<img src=fake onerror="prompt(1)">');

npm - "Can't find Python executable "python", you can set the PYTHON env variable."

You got to add python to your PATH variable. One thing you can do is Edit your Path variable now and add


Your variable PYTHON should point to the root directory of your python installation.

Python read JSON file and modify

There is really quite a number of ways to do this and all of the above are in one way or another valid approaches... Let me add a straightforward proposition. So assuming your current existing json file looks is this....


And you want to bring in this new json content (adding key "id")

     "id": "134",
     "name": "myname"

My approach has always been to keep the code extremely readable with easily traceable logic. So first, we read the entire existing json file into memory, assuming you are very well aware of your json's existing key(s).

import json 

# first, get the absolute path to json file
PATH_TO_JSON = 'data.json' #  assuming same directory (but you can work your magic here with os.)

# read existing json to memory. you do this to preserve whatever existing data. 
with open(PATH_TO_JSON,'r') as jsonfile:
    json_content = json.load(jsonfile) # this is now in memory! you can use it outside 'open'

Next, we use the 'with open()' syntax again, with the 'w' option. 'w' is a write mode which lets us edit and write new information to the file. Here s the catch that works for us ::: any existing json with the same target write name will be erased automatically.

So what we can do now, is simply write to the same filename with the new data

# add the id key-value pair (rmbr that it already has the "name" key value)
json_content["id"] = "134"

with open(PATH_TO_JSON,'w') as jsonfile:
    json.dump(json_content, jsonfile, indent=4) # you decide the indentation level

And there you go! data.json should be good to go for an good old POST request

How to exit if a command failed?

Note also, each command's exit status is stored in the shell variable $?, which you can check immediately after running the command. A non-zero status indicates failure:

if [ $? -eq 0 ]
    echo "it worked"
    echo "it failed"

Load and execute external js file in node.js with access to local variables?

You need to understand CommonJS, which is a pattern to define modules. You shouldn't abuse GLOBAL scope that's always a bad thing to do, instead you can use the 'exports' token, like this:

// circle.js

var PI = 3.14; // PI will not be accessible from outside this module

exports.area = function (r) {
  return PI * r * r;

exports.circumference = function (r) {
  return 2 * PI * r;

And the client code that will use our module:

// client.js

var circle = require('./circle');
console.log( 'The area of a circle of radius 4 is '
           + circle.area(4));

This code was extracted from node.js documentation API:

Also, if you want to use something like Rails or Sinatra, I recommend Express (I couldn't post the URL, shame on Stack Overflow!)

Run local python script on remote server

Although this question isn't quite new and an answer was already chosen, I would like to share another nice approach.

Using the paramiko library - a pure python implementation of SSH2 - your python script can connect to a remote host via SSH, copy itself (!) to that host and then execute that copy on the remote host. Stdin, stdout and stderr of the remote process will be available on your local running script. So this solution is pretty much independent of an IDE.

On my local machine, I run the script with a cmd-line parameter 'deploy', which triggers the remote execution. Without such a parameter, the actual code intended for the remote host is run.

import sys
import os

def main():

if __name__ == '__main__':
        if sys.argv[1] == 'deploy':
            import paramiko

            # Connect to remote host
            client = paramiko.SSHClient()
            client.connect('remote_hostname_or_IP', username='john', password='secret')

            # Setup sftp connection and transmit this script
            sftp = client.open_sftp()
            sftp.put(__file__, '/tmp/')

            # Run the transmitted script remotely without args and show its output.
            # SSHClient.exec_command() returns the tuple (stdin,stdout,stderr)
            stdout = client.exec_command('python /tmp/')[1]
            for line in stdout:
                # Process each line in the remote output
                print line

    except IndexError:

    # No cmd-line args provided, run script normally

Exception handling is left out to simplify this example. In projects with multiple script files you will probably have to put all those files (and other dependencies) on the remote host.

Change icons of checked and unchecked for Checkbox for Android

Kind of a mix:

Set it in your layout file :-

 <CheckBox android:layout_width="wrap_content"
           android:text="new checkbox"
           android:button="@drawable/checkbox" />

where the @drawable/checkbox will look like:

<?xml version="1.0" encoding="utf-8"?>

<selector xmlns:android="">
 <item android:state_checked="true" android:state_focused="true"
  android:drawable="@drawable/checkbox_on_background_focus_yellow" />
 <item android:state_checked="false" android:state_focused="true"
  android:drawable="@drawable/checkbox_off_background_focus_yellow" />
 <item android:state_checked="false"
  android:drawable="@drawable/checkbox_off_background" />
 <item android:state_checked="true"
  android:drawable="@drawable/checkbox_on_background" />

Offline Speech Recognition In Android (JellyBean)

A simple and flexible offline recognition on Android is implemented by CMUSphinx, an open source speech recognition toolkit. It works purely offline, fast and configurable It can listen continuously for keyword, for example.

You can find latest code and tutorial here.

Update in 2019: Time goes fast, CMUSphinx is not that accurate anymore. I recommend to try Kaldi toolkit instead. The demo is here.

'MOD' is not a recognized built-in function name

The MOD keyword only exists in the DAX language (tabular dimensional queries), not TSQL

Use % instead.

Ref: Modulo

Gather multiple sets of columns

With the recent update to, we can now melt multiple columns. With that, we can do:

require(data.table) ## 1.9.5
melt(setDT(df), id=1:2, measure=patterns("^Q3.2", "^Q3.3"),"Q3.2", "Q3.3"),"loop_number")
 #    id       time loop_number         Q3.2        Q3.3
 # 1:  1 2009-01-01           1 -0.433978480  0.41227209
 # 2:  2 2009-01-02           1 -0.567995351  0.30701144
 # 3:  3 2009-01-03           1 -0.092041353 -0.96024077
 # 4:  4 2009-01-04           1  1.137433487  0.60603396
 # 5:  5 2009-01-05           1 -1.071498263 -0.01655584
 # 6:  6 2009-01-06           1 -0.048376809  0.55889996
 # 7:  7 2009-01-07           1 -0.007312176  0.69872938

You can get the development version from here.

GCM with PHP (Google Cloud Messaging)

    // Replace with the real server API key from Google APIs
    $apiKey = "your api key";

    // Replace with the real client registration IDs
    $registrationIDs = array( "reg id1","reg id2");

    // Message to be sent
    $message = "hi Shailesh";

    // Set POST variables
    $url = '';

    $fields = array(
        'registration_ids' => $registrationIDs,
        'data' => array( "message" => $message ),
    $headers = array(
        'Authorization: key=' . $apiKey,
        'Content-Type: application/json'

    // Open connection
    $ch = curl_init();

    // Set the URL, number of POST vars, POST data
    curl_setopt( $ch, CURLOPT_URL, $url);
    curl_setopt( $ch, CURLOPT_POST, true);
    curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true);
    //curl_setopt( $ch, CURLOPT_POSTFIELDS, json_encode( $fields));

    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    // curl_setopt($ch, CURLOPT_POST, true);
    // curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode( $fields));

    // Execute post
    $result = curl_exec($ch);

    // Close connection
    echo $result;

VBA Check if variable is empty

For a number, it is tricky because if a numeric cell is empty VBA will assign a default value of 0 to it, so it is hard for your VBA code to tell the difference between an entered zero and a blank numeric cell.

The following check worked for me to see if there was an actual 0 entered into the cell:

If CStr(rng.value) = "0" then
    'your code here'
End If

How do I fix the error "Only one usage of each socket address (protocol/network address/port) is normally permitted"?

I faced similar problem on windows server 2012 STD 64 bit , my problem is resolved after updating windows with all available windows updates.

Create an Array of Arraylists

The problem with this situation is by using a arraylist you get a time complexity of o(n) for adding at a specific position. If you use an array you create a memory location by declaring your array therefore it is constant

Remove array element based on object property

Following is the code if you are not using jQuery. Demo

var myArray = [
    {field: 'id', operator: 'eq', value: 'id'}, 
    {field: 'cStatus', operator: 'eq', value: 'cStatus'}, 
    {field: 'money', operator: 'eq', value: 'money'}


for(var i=0 ; i<myArray.length; i++)


You can also use underscore library which have lots of function.

Underscore is a utility-belt library for JavaScript that provides a lot of the functional programming support

How to store arrays in MySQL?

Use database field type BLOB to store arrays.


Return Values

Returns a string containing a byte-stream representation of value that can be stored anywhere.

Note that this is a binary string which may include null bytes, and needs to be stored and handled as such. For example, serialize() output should generally be stored in a BLOB field in a database, rather than a CHAR or TEXT field.

Update date + one year in mysql

You could use DATE_ADD : (or ADDDATE with INTERVAL)

UPDATE table SET date = DATE_ADD(date, INTERVAL 1 YEAR) 

How to get all child inputs of a div element (jQuery)

Use it without the greater than:

$("#panel :input");

The > means only direct children of the element, if you want all children no matter the depth just use a space.

Regular expression for 10 digit number without any special characters

Use this regular expression to match ten digits only:


To find a sequence of ten consecutive digits anywhere in a string, use:


Note that this will also find the first 10 digits of an 11 digit number. To search anywhere in the string for exactly 10 consecutive digits and not more you can use negative lookarounds:


Sourcetree - undo unpushed commits

  1. Right click on the commit you like to reset to (not the one you like to delete!)
  2. Select "Reset master to this commit"
  3. Select "Soft" reset.

A soft reset will keep your local changes.



About git revert: This command creates a new commit which will undo other commits. E.g. if you have a commit which adds a new file, git revert could be used to make a commit which will delete the new file.

About applying a soft reset: Assume you have the commits A to E (A---B---C---D---E) and you like to delete the last commit (E). Then you can do a soft reset to commit D. With a soft reset commit E will be deleted from git but the local changes will be kept. There are more examples in the git reset documentation.

Twitter Bootstrap - add top space between rows

There is a trick for adding margin automatically only for the 2nd+ row in the container.

.container-row-margin .row + .row {
    margin-top: 1rem;

Adding the .container-row-margin to the container, results in:

enter image description here

Complete HTML:

<div class="bg-secondary text-white">
    div outside of the container.
<div class="container container-row-margin">
    <div class="row">
        <div class="col col-4 bg-warning">
            Row without top margin
    <div class="row">
        <div class="col col-4 bg-primary text-white">
            Row with top margin
    <div class="row">
        <div class="col col-4 bg-primary text-white">
            Row with top margin
<div class="bg-secondary text-white">
    div outside of the container.

Taken from official samples.

Which is faster: multiple single INSERTs or one multiple-row INSERT?

MYSQL 5.5 One sql insert statement took ~300 to ~450ms. while the below stats is for inline multiple insert statments.

(25492 row(s) affected)
Execution Time : 00:00:03:343
Transfer Time  : 00:00:00:000
Total Time     : 00:00:03:343

I would say inline is way to go :)

Using GitLab token to clone without authentication

Customising the URL is not needed. Just use a git configuration for gitlab tokens such as

git config --global gitlab.accesstoken {TOKEN_VALUE}

extended description here

How to get label text value form a html page?

For cases where the data element is inside the label like in this example:

<label for="subscription">Subscription period
    <select id='subscription' name='subscription'>
        <option>1 year</option>
        <option>2 years</option>
        <option>3 years</option>

all the previous answers will give an unexpected result:

"Subscription period

                    1 year
                    2 years
                    3 years


While the expected result would be:

"Subscription period"

So, the correct solution will be like this:

const label = document.getElementById('yourLableId');
const labelText = Array.prototype.filter
    .call(label.childNodes, x => x.nodeName === "#text")
    .map(x => x.textContent)
    .join(" ")

jQuery - replace all instances of a character in a string

RegEx is the way to go in most cases.

In some cases, it may be faster to specify more elements or the specific element to perform the replace on:

$(document).ready(function () {
    $('.myclass').each(function () {
        $('img').each(function () {
            $(this).attr('src', $(this).attr('src').replace('_s.jpg', '_n.jpg'));

This does the replace once on each string, but it does it using a more specific selector.

Two HTML tables side by side, centered on the page

#outer { text-align: center; }
#inner { width:500px; text-align: left; margin: 0 auto; }
.t { float: left; width:240px; border: 1px solid black;}
#clearit { clear: both; }

did you register the component correctly? For recursive components, make sure to provide the "name" option

I had this error as well. I triple checked that names were correct.

However I got this error simply because I was not terminating the script tag.

    <p>My Form</p>

import PageA from "./PageA.vue"

export default {
  name: "MyForm",
  components: {

Notice there is no </script> at the end.

So be sure to double check this.

How to echo in PHP, HTML tags

Separating HTML from PHP is the best method. It's less confusing and easy to debug.


         <h3><a href="User<?php echo $i;?>"><?php echo $i;?></a></h3>
         <div>Lorem ipsum dolor sit amet.</div>


How can I get the console logs from the iOS Simulator?

XCode > 6.0 AND iOS > 8.0 The below script works if you have XCode version > 8.0

I use the below small Script to tail the simulator logs onto the system console.

sim_dir=`xcrun instruments -s | grep "iPhone 6 (8.2 Simulator)" | awk {'print $NF'} | tr -d '[]'`
tail -f ~/Library/Logs/CoreSimulator/$sim_dir/system.log

You can pass in the simulator type used in the Grep as an argument. As mentioned in the above posts, there are simctl and instruments command to view the type of simulators available for use depending on the Xcode version. To View the list of available devices/simulators.

xcrun instruments -s


xcrun simctl list

Now you can pass in the Device code OR Simulator type as an argument to the script and replace the "iPhone 6 (8.2 Simulator)" inside grep to be $1

In Android EditText, how to force writing uppercase?

You can used two way.

First Way:

Set android:inputType="textCapSentences" on your EditText.

Second Way:

When user enter the number you have to used text watcher and change small to capital letter.

edittext.addTextChangedListener(new TextWatcher() {

    public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {            

    public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                    int arg3) {             
    public void afterTextChanged(Editable et) {
          String s=et.toString();
         edittext.setSelection(edittext.length()); //fix reverse texting

How to check if a database exists in SQL Server?

Actually it's best to use:

   --code mine :)
   print 'db exists'

See and note that this does not make sense with the Azure SQL Database.

How to markdown nested list items in Bitbucket?

Even a single space works

...Just open this answer for edit to see it.

Nested lists, deeper levels: ---- leave here an empty row * first level A item - no space in front the bullet character * second level Aa item - 1 space is enough * third level Aaa item - 5 spaces min * second level Ab item - 4 spaces possible too * first level B item

Nested lists, deeper levels:

  • first level A item - no space in front the bullet character
    • second level Aa item - 1 space is enough
      • third level Aaa item - 5 spaces min
    • second level Ab item - 4 spaces possible too
  • first level B item

    Nested lists, deeper levels:
     ...Skip a line and indent eight spaces. (as said in the editor-help, just on this page)
    * first level A item - no space in front the bullet character
     * second level Aa item - 1 space is enough
         * third level Aaa item - 5 spaces min
        * second level Ab item - 4 spaces possible too
    * first level B item

How do I force git to use LF instead of CR+LF under windows?

core.autocrlf=input is the right setting for what you want, but you might have to do a git update-index --refresh and/or a git reset --hard for the change to take effect.

With core.autocrlf set to input, git will not apply newline-conversion on check-out (so if you have LF in the repo, you'll get LF), but it will make sure that in case you mess up and introduce some CRLFs in the working copy somehow, they won't make their way into the repo.

Display label text with line breaks in c#

Also you can use the following

@"Italian naval...<br><br>"+

Above code you can achieve double space. If you want single one means you simply use

Prolog "or" operator, query

Just another viewpoint. Performing an "or" in Prolog can also be done with the "disjunct" operator or semi-colon:

registered(X, Y) :-
    X = ct101; X = ct102; X = ct103.

For a fuller explanation:

Predicate control in Prolog

How to remove docker completely from ubuntu 14.04

Probably your problem is that for Docker that has been installed from default Ubuntu repository, the package name is

Or package name may be something like docker-ce. Try running

dpkg -l | grep -i docker

to identify what installed package you have

So you need to change package name in commands from to match package name. For example, for it would be:

sudo apt-get purge -y
sudo apt-get autoremove -y --purge
sudo apt-get autoclean

It adds:

The above commands will not remove images, containers, volumes, or user created configuration files on your host. If you wish to delete all images, containers, and volumes run the following command:

sudo rm -rf /var/lib/docker

Remove docker from apparmor.d:

sudo rm /etc/apparmor.d/docker

Remove docker group:

sudo groupdel docker

How to move an element into another element?

What about a JavaScript solution?

// Declare a fragment:
var fragment = document.createDocumentFragment();

// Append desired element to the fragment:

// Append fragment to desired element:

Check it out.

How to generate javadoc comments in Android Studio

Simply select (i.e. click) the method name, then use the key combo Alt+Enter, select "Add JavaDoc"

This assumes that you have not already added comments above the method, else the "Add JavaDoc" option will not appear.

Spring 3 RequestMapping: Get path value

Here is how I did it. You can see how I convert the requestedURI to a filesystem path (what this SO question is about). Bonus: and also how to respond with the file.

@RequestMapping(value = "/file/{userId}/**", method = RequestMethod.GET)
public void serveFile(@PathVariable("userId") long userId, HttpServletRequest request, HttpServletResponse response) {
    assert request != null;
    assert response != null;

    // requestURL:
    // requestURI:  /file/54/documents/tutorial.pdf
    // servletPath: /file/54/documents/tutorial.pdf
    // logger.debug("requestURL: " + request.getRequestURL());
    // logger.debug("requestURI: " + request.getRequestURI());
    // logger.debug("servletPath: " + request.getServletPath());

    String requestURI = request.getRequestURI();
    String relativePath = requestURI.replaceFirst("^/file/", "");

    Path path = Paths.get("/user_files").resolve(relativePath);
    try {
        InputStream is = new FileInputStream(path.toFile()); , response.getOutputStream());
    } catch (IOException ex) {
        logger.error("Error writing file to output stream. Path: '" + path + "', requestURI: '" + requestURI + "'");
        throw new RuntimeException("IOError writing file to output stream");

Capturing TAB key in text box

In Chrome on the Mac, alt-tab inserts a tab character into a <textarea> field.

Here’s one: . Wee! mvc3 return raw html to view

What was working for me (ASP.NET Core), was to set return type ContentResult, then wrap the HMTL into it and set the ContentType to "text/html; charset=UTF-8". That is important, because, otherwise it will not be interpreted as HTML and the HTML language would be displayed as text.

Here's the example, part of a Controller class:

/// <summary>
/// Startup message displayed in browser.
/// </summary>
/// <returns>HTML result</returns>
public ContentResult Get()
    var result = Content("<html><title>DEMO</title><head><h2>Demo started successfully."
      + "<br/>Use <b><a href=\"http://localhost:5000/swagger\">Swagger</a></b>"
      + " to view API.</h2></head><body/></html>");
    result.ContentType = "text/html; charset=UTF-8";
    return result;

What is a non-capturing group in regular expressions?

You can use capturing groups to organize and parse an expression. A non-capturing group has the first benefit, but doesn't have the overhead of the second. You can still say a non-capturing group is optional, for example.

Say you want to match numeric text, but some numbers could be written as 1st, 2nd, 3rd, 4th,... If you want to capture the numeric part, but not the (optional) suffix you can use a non-capturing group.


That will match numbers in the form 1, 2, 3... or in the form 1st, 2nd, 3rd,... but it will only capture the numeric part.

How to change folder with git bash?

The command is:

cd  /c/project/

Use the pwd command to see which path you are currently in, handy when you did a right-click "Git Bash here..."

How to pass a datetime parameter?

As a similar alternative to s k's answer, I am able to pass a date formatted by Date.prototype.toISOString() in the query string. This is the standard ISO 8601 format, and it is accepted by .Net Web API controllers without any additional configuration of the route or action.


var dateString = dateObject.toISOString(); // "2019-07-01T04:00:00.000Z"

No submodule mapping found in .gitmodule for a path that's not a submodule

Just git rm subdir will be ok. that will remove the subdir as an index.

What are the differences between Deferred, Promise and Future in JavaScript?

These answers, including the selected answer, are good for introducing promises conceptually, but lacking in specifics of what exactly the differences are in the terminology that arises when using libraries implementing them (and there are important differences).

Since it is still an evolving spec, the answer currently comes from attempting to survey both references (like wikipedia) and implementations (like jQuery):

  • Deferred: Never described in popular references, 1 2 3 4 but commonly used by implementations as the arbiter of promise resolution (implementing resolve and reject). 5 6 7

    Sometimes deferreds are also promises (implementing then), 5 6 other times it's seen as more pure to have the Deferred only capable of resolution, and forcing the user to access the promise for using then. 7

  • Promise: The most all-encompasing word for the strategy under discussion.

    A proxy object storing the result of a target function whose synchronicity we would like to abstract, plus exposing a then function accepting another target function and returning a new promise. 2

    Example from CommonJS:

    > asyncComputeTheAnswerToEverything()


    Always described in popular references, although never specified as to whose responsibility resolution falls to. 1 2 3 4

    Always present in popular implementations, and never given resolution abilites. 5 6 7

  • Future: a seemingly deprecated term found in some popular references 1 and at least one popular implementation, 8 but seemingly being phased out of discussion in preference for the term 'promise' 3 and not always mentioned in popular introductions to the topic. 9

    However, at least one library uses the term generically for abstracting synchronicity and error handling, while not providing then functionality. 10 It's unclear if avoiding the term 'promise' was intentional, but probably a good choice since promises are built around 'thenables.' 2


  1. Wikipedia on Promises & Futures
  2. Promises/A+ spec
  3. DOM Standard on Promises
  4. DOM Standard Promises Spec WIP
  5. DOJO Toolkit Deferreds
  6. jQuery Deferreds
  7. Q
  8. FutureJS
  9. Functional Javascript section on Promises
  10. Futures in AngularJS Integration Testing

Misc potentially confusing things

Center a 'div' in the middle of the screen, even when the page is scrolled up or down?

Change the position attribute to fixed instead of absolute.

Populate data table from data reader

You can load a DataTable directly from a data reader using the Load() method that accepts an IDataReader.

var dataReader = cmd.ExecuteReader();
var dataTable = new DataTable();

Use table row coloring for cells in Bootstrap

Updated html for the newer bootstrap

    .table-hover > tbody > tr.danger:hover > td {
     background-color: red !important;
.table-hover > tbody > tr.warning:hover > td {
     background-color: yellow !important;
.table-hover > tbody > tr.success:hover > td {
     background-color: blue !important;

Hidden Features of Xcode

Use #pragma for organization

You can use:

#pragma mark Foo

... as a way to organize methods in your source files. When browsing symbols via the pop up menu, whatever you place in Foo will appear bold in the list.

To display a separator (i.e. horizontal line), use:

#pragma mark -

It's very useful, especially for grouping together delegate methods or other groups of methods.

Php multiple delimiters in explode

Try about using:

$output = preg_split('/ (@|vs) /', $input);

Why doesn't "System.out.println" work in Android?


On the emulator and most devices System.out.println gets redirected to LogCat and printed using Log.i(). This may not be true on very old or custom Android versions.


There is no console to send the messages to so the System.out.println messages get lost. In the same way this happens when you run a "traditional" Java application with javaw.

Instead, you can use the Android Log class:

Log.d("MyApp","I am here");

You can then view the log either in the Logcat view in Eclipse, or by running the following command:

adb logcat

It's good to get in to the habit of looking at logcat output as that is also where the Stack Traces of any uncaught Exceptions are displayed.

The first Entry to every logging call is the log tag which identifies the source of the log message. This is helpful as you can filter the output of the log to show just your messages. To make sure that you're consistent with your log tag it's probably best to define it once as a static final String somewhere.

Log.d(MyActivity.LOG_TAG,"Application started");

There are five one-letter methods in Log corresponding to the following levels:

  • e() - Error
  • w() - Warning
  • i() - Information
  • d() - Debug
  • v() - Verbose
  • wtf() - What a Terrible Failure

The documentation says the following about the levels:

Verbose should never be compiled into an application except during development. Debug logs are compiled in but stripped at runtime. Error, warning and info logs are always kept.

Proper way to return JSON using node or Express

Older version of Express use app.use(express.json()) or bodyParser.json() read more about bodyParser middleware

On latest version of express we could simply use res.json()

const express = require('express'),
    port = process.env.port || 3000,
    app = express()

app.get('/', (req, res) => res.json({key: "value"}))

app.listen(port, () => console.log(`Server start at ${port}`))

How can compare-and-swap be used for a wait-free mutual exclusion for any shared data structure?

The linked list holds operations on the shared data structure.

For example, if I have a stack, it will be manipulated with pushes and pops. The linked list would be a set of pushes and pops on the pseudo-shared stack. Each thread sharing that stack will actually have a local copy, and to get to the current shared state, it'll walk the linked list of operations, and apply each operation in order to its local copy of the stack. When it reaches the end of the linked list, its local copy holds the current state (though, of course, it's subject to becoming stale at any time).

In the traditional model, you'd have some sort of locks around each push and pop. Each thread would wait to obtain a lock, then do a push or pop, then release the lock.

In this model, each thread has a local snapshot of the stack, which it keeps synchronized with other threads' view of the stack by applying the operations in the linked list. When it wants to manipulate the stack, it doesn't try to manipulate it directly at all. Instead, it simply adds its push or pop operation to the linked list, so all the other threads can/will see that operation and they can all stay in sync. Then, of course, it applies the operations in the linked list, and when (for example) there's a pop it checks which thread asked for the pop. It uses the popped item if and only if it's the thread that requested this particular pop.

Differences between dependencyManagement and dependencies in Maven

In Eclipse, there is one more feature in the dependencyManagement. When dependencies is used without it, the unfound dependencies are noticed in the pom file. If dependencyManagement is used, the unsolved dependencies remain unnoticed in the pom file and errors appear only in the java files. (imports and such...)

Difference between a script and a program?


The Difference Between a Program and a Script

A Script is also a program but without an opaque layer hiding the (source code) whereas a program is one having clothes, you can't see it's source code unless it is decompilable.

Scripts need other programs to execute them while programs don't need one.

CMake is not able to find BOOST libraries

Long answer to short, if you install boost in custom path, all header files must in ${path}/boost/.

if you want to konw why cmake can't find the requested Boost libraries after you have set BOOST_ROOT/BOOST_INCLUDEDIR, you can check cmake install location path_to_cmake/share/cmake-xxx/Modules/FindBoost.

cmake which will find Boost_INCLUDE_DIR in boost/config.hpp in BOOST_ROOT. That means your boost header file must in ${path}/boost/, any other format (such as ${path}/boost-x.y.z) will not be suitable for find_package in CMakeLists.txt.

How to display a jpg file in Python?

Don't forget to include

import Image

In order to show it use this :'pathToFile').show()

Writelines writes lines without newline, Just fills the file

As we want to only separate lines, and the writelines function in python does not support adding separator between lines, I have written the simple code below which best suits this problem:

sep = "\n" # defining the separator
new_lines = sep.join(lines) # lines as an iterator containing line strings

and finally:

with open("file_name", 'w') as file:

and you are done.

Git, How to reset origin/master to a commit?

Since I had a similar situation, I thought I'd share my situation and how these answers helped me (thanks everyone).

So I decided to work locally by amending my last commit every time I wanted to save my progress on the main branch (I know, I should've branched out, committed on that, kept pushing and later merge back to master).

One late night, in paranoid fear of loosing my progress to hardware failure or something out of the ether, I decided to push master to origin. Later I kept amending my local master branch and when I decided it's time to push again, I was faced with different master branches and found out I can't amend origin/upstream (duh!) like I can local development branches.

So I didn't checkout master locally because I already was after a commit. Master was unchanged. I didn't even need to reset --hard, my current commit was OK.

I just forced push to origin, without even specifying what commit I wanted to force on master since in this case it's whatever HEAD is at. Checked git diff master..origin/master so there weren't any differences and that's it. All fixed. Thanks! (I know, I'm a git newbie, please forgive!).

So if you're already OK with your master branch locally, just:

git push --force origin master
git diff master..origin/master

Eclipse and Windows newlines

There is a handy bash utility - dos2unix - which is a DOS/MAC to UNIX text file format converter, that if not already installed on your distro, should be able to be easily installed via a package manager. dos2unix man page

string sanitizer for filename

What about using rawurlencode() ?

Here is a function that sanitize even Chinese Chars:

public static function normalizeString ($str = '')
    $str = strip_tags($str); 
    $str = preg_replace('/[\r\n\t ]+/', ' ', $str);
    $str = preg_replace('/[\"\*\/\:\<\>\?\'\|]+/', ' ', $str);
    $str = strtolower($str);
    $str = html_entity_decode( $str, ENT_QUOTES, "utf-8" );
    $str = htmlentities($str, ENT_QUOTES, "utf-8");
    $str = preg_replace("/(&)([a-z])([a-z]+;)/i", '$2', $str);
    $str = str_replace(' ', '-', $str);
    $str = rawurlencode($str);
    $str = str_replace('%', '-', $str);
    return $str;

Here is the explaination

  1. Strip HTML Tags
  2. Remove Break/Tabs/Return Carriage
  3. Remove Illegal Chars for folder and filename
  4. Put the string in lower case
  5. Remove foreign accents such as Éàû by convert it into html entities and then remove the code and keep the letter.
  6. Replace Spaces with dashes
  7. Encode special chars that could pass the previous steps and enter in conflict filename on server. ex. "?????"
  8. Replace "%" with dashes to make sure the link of the file will not be rewritten by the browser when querying th file.

OK, some filename will not be releavant but in most case it will work.

ex. Original Name: "???????-??-????????????.jpg"

Output Name: "-E1-83-A1-E1-83-90-E1-83-91-E1-83-94-E1-83-AD-E1-83-93-E1-83-98--E1-83-93-E1-83-90--E1-83-A2-E1-83-98-E1-83-9E-E1-83-9D-E1-83-92-E1-83-A0-E1-83-90-E1-83-A4-E1-83-98-E1-83-A3-E1-83-9A-E1-83-98.jpg"

It's better like that than an 404 error.

Hope that was helpful.


What is the iBeacon Bluetooth Profile

It’s very simple, it just advertises a string which contains a few characters conforming to Apple’s iBeacon standard. you can refer the Link

-XX:MaxPermSize with or without -XX:PermSize

-XX:PermSize specifies the initial size that will be allocated during startup of the JVM. If necessary, the JVM will allocate up to -XX:MaxPermSize.

How to use Redirect in the new react-router-dom of Reactjs

You have to use setState to set a property that will render the <Redirect> inside your render() method.


class MyComponent extends React.Component {
  state = {
    redirect: false

  handleSubmit () {**/)
      .then(() => this.setState({ redirect: true }));

  render () {
    const { redirect } = this.state;

     if (redirect) {
       return <Redirect to='/somewhere'/>;

     return <RenderYourForm/>;

You can also see an example in the official documentation:

That said, I would suggest you to put the API call inside a service or something. Then you could just use the history object to route programatically. This is how the integration with redux works.

But I guess you have your reasons to do it this way.

Multiple github accounts on the same computer?

I use shell scripts to switch me to whatever account I want to be "active". Essentially you start from a fresh start, get one account configured properly and working, then move the these files to a name with the proper prefix. From then on you can use the command "github", or "gitxyz" to switch:

# my github script
cd ~/.ssh

if [ -f git_dhoerl -a -f -a -f config_dhoerl ]
    echo "Error: missing new files"
    exit 1

# Save a copy in /tmp, just in case
cp id_rsa /tmp
cp /tmp
cp config /tmp
echo "Saved old files in /tmp, just in case"

rm id_rsa
rm config
echo "Removed current links/files"

ln git_dhoerl id_rsa
ln config_dhoerl config

git config --global "dhoerl@<company>.com"
git config --global github.user "dhoerl"        
git config --global github.token "whatever_it_is"

ssh-add -D

I've had great luck with this. I also created a run script in Xcode (for you Mac users) so it would not build my project unless I had the proper setting (since its using git):

Run Script placed after Dependencies (using /bin/ksh as the shell):

if [ "$(git config --global --get" != "dhoerl@<company>.com" ]
    exit 1

EDIT: added tests for new files existence and copying old files to /tmp to address comment by @naomik below.

selenium get current url after loading a page

It's been a little while since I coded with selenium, but your code looks ok to me. One thing to note is that if the element is not found, but the timeout is passed, I think the code will continue to execute. So you can do something like this:

boolean exists = driver.findElements(By.xpath("//*[@id='someID']")).size() != 0

What does the above boolean return? And are you sure selenium actually navigates to the expected page? (That may sound like a silly question but are you actually watching the pages change... selenium can be run remotely you know...)

Launching an application (.EXE) from C#?

Additionally you will want to use the Environment Variables for your paths if at all possible:


  • %WINDIR% = Windows Directory
  • %APPDATA% = Application Data - Varies alot between Vista and XP.

There are many more check out the link for a longer list.

In Angular, how to redirect with $location.path as $ success callback

it's very easy code .. but hard to fined..

detailsApp.controller("SchoolCtrl", function ($scope, $location) { 
      $scope.addSchool = function () {

        location.href='/ManageSchool/TeacherProfile?ID=' + $scope.TeacherID;

"Parse Error : There is a problem parsing the package" while installing Android application

I got the same error (Parse Error, There is a problem parsing the package) while trying to install an .apk package from email. I was able to get around the problem by installing the 3rd party package installer ApKatcher:

ApKatcher isn't the only solution. A colleague of mine got around the problem by installing Astro File Manager.

You can find both applications in the Android Marketplace.

Writing to an Excel spreadsheet

Use DataFrame.to_excel from pandas. Pandas allows you to represent your data in functionally rich datastructures and will let you read in excel files as well.

You will first have to convert your data into a DataFrame and then save it into an excel file like so:

In [1]: from pandas import DataFrame
In [2]: l1 = [1,2,3,4]
In [3]: l2 = [1,2,3,4]
In [3]: df = DataFrame({'Stimulus Time': l1, 'Reaction Time': l2})
In [4]: df
   Reaction Time  Stimulus Time
0              1              1
1              2              2
2              3              3
3              4              4

In [5]: df.to_excel('test.xlsx', sheet_name='sheet1', index=False)

and the excel file that comes out looks like this:

enter image description here

Note that both lists need to be of equal length else pandas will complain. To solve this, replace all missing values with None.

Switch case with conditions

You should not use switch for this scenario. This is the proper approach:

var cnt = $("#div1 p").length;


if (cnt >= 10 && cnt <= 20)
else if (cnt >= 21 && cnt <= 30)
else if (cnt >= 31 && cnt <= 40)

Call a Javascript function every 5 seconds continuously

Do a "recursive" setTimeout of your function, and it will keep being executed every amount of time defined:

function yourFunction(){
    // do whatever you like here

    setTimeout(yourFunction, 5000);


File URL "Not allowed to load local resource" in the Internet Browser

For people do not like to modify chrome's security options, we can simply start a python http server from directory which contains your local file:

python -m SimpleHTTPServer

and for python 3:

python3 -m http.server

Now you can reach any local file directly from your js code or externally with

How to add a color overlay to a background image?

Try this, it's simple and clear. I have found it from here :

.tinted-image {

  width: 300px;
  height: 200px;

    /* top, transparent red */ 
      rgba(255, 0, 0, 0.45), 
      rgba(255, 0, 0, 0.45)
    /* bottom, image */

How to specify a editor to open crontab file? "export EDITOR=vi" does not work

If the above methods don't work (as they didn't work on my Ubuntu 13.04 installation) try:

There are a number of alternative ways:

1) Run select-editor


2) Manually edit the file: ~/.selected_editor specifying your preferred editor. With this option you can specify editor parameters.

# Generated by /usr/bin/select-editor
SELECTED_EDITOR="/usr/bin/emacs -nw"

3) You can specify on the fly on the commandline with:

env VISUAL="emacs -nw" crontab -e

How to hide 'Back' button on navigation bar on iPhone?

Don't forget that we have the slide to back gesture now. You probably want to remove this as well. Don't forget to enable it back again if necessary.

if ([self.navigationItem respondsToSelector:@selector(hidesBackButton)]) {
    self.navigationItem.hidesBackButton = YES;

if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
    self.navigationController.interactivePopGestureRecognizer.enabled = NO;

What permission do I need to access Internet from an Android application?

just put above line like below

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

    android:targetSdkVersion="16" />

 <uses-permission android:name="android.permission.INTERNET" />

    android:theme="@style/AppTheme" >

        android:label="@string/app_name" >
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />

Javascript to check whether a checkbox is being checked or unchecked

The value attribute of a checkbox is what you set by:

<input type='checkbox' name='test' value='1'>

So when someone checks that box, the server receives a variable named test with a value of 1 - what you want to check for is not the value of it (which will never change, whether it is checked or not) but the checked status of the checkbox.

So, if you replace this code:

if (arrChecks[i].value == "on") 
    arrChecks[i].checked = 1;
} else {
    arrChecks[i].checked = 0;

With this:

arrChecks[i].checked = !arrChecks[i].checked;

It should work. You should use true and false instead of 0 and 1 for this.

Python logging: use milliseconds in time format

Many outdated, over-complicated and weird answers here. The reason is that the documentation is inadequate and the simple solution is to just use basicConfig() and set it as follows:

logging.basicConfig(datefmt='%Y-%m-%d %H:%M:%S', format='{asctime}.{msecs:0<3.0f} {name} {threadName} {levelname}: {message}', style='{')

The trick here was that you have to also set the datefmt argument, as the default messes it up and is not what is (currently) shown in the how-to python docs. So rather look here.

An alternative and possibly cleaner way, would have been to override the default_msec_format variable with:

formatter = logging.Formatter('%(asctime)s')
formatter.default_msec_format = '%s.%03d'

However, that did not work for unknown reasons.

PS. I am using Python 3.8.

View a file in a different Git branch without changing branches

Add the following to your ~/.gitconfig file

  cat = "!git show \"$1:$2\" #"

And then try this


Personally I prefer separate parameters without a colon. Why? This choice mirrors the parameters of the checkout command, which I tend to use rather frequently and I find it thus much easier to remember than the bizarro colon-separated parameter of the show command.

Add a new item to recyclerview programmatically?

First add your item to mItems and then use:

mAdapter.notifyItemInserted(mItems.size() - 1);

this method is better than using:


in performance.

sql set variable using COUNT

You can select directly into the variable rather than using set:

DECLARE @times int

SELECT @times = COUNT(DidWin)
FROM thetable
WHERE DidWin = 1 AND Playername='Me'

If you need to set multiple variables you can do it from the same select (example a bit contrived):

DECLARE @wins int, @losses int

SELECT @wins = SUM(DidWin), @losses = SUM(DidLose)
FROM thetable
WHERE Playername='Me'

If you are partial to using set, you can use parentheses:

DECLARE @wins int, @losses int

SET (@wins, @losses) = (SELECT SUM(DidWin), SUM(DidLose)
FROM thetable
WHERE Playername='Me');

Why do we need to install gulp globally and locally?

You can link the globally installed gulp locally with

npm link gulp

Host '' is not allowed to connect to this MySQL server

The message *Host '''' is not allowed to connect to this MySQL server is a reply from the MySQL server to the MySQL client. Notice how its returning the IP address and not the hostname.

If you're trying to connect with mysql -h<hostname> -u<somebody> -p and it returns this message with the IP address, then the MySQL server isn't able to do a reverse lookup on the client. This is critical because thats how it maps the MySQL client to the grants.

Make sure you can do an nslookup <mysqlclient> FROM the MySQL server. If that doesn't work, then there's no entry in the DNS server. Alternatively, you can put an entry in the MySQL server's HOSTS file (<ipaddress> <fullyqualifiedhostname> <hostname> <- The order here might matter).

An entry in my server's host file allowing a reverse lookup of the MySQL client solved this very problem.

How to use a table type in a SELECT FROM statement?

You can't do it in a single query inside the package - you can't mix the SQL and PL/SQL types, and would need to define the types in the SQL layer as Tony, Marcin and Thio have said.

If you really want this done locally, and you can index the table type by VARCHAR instead of BINARY_INTEGER, you can do something like this:

-- dummy ITEM table as we don't know what the real ones looks like
create table item(
    item_num number,
    currency varchar2(9)

insert into item values(1,'GBP');
insert into item values(2,'AUD');
insert into item values(3,'GBP');
insert into item values(4,'AUD');
insert into item values(5,'CDN');

create package so_5165580 as
    type exch_row is record(
        exch_rt_eur number,
        exch_rt_usd number);
    type exch_tbl is table of exch_row index by varchar2(9);
    exch_rt exch_tbl;
    procedure show_items;
end so_5165580;

create package body so_5165580 as
    procedure populate_rates is
        rate exch_row;
        rate.exch_rt_eur := 0.614394;
        rate.exch_rt_usd := 0.8494;
        exch_rt('GBP') := rate;
        rate.exch_rt_eur := 0.9817;
        rate.exch_rt_usd := 1.3572;
        exch_rt('AUD') := rate;

    procedure show_items is
        cursor c0 is
            select i.*
            from item i;
        for r0 in c0 loop
            if exch_rt.exists(r0.currency) then
                dbms_output.put_line('Item ' || r0.item_num
                    || ' Currency ' || r0.currency
                    || ' EUR ' || exch_rt(r0.currency).exch_rt_eur
                    || ' USD ' || exch_rt(r0.currency).exch_rt_usd);
                dbms_output.put_line('Item ' || r0.item_num
                    || ' Currency ' || r0.currency
                    || ' ** no rates defined **');
            end if;
        end loop;
end so_5165580;

So inside your loop, wherever you would have expected to use r0.exch_rt_eur you instead use exch_rt(r0.currency).exch_rt_eur, and the same for USD. Testing from an anonymous block:


Item 1 Currency GBP EUR .614394 USD .8494
Item 2 Currency AUD EUR .9817 USD 1.3572
Item 3 Currency GBP EUR .614394 USD .8494
Item 4 Currency AUD EUR .9817 USD 1.3572
Item 5 Currency CDN ** no rates defined **

Based on the answer Stef posted, this doesn't need to be in a package at all; the same results could be achieved with an insert statement. Assuming EXCH holds exchange rates of other currencies against the Euro, including USD with currency_key=1:

insert into detail_items
with rt as (select c.currency_cd as currency_cd,
        e.exch_rt as exch_rt_eur,
        (e.exch_rt / usd.exch_rt) as exch_rt_usd
    from exch e,
        currency c,
        (select exch_rt from exch where currency_key = 1) usd
    where c.currency_key = e.currency_key)
select i.doc,
    i.net_value / rt.exch_rt_usd AS net_value_in_usd,
    i.net_value / rt.exch_rt_eur as net_value_in_euro
from item i
join rt on i.doc_currency = rt.currency_cd;

With items valued at 19.99 GBP and 25.00 AUD, you get detail_items:

--- ------------ ----------------- ----------------- -----------------
1   GBP          19.99             32.53611          23.53426
2   AUD          25                25.46041          18.41621

If you want the currency stuff to be more re-usable you could create a view:

create view rt as
select c.currency_cd as currency_cd,
    e.exch_rt as exch_rt_eur,
    (e.exch_rt / usd.exch_rt) as exch_rt_usd
from exch e,
    currency c,
    (select exch_rt from exch where currency_key = 1) usd
where c.currency_key = e.currency_key;

And then insert using values from that:

insert into detail_items
select i.doc,
    i.net_value / rt.exch_rt_usd AS net_value_in_usd,
    i.net_value / rt.exch_rt_eur as net_value_in_euro
from item i
join rt on i.doc_currency = rt.currency_cd;

Printing one character at a time from a string, using the while loop

   # make a list out of text - ['h','e','l','l','o']
   text = list('hello') 

   while text:
       print text.pop()


In python empty object are evaluated as false. The .pop() removes and returns the last item on a list. And that's why it prints on reverse !

But can be fixed by using:

text.pop( 0 )

iframe to Only Show a Certain Part of the Page

Set the iframe to the appropriate width and height and set the scrolling attribute to "no".

If the area you want is not in the top-left portion of the page, you can scroll the content to the appropriate area. Refer to this question:

Scrolling an iframe with javascript?

I believe you'll only be able to scroll it if both pages are on the same domain.

Show Error on the tip of the Edit Text Android

Using Kotlin Language,


 login_ID.setOnClickListener {
                email_address_Id.error = "Please Enter Email Address"
                Password_ID.error = "Please Enter Password"

Passing an array as an argument to a function in C

Passing a multidimensional array as argument to a function. Passing an one dim array as argument is more or less trivial. Let's take a look on more interesting case of passing a 2 dim array. In C you can't use a pointer to pointer construct (int **) instead of 2 dim array. Let's make an example:

void assignZeros(int(*arr)[5], const int rows) {
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < 5; j++) {
            *(*(arr + i) + j) = 0;
            // or equivalent assignment
            arr[i][j] = 0;

Here I have specified a function that takes as first argument a pointer to an array of 5 integers. I can pass as argument any 2 dim array that has 5 columns:

int arr1[1][5]
int arr1[2][5]
int arr1[20][5]

You may come to an idea to define a more general function that can accept any 2 dim array and change the function signature as follows:

void assignZeros(int ** arr, const int rows, const int cols) {
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            *(*(arr + i) + j) = 0;

This code would compile but you will get a runtime error when trying to assign the values in the same way as in the first function. So in C a multidimensional arrays are not the same as pointers to pointers ... to pointers. An int(*arr)[5] is a pointer to array of 5 elements, an int(*arr)[6] is a pointer to array of 6 elements, and they are a pointers to different types!

Well, how to define functions arguments for higher dimensions? Simple, we just follow the pattern! Here is the same function adjusted to take an array of 3 dimensions:

void assignZeros2(int(*arr)[4][5], const int dim1, const int dim2, const int dim3) {
    for (int i = 0; i < dim1; i++) {
        for (int j = 0; j < dim2; j++) {
            for (int k = 0; k < dim3; k++) {
                *(*(*(arr + i) + j) + k) = 0;
                // or equivalent assignment
                arr[i][j][k] = 0;

How you would expect, it can take as argument any 3 dim arrays that have in the second dimensions 4 elements and in the third dimension 5 elements. Anything like this would be OK:


But we have to specify all dimensions sizes up to the first one.

Delete duplicate elements from an array

Try following from Removing duplicates from an Array(simple):

Array.prototype.removeDuplicates = function (){
  var temp=new Array();
    if(this[i]==this[i+1]) {continue}
  return temp;


This code doesn't need sort:

Array.prototype.removeDuplicates = function (){
  var temp=new Array();
        for(var j=0; j<temp.length;j++ ){//check duplicates
            if(temp[j]==this[i])//skip if already present 
               continue label;      
        temp[temp.length] = this[i];
  return temp;

(But not a tested code!)

Git on Mac OS X v10.7 (Lion)

The default install location is /usr/local, so add this to your ~/.bash_profile file:

export PATH=$PATH:/usr/local/git/bin/

Then run source ~/.bash_profile in Terminal.

How to round an image with Glide library?

I was looking for it earlier and I made it in very easiest way, I hope you would like this.

 //crete this method into your Utils class and call this method wherever you want to use.
    //you can set these placeHolder() and error() image static as well. I made it as comment inside this method, then no need to use [placeHolderUrl and errorImageUrl] parameters. remove it from this method.
    public static void loadImage(final Activity context, ImageView imageView, String url, int placeHolderUrl, int errorImageUrl) {
        if (context == null || context.isDestroyed()) return;

            Glide.with(context) //passing context
                    .load(getFullUrl(url)) //passing your url to load image.
                    .placeholder(placeHolderUrl) //this would be your default image (like default profile or logo etc). it would be loaded at initial time and it will replace with your loaded image once glide successfully load image using url.
                    .error(errorImageUrl)//in case of any glide exception or not able to download then this image will be appear . if you won't mention this error() then nothing to worry placeHolder image would be remain as it is.
                    .diskCacheStrategy(DiskCacheStrategy.ALL) //using to load into cache then second time it will load fast.
                    .transform(new CircleTransform(context))//this CircleTransform class help to crop an image as circle.
                    .animate(R.anim.fade_in) // when image (url) will be loaded by glide then this face in animation help to replace url image in the place of placeHolder (default) image.
                    .fitCenter()//this method help to fit image into center of your ImageView
                    .into(imageView); //pass imageView reference to appear the image.

  public class CircleTransform extends BitmapTransformation {
    public CircleTransform(Context context) {


    private static Bitmap circleCrop(BitmapPool pool, Bitmap source) {
        if (source == null) return null;

        int size = Math.min(source.getWidth(), source.getHeight());
        int x = (source.getWidth() - size) / 2;
        int y = (source.getHeight() - size) / 2;

        Bitmap squared = Bitmap.createBitmap(source, x, y, size, size);

        Bitmap result = pool.get(size, size, Bitmap.Config.ARGB_8888);
        if (result == null) {
            result = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(result);
        Paint paint = new Paint();
        paint.setShader(new BitmapShader(squared, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));
        float r = size / 2f;
        canvas.drawCircle(r, r, r, paint);
        return result;

    protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
        return circleCrop(pool, toTransform);

    public String getId() {
        return getClass().getName();

fade_in.xml for fade in animation .

    <set xmlns:android="">

    android:toAlpha="1.0" />

finally to call this method.


What's the actual use of 'fail' in JUnit test case?

This is how I use the Fail method.

There are three states that your test case can end up in

  1. Passed : The function under test executed successfully and returned data as expected
  2. Not Passed : The function under test executed successfully but the returned data was not as expected
  3. Failed : The function did not execute successfully and this was not

intended (Unlike negative test cases that expect a exception to occur).

If you are using eclipse there three states are indicated by a Green, Blue and red marker respectively.

I use the fail operation for the the third scenario.

e.g. : public Integer add(integer a, Integer b) { return new Integer(a.intValue() + b.intValue())}

  1. Passed Case : a = new Interger(1), b= new Integer(2) and the function returned 3
  2. Not Passed Case: a = new Interger(1), b= new Integer(2) and the function returned soem value other than 3
  3. Failed Case : a =null , b= null and the function throws a NullPointerException

LDAP Authentication using Java

This is my LDAP Java login test application supporting LDAP:// and LDAPS:// self-signed test certificate. Code is taken from few SO posts, simplified implementation and removed legacy* imports.

I have run this in Windows7 and Linux machines against WinAD directory service. Application prints username and member groups.

$ java -cp classes test.LoginLDAP url=ldap:// [email protected] password=mypwd

$ java -cp classes test.LoginLDAP url=ldaps:// [email protected] password=mypwd

Test application supports temporary self-signed test certificates for ldaps:// protocol, this DummySSLFactory accepts any server cert so man-in-the-middle is possible. Real life installation should import server certificate to a local JKS keystore file and not using dummy factory.

Application uses enduser's username+password for initial context and ldap queries, it works for WinAD but don't know if can be used for all ldap server implementations. You could create context with internal username+pwd then run queries to see if given enduser is found.

package test;

import java.util.*;
import javax.naming.*;

public class LoginLDAP {

    public static void main(String[] args) throws Exception {
        Map<String,String> params = createParams(args);

        String url = params.get("url"); // ldap:// or ldaps://
        String principalName = params.get("username"); // [email protected]
        String domainName = params.get("domain"); // or empty

        if (domainName==null || "".equals(domainName)) {
            int delim = principalName.indexOf('@');
            domainName = principalName.substring(delim+1);

        Properties props = new Properties();
        props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
        props.put(Context.PROVIDER_URL, url); 
        props.put(Context.SECURITY_PRINCIPAL, principalName); 
        props.put(Context.SECURITY_CREDENTIALS, params.get("password")); // secretpwd
        if (url.toUpperCase().startsWith("LDAPS://")) {
            props.put(Context.SECURITY_PROTOCOL, "ssl");
            props.put(Context.SECURITY_AUTHENTICATION, "simple");
            props.put("java.naming.ldap.factory.socket", "test.DummySSLSocketFactory");         

        InitialDirContext context = new InitialDirContext(props);
        try {
            SearchControls ctrls = new SearchControls();
            NamingEnumeration<SearchResult> results =,"(& (userPrincipalName="+principalName+")(objectClass=user))", ctrls);
                throw new AuthenticationException("Principal name not found");

            SearchResult result =;
            System.out.println("distinguisedName: " + result.getNameInNamespace() ); // CN=Firstname Lastname,OU=Mycity,DC=mydomain,DC=com

            Attribute memberOf = result.getAttributes().get("memberOf");
            if(memberOf!=null) {
                for(int idx=0; idx<memberOf.size(); idx++) {
                    System.out.println("memberOf: " + memberOf.get(idx).toString() ); // CN=Mygroup,CN=Users,DC=mydomain,DC=com
                    //Attribute att = context.getAttributes(memberOf.get(idx).toString(), new String[]{"CN"}).get("CN");
                    //System.out.println( att.get().toString() ); //  CN part of groupname
        } finally {
            try { context.close(); } catch(Exception ex) { }

     * Create "DC=sub,DC=mydomain,DC=com" string
     * @param domainName
     * @return
    private static String toDC(String domainName) {
        StringBuilder buf = new StringBuilder();
        for (String token : domainName.split("\\.")) {
            if(token.length()==0) continue;
            if(buf.length()>0)  buf.append(",");
        return buf.toString();

    private static Map<String,String> createParams(String[] args) {
        Map<String,String> params = new HashMap<String,String>();  
        for(String str : args) {
            int delim = str.indexOf('=');
            if (delim>0) params.put(str.substring(0, delim).trim(), str.substring(delim+1).trim());
            else if (delim==0) params.put("", str.substring(1).trim());
            else params.put(str, null);
        return params;


And SSL helper class.

package test;


public class DummySSLSocketFactory extends SSLSocketFactory {
    private SSLSocketFactory socketFactory;
    public DummySSLSocketFactory() {
        try {
          SSLContext ctx = SSLContext.getInstance("TLS");
          ctx.init(null, new TrustManager[]{ new DummyTrustManager()}, new SecureRandom());
          socketFactory = ctx.getSocketFactory();
        } catch ( Exception ex ){ throw new IllegalArgumentException(ex); }

      public static SocketFactory getDefault() { return new DummySSLSocketFactory(); }

      @Override public String[] getDefaultCipherSuites() { return socketFactory.getDefaultCipherSuites(); }
      @Override public String[] getSupportedCipherSuites() { return socketFactory.getSupportedCipherSuites(); }

      @Override public Socket createSocket(Socket socket, String string, int i, boolean bln) throws IOException {
        return socketFactory.createSocket(socket, string, i, bln);
      @Override public Socket createSocket(String string, int i) throws IOException, UnknownHostException {
        return socketFactory.createSocket(string, i);
      @Override public Socket createSocket(String string, int i, InetAddress ia, int i1) throws IOException, UnknownHostException {
        return socketFactory.createSocket(string, i, ia, i1);
      @Override public Socket createSocket(InetAddress ia, int i) throws IOException {
        return socketFactory.createSocket(ia, i);
      @Override public Socket createSocket(InetAddress ia, int i, InetAddress ia1, int i1) throws IOException {
        return socketFactory.createSocket(ia, i, ia1, i1);

class DummyTrustManager implements X509TrustManager {
    @Override public void checkClientTrusted(X509Certificate[] xcs, String str) {
        // do nothing
    @Override public void checkServerTrusted(X509Certificate[] xcs, String str) {
        /*System.out.println("checkServerTrusted for authType: " + str); // RSA
        for(int idx=0; idx<xcs.length; idx++) {
            X509Certificate cert = xcs[idx];
            System.out.println("X500Principal: " + cert.getSubjectX500Principal().getName());
    @Override public X509Certificate[] getAcceptedIssuers() {
        return new[0];

How do I turn a C# object into a JSON string in .NET?

If they are not very big, what's probably your case export it as JSON.

Also this makes it portable among all platforms.

using Newtonsoft.Json;

public void ExportJson()
    double[,] b = new double[,]
            { 110,  120,  130,  140, 150 },
            {1110, 1120, 1130, 1140, 1150},
            {1000,    1,   5,     9, 1000},
            {1110,    2,   6,    10, 1110},
            {1220,    3,   7,    11, 1220},
            {1330,    4,   8,    12, 1330}

    string jsonStr = JsonConvert.SerializeObject(b);


    string path = "X:\\Programming\\workspaceEclipse\\PyTutorials\\src\\tensorflow_tutorials\\export.txt";

    File.WriteAllText(path, jsonStr);

Facebook Graph API : get larger pictures in one request

Hum... I think I've found a solution.

In fact, in can just request,name

According to (section "Pictures"), url of profile's photos can be built with the user id

For example, assuming user id is in $id :


But it's not the final image URL, so if someone have a better solution, i would be glad to know :)

Cordova - Error code 1 for command | Command failed for

Delete platforms/android folder and try to rebuild. That helped me a lot.

(Visual Studio Tools for Apache Cordova)

usr/bin/ld: cannot find -l<nameOfTheLibrary>

To figure out what the linker is looking for, run it in verbose mode.

For example, I encountered this issue while trying to compile MySQL with ZLIB support. I was receiving an error like this during compilation:

/usr/bin/ld: cannot find -lzlib

I did some Googl'ing and kept coming across different issues of the same kind where people would say to make sure the .so file actually exists and if it doesn't, then create a symlink to the versioned file, for example, But, when I checked, DID exist. So, I thought, surely that couldn't be the problem.

I came across another post on the Internets that suggested to run make with LD_DEBUG=all:

LD_DEBUG=all make

Although I got a TON of debugging output, it wasn't actually helpful. It added more confusion than anything else. So, I was about to give up.

Then, I had an epiphany. I thought to actually check the help text for the ld command:

ld --help

From that, I figured out how to run ld in verbose mode (imagine that):

ld -lzlib --verbose

This is the output I got:

attempt to open /usr/x86_64-linux-gnu/lib64/ failed
attempt to open /usr/x86_64-linux-gnu/lib64/libzlib.a failed
attempt to open /usr/local/lib64/ failed
attempt to open /usr/local/lib64/libzlib.a failed
attempt to open /lib64/ failed
attempt to open /lib64/libzlib.a failed
attempt to open /usr/lib64/ failed
attempt to open /usr/lib64/libzlib.a failed
attempt to open /usr/x86_64-linux-gnu/lib/ failed
attempt to open /usr/x86_64-linux-gnu/lib/libzlib.a failed
attempt to open /usr/local/lib/ failed
attempt to open /usr/local/lib/libzlib.a failed
attempt to open /lib/ failed
attempt to open /lib/libzlib.a failed
attempt to open /usr/lib/ failed
attempt to open /usr/lib/libzlib.a failed
/usr/bin/ld.bfd.real: cannot find -lzlib

Ding, ding, ding...

So, to finally fix it so I could compile MySQL with my own version of ZLIB (rather than the bundled version):

sudo ln -s /usr/lib/ /usr/lib/


How can I insert new line/carriage returns into an element.textContent?

None of the above solutions worked for me. I was trying to add a line feed and additional text to a <p> element. I typically use Firefox, but I do need browser compatibility. I read that only Firefox supports the textContent property, only Internet Explorer supports the innerText property, but both support the innerHTML property. However, neither adding <br /> nor \n nor \r\n to any of those properties resulted in a new line. The following, however, did work:

<script type="text/javascript">
  function modifyParagraph() {

  var p;
  p.appendChild(document.createTextNode("Additional text."));

<p id="paragraphID">Original text.</p>

<input type="button" id="pbutton" value="Modify Paragraph" onClick="modifyParagraph()" />

How to express a NOT IN query with ActiveRecord/Rails?

You may want to have a look at the meta_where plugin by Ernie Miller. Your SQL statement:

SELECT * FROM topics WHERE forum_id NOT IN (<@forum ids>)

...could be expressed like this:

Topic.where(:forum_id.nin => @forum_ids)

Ryan Bates of Railscasts created a nice screencast explaining MetaWhere.

Not sure if this is what you're looking for but to my eyes it certainly looks better than an embedded SQL query.

Remove all padding and margin table HTML and CSS

Try to use this CSS:

/* Apply this to your `table` element. */
#page {
   border-collapse: collapse;

/* And this to your table's `td` elements. */
#page td {
   padding: 0; 
   margin: 0;

How to set div width using ng-style

ngStyle accepts a map:

$scope.myStyle = {
    "width" : "900px",
    "background" : "red"


How to hide console window in python?

Simply save it with a .pyw extension. This will prevent the console window from opening.

On Windows systems, there is no notion of an “executable mode”. The Python installer automatically associates .py files with python.exe so that a double-click on a Python file will run it as a script. The extension can also be .pyw, in that case, the console window that normally appears is suppressed.

Explanation at the bottom of section 2.2.2

Print current call stack from a method in Python code

Here's an example of getting the stack via the traceback module, and printing it:

import traceback

def f():

def g():
    for line in traceback.format_stack():


# Prints:
# File "", line 10, in <module>
#     f()
# File "", line 4, in f
#     g()
# File "", line 7, in g
#     for line in traceback.format_stack():

If you really only want to print the stack to stderr, you can use:


Or to print to stdout (useful if want to keep redirected output together), use:


But getting it via traceback.format_stack() lets you do whatever you like with it.

Using Javascript in CSS

I ran into a similar problem and have developed two standalone tools to accomplish this:

  • CjsSS.js is a Vanilla Javascript tool (so no external dependencies) that supports back to IE6.

  • ngCss is an Angular Module+Filter+Factory (aka: plugin) that supports Angular 1.2+ (so back to IE8)

Both of these tool sets allow you to do this in a STYLE tag or within an external *.css file:

    /*<script src='some.js'></script>
        var mainColor = "#cccccc";

    BODY {
        color: /*{{mainColor}}*/;

And this in your on-page style attributes:

    <div style="color: {{mainColor}}" cjsss="#sourceCSS">blah</div>


    <div style="color: {{mainColor}}" ng-css="sourceCSS">blah</div>

NOTE: In ngCss, you could also do $scope.mainColor in place of var mainColor

By default, the Javascript is executed in a sandboxed IFRAME, but since you author your own CSS and host it on your own server (just like your *.js files) then XSS isn't an issue. But the sandbox provides that much more security and peace of mind.

CjsSS.js and ngCss fall somewhere in-between the other tools around to accomplish similar tasks:

  • LESS, SASS and Stylus are all Preprocessors only and require you to learn a new language and mangle your CSS. Basically they extended CSS with new language features. All are also limited to plugins developed for each platform while CjsSS.js and ngCss both allow you to include any Javascript library via <script src='blah.js'></script> straight in your CSS!

  • AbsurdJS saw the same problems and went the exact opposite direction of the Preprocessors above; rather than extending CSS, AbsurdJS created a Javascript library to generate CSS.

CjsSS.js and ngCss took the middle ground; you already know CSS, you already know Javascript, so just let them work together in a simple, intuitive way.

Best way to select random rows PostgreSQL

A variation of the materialized view "Possible alternative" outlined by Erwin Brandstetter is possible.

Say, for example, that you don't want duplicates in the randomized values that are returned. So you will need to set a boolean value on the primary table containing your (non-randomized) set of values.

Assuming this is the input table:

id_values  id  |   used
           1   |   FALSE
           2   |   FALSE
           3   |   FALSE
           4   |   FALSE
           5   |   FALSE

Populate the ID_VALUES table as needed. Then, as described by Erwin, create a materialized view that randomizes the ID_VALUES table once:

CREATE MATERIALIZED VIEW id_values_randomized AS
  FROM id_values
  ORDER BY random();

Note that the materialized view does not contain the used column, because this will quickly become out-of-date. Nor does the view need to contain other columns that may be in the id_values table.

In order to obtain (and "consume") random values, use an UPDATE-RETURNING on id_values, selecting id_values from id_values_randomized with a join, and applying the desired criteria to obtain only relevant possibilities. For example:

UPDATE id_values
SET used = TRUE
    FROM id_values_randomized r INNER JOIN id_values i ON =
    WHERE (NOT i.used)
    LIMIT 5)

Change LIMIT as necessary -- if you only need one random value at a time, change LIMIT to 1.

With the proper indexes on id_values, I believe the UPDATE-RETURNING should execute very quickly with little load. It returns randomized values with one database round-trip. The criteria for "eligible" rows can be as complex as required. New rows can be added to the id_values table at any time, and they will become accessible to the application as soon as the materialized view is refreshed (which can likely be run at an off-peak time). Creation and refresh of the materialized view will be slow, but it only needs to be executed when new id's are added to the id_values table.

jQuery UI Dialog with ASP.NET button postback


Using this code solved my problem and it worked in every browser, Internet Explorer 7, Firefox 3, and Google Chrome. I start to love jQuery... It's a cool framework.

I have tested with partial render too, exactly what I was looking for. Great!

<script type="text/javascript">
    function openModalDiv(divname) {
        $('#' + divname).dialog({ autoOpen: false, bgiframe: true, modal: true });
        $('#' + divname).dialog('open');
        $('#' + divname).parent().appendTo($("form:first"));

    function closeModalDiv(divname) {
        $('#' + divname).dialog('close');
<input id="Button1" type="button" value="Open 1" onclick="javascript:openModalDiv('Div1');" />
<div id="Div1" title="Basic dialog" >
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
          postback test<br />
          <asp:Button ID="but_OK" runat="server" Text="Send request" /><br />
          <asp:TextBox ID="tb_send" runat="server"></asp:TextBox><br />
          <asp:Label ID="lbl_result" runat="server" Text="prova" BackColor="#ff0000></asp:Label>
    <input id="Button2" type="button" value="cancel" onclick="javascript:closeModalDiv('Div1');" />

In .NET, which loop runs faster, 'for' or 'foreach'?

It is what you do inside the loop that affects perfomance, not the actual looping construct (assuming your case is non-trivial).

Dataset - Vehicle make/model/year (free)

How about Freebase? I think they have an API available, too.

Disable a Button

The button can be Disabled in Swift 4 by the code

@IBAction func yourButtonMethodname(sender: UIButon) {
 yourButton.isEnabled = false 

Rmi connection refused with localhost

One difference we can note in Windows is:

If you use Runtime.getRuntime().exec("rmiregistry 1024");

you can see rmiregistry.exe process will run in your Task Manager

whereas if you use Registry registry = LocateRegistry.createRegistry(1024);

you can not see the process running in Task Manager,

I think Java handles it in a different way.

and this is my server.policy file

Before running the the application, make sure that you killed all your existing javaw.exe and rmiregistry.exe corresponds to your rmi programs which are already running.

The following code works for me by using Registry.LocateRegistry() or


// Standard extensions get all permissions by default

grant {

VM argument



package server;    

import java.rmi.Naming;
import java.rmi.RMISecurityManager;
import java.rmi.Remote;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

public class HelloServer 
  public static void main (String[] argv) 
    try {

            System.setSecurityManager(new RMISecurityManager());

 Runtime.getRuntime().exec("rmiregistry 1024");

 //     Registry registry = LocateRegistry.createRegistry(1024);
   //   registry.rebind ("Hello", new Hello ("Hello,From pvt ltd!"));
   //Process process = Runtime.getRuntime().exec("C:\\Users\\Durai\\workspace\\RMI\\src\\server\\rmi_registry_start.bat");

        Naming.rebind ("//localhost:1024/Hello",new Hello ("Hello,From pvt ltd!")); 
      System.out.println ("Server is connected and ready for operation.");
    catch (Exception e) {
      System.out.println ("Server not connected: " + e);

How do I debug jquery AJAX calls?

You can use the "Network" tab in the browser (shift+ctrl+i) or Firebug.
But an even better solution - in my opinion - is in addition to use an external program such as Fiddler to monitor/catch the traffic between browser and server.

How do I restart my C# WinForm Application?

I figured an another solution out, perhaps anyone can use it, too.

string batchContent = "/c \"@ECHO OFF & timeout /t 6 > nul & start \"\" \"$[APPPATH]$\" & exit\"";
batchContent = batchContent.Replace("$[APPPATH]$", Application.ExecutablePath);
Process.Start("cmd", batchContent);

Code is simplified so take care of Exceptions and stuff ;)

Simplest way to do a recursive self-join?

Check following to help the understand the concept of CTE recursion

@startDate DATETIME,

SET @startDate = '11/10/2011'
SET @endDate = '03/25/2012'

        YEAR(@startDate) AS 'yr',
        MONTH(@startDate) AS 'mm',
        DATENAME(mm, @startDate) AS 'mon',
        DATEPART(d,@startDate) AS 'dd',
        @startDate 'new_date'
        YEAR(new_date) AS 'yr',
        MONTH(new_date) AS 'mm',
        DATENAME(mm, new_date) AS 'mon',
        DATEPART(d,@startDate) AS 'dd',
        DATEADD(d,1,new_date) 'new_date'
    WHERE new_date < @endDate
SELECT yr AS 'Year', mon AS 'Month', count(dd) AS 'Days'
GROUP BY mon, yr, mm
ORDER BY yr, mm

How to copy file from host to container using Dockerfile

I was able to copy a file from my host to the container within a dockerfile as such:

  1. Created a folder on my c driver --> c:\docker
  2. Create a test file in the same folder --> c:\docker\test.txt
  3. Create a docker file in the same folder --> c:\docker\dockerfile
  4. The contents of the docker file as follows,to copy a file from local host to the root of the container: FROM ubuntu:16.04

    COPY test.txt /

  5. Pull a copy of ubuntu from docker hub --> docker pull ubuntu:16.04
  6. Build the image from the dockerfile --> docker build -t myubuntu c:\docker\
  7. Build the container from your new image myubuntu --> docker run -d -it --name myubuntucontainer myubuntu "/sbin/init"
  8. Connect to the newly created container -->docker exec -it myubuntucontainer bash
  9. Check if the text.txt file is in the root --> ls

You should see the file.

Make an Android button change background on click through XML

public void methodOnClick(View view){



i recommend use button inside LinearLayout for adjust to size of Linear.

Iterate all files in a directory using a 'for' loop

In my case I had to delete all the files and folders underneath a temp folder. So this is how I ended up doing it. I had to run two loops one for file and one for folders. If files or folders have spaces in their names then you have to use " "

cd %USERPROFILE%\AppData\Local\Temp\
rem files only
for /r %%a in (*) do (
echo deleting file "%%a" ...
if exist "%%a" del /s /q "%%a"
rem folders only
for /D %%a in (*) do (
echo deleting folder "%%a" ...
if exist "%%a" rmdir /s /q "%%a"

Is it possible to compile a program written in Python?

If you really want, you could always compile with Cython. This will generate C code, which you can then compile with any C compiler such as GCC.

Getting new Twitter API consumer and secret keys

consumer_key = API key

consumer_secret = API key secret

Found it hidden in Twitter API Docs

Twitter Docs screenshot

Twitter's naming is just too confusing.

R Language: How to print the first or last rows of a data set?

If you want to print the last 10 lines, use

tail(dataset, 10)

for the first 10, you could also do

head(dataset, 10)

Android: Rotate image in imageview by an angle

If you're supporting API 11 or higher, you can just use the following XML attribute:


It might not display correctly in Android Studio xml preview, but it works as expected.

jQuery: Slide left and slide right

You can always just use jQuery to add a class, .addClass or .toggleClass. Then you can keep all your styles in your CSS and out of your scripts.

show dbs gives "Not Authorized to execute command" error

It was Docker running in the background in my case. If you have Docker installed, you may wanna close it and try again.

Update Row if it Exists Else Insert Logic with Entity Framework


public static void InsertOrUpdateRange<T, T2>(this T entity, List<T2> updateEntity) 
        where T : class
        where T2 : class
            foreach(var e in updateEntity)

        public static void InsertOrUpdate<T, T2>(this T entity, T2 updateEntity) 
        where T : class
        where T2 : class
            if (context.Entry(updateEntity).State == EntityState.Detached)
                if (context.Set<T2>().Any(t => t == updateEntity))


Getting RSA private key from PEM BASE64 Encoded private key file

This is PKCS#1 format of a private key. Try this code. It doesn't use Bouncy Castle or other third-party crypto providers. Just and for DER sequece parsing. Also it supports parsing of a private key in PKCS#8 format (PEM file that has a header "-----BEGIN PRIVATE KEY-----").


import java.math.BigInteger;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Base64;

public static PrivateKey pemFileLoadPrivateKeyPkcs1OrPkcs8Encoded(File pemFileName) throws GeneralSecurityException, IOException {
        // PKCS#8 format
        final String PEM_PRIVATE_START = "-----BEGIN PRIVATE KEY-----";
        final String PEM_PRIVATE_END = "-----END PRIVATE KEY-----";

        // PKCS#1 format
        final String PEM_RSA_PRIVATE_START = "-----BEGIN RSA PRIVATE KEY-----";
        final String PEM_RSA_PRIVATE_END = "-----END RSA PRIVATE KEY-----";

        Path path = Paths.get(pemFileName.getAbsolutePath());

        String privateKeyPem = new String(Files.readAllBytes(path));

        if (privateKeyPem.indexOf(PEM_PRIVATE_START) != -1) { // PKCS#8 format
            privateKeyPem = privateKeyPem.replace(PEM_PRIVATE_START, "").replace(PEM_PRIVATE_END, "");
            privateKeyPem = privateKeyPem.replaceAll("\\s", "");

            byte[] pkcs8EncodedKey = Base64.getDecoder().decode(privateKeyPem);

            KeyFactory factory = KeyFactory.getInstance("RSA");
            return factory.generatePrivate(new PKCS8EncodedKeySpec(pkcs8EncodedKey));

        } else if (privateKeyPem.indexOf(PEM_RSA_PRIVATE_START) != -1) {  // PKCS#1 format

            privateKeyPem = privateKeyPem.replace(PEM_RSA_PRIVATE_START, "").replace(PEM_RSA_PRIVATE_END, "");
            privateKeyPem = privateKeyPem.replaceAll("\\s", "");

            DerInputStream derReader = new DerInputStream(Base64.getDecoder().decode(privateKeyPem));

            DerValue[] seq = derReader.getSequence(0);

            if (seq.length < 9) {
                throw new GeneralSecurityException("Could not parse a PKCS1 private key.");

            // skip version seq[0];
            BigInteger modulus = seq[1].getBigInteger();
            BigInteger publicExp = seq[2].getBigInteger();
            BigInteger privateExp = seq[3].getBigInteger();
            BigInteger prime1 = seq[4].getBigInteger();
            BigInteger prime2 = seq[5].getBigInteger();
            BigInteger exp1 = seq[6].getBigInteger();
            BigInteger exp2 = seq[7].getBigInteger();
            BigInteger crtCoef = seq[8].getBigInteger();

            RSAPrivateCrtKeySpec keySpec = new RSAPrivateCrtKeySpec(modulus, publicExp, privateExp, prime1, prime2, exp1, exp2, crtCoef);

            KeyFactory factory = KeyFactory.getInstance("RSA");

            return factory.generatePrivate(keySpec);

        throw new GeneralSecurityException("Not supported format of a private key");

Eclipse: "'Periodic workspace save.' has encountered a pro?blem."

I fixed mine by closing eclipse and deleting the whole .metadata folder inside my workspace folder.

PHP date() format when inserting into datetime in MySQL

Here's an alternative solution: if you have the date in PHP as a timestamp, bypass handling it with PHP and let the DB take care of transforming it by using the FROM_UNIXTIME function.

mysql> insert into a_table values(FROM_UNIXTIME(1231634282));
Query OK, 1 row affected (0.00 sec)

mysql> select * from a_table;

| a_date              |
| 2009-01-10 18:38:02 |

How to get the system uptime in Windows?

Following are eight ways to find the Uptime in Windows OS.

1: By using the Task Manager

In Windows Vista and Windows Server 2008, the Task Manager has been beefed up to show additional information about the system. One of these pieces of info is the server’s running time.

  1. Right-click on the Taskbar, and click Task Manager. You can also click CTRL+SHIFT+ESC to get to the Task Manager.
  2. In Task Manager, select the Performance tab.
  3. The current system uptime is shown under System or Performance ⇒ CPU for Win 8/10.

    "Up Time" field in Task Manager

2: By using the System Information Utility

The systeminfo command line utility checks and displays various system statistics such as installation date, installed hotfixes and more. Open a Command Prompt and type the following command:


You can also narrow down the results to just the line you need:

systeminfo | find "System Boot Time:"

enter image description here

3: By using the Uptime Utility

Microsoft have published a tool called Uptime.exe. It is a simple command line tool that analyses the computer's reliability and availability information. It can work locally or remotely. In its simple form, the tool will display the current system uptime. An advanced option allows you to access more detailed information such as shutdown, reboots, operating system crashes, and Service Pack installation.

Read the following KB for more info and for the download links:

To use it, follow these steps:

  1. Download uptime.exe from the above link, and save it to a folder, preferably in one that's in the system's path (such as SYSTEM32).
  2. Open an elevated Command Prompt window. To open an elevated Command Prompt, click Start, click All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator. You can also type CMD in the search box of the Start menu, and when you see the Command Prompt icon click on it to select it, hold CTRL+SHIFT and press ENTER.
  3. Navigate to where you've placed the uptime.exe utility.
  4. Run the uptime.exe utility. You can add a /? to the command in order to get more options. enter image description here

It does not offer many command line parameters:

C:\uptimefromcodeplex\> uptime /?
usage: Uptime [-V]
    -V   display version

C:\uptimefromcodeplex\> uptime -V
version 1.1.0

3.1: By using the old Uptime Utility

There is an older version of the "uptime.exe" utility. This has the advantage of NOT needing .NET. (It also has a lot more features beyond simple uptime.)

Download link: Windows NT 4.0 Server Uptime Tool (uptime.exe) (final x86)

C:\uptimev100download>uptime.exe /?

UPTIME, Version 1.00
(C) Copyright 1999, Microsoft Corporation

Uptime [server] [/s ] [/a] [/d:mm/dd/yyyy | /p:n] [/heartbeat] [/? | /help]
        server          Name or IP address of remote server to process.
        /s              Display key system events and statistics.
        /a              Display application failure events (assumes /s).
        /d:             Only calculate for events after mm/dd/yyyy.
        /p:             Only calculate for events in the previous n days.
        /heartbeat      Turn on/off the system's heartbeat
        /?              Basic usage.
        /help           Additional usage information.

4: By using the NET STATISTICS Utility

Another easy method, if you can remember it, is to use the approximate information found in the statistics displayed by the NET STATISTICS command. Open a Command Prompt and type the following command:

net statistics workstation

The statistics should tell you how long it’s been running, although in some cases this information is not as accurate as other methods.

enter image description here

5: By Using the Event Viewer

Probably the most accurate of them all, but it does require some clicking. It does not display an exact day or hour count since the last reboot, but it will display important information regarding why the computer was rebooted and when it did so. We need to look at Event ID 6005, which is an event that tells us that the computer has just finished booting, but you should be aware of the fact that there are virtually hundreds if not thousands of other event types that you could potentially learn from.

Note: BTW, the 6006 Event ID is what tells us when the server has gone down, so if there’s much time difference between the 6006 and 6005 events, the server was down for a long time.

Note: You can also open the Event Viewer by typing eventvwr.msc in the Run command, and you might as well use the shortcut found in the Administrative tools folder.

  1. Click on Event Viewer (Local) in the left navigation pane.
  2. In the middle pane, click on the Information event type, and scroll down till you see Event ID 6005. Double-click the 6005 Event ID, or right-click it and select View All Instances of This Event.
  3. A list of all instances of the 6005 Event ID will be displayed. You can examine this list, look at the dates and times of each reboot event, and so on.
  4. Open Server Manager tool by right-clicking the Computer icon on the start menu (or on the Desktop if you have it enabled) and select Manage. Navigate to the Event Viewer.

enter image description here

5.1: Eventlog via PowerShell

Get-WinEvent -ProviderName eventlog | Where-Object {$_.Id -eq 6005 -or $_.Id -eq 6006}

6: Programmatically, by using GetTickCount64

GetTickCount64 retrieves the number of milliseconds that have elapsed since the system was started.

7: By using WMI

wmic os get lastbootuptime

8: The new uptime.exe for Windows XP and up

Like the tool from Microsoft, but compatible with all operating systems up to and including Windows 10 and Windows Server 2016, this uptime utility does not require an elevated command prompt and offers an option to show the uptime in both DD:HH:MM:SS and in human-readable formats (when executed with the -h command-line parameter).

Additionally, this version of uptime.exe will run and show the system uptime even when launched normally from within an explorer.exe session (i.e. not via the command line) and pause for the uptime to be read:

enter image description here

and when executed as uptime -h:

enter image description here

OSX - How to auto Close Terminal window after the "exit" command executed.

You can also use this convoluted command, which does not trigger a warning about terminating its own process:
osascript -e "do shell script \"osascript -e \\\"tell application \\\\\\\"Terminal\\\\\\\" to quit\\\" &> /dev/null &\""; exit

This command is quite long, so you could define an alias (such as quit) in your bash profile:
alias quit='osascript -e "do shell script \"osascript -e \\\"tell application \\\\\\\"Terminal\\\\\\\" to quit\\\" &> /dev/null &\""; exit'

This would allow you to simply type quit into terminal without having to fiddle with any other settings.

Difference in System. exit(0) , System.exit(-1), System.exit(1 ) in Java

class calc{
public static void main(String args[])
    int a, b, c;
    char ch;

        Scanner s=new Scanner(;

                System.out.print("1. Addition\n");
                System.out.print("2. Substraction\n");
                System.out.print("3. Multiplication\n");
                System.out.print("4. Division\n");
                System.out.print("5. Exit\n\n");

                System.out.print("Enter your choice : ");
                    switch (ch)
                        case '1' :
                        Addition chose1=new Addition();

                        case '2' :
                        Substraction chose2=new Substraction();

                        case '3' :
                        Multiplication chose3= new Multiplication();

                        case '4' :
                        Division chose4=new Division();

                        case '5' :

                        default :
                        System.out.print("wrong choice!!!");
    }while(ch !=5); 


In the above code when its System.exit(0); and when i press case 5 it exits properly but when i use System.exit(1); and press case 5 it exits with error and again when i try with case 15 it exits properly by this i got to know that, when ever we put any int inside argument it specifies that, it take the character from that position i.e if i put (4) that it means take 5th character from that string if its (3) then it means take 4th character from that inputed string

How to tell if a <script> tag failed to load

It was proposed to set a timeout and then assume load failure after a timeout.

setTimeout(fireCustomOnerror, 4000);

The problem with that approach is that the assumption is based on chance. After your timeout expires, the request is still pending. The request for the pending script may load, even after the programmer assumed that load won't happen.

If the request could be canceled, then the program could wait for a period, then cancel the request.

Read XML Attribute using XmlDocument

If your XML contains namespaces, then you can do the following in order to obtain the value of an attribute:

var xmlDoc = new XmlDocument();

// content is your XML as string

XmlNamespaceManager nsmgr = new XmlNamespaceManager(new NameTable());

// make sure the namespace identifier, URN in this case, matches what you have in your XML 
nsmgr.AddNamespace("ns", "urn:oasis:names:tc:SAML:2.0:protocol");

// get the value of Destination attribute from within the Response node with a prefix who's identifier is "urn:oasis:names:tc:SAML:2.0:protocol" using XPath
var str = xmlDoc.SelectSingleNode("/ns:Response/@Destination", nsmgr);
if (str != null)

More on XML namespaces here and here.

How can I get a count of the total number of digits in a number?

The answer of Steve is correct, but it doesn't work for integers less than 1.

Here an updated version that does work for negatives:

int digits = n == 0 ? 1 : Math.Floor(Math.Log10(Math.Abs(n)) + 1)


UPDATE will not do anything if the row does not exist.

Where as the INSERT OR REPLACE would insert if the row does not exist, or replace the values if it does.

How to do a join in linq to sql with method syntax?

var result = from sc in enumerableOfSomeClass
             join soc in enumerableOfSomeOtherClass
             on sc.Property1 equals soc.Property2
             select new { SomeClass = sc, SomeOtherClass = soc };

Would be equivalent to:

var result = enumerableOfSomeClass
          sc => sc.Property1,
          soc => soc.Property2,
          (sc, soc) => new
                           SomeClass = sc,
                           SomeOtherClass = soc

As you can see, when it comes to joins, query syntax is usually much more readable than lambda syntax.

Having issues with a MySQL Join that needs to meet multiple conditions

    u . *
    room u
    facilities_r fu ON fu.id_uc = u.id_uc
        AND (fu.id_fu = '4' OR fu.id_fu = '3')
    1 and vizibility = '1'
GROUP BY id_uc
ORDER BY u_premium desc , id_uc desc

You must use OR here, not AND.

Since id_fu cannot be equal to 4 and 3, both at once.

Find empty or NaN entry in Pandas Dataframe

To obtain all the rows that contains an empty cell in in a particular column.


This will give the subset of DF_raw, which satisfy the checking condition.

Write objects into file with Node.js

could you try doing JSON.stringify(obj);

Like this

 var stringify = JSON.stringify(obj);
fs.writeFileSync('./data.json', stringify , 'utf-8'); 

Read lines from a text file but skip the first two lines

May be I am oversimplifying?

Just add the following code:

Open sFileName For Input as iFileNum
Line Input #iFileNum, dummy1
Line Input #iFileNum, dummy2


uppercase first character in a variable with bash

One way with bash (version 4+):

echo "${foo^}"



PHP - Merging two arrays into one array (also Remove Duplicates)

As already mentioned, array_unique() could be used, but only when dealing with simple data. The objects are not so simple to handle.

When php tries to merge the arrays, it tries to compare the values of the array members. If a member is an object, it cannot get its value and uses the spl hash instead. Read more about spl_object_hash here.

Simply told if you have two objects, instances of the very same class and if one of them is not a reference to the other one - you will end up having two objects, no matter the value of their properties.

To be sure that you don't have any duplicates within the merged array, Imho you should handle the case on your own.

Also if you are going to merge multidimensional arrays, consider using array_merge_recursive() over array_merge().

How to ORDER BY a SUM() in MySQL?

Without a GROUP BY clause, any summation will roll all rows up into a single row, so your query will indeed not work. If you grouped by, say, name, and ordered by sum(c_counts+f_counts), then you might get some useful results. But you would have to group by something.

How do you convert a byte array to a hexadecimal string, and vice versa?

You can use the BitConverter.ToString method:

byte[] bytes = {0, 1, 2, 4, 8, 16, 32, 64, 128, 256}
Console.WriteLine( BitConverter.ToString(bytes));



More information: BitConverter.ToString Method (Byte[])

Spring get current ApplicationContext

I think this link demonstrates the best way to get application context anywhere, even in the non-bean class. I find it very useful. Hope its the same for you. The below is the abstract code of it

Create a new class

package com.java2novice.spring;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

public class ApplicationContextProvider implements ApplicationContextAware{

    private static ApplicationContext context;

    public static ApplicationContext getApplicationContext() {
        return context;

    public void setApplicationContext(ApplicationContext ac)
            throws BeansException {
        context = ac;

Add an entry in application-context.xml

<bean id="applicationContextProvider"

In annotations case (instead of application-context.xml)

public class ApplicationContextProvider implements ApplicationContextAware{

Get the context like this

TestBean tb = ApplicationContextProvider.getApplicationContext().getBean("testBean", TestBean.class);


What is the symbol for whitespace in C?

The character representation of a Space is simply ' '.

void foo (const char *s)
    unsigned char c;
    if (c == ' ')

But if you are really looking for all whitespace, then C has a function (actually it's often a macro) for that:

#include <ctype.h>

void foo (const char *s)
    char c;
    if (isspace(c))

You can read about isspace here

If you really want to catch all non-printing characters, the function to use is isprint from the same library. This deals with all of the characters below 0x20 (the ASCII code for a space) and above 0x7E (0x7f is the code for DEL, and everything above that is an extension).

In raw code this is equivalent to:

if (c < ' ' || c >= 0x7f)
    // Deal with non-printing characters.