Programs & Examples On #Web architecture

Android - Start service on boot

Looks very similar to mine but I use the full package name for the receiver:

<receiver android:name=".StartupIntentReceiver">

I have:

<receiver android:name="com.your.package.AutoStart"> 

Function to get yesterday's date in Javascript in format DD/MM/YYYY

You override $today in the if statement.

if($dd<10){$dd='0'+dd} if($mm<10){$mm='0'+$mm} $today = $dd+'/'+$mm+'/'+$yyyy;

It is then not a Date() object anymore - hence the error.

How to remove newlines from beginning and end of a string?

This Java code does exactly what is asked in the title of the question, that is "remove newlines from beginning and end of a string-java":

String.replaceAll("^[\n\r]", "").replaceAll("[\n\r]$", "")

Remove newlines only from the end of the line:

String.replaceAll("[\n\r]$", "")

Remove newlines only from the beginning of the line:

String.replaceAll("^[\n\r]", "")

Group by multiple field names in java 8

Hi You can simply concatenate your groupingByKey such as

Map<String, List<Person>> peopleBySomeKey = people
                .collect(Collectors.groupingBy(p -> getGroupingByKey(p), Collectors.mapping((Person p) -> p, toList())));

//write getGroupingByKey() function
private String getGroupingByKey(Person p){
return p.getAge()+"-"+p.getName();

How to deal with certificates using Selenium?

For Firefox Python:

The Firefox Self-signed certificate bug has now been fixed: accept ssl cert with marionette firefox webdrive python splinter

"acceptSslCerts" should be replaced by "acceptInsecureCerts"

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
from selenium.webdriver.firefox.firefox_binary import FirefoxBinary

caps = DesiredCapabilities.FIREFOX.copy()
caps['acceptInsecureCerts'] = True
ff_binary = FirefoxBinary("path to the Nightly binary")

driver = webdriver.Firefox(firefox_binary=ff_binary, capabilities=caps)

How to trigger a phone call when clicking a link in a web page on mobile phone

Want to add an answer here for the sake of completeness.

<a href="tel:1234567">Call 123-4567</a>

Works just fine on most devices. However, on desktops this will appear as a link which does nothing when you click on it so you should consider using CSS to make it conditionally visible only on mobile devices.

Also, you should know that Skype (which is fairly popular) uses a different syntax by default (but can be parametered to use tel:).

<a href="callto:1234567">Call 123-4567</a>

However, I think in latest mobile browsers (I know for sure on Android) now the tel syntax should offer a popup of available applications that can be used to complete the calling action.

How to fix libeay32.dll was not found error

I encountered the same problem when I tried to install curl in my 32 bit win 7 machine. As answered by Buravchik it is indeed dependency of SSL and installing openssl fixed it. Just a point to take care is that while installing openssl you will get a prompt to ask where do you wish to put the dependent DLLS. Make sure to put it in windows system directory as other programs like curl and wget will also be needing it.

enter image description here

Error : No resource found that matches the given name (at 'icon' with value '@drawable/icon')

You need to add icon.png through visual.

Resouces... / Dravable/ Add ///

ASP.NET MVC5/IIS Express unable to debug - Code Not Running

Another scenario may be that the port that IIS is using for your application is already being used by another running application. Try changing the port and see if it works for you.

How do I add images in laravel view?

If Image folder location is public/assets/img/default.jpg. You can try in view

   <img src="{{ URL::to('/assets/img/default.jpg') }}">

Python copy files to a new directory and rename if file name already exists

I always use the time-stamp - so its not possible, that the file exists already:

import os
import shutil
import datetime

now = str([:19]
now = now.replace(":","_")

src_dir="C:\\Users\\Asus\\Desktop\\Versand Verwaltung\\Versand.xlsx"
dst_dir="C:\\Users\\Asus\\Desktop\\Versand Verwaltung\\Versand_"+str(now)+".xlsx"

How to display request headers with command line curl

I believe the command line switch you are looking for to pass to curl is -I.

Example usage:

$ curl -I  
HTTP/1.1 301 Moved Permanently
Date: Sat, 29 Dec 2012 15:22:05 GMT
Server: Apache
Content-Type: text/html; charset=iso-8859-1

Additionally, if you encounter a response HTTP status code of 301, you might like to also pass a -L argument switch to tell curl to follow URL redirects, and, in this case, print the headers of all pages (including the URL redirects), illustrated below:

$ curl -I -L
HTTP/1.1 301 Moved Permanently
Date: Sat, 29 Dec 2012 15:22:13 GMT
Server: Apache
Content-Type: text/html; charset=iso-8859-1

HTTP/1.1 302 Found
Date: Sat, 29 Dec 2012 15:22:13 GMT
Server: Apache
Set-Cookie: UID=b8c37e33defde51cf91e1e03e51657da
Location: noaccess.php
Content-Type: text/html

HTTP/1.1 200 OK
Date: Sat, 29 Dec 2012 15:22:13 GMT
Server: Apache
Content-Type: text/html

jQuery - Create hidden form element on the fly


To answer your second question:

    type: 'hidden',
    id: 'foo',
    name: 'bar'

Reshape an array in NumPy

a = np.arange(18).reshape(9,2)
b = a.reshape(3,3,2).swapaxes(0,2)

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

# b:
array([[[ 0,  6, 12],
        [ 2,  8, 14],
        [ 4, 10, 16]],

       [[ 1,  7, 13],
        [ 3,  9, 15],
        [ 5, 11, 17]]])

Read a local text file using Javascript

Please find below the code that generates automatically the content of the txt local file and display it html. Good luck!

  <meta charset="utf-8">
  <script type="text/javascript">

  var x;
  if('Microsoft')>-1) { x = new ActiveXObject('MSXML2.XMLHTTP'); }
  else { x = new XMLHttpRequest(); }

  function getdata() {'get', 'data1.txt', true); 
    x.onreadystatechange= showdata;

  function showdata() {
    if(x.readyState==4) {
      var el = document.getElementById('content');
      el.innerHTML = x.responseText;

<body onload="getdata();showdata();">

  <div id="content"></div>


What is the difference between git clone and checkout?

One thing to notice is the lack of any "Copyout" within git. That's because you already have a full copy in your local repo - your local repo being a clone of your chosen upstream repo. So you have effectively a personal checkout of everything, without putting some 'lock' on those files in the reference repo.

Git provides the SHA1 hash values as the mechanism for verifying that the copy you have of a file / directory tree / commit / repo is exactly the same as that used by whoever is able to declare things as "Master" within the hierarchy of trust. This avoids all those 'locks' that cause most SCM systems to choke (with the usual problems of private copies, big merges, and no real control or management of source code ;-) !

border-radius not working

For some reason your padding: 7px setting is nullifying the border-radius. Change it to padding: 0px 7px

How do I add comments to package.json for npm install?

Here's my take on comments within package.json / bower.json:

I have file package.json.js that contains a script that exports the actual package.json. Running the script overwrites the old package.json and tells me what changes it made, perfect to help you keep track of automatic changes npm made. That way I can even programmatically define what packages I want to use.

The latest Grunt task is here:

Java ArrayList of Doubles

Using guava

Doubles.asList(1.2, 5.6, 10.1);

or immutable list

ImmutableList.of(1.2, 5.6, 10.1);

Accessing a class' member variables in Python?

If you have an instance function (i.e. one that gets passed self) you can use self to get a reference to the class using self.__class__

For example in the code below tornado creates an instance to handle get requests, but we can get hold of the get_handler class and use it to hold a riak client so we do not need to create one for every request.

import tornado.web
import riak

class get_handler(tornado.web.requestHandler):
    riak_client = None

    def post(self):
        cls = self.__class__
        if cls.riak_client is None:
            cls.riak_client = riak.RiakClient(pb_port=8087, protocol='pbc')
        # Additional code to send response to the request ...

Run task only if host does not belong to a group

Here's another way to do this:

- name: my command
  command: echo stuff
  when: "'groupname' not in group_names"

group_names is a magic variable as documented here: :

group_names is a list (array) of all the groups the current host is in.

How to check if a Ruby object is a Boolean

An object that is a boolean will either have a class of TrueClass or FalseClass so the following one-liner should do the trick

mybool = true
mybool.class == TrueClass || mybool.class == FalseClass
=> true

The following would also give you true/false boolean type check result

mybool = true    
[TrueClass, FalseClass].include?(mybool.class)
=> true

Why do I get "Pickle - EOFError: Ran out of input" reading an empty file?

You can catch that exception and return whatever you want from there.

open(target, 'a').close()
scores = {};
    with open(target, "rb") as file:
        unpickler = pickle.Unpickler(file);
        scores = unpickler.load();
        if not isinstance(scores, dict):
            scores = {};
except EOFError:
    return {}

cannot convert 'std::basic_string<char>' to 'const char*' for argument '1' to 'int system(const char*)'

try using concatenation of string

Statistics(string date)
        this->date += date;

acually this was a part of a class..

How to remove non UTF-8 characters from text file

Your method must read byte by byte and fully understand and appreciate the byte wise construction of characters. The simplest method is to use an editor which will read anything but only output UTF-8 characters. Textpad is one choice.

How to print Two-Dimensional Array like table

You could write a method to print a 2d array like this:

//Displays a 2d array in the console, one line per row.
static void printMatrix(int[][] grid) {
    for(int r=0; r<grid.length; r++) {
       for(int c=0; c<grid[r].length; c++)
           System.out.print(grid[r][c] + " ");

scp files from local to remote machine error: no such file or directory

If you want to copy everything in a Folder + have a special Port use this one. Works for me on Ubuntu 18.04 and a local machine with Mac OS X.

-r for recursive
-P for Port

scp -rP 1234 /Your_Directory/Source_Folder/ [email protected]:/target/folder

How To Upload Files on GitHub

Here are the steps (in-short), since I don't know what exactly you have done:
1. Download and install Git on your system:
2. Using the Git Bash (a command prompt for Git) or your system's native command prompt, set up a local git repository.
3. Use the same console to checkout, commit, push, etc. the files on the Git.

Hope this helps to those who come searching here.

How do I get an apk file from an Android device?

  1. Open the app you wish to extract the apk from on your phone.
  2. Get the currently opened app with:

    adb shell dumpsys activity activities | grep mFocusedActivity
  3. Get the path to the package name

    adb shell pm path <packagename.apk>

4.Copy the path you got to the sdcard directory

    adb shell cp /data/app/<packagename.apk> /sdcard

5.Pull the apk

    adb pull /sdcard/base.apk


If step no 2 doesn't work use this:

adb shell dumpsys window windows | grep mCurrentFocus

How to dynamically create columns in datatable and assign values to it?

If you want to create dynamically/runtime data table in VB.Net then you should follow these steps as mentioned below :

  • Create Data table object.
  • Add columns into that data table object.
  • Add Rows with values into the object.

For eg.

Dim dt As New DataTable

dt.Columns.Add("Id", GetType(Integer))
dt.Columns.Add("FirstName", GetType(String))
dt.Columns.Add("LastName", GetType(String))

dt.Rows.Add(1, "Test", "data")
dt.Rows.Add(15, "Robert", "Wich")
dt.Rows.Add(18, "Merry", "Cylon")
dt.Rows.Add(30, "Tim", "Burst")

How to execute AngularJS controller function on page load?

On the one hand as @Mark-Rajcok said you can just get away with private inner function:

// at the bottom of your controller
var init = function () {
   // check if there is query in url
   // and fire search in case its value is not empty
// and fire it after definition

Also you can take a look at ng-init directive. Implementation will be much like:

// register controller in html
<div data-ng-controller="myCtrl" data-ng-init="init()"></div>

// in controller
$scope.init = function () {
    // check if there is query in url
    // and fire search in case its value is not empty

But take care about it as angular documentation implies (since v1.2) to NOT use ng-init for that. However imo it depends on architecture of your app.

I used ng-init when I wanted to pass a value from back-end into angular app:

<div data-ng-controller="myCtrl" data-ng-init="init('%some_backend_value%')"></div>

How do you reverse a string in place in C or C++?

Yet another:

#include <stdio.h>
#include <strings.h>

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

  char *reverse = argv[argc-1];
  char *left = reverse;
  int length = strlen(reverse);
  char *right = reverse+length-1;
  char temp;




  printf("%s\n", reverse);


What do .c and .h file extensions mean to C?

Of course, there is nothing that says the extension of a header file must be .h and the extension of a C source file must be .c. These are useful conventions.

E:\Temp> type my.interface

E:\Temp> type my.source
#include <stdio.h>

#include "my.interface"

int main(void) {
    char x[MYBUFFERSIZE] = {0};
    x[0] = 'a';
    return 0;

E:\Temp> gcc -x c my.source -o my.exe

E:\Temp> my

Google drive limit number of download


This means to me that the download limit is calculated based on a set of factors that describe the user and is subject to change from one to another.

Maybe using the TOR network may help you do your job.

How do I output text without a newline in PowerShell?

The following will place the cursor back at beginning of the previous row. It's up to you to place it in the right horizontal position (using $pos.X to move it sideways):

$pos = $host.ui.RawUI.get_cursorPosition()
$pos.Y -= 1

Your current output is 27 spaces over, so $pos.X = 27 might work.

Is there any way to return HTML in a PHP function? (without building the return value as a string)

If you don't want to have to rely on a third party tool you can use this technique:

function TestBlockHTML($replStr){
  $template = 
 return strtr($template, array( '$str' => $replStr));

Junit - run set up method once

Try this solution: :

with @BeforeAllMethods/@AfterAllMethods annotation you could execute any method in Test class in an instance context, where all injected values are available.

How can I get all element values from Request.Form without specifying exactly which one with .GetValues("ElementIdName")

Here is a way to do it without adding an ID to the form elements.

<form method="post">
    <select name="List">
        <option value="1">Test1</option>
        <option value="2">Test2</option>
    <select name="List">
        <option value="3">Test3</option>
        <option value="4">Test4</option>

public ActionResult OrderProcessor()
    string[] ids = Request.Form.GetValues("List");

Then ids will contain all the selected option values from the select lists. Also, you could go down the Model Binder route like so:

public class OrderModel
    public string[] List { get; set; }

public ActionResult OrderProcessor(OrderModel model)
    string[] ids = model.List;

Hope this helps.

Play an audio file using jQuery when a button is clicked


It doesn't work with $("#myAudioElement").play() like you would expect. The official reason is that incorporating it into jQuery would add a play() method to every single element, which would cause unnecessary overhead. So instead you have to refer to it by its position in the array of DOM elements that you're retrieving with $("#myAudioElement"), aka 0.

This quote is from a bug that was submitted about it, which was closed as "feature/wontfix":

To do that we'd need to add a jQuery method name for each DOM element method name. And of course that method would do nothing for non-media elements so it doesn't seem like it would be worth the extra bytes it would take.

How to send objects through bundle

another simple way to pass object using a bundle:

  • in the class object, create a static list or another data structure with a key
  • when you create the object, put it in the list/data structure with the key (es. the long timestamp when the object is created)
  • create the method static getObject(long key) to get the object from the list
  • in the bundle pass the key, so you can get the object later from another point in the code

Powershell script to locate specific file/file name?

To search the whole computer:

gdr -PSProvider 'FileSystem' | %{ ls -r $.root} 2>$null | where { $.name -eq "httpd.exe" }

I am pretty sure this is a much less efficient command, for MANY reasons, but the simplest is your piping everything to your where-object command, when you could still use -filter "httpd.exe" and save a ton of cycles.

Also, on a lot of computers the get-psdrive is gonna grab shared drives, and I am pretty sure you wanted that to get a complete search. Most shares can be IMMENSE with regard to the sheer number of files and folders, so at the very least I would sort my drives by size, and add a check after each search to exit the loop if we locate the file. That is if you are looking for a single instance, if not the only way to save yourself the IMMENSE time sink of searching a 10TB share or two, is to comment the command and highly suggest any user who were to need to use it should limit their search as much as they can. For instance our User Profile share is 10TB, at least the one I am on is, and I can limit my search to the directory $sharedrive\users\myname and search my 116GB directory rather than the 10TB one. Too many unknowns with shares for this type of script, which is already super inefficient with regard to resources and speed.

If I was seriously considering using something like this, I would add a call to a 3rd party package and leverage a DB.

Solutions for INSERT OR UPDATE on SQL Server

CREATE TABLE ApplicationsDesSocietes (
   id                   INT IDENTITY(0,1)    NOT NULL,
   applicationId        INT                  NOT NULL,
   societeId            INT                  NOT NULL,
   suppression          BIT                  NULL,

DECLARE @applicationId INT = 81, @societeId INT = 43, @suppression BIT = 0

MERGE dbo.ApplicationsDesSocietes WITH (HOLDLOCK) AS target
--set the SOURCE table one row
USING (VALUES (@applicationId, @societeId, @suppression))
    AS source (applicationId, societeId, suppression)
    --here goes the ON join condition
    ON target.applicationId = source.applicationId and target.societeId = source.societeId
    --place your list of SET here
    SET target.suppression = source.suppression
    --insert a new line with the SOURCE table one row
    INSERT (applicationId, societeId, suppression)
    VALUES (source.applicationId, source.societeId, source.suppression);

Replace table and field names by whatever you need. Take care of the using ON condition. Then set the appropriate value (and type) for the variables on the DECLARE line.


Python Anaconda - How to Safely Uninstall

In case you have multiple version of anaconda,

rm -rf ~/anaconda2 [for version 2]

rm -rf ~/anaconda3 [for version 3]

Open .bashrc file in a text editor

vim .bashrc

remove anaconda directory from your PATH.

export PATH="/home/{username}/anaconda2/bin:$PATH" [for version 2]

export PATH="/home/{username}/anaconda3/bin:$PATH" [for version 3]

Java - How to convert type collection into ArrayList?

Try this code

Convert ArrayList to Collection

  ArrayList<User> usersArrayList = new ArrayList<User>();

  Collection<User> userCollection = new HashSet<User>(usersArrayList);

Convert Collection to ArrayList

  Collection<User> userCollection = new HashSet<User>(usersArrayList);

  List<User> userList = new ArrayList<User>(userCollection );

Rounding to 2 decimal places in SQL

Try using the COLUMN command with the FORMAT option for that:


How do I auto-submit an upload form when a file is selected?

Using jQuery:

$('#file').change(function() {_x000D_
<script src=""></script>_x000D_
<form id="target" action="destination.html">_x000D_
  <input type="file" id="file" value="Go" />_x000D_

Disable vertical sync for glxgears

For Intel graphics and AMD/ATI opensource graphics drivers

Find the "Device" section of /etc/X11/xorg.conf which contains one of the following directives:

  • Driver "intel"
  • Driver "radeon"
  • Driver "fglrx"

And add the following line to that section:

Option     "SwapbuffersWait"       "false"

And run your application with vblank_mode environment variable set to 0:

$ vblank_mode=0 glxgears

For Nvidia graphics with the proprietary Nvidia driver

$ echo "0/SyncToVBlank=0" >> ~/.nvidia-settings-rc

The same change can be made in the nvidia-settings GUI by unchecking the option at X Screen 0 / OpenGL Settings / Sync to VBlank. Or, if you'd like to just test the setting without modifying your ~/.nvidia-settings-rc file you can do something like:

$ nvidia-settings --load-config-only --assign="SyncToVBlank=0"  # disable vertical sync
$ glxgears  # test it out
$ nvidia-settings --load-config-only  # restore your original vertical sync setting

Abstract class in Java

From oracle documentation

Abstract Methods and Classes:

An abstract class is a class that is declared abstract—it may or may not include abstract methods

Abstract classes cannot be instantiated, but they can be subclassed

An abstract method is a method that is declared without an implementation (without braces, and followed by a semicolon), like this:

abstract void moveTo(double deltaX, double deltaY);

If a class includes abstract methods, then the class itself must be declared abstract, as in:

public abstract class GraphicObject {
   // declare fields
   // declare nonabstract methods
   abstract void draw();

When an abstract class is subclassed, the subclass usually provides implementations for all of the abstract methods in its parent class. However, if it does not, then the subclass must also be declared abstract.

Since abstract classes and interfaces are related, have a look at below SE questions:

What is the difference between an interface and abstract class?

How should I have explained the difference between an Interface and an Abstract class?

How to put a link on a button with bootstrap?

If you don't really need the button element, just move the classes to a regular link:

<div class="btn-group">
    <a href="/save/1" class="btn btn-primary active">
        <i class="glyphicon glyphicon-floppy-disk" aria-hidden="true"></i> Save
    <a href="/cancel/1" class="btn btn-default">Cancel</a>

Conversely, you can also change a button to appear like a link:

<button type="button" class="btn btn-link">Link</button>

jQuery has deprecated synchronous XMLHTTPRequest

My workabout: I use asynchronous requests dumping the code to a buffer. I have a loop checking the buffer every second. When the dump has arrived to the buffer I execute the code. I also use a timeout. For the end user the page works as if synchronous requests would be used.

What is token-based authentication?

It's just hash which is associated with user in database or some other way. That token can be used to authenticate and then authorize a user access related contents of the application. To retrieve this token on client side login is required. After first time login you need to save retrieved token not any other data like session, session id because here everything is token to access other resources of application.

Token is used to assure the authenticity of the user.

UPDATES: In current time, We have more advanced token based technology called JWT (Json Web Token). This technology helps to use same token in multiple systems and we call it single sign-on.

Basically JSON Based Token contains information about user details and token expiry details. So that information can be used to further authenticate or reject the request if token is invalid or expired based on details.

Convert string to date in bash

just use the -d option of the date command, e.g.

date -d '20121212' +'%Y %m'

Laravel Soft Delete posts

Updated Version (Version 5.0 & Later):

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

class Post extends Model {

    use SoftDeletes;

    protected $table = 'posts';

    // ...

When soft deleting a model, it is not actually removed from your database. Instead, a deleted_at timestamp is set on the record. To enable soft deletes for a model, specify the softDelete property on the model (Documentation).

For (Version 4.2):

use Illuminate\Database\Eloquent\SoftDeletingTrait; // <-- This is required

class Post extends Eloquent {

    use SoftDeletingTrait;

    protected $table = 'posts';

    // ...

Prior to Version 4.2 (But not 4.2 & Later)

For example (Using a posts table and Post model):

class Post extends Eloquent {

    protected $table = 'posts';
    protected $softDelete = true;
    // ...

To add a deleted_at column to your table, you may use the softDeletes method from a migration:

For example (Migration class' up method for posts table) :

 * Run the migrations.
 * @return void
public function up()
    Schema::create('posts', function(Blueprint $table)
        // more fields
        $table->softDeletes(); // <-- This will add a deleted_at field

Now, when you call the delete method on the model, the deleted_at column will be set to the current timestamp. When querying a model that uses soft deletes, the "deleted" models will not be included in query results. To soft delete a model you may use:

$model = Contents::find( $id );

Deleted (soft) models are identified by the timestamp and if deleted_at field is NULL then it's not deleted and using the restore method actually makes the deleted_at field NULL. To permanently delete a model you may use forceDelete method.

install apt-get on linux Red Hat server

I think you're running into problems because RedHat uses RPM for managing packages. Debian based systems use DEBs, which are managed with tools like apt.

In PHP, what is a closure and why does it use the "use" identifier?

Until very recent years, PHP has defined its AST and PHP interpreter has isolated the parser from the evaluation part. During the time when the closure is introduced, PHP's parser is highly coupled with the evaluation.

Therefore when the closure was firstly introduced to PHP, the interpreter has no method to know which which variables will be used in the closure, because it is not parsed yet. So user has to pleased the zend engine by explicit import, doing the homework that zend should do.

This is the so-called simple way in PHP.

Display HTML snippets in HTML

This is a simple trick and I have tried it in Safari and Firefox

    <span><</span>meta property="og:title" content="A very fine cuisine" /><br>
    <span><</span>meta property="og:image" content="" />

It will show like this:

enter image description here

You can see it live Here

sed command with -i option failing on Mac, but works on Linux

I believe on OS X when you use -i an extension for the backup files is required. Try:

sed -i .bak 's/hello/gbye/g' *

Using GNU sed the extension is optional.

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

Just try encodeURI() and encodeURIComponent() yourself...


Input: @#$%^&*. Output: %40%23%24%25%5E%26*. So, wait, what happened to *? Why wasn't this converted? It could definitely cause problems if you tried to do linux command "$string". TLDR: You actually want fixedEncodeURIComponent() and fixedEncodeURI(). Long-story...

When to use encodeURI()? Never. encodeURI() fails to adhere to RFC3986 with regard to bracket-encoding. Use fixedEncodeURI(), as defined and further explained at the MDN encodeURI() Documentation...

function fixedEncodeURI(str) { return encodeURI(str).replace(/%5B/g, '[').replace(/%5D/g, ']'); }

When to use encodeURIComponent()? Never. encodeURIComponent() fails to adhere to RFC3986 with regard to encoding: !'()*. Use fixedEncodeURIComponent(), as defined and further explained at the MDN encodeURIComponent() Documentation...

function fixedEncodeURIComponent(str) { return encodeURIComponent(str).replace(/[!'()*]/g, function(c) { return '%' + c.charCodeAt(0).toString(16); }); }

Then you can use fixedEncodeURI() to encode a single URL piece, whereas fixedEncodeURIComponent() will encode URL pieces and connectors; or, simply, fixedEncodeURI() will not encode +@?=:#;,$& (as & and + are common URL operators), but fixedEncodeURIComponent() will.

How do I prompt a user for confirmation in bash script?

Here's the function I use :

function ask_yes_or_no() {
    read -p "$1 ([y]es or [N]o): "
    case $(echo $REPLY | tr '[A-Z]' '[a-z]') in
        y|yes) echo "yes" ;;
        *)     echo "no" ;;

And an example using it:

if [[ "no" == $(ask_yes_or_no "Are you sure?") || \
      "no" == $(ask_yes_or_no "Are you *really* sure?") ]]
    echo "Skipped."
    exit 0

# Do something really dangerous...
  • The output is always "yes" or "no"
  • It's "no" by default
  • Everything except "y" or "yes" returns "no", so it's pretty safe for a dangerous bash script
  • And it's case insensitive, "Y", "Yes", or "YES" work as "yes".

I hope you like it,

How to find a value in an array of objects in JavaScript?

If You want to find a specific object via search function just try something like this:

    function findArray(value){

        let countLayer = dataLayer.length;
        for(var x = 0 ; x < countLayer ; x++){

                let newArr = dataLayer[x].user;
                let data = newArr[value];
                return data;


        return null;



This is an example object:

layerObj = {
    0: { gtm.start :1232542, event: "gtm.js"},
    1: { event: "gtm.dom", gtm.uniqueEventId: 52},
    2: { visitor id: "abcdef2345"},
    3: { user: { id: "29857239", verified: "Null", user_profile: "Personal", billing_subscription: "True", partners_user: "adobe"}

Code will iterate and find the "user" array and will search for the object You seek inside.

My problem was when the array index changed every window refresh and it was either in 3rd or second array, but it does not matter.

Worked like a charm for Me!

In Your example it is a bit shorter:

function findArray(value){

    let countLayer = Object.length;
    for(var x = 0 ; x < countLayer ; x++){

        if(Object[x].dinner === value){
            return Object[x];


    return null;



SQL Server - stop or break execution of a SQL script

If you are simply executing a script in Management Studio, and want to stop execution or rollback transaction (if used) on first error, then the best way I reckon is to use try catch block (SQL 2005 onward). This works well in Management studio if you are executing a script file. Stored proc can always use this as well.

EC2 instance types's exact network performance?

Bandwidth is tiered by instance size, here's a comprehensive answer:

For t2/m3/c3/c4/r3/i2/d2 instances:

  • t2.nano = ??? (Based on the scaling factors, I'd expect 20-30 MBit/s)
  • t2.micro = ~70 MBit/s (qiita says 63 MBit/s) - t1.micro gets about ~100 Mbit/s
  • t2.small = ~125 MBit/s (t2, qiita says 127 MBit/s, cloudharmony says 125 Mbit/s with spikes to 200+ Mbit/s)
  • *.medium = t2.medium gets 250-300 MBit/s, m3.medium ~400 MBit/s
  • *.large = ~450-600 MBit/s (the most variation, see below)
  • *.xlarge = 700-900 MBit/s
  • *.2xlarge = ~1 GBit/s +- 10%
  • *.4xlarge = ~2 GBit/s +- 10%
  • *.8xlarge and marked specialty = 10 Gbit, expect ~8.5 GBit/s, requires enhanced networking & VPC for full throughput

m1 small, medium, and large instances tend to perform higher than expected. c1.medium is another freak, at 800 MBit/s.

I gathered this by combing dozens of sources doing benchmarks (primarily using iPerf & TCP connections). Credit to CloudHarmony & flux7 in particular for many of the benchmarks (note that those two links go to google searches showing the numerous individual benchmarks).

Caveats & Notes:

The large instance size has the most variation reported:

  • m1.large is ~800 Mbit/s (!!!)
  • t2.large = ~500 MBit/s
  • c3.large = ~500-570 Mbit/s (different results from different sources)
  • c4.large = ~520 MBit/s (I've confirmed this independently, by the way)
  • m3.large is better at ~700 MBit/s
  • m4.large is ~445 Mbit/s
  • r3.large is ~390 Mbit/s

Burstable (T2) instances appear to exhibit burstable networking performance too:

  • The CloudHarmony iperf benchmarks show initial transfers start at 1 GBit/s and then gradually drop to the sustained levels above after a few minutes. PDF links to reports below:

  • t2.small (PDF)

  • t2.medium (PDF)
  • t2.large (PDF)

Note that these are within the same region - if you're transferring across regions, real performance may be much slower. Even for the larger instances, I'm seeing numbers of a few hundred MBit/s.

Get a random item from a JavaScript array

If you are using node.js, you can use unique-random-array. It simply picks something random from an array.

How to show data in a table by using psql command line interface?

On windows use the name of the table in quotes: TABLE "user"; or SELECT * FROM "user";

Count number of times a date occurs and make a graph out of it

If you have Excel 2010 you can copy your data into another column, than select it and choose Data -> Remove Duplicates. You can then write =COUNTIF($A$1:$A$100,B1) next to it and copy the formula down. This assumes you have your values in range A1:A100 and the de-duplicated values are in column B.

Do I need to explicitly call the base virtual destructor?

No. Unlike other virtual methods, where you would explicitly call the Base method from the Derived to 'chain' the call, the compiler generates code to call the destructors in the reverse order in which their constructors were called.

Getting values from query string in an url using AngularJS $location

In my NodeJS example, I have an url "localhost:8080/Lists/list1.html?x1=y" that I want to traverse and acquire values.

In order to work with $ to get x1=y, I have done a few things

  1. script source to angular-route.js
  2. Inject 'ngRoute' into your app module's dependencies
  3. Config your locationProvider
  4. Add the base tag for $location (if you don't, your search().x1 would return nothing or undefined. Or if the base tag has the wrong info, your browser would not be able to find your files inside script src that your .html needs. Always open page's view source to test your file locations!)
  5. invoke the location service (search())

my list1.js has

    var app = angular.module('NGApp', ['ngRoute']);  //dependencies : ngRoute
    app.config(function ($locationProvider) { //config your locationProvider

    app.controller('NGCtrl', function ($scope, datasvc, $location) {// inject your location service
        //var val = window.location.href.toString().split('=')[1];
        var val = $;    alert(val);
        $scope.xout = function () {
           .then(function (data) {
              $scope.x1 = val;
              $scope.allMyStuffs = data.all;

and my list1.html has

    <base href=".">
<body ng-controller="NGCtrl">
<div>A<input ng-model="x1"/><br/><textarea ng-model="allMyStuffs"/></div>
<script src="../js/jquery-2.1.4.min.js"></script>
<script src="../js/jquery-ui.min.js"></script>
<script src=""></script>
<script src=""></script>
<script src="../js/bootstrap.min.js"></script>
<script src="../js/ui-bootstrap-tpls-0.14.3.min.js"></script>
<script src="list1.js"></script>


How to insert DECIMAL into MySQL database

MySql decimal types are a little bit more complicated than just left-of and right-of the decimal point.

The first argument is precision, which is the number of total digits. The second argument is scale which is the maximum number of digits to the right of the decimal point.

Thus, (4,2) can be anything from -99.99 to 99.99.

As for why you're getting 99.99 instead of the desired 3.80, the value you're inserting must be interpreted as larger than 99.99, so the max value is used. Maybe you could post the code that you are using to insert or update the table.


Corrected a misunderstanding of the usage of scale and precision, per

Text was truncated or one or more characters had no match in the target code page including the primary key in an unpivot

None of the above worked for me. I SOLVED my problem by saving my source data (save as) Excel file as a single xls Worksheet Excel 5.0/95 and imported without column headings. Also, I created the table in advance and mapped manually instead of letting SQL create the table.

how to call an ASP.NET c# method using javascript

You will need to do an Ajax call I suspect. Here is an example of an Ajax called made by jQuery to get you started. The Code logs in a user to my system but returns a bool as to whether it was successful or not. Note the ScriptMethod and WebMethod attributes on the code behind method.

in markup:

 var $Username = $("#txtUsername").val();
            var $Password = $("#txtPassword").val();

            //Call the approve method on the code behind
                type: "POST",
                url: "Pages/Mobile/Login.aspx/LoginUser",
                data: "{'Username':'" + $Username + "', 'Password':'" + $Password + "' }", //Pass the parameter names and values
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                async: true,
                error: function (jqXHR, textStatus, errorThrown) {
                    alert("Error- Status: " + textStatus + " jqXHR Status: " + jqXHR.status + " jqXHR Response Text:" + jqXHR.responseText) },
                success: function (msg) {
                    if (msg.d == true) {
                        window.location.href = "Pages/Mobile/Basic/Index.aspx";
                    else {
                        //show error
                        alert('login failed');

In Code Behind:

/// <summary>
/// Logs in the user
/// </summary>
/// <param name="Username">The username</param>
/// <param name="Password">The password</param>
/// <returns>true if login successful</returns>
[WebMethod, ScriptMethod]
public static bool LoginUser( string Username, string Password )
        StaticStore.CurrentUser = new User( Username, Password );

        //check the login details were correct
        if ( StaticStore.CurrentUser.IsAuthentiacted )
            //change the status to logged in
            StaticStore.CurrentUser.LoginStatus = Objects.Enums.LoginStatus.LoggedIn;

            //Store the user ID in the list of active users
            ( HttpContext.Current.Application[ SessionKeys.ActiveUsers ] as Dictionary<string, int> )[ HttpContext.Current.Session.SessionID ] = StaticStore.CurrentUser.UserID;

            return true;
            return false;
    catch ( Exception ex )
        return false;


enter image description here

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

This gets conflicted if you have the support jar in your libs folder. If you have the support jar in your project libs folder and you have the module dependency added to compile '' the UNEXPECTED_TOPLEVEL_DEPENDANCY exception will be thrown. conflicting folder structure and build.gradle

How can I check if a view is visible or not in Android?

Although View.getVisibility() does get the visibility, its not a simple true/false. A view can have its visibility set to one of three things.

View.VISIBLE The view is visible.

View.INVISIBLE The view is invisible, but any spacing it would normally take up will still be used. Its "invisible"

View.GONE The view is gone, you can't see it and it doesn't take up the "spot".

So to answer your question, you're looking for:

if (myImageView.getVisibility() == View.VISIBLE) {
    // Its visible
} else {
    // Either gone or invisible

Get product id and product type in magento?

Item collection.


Product :


How to set shape's opacity?

In general you just have to define a slightly transparent color when creating the shape.

You can achieve that by setting the colors alpha channel.

#FF000000 will get you a solid black whereas #00000000 will get you a 100% transparent black (well it isn't black anymore obviously).

The color scheme is like this #AARRGGBB there A stands for alpha channel, R stands for red, G for green and B for blue.

The same thing applies if you set the color in Java. There it will only look like 0xFF000000.


In your case you'd have to add a solid node. Like below.

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android=""
    <stroke android:width="4dp" android:color="#636161" />
    <padding android:left="20dp"
        android:bottom="20dp" />
    <corners android:radius="24dp" />
    <solid android:color="#88000000" />

The color here is a half transparent black.

What is causing ImportError: No module named pkg_resources after upgrade of Python on os X?

In case of upgrading your python on mac os 10.7 and pkg_resources doesn't work, the simplest way to fix this is just reinstall setuptools as Ned mentioned above.

sudo pip install setuptools --upgrade
or sudo easy_install install setuptools --upgrade

To enable extensions, verify that they are enabled in those .ini files - Vagrant/Ubuntu/Magento 2.0.2

I used below to fix issue

yum install -y php-intl php-xsl php-opcache php-xml php-mcrypt php-gd php-devel php-mysql php-mbstring php-bcmath

Store mysql query output into a shell variable

I don't know much about the MySQL command line interface, but assuming you only need help with the bashing, you should try to either swap the commands around like so:

myvariable=$(echo "SELECT A, B, C FROM table_a" | mysql database -u $user -p$password)

which echos the string into MySQL. Or, you can be more fancy and use some new bash-features (the here string)

myvariable=$(mysql database -u $user -p$password<<<"SELECT A, B, C FROM table_a")

resulting in the same thing (assuming you're using a recent enough bash version), without involving echo.

Please note that the -p$password is not a typo, but is the way MySQL expects passwords to be entered through the command line (with no space between the option and value).

Note that myvariable will contain everything that MySQL outputs on standard out (usually everything but error messages), including any and all column headers, ASCII-art frames and so on, which may or may not be what you want.

As has been noted, there appears to be a -e parameter to MySQL, I'd go for that one, definitely.

How to limit the maximum value of a numeric field in a Django model?

There are two ways to do this. One is to use form validation to never let any number over 50 be entered by a user. Form validation docs.

If there is no user involved in the process, or you're not using a form to enter data, then you'll have to override the model's save method to throw an exception or limit the data going into the field.

NoSQL Use Case Scenarios or WHEN to use NoSQL

It really is an "it depends" kinda question. Some general points:

  • NoSQL is typically good for unstructured/"schemaless" data - usually, you don't need to explicitly define your schema up front and can just include new fields without any ceremony
  • NoSQL typically favours a denormalised schema due to no support for JOINs per the RDBMS world. So you would usually have a flattened, denormalized representation of your data.
  • Using NoSQL doesn't mean you could lose data. Different DBs have different strategies. e.g. MongoDB - you can essentially choose what level to trade off performance vs potential for data loss - best performance = greater scope for data loss.
  • It's often very easy to scale out NoSQL solutions. Adding more nodes to replicate data to is one way to a) offer more scalability and b) offer more protection against data loss if one node goes down. But again, depends on the NoSQL DB/configuration. NoSQL does not necessarily mean "data loss" like you infer.
  • IMHO, complex/dynamic queries/reporting are best served from an RDBMS. Often the query functionality for a NoSQL DB is limited.
  • It doesn't have to be a 1 or the other choice. My experience has been using RDBMS in conjunction with NoSQL for certain use cases.
  • NoSQL DBs often lack the ability to perform atomic operations across multiple "tables".

You really need to look at and understand what the various types of NoSQL stores are, and how they go about providing scalability/data security etc. It's difficult to give an across-the-board answer as they really are all different and tackle things differently.

For MongoDb as an example, check out their Use Cases to see what they suggest as being "well suited" and "less well suited" uses of MongoDb.

Shortcut key for commenting out lines of Python code in Spyder

On macOS:

Cmd + 1

On Windows, probably

Ctrl + (/) near right shift key

Whitespace Matching Regex - Java

Use of whitespace in RE is a pain, but I believe they work. The OP's problem can also be solved using StringTokenizer or the split() method. However, to use RE (uncomment the println() to view how the matcher is breaking up the String), here is a sample code:

import java.util.regex.*;

public class Two21WS {
    private String  str = "";
    private Pattern pattern = Pattern.compile ("\\s{2,}");  // multiple spaces

    public Two21WS (String s) {
            StringBuffer sb = new StringBuffer();
            Matcher matcher = pattern.matcher (s);
            int startNext = 0;
            while (matcher.find (startNext)) {
                    if (startNext == 0)
                            sb.append (s.substring (0, matcher.start()));
                            sb.append (s.substring (startNext, matcher.start()));
                    sb.append (" ");
                    startNext = matcher.end();
                    //System.out.println ("Start, end = " + matcher.start()+", "+matcher.end() +
                    //                      ", sb: \"" + sb.toString() + "\"");
            sb.append (s.substring (startNext));
            str = sb.toString();

    public String toString () {
            return str;

    public static void main (String[] args) {
            String tester = " a    b      cdef     gh  ij   kl";
            System.out.println ("Initial: \"" + tester + "\"");
            System.out.println ("Two21WS: \"" + new Two21WS(tester) + "\"");

It produces the following (compile with javac and run at the command prompt):

% java Two21WS Initial: " a b cdef gh ij kl" Two21WS: " a b cdef gh ij kl"

SSL certificate rejected trying to access GitHub over HTTPS behind firewall

If you used debian-based OS, you can simply run

apt-get install ca-certificates

Get string character by index - Java

Here's the correct code. If you're using zybooks this will answer all the problems.

for (int i = 0; i<passCode.length(); i++)
    char letter = passCode.charAt(i);
    if (letter == ' ' )
        System.out.println("Space at " + i);

error opening trace file: No such file or directory (2)

Try removing the uses-sdk part form AndroidManifest.xml file. it worked for me!

Don't use the Android Virtual Device with too low configuration. Let it be medium.

How to use if, else condition in jsf to display image

Instead of using the "c" tags, you could also do the following:

<h:outputLink value="Images/thumb_02.jpg" target="_blank" rendered="#{not empty user or user.userId eq 0}" />
<h:graphicImage value="Images/thumb_02.jpg" rendered="#{not empty user or user.userId eq 0}" />

<h:outputLink value="/DisplayBlobExample?userId=#{user.userId}" target="_blank" rendered="#{not empty user and user.userId neq 0}" />
<h:graphicImage value="/DisplayBlobExample?userId=#{user.userId}" rendered="#{not empty user and user.userId neq 0}"/>

I think that's a little more readable alternative to skuntsel's alternative answer and is utilizing the JSF rendered attribute instead of nesting a ternary operator. And off the answer, did you possibly mean to put your image in between the anchor tags so the image is clickable?

javascript createElement(), style problem

Works fine:

var obj = document.createElement('div'); = "::img"; = 'position:absolute;top:300px;left:300px;width:200px;height:200px;-moz-border-radius:100px;border:1px  solid #ddd;-moz-box-shadow: 0px 0px 8px  #fff;display:none;';


You can also see how to set the the CSS in one go (using

I suggest you use some more meaningful variable names and don't use the same name for different elements. It looks like you are using obj for different elements (overwriting the value in the function) and this can be confusing.

Evaluate a string with a switch in C++

Switch value must have an Integral type. Also, since you know that differenciating character is in position 7, you could switch on But you are not sure the user entered 8 characters. He may as well have done some typing mistake. So you are to surround your switch statement within a Try Catch. Something with this flavour

using namespace std;
int main() {
    string a;

    switch ( {
    case '1':
        cout<<"It pressed number 1"<<endl;
    case '2':
        cout<<"It pressed number 2"<<endl;
    case '3':
        cout<<"It pressed number 3"<<endl;
        cout<<"She put no choice"<<endl;

    return 0;

The default clause in switch statement captures cases when users input is at least 8 characters, but not in {1,2,3}.

Alternatively, you can switch on values in an enum.


Fetching 7th character with operator[]() does not perform bounds check, so that behavior would be undefined. we use at() from std::string, which is bounds-checked, as explained here.

Angular 2 router.navigate

import { ActivatedRoute } from '@angular/router';_x000D_
export class ClassName {_x000D_
  private router = ActivatedRoute;_x000D_
    constructor(r: ActivatedRoute) {_x000D_
        this.router =r;_x000D_
onSuccess() {_x000D_
         {queryParams: {email: loginEmail, code: userCode}});_x000D_
Get this values:_x000D_
ngOnInit() {_x000D_
        .subscribe(params => {_x000D_
            let code = params['code'];_x000D_
            let userEmail = params['email'];_x000D_


is it possible to get the MAC address for machine using nmap

Just the standard scan will return the MAC.

nmap -sS target

DateTime vs DateTimeOffset

This piece of code from Microsoft explains everything:

// Find difference between Date.Now and Date.UtcNow
  date1 = DateTime.Now;
  date2 = DateTime.UtcNow;
  difference = date1 - date2;
  Console.WriteLine("{0} - {1} = {2}", date1, date2, difference);

  // Find difference between Now and UtcNow using DateTimeOffset
  dateOffset1 = DateTimeOffset.Now;
  dateOffset2 = DateTimeOffset.UtcNow;
  difference = dateOffset1 - dateOffset2;
  Console.WriteLine("{0} - {1} = {2}", 
                    dateOffset1, dateOffset2, difference);
  // If run in the Pacific Standard time zone on 4/2/2007, the example
  // displays the following output to the console:
  //    4/2/2007 7:23:57 PM - 4/3/2007 2:23:57 AM = -07:00:00
  //    4/2/2007 7:23:57 PM -07:00 - 4/3/2007 2:23:57 AM +00:00 = 00:00:00

How do I concatenate two strings in C?

#include <stdio.h>

int main(){
    char name[] =  "derp" "herp";
    printf("\"%s\"\n", name);//"derpherp"
    return 0;

Get environment variable value in Dockerfile

So you can do: cat Dockerfile | envsubst | docker build -t my-target -

Then have a Dockerfile with something like:


I guess there might be a problem with some special characters, but this works for most cases at least.

Can I specify multiple users for myself in .gitconfig?

With conditional includes in Git 2.13, it is now possible to have multiple user/email coexist on one machine with little work.

user.gitconfig has my personal name and email. work-user.gitconfig has my work name and email. Both files are at ~ path.

So my personal name/email applies by default. For c:/work/ dir, my work name/email is applied. For c:/work/github/ dir, my personal name/email is applied. This works as the last setting gets applied.

# ~/.gitconfig
    path = user.gitconfig
[includeIf "gitdir/i:c:/work/"]
    path = work-user.gitconfig
[includeIf "gitdir/i:c:/work/github/"]
    path = user.gitconfig

gitdir is case-sensitive and gitdir/i is case-insensitive.

"gitdir/i:github/" would apply the conditional include for any directory with github in its path.

Understanding Python super() with __init__() methods

The main difference is that ChildA.__init__ will unconditionally call Base.__init__ whereas ChildB.__init__ will call __init__ in whatever class happens to be ChildB ancestor in self's line of ancestors (which may differ from what you expect).

If you add a ClassC that uses multiple inheritance:

class Mixin(Base):
  def __init__(self):
    print "Mixin stuff"
    super(Mixin, self).__init__()

class ChildC(ChildB, Mixin):  # Mixin is now between ChildB and Base

help(ChildC) # shows that the Method Resolution Order is ChildC->ChildB->Mixin->Base

then Base is no longer the parent of ChildB for ChildC instances. Now super(ChildB, self) will point to Mixin if self is a ChildC instance.

You have inserted Mixin in between ChildB and Base. And you can take advantage of it with super()

So if you are designed your classes so that they can be used in a Cooperative Multiple Inheritance scenario, you use super because you don't really know who is going to be the ancestor at runtime.

The super considered super post and pycon 2015 accompanying video explain this pretty well.

Python re.sub replace with matched content

Use \1 instead of $1.

\number Matches the contents of the group of the same number.

min and max value of data type in C

Maximum value of any unsigned integral type:

  • ((t)~(t)0) // Generic expression that would work in almost all circumstances.

  • (~(t)0) // If you know your type t have equal or larger size than unsigned int. (This cast forces type promotion.)

  • ((t)~0U) // If you know your type t have smaller size than unsigned int. (This cast demotes type after the unsigned int-type expression ~0U is evaluated.)

Maximum value of any signed integral type:

  • If you have an unsigned variant of type t, ((t)(((unsigned t)~(unsigned t)0)>>1)) would give you the fastest result you need.

  • Otherwise, use this (thanks to @vinc17 for suggestion): (((1ULL<<(sizeof(t)*CHAR_BIT-2))-1)*2+1)

Minimum value of any signed integral type:

You have to know the signed number representation of your machine. Most machines use 2's complement, and so -(((1ULL<<(sizeof(t)*CHAR_BIT-2))-1)*2+1)-1 will work for you.

To detect whether your machine uses 2's complement, detect whether (~(t)0U) and (t)(-1) represent the same thing.

So, combined with above:


will give you the minimum value of any signed integral type.

As an example: Maximum value of size_t (a.k.a. the SIZE_MAX macro) can be defined as (~(size_t)0). Linux kernel source code define SIZE_MAX macro this way.

One caveat though: All of these expressions use either type casting or sizeof operator and so none of these would work in preprocessor conditionals (#if ... #elif ... #endif and like).

(Answer updated for incorpoating suggestions from @chux and @vinc17. Thank you both.)

JSON.stringify output to div in pretty print way

print the state of a component with JSX

render() {
  return (
      <h1>Adopt Me!</h1>
        <code>{JSON.stringify(this.state, null, 4)}</code>


Overflow-x:hidden doesn't prevent content from overflowing in mobile browsers

Adding a wrapper <div> around the entirety of your content will indeed work. While semantically "icky", I added an div with a class of overflowWrap right inside the body tag and then set set my CSS like this:

html, body, .overflowWrap {
overflow-x: hidden;

Might be overkill now, but works like a charm!

First letter capitalization for EditText


TextView firstline = (TextView) findViewById(;

How do you test your Request.QueryString[] variables?

I do have functions for each (actually it's one small class, with lots of statics):

  • GetIntegerFromQuerystring(val)
  • GetIntegerFromPost(val)
  • ....

It returns -1 if fails (which is almost always OK for me, I have some other functions for negative numbers as well).

Dim X as Integer = GetIntegerFromQuerystring("id")
If x = -1 Then Exit Sub

What is the default text size on Android?

Looks like someone else found it: What are the default font characteristics in Android ?

There someone discovered the default text size, for TextViews (which use TextAppearance.Small) it's 14sp.

How can I capitalize the first letter of each word in a string?

Capitalize string with non-uniform spaces

I would like to add to @Amit Gupta's point of non-uniform spaces:

From the original question, we would like to capitalize every word in the string s = 'the brown fox'. What if the string was s = 'the brown fox' with non-uniform spaces.

def solve(s):
    # If you want to maintain the spaces in the string, s = 'the brown      fox'
    # Use s.split(' ') instead of s.split().
    # s.split() returns ['the', 'brown', 'fox']
    # while s.split(' ') returns ['the', 'brown', '', '', '', '', '', 'fox']
    capitalized_word_list = [word.capitalize() for word in s.split(' ')]
    return ' '.join(capitalized_word_list)

Eclipse: How do I add the javax.servlet package to a project?

When you define a server in server view, then it will create you a server runtime library with server libs (including servlet api), that can be assigned to your project. However, then everybody that uses your project, need to create the same type of runtime in his/her eclipse workspace even for compiling.

If you directly download the servlet api jar, than it could lead to problems, since it will be included into the artifacts of your projects, but will be also present in servlet container.

In Maven it is much nicer, since you can define the servlet api interfaces as a "provided" dependency, that means it is present in the "to be production" environment.

How to create image slideshow in html?

  1. Set var step=1 as global variable by putting it above the function call
  2. put semicolons

It will look like this

<script type="text/javascript">
var image1 = new Image()
image1.src = "images/pentagg.jpg"
var image2 = new Image()
image2.src = "images/promo.jpg"
<p><img src="images/pentagg.jpg" width="500" height="300" name="slide" /></p>
<script type="text/javascript">
        var step=1;
        function slideit()
            document.images.slide.src = eval("image"+step+".src");

How to mock a final class with mockito

For us, it was because we excluded mockito-inline from koin-test. One gradle module actually needed this and for reason only failed on release builds (debug builds in the IDE worked) :-P

Assign a synthesizable initial value to a reg in Verilog

The other answers are all good. For Xilinx FPGA designs, it is best not to use global reset lines, and use initial blocks for reset conditions for most logic. Here is the white paper from Ken Chapman (Xilinx FPGA guru)

Replace all occurrences of a String using StringBuilder?

Here is an in place replaceAll that will modify the passed in StringBuilder. I thought that I would post this as I was looking to do replaceAll with out creating a new String.

public static void replaceAll(StringBuilder sb, Pattern pattern, String replacement) {
    Matcher m = pattern.matcher(sb);
    while(m.find()) {
        sb.replace(m.start(), m.end(), replacement);

I was shocked how simple the code to do this was (for some reason I thought changing the StringBuilder while using the matcher would throw of the group start/end but it does not).

This is probably faster than the other regex answers because the pattern is already compiled and your not creating a new String but I didn't do any benchmarking.

ps command doesn't work in docker container

ps is not installed in the base wheezy image. Try this from within the container:

RUN apt-get update && apt-get install -y procps

How to drop a database with Mongoose?

beforeEach((done) => {
      mongoose.connection.dropCollection('products',(error ,result) => {
      if (error) {
        console.log('Products Collection is not dropped')
      } else {

rails simple_form - hidden field - create?

Shortest Yet !!!

=f.hidden_field :title, :value => "some value"

Shorter, DRYer and perhaps more obvious.

Of course with ruby 1.9 and the new hash format we can go 3 characters shorter with...

=f.hidden_field :title, value: "some value"

How can I center an image in Bootstrap?

Image by default is displayed as inline-block, you need to display it as block in order to center it with .mx-auto. This can be done with built-in .d-block:

<div class="container">
    <div class="row">
        <div class="col-4">
            <img class="mx-auto d-block" src="...">  

Or leave it as inline-block and wrapped it in a div with .text-center:

<div class="container">
    <div class="row">
        <div class="col-4">
          <div class="text-center">
            <img src="..."> 

I made a fiddle showing both ways. They are documented here as well.

How do I programmatically set the value of a select box element using JavaScript?

function setSelectValue (id, val) {
    document.getElementById(id).value = val;
setSelectValue('leaveCode', 14);

Python: How to create a unique file name?

To create a unique file path if its exist, use random package to generate a new string name for file. You may refer below code for same.

import os
import random
import string

def getUniquePath(folder, filename):    
    path = os.path.join(folder, filename)
    while os.path.exists(path):
         path = path.split('.')[0] + ''.join(random.choice(string.ascii_lowercase) for i in range(10)) + '.' + path.split('.')[1]
    return path

Now you can use this path to create file accordingly.

How to check if a variable is not null?

if myVar is null then if block not execute other-wise it will execute.

if (myVar != null) {...}

Nested select statement in SQL Server

The answer provided by Joe Stefanelli is already correct.

SELECT name FROM (SELECT name FROM agentinformation) as a  

We need to make an alias of the subquery because a query needs a table object which we will get from making an alias for the subquery. Conceptually, the subquery results are substituted into the outer query. As we need a table object in the outer query, we need to make an alias of the inner query.

Statements that include a subquery usually take one of these forms:

  • WHERE expression [NOT] IN (subquery)
  • WHERE expression comparison_operator [ANY | ALL] (subquery)
  • WHERE [NOT] EXISTS (subquery)

Check for more subquery rules and subquery types.

More examples of Nested Subqueries.

  1. IN / NOT IN – This operator takes the output of the inner query after the inner query gets executed which can be zero or more values and sends it to the outer query. The outer query then fetches all the matching [IN operator] or non matching [NOT IN operator] rows.

  2. ANY – [>ANY or ANY operator takes the list of values produced by the inner query and fetches all the values which are greater than the minimum value of the list. The

e.g. >ANY(100,200,300), the ANY operator will fetch all the values greater than 100.

  1. ALL – [>ALL or ALL operator takes the list of values produced by the inner query and fetches all the values which are greater than the maximum of the list. The

e.g. >ALL(100,200,300), the ALL operator will fetch all the values greater than 300.

  1. EXISTS – The EXISTS keyword produces a Boolean value [TRUE/FALSE]. This EXISTS checks the existence of the rows returned by the sub query.

How do I horizontally center a span element inside a div

I assume you want to center them on one line and not on two separate lines based on your fiddle. If that is the case, try the following css:

 div { background:red;
span { display:block;
       margin:0 auto;
span a { padding:5px 10px;

I removed the float since you want to center it, and then made the span surrounding the links centered by adding margin:0 auto to them. Finally, I added a static width to the span. This centers the links on one line within the red div.

What does mysql error 1025 (HY000): Error on rename of './foo' (errorno: 150) mean?

averageRatings= FOREACH groupedRatings GENERATE group AS movieID, AVG(ratings.rating) AS avgRating, COUNT(ratings.rating) AS numRatings;

If you are using any command like above you must use group in small letters. This may solve your problem it solved mine. At least in PIG script.

How do I get just the date when using MSSQL GetDate()?

You can use


Deny direct access to all .php files except index.php

You can try defining a constant in index.php and add something like

if (!defined("YOUR_CONSTANT")) die('No direct access');

to the beginning of the other files.

OR, you can use mod_rewrite and redirect requests to index.php, editing .htaccess like this:

RewriteEngine on
RewriteCond $1 !^(index\.php)
RewriteRule ^(.*)$ /index.php/$1 [L,R=301]

Then you should be able to analyze all incoming requests in the index.php and take according actions.

If you want to leave out all *.jpg, *.gif, *.css and *.png files, for example, then you should edit second line like this:

RewriteCond $1 !^(index\.php|*\.jpg|*\.gif|*\.css|*\.png)

Call an activity method from a fragment

Update after I understand more how fragments work. Each fragment belongs to a parent activity. So just use:


From within the fragment. It is a better answer because you avoid superflous casts. If you cannot avoid the casts with this solution use the one below.


what you have to do is to cast to the outer activity

((MainActivity) getActivity()).Method();

creating a new instance will be confusing the android frame and it will not be able to recognize it. see also :

How to replace deprecated

Insted of


You can use


How to cast Object to its actual type?

Implement an interface to call your function in your method
interface IMyInterface
 void MyinterfaceMethod();

IMyInterface MyObj = obj as IMyInterface;
if ( MyObj != null)
MyMethod(IMyInterface MyObj );

RequestDispatcher.forward() vs HttpServletResponse.sendRedirect()

SendRedirect() will search the content between the servers. it is slow because it has to intimate the browser by sending the URL of the content. then browser will create a new request for the content within the same server or in another one.

RquestDispatcher is for searching the content within the server i think. its the server side process and it is faster compare to the SendRedirect() method. but the thing is that it will not intimate the browser in which server it is searching the required date or content, neither it will not ask the browser to change the URL in URL tab. so it causes little inconvenience to the user.

Java Long primitive type maximum limit

Ranges from -9,223,372,036,854,775,808 to +9,223,372,036,854,775,807.

It will start from -9,223,372,036,854,775,808


How to use http.client in Node.js if there is basic authorization

I came across this recently. Which among Proxy-Authorization and Authorization headers to set depends on the server the client is talking to. If it is a Webserver, you need to set Authorization and if it a proxy, you have to set the Proxy-Authorization header

List Git commits not pushed to the origin yet

git log origin/master..master

or, more generally:

git log <since>..<until>

You can use this with grep to check for a specific, known commit:

git log <since>..<until> | grep <commit-hash>

Or you can also use git-rev-list to search for a specific commit:

git rev-list origin/master | grep <commit-hash>

RequiredIf Conditional Validation Attribute

The main difference from other solutions here is that this one reuses logic in RequiredAttribute on the server side, and uses required's validation method depends property on the client side:

public class RequiredIf : RequiredAttribute, IClientValidatable
    public string OtherProperty { get; private set; }
    public object OtherPropertyValue { get; private set; }

    public RequiredIf(string otherProperty, object otherPropertyValue)
        OtherProperty = otherProperty;
        OtherPropertyValue = otherPropertyValue;

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        PropertyInfo otherPropertyInfo = validationContext.ObjectType.GetProperty(OtherProperty);
        if (otherPropertyInfo == null)
            return new ValidationResult($"Unknown property {OtherProperty}");

        object otherValue = otherPropertyInfo.GetValue(validationContext.ObjectInstance, null);
        if (Equals(OtherPropertyValue, otherValue)) // if other property has the configured value
            return base.IsValid(value, validationContext);

        return null;

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
        var rule = new ModelClientValidationRule();
        rule.ErrorMessage = FormatErrorMessage(metadata.GetDisplayName());
        rule.ValidationType = "requiredif"; // data-val-requiredif
        rule.ValidationParameters.Add("other", OtherProperty); // data-val-requiredif-other
        rule.ValidationParameters.Add("otherval", OtherPropertyValue); // data-val-requiredif-otherval

        yield return rule;

$.validator.unobtrusive.adapters.add("requiredif", ["other", "otherval"], function (options) {
    var value = {
        depends: function () {
            var element = $(options.form).find(":input[name='" + options.params.other + "']")[0];
            return element && $(element).val() == options.params.otherval;
    options.rules["required"] = value;
    options.messages["required"] = options.message;

Understanding the Rails Authenticity Token

Beware the Authenticity Token mechanism can result in race conditions if you have multiple, concurrent requests from the same client. In this situation your server can generate multiple authenticity tokens when there should only be one, and the client receiving the earlier token in a form will fail on it's next request because the session cookie token has been overwritten. There is a write up on this problem and a not entirely trivial solution here:

Get-WmiObject : The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)

It might be due to various issues.I cant say which one is there in your case.

Below given reasons may be there:

  • DCOM is not enabled in host PC or target PC or on both.
  • Your Firewall or even your antivirus is preventing the access.
  • Any WMI related service is disabled.

Some WMI related services are as given:

  • Remote Access Auto Connection Manager
  • Remote Access Connection Manager
  • Remote Procedure Call (RPC)
  • Remote Procedure Call (RPC) Locator
  • Remote Registry

For DCOM setting refer:

  • Key: HKLM\Software\Microsoft\OLE, Value: EnableDCOM

The value should be set to 'Y' .

How to scroll the window using JQuery $.scrollTo() function

Looks like you've got the syntax slightly wrong... I'm assuming based on your code that you're trying to scroll down 100px in 800ms, if so then this works (using scrollTo 1.4.1):

$.scrollTo('+=100px', 800, { axis:'y' });

Can regular JavaScript be mixed with jQuery?

Or no JavaScript load function at all...

    <canvas id="canvas" width="150" height="150"></canvas>
<script type="text/javascript">
    var draw = function() {
        var canvas = document.getElementById("canvas");
        if (canvas.getContext) {
            var ctx = canvas.getContext("2d");

            ctx.fillStyle = "rgb(200,0,0)";
            ctx.fillRect (10, 10, 55, 50);

            ctx.fillStyle = "rgba(0, 0, 200, 0.5)";
            ctx.fillRect (30, 30, 55, 50);

    //or self executing...

        var canvas = document.getElementById("canvas");
        if (canvas.getContext) {
            var ctx = canvas.getContext("2d");

            ctx.fillStyle = "rgb(200,0,0)";
            ctx.fillRect (50, 50, 55, 50);

            ctx.fillStyle = "rgba(0, 0, 200, 0.5)";
            ctx.fillRect (70, 70, 55, 50);

Permutations between two lists of unequal length

the best way to find out all the combinations for large number of lists is:

import itertools
from pprint import pprint

inputdata = [
    ['a', 'b', 'c'],
    ['e', 'f'],
result = list(itertools.product(*inputdata))

the result will be:

[('a', 'd', 'e'),
 ('a', 'd', 'f'),
 ('b', 'd', 'e'),
 ('b', 'd', 'f'),
 ('c', 'd', 'e'),
 ('c', 'd', 'f')]

How to find SQL Server running port?

try once:-

USE master
DECLARE       @portNumber   NVARCHAR(10)
EXEC   xp_instance_regread
@rootkey    = 'HKEY_LOCAL_MACHINE',
@key        =
'Software\Microsoft\Microsoft SQL Server\MSSQLServer\SuperSocketNetLib\Tcp\IpAll',
@value_name = 'TcpDynamicPorts',
@value      = @portNumber OUTPUT
SELECT [Port Number] = @portNumber

"implements Runnable" vs "extends Thread" in Java

if you use runnable you can save the space to extend to any of your other class.

Python For loop get index

Do you want to iterate over characters or words?

For words, you'll have to split the words first, such as

for index, word in enumerate(loopme.split(" ")):
    print "CURRENT WORD IS", word, "AT INDEX", index

This prints the index of the word.

For the absolute character position you'd need something like

chars = 0
for index, word in enumerate(loopme.split(" ")):
    print "CURRENT WORD IS", word, "AT INDEX", index, "AND AT CHARACTER", chars
    chars += len(word) + 1

How to set minDate to current date in jQuery UI Datepicker?

Use this one :

 onSelect: function(dateText) {
                 $("input#DateTo").datepicker('option', 'minDate', dateText);

This may be useful :

Retrieve list of tasks in a queue in Celery

As far as I know Celery does not give API for examining tasks that are waiting in the queue. This is broker-specific. If you use Redis as a broker for an example, then examining tasks that are waiting in the celery (default) queue is as simple as:

  1. connect to the broker database
  2. list items in the celery list (LRANGE command for an example)

Keep in mind that these are tasks WAITING to be picked by available workers. Your cluster may have some tasks running - those will not be in this list as they have already been picked.

invalid operands of types int and double to binary 'operator%'

Because % is only defined for integer types. That's the modulus operator.

5.6.2 of the standard:

The operands of * and / shall have arithmetic or enumeration type; the operands of % shall have integral or enumeration type. [...]

As Oli pointed out, you can use fmod(). Don't forget to include math.h.

Python object.__repr__(self) should be an expression?

"but does that mean it should just be an example of the sort of expression you could use, or should it be an actual expression, that can be executed (eval etc..) to recreate the object? Or... should it be just a rehasing of the actual expression which was used, for pure information purposes?"

Wow, that's a lot of hand-wringing.

  1. An "an example of the sort of expression you could use" would not be a representation of a specific object. That can't be useful or meaningful.

  2. What is the difference between "an actual expression, that can ... recreate the object" and "a rehasing of the actual expression which was used [to create the object]"? Both are an expression that creates the object. There's no practical distinction between these. A repr call could produce either a new expression or the original expression. In many cases, they're the same.

Note that this isn't always possible, practical or desirable.

In some cases, you'll notice that repr() presents a string which is clearly not an expression of any kind. The default repr() for any class you define isn't useful as an expression.

In some cases, you might have mutual (or circular) references between objects. The repr() of that tangled hierarchy can't make sense.

In many cases, an object is built incrementally via a parser. For example, from XML or JSON or something. What would the repr be? The original XML or JSON? Clearly not, since they're not Python. It could be some Python expression that generated the XML. However, for a gigantic XML document, it might not be possible to write a single Python expression that was the functional equivalent of parsing XML.

Throw away local commits in Git

Before answering let's add some background, explaining what is this HEAD. since some of the options below will result in detached head

First of all what is HEAD?

HEAD is simply a reference to the current commit (latest) on the current branch.
There can only be a single HEAD at any given time. (excluding git worktree)

The content of HEAD is stored inside .git/HEAD and it contains the 40 bytes SHA-1 of the current commit.

detached HEAD

If you are not on the latest commit - meaning that HEAD is pointing to a prior commit in history its called detached HEAD.

enter image description here

On the command line, it will look like this- SHA-1 instead of the branch name since the HEAD is not pointing to the tip of the current branch

enter image description here

enter image description here

A few options on how to recover from a detached HEAD:

git checkout

git checkout <commit_id>
git checkout -b <new branch> <commit_id>
git checkout HEAD~X // x is the number of commits t go back

This will checkout new branch pointing to the desired commit.
This command will checkout to a given commit.
At this point, you can create a branch and start to work from this point on.

# Checkout a given commit. 
# Doing so will result in a `detached HEAD` which mean that the `HEAD`
# is not pointing to the latest so you will need to checkout branch
# in order to be able to update the code.
git checkout <commit-id>

# create a new branch forked to the given commit
git checkout -b <branch name>

git reflog

You can always use the reflog as well.
git reflog will display any change which updated the HEAD and checking out the desired reflog entry will set the HEAD back to this commit.

Every time the HEAD is modified there will be a new entry in the reflog

git reflog
git checkout HEAD@{...}

This will get you back to your desired commit

enter image description here

git reset --hard <commit_id>

"Move" your HEAD back to the desired commit.

# This will destroy any local modifications.
# Don't do it if you have uncommitted work you want to keep.
git reset --hard 0d1d7fc32

# Alternatively, if there's work to keep:
git stash
git reset --hard 0d1d7fc32
git stash pop
# This saves the modifications, then reapplies that patch after resetting.
# You could get merge conflicts if you've modified things which were
# changed since the commit you reset to.
  • Note: (Since Git 2.7)
    you can also use the git rebase --no-autostash as well.

git revert <sha-1>

"Undo" the given commit or commit range.
The reset command will "undo" any changes made in the given commit.
A new commit with the undo patch will be committed while the original commit will remain in the history as well.

# add new commit with the undo of the original one.
# the <sha-1> can be any commit(s) or commit range
git revert <sha-1>

This schema illustrates which command does what.
As you can see there reset && checkout modify the HEAD.

enter image description here

Simple 3x3 matrix inverse code (C++)

I went ahead and wrote it in python since I think it's a lot more readable than in c++ for a problem like this. The function order is in order of operations for solving this by hand via this video. Just import this and call "print_invert" on your matrix.

def print_invert (matrix):
  i_matrix = invert_matrix (matrix)
  for line in i_matrix:
    print (line)

def invert_matrix (matrix):
  determinant = str (determinant_of_3x3 (matrix))
  cofactor = make_cofactor (matrix)
  trans_matrix = transpose_cofactor (cofactor)

  trans_matrix[:] = [[str (element) +'/'+ determinant for element in row] for row in trans_matrix]

  return trans_matrix

def determinant_of_3x3 (matrix):
  multiplication = 1
  neg_multiplication = 1
  total = 0
  for start_column in range (3):
    for row in range (3):
      multiplication *= matrix[row][(start_column+row)%3]
      neg_multiplication *= matrix[row][(start_column-row)%3]
    total += multiplication - neg_multiplication
    multiplication = neg_multiplication = 1
  if total == 0:
    total = 1
  return total

def make_cofactor (matrix):
  cofactor = [[0,0,0],[0,0,0],[0,0,0]]
  matrix_2x2 = [[0,0],[0,0]]
  # For each element in matrix...
  for row in range (3):
    for column in range (3):

      # ...make the 2x2 matrix in this inner loop
      matrix_2x2 = make_2x2_from_spot_in_3x3 (row, column, matrix)
      cofactor[row][column] = determinant_of_2x2 (matrix_2x2)

  return flip_signs (cofactor)

def make_2x2_from_spot_in_3x3 (row, column, matrix):
  c_count = 0
  r_count = 0
  matrix_2x2 = [[0,0],[0,0]]
  # ...make the 2x2 matrix in this inner loop
  for inner_row in range (3):
    for inner_column in range (3):
      if row is not inner_row and inner_column is not column:
        matrix_2x2[r_count % 2][c_count % 2] = matrix[inner_row][inner_column]
        c_count += 1
    if row is not inner_row:
      r_count += 1
  return matrix_2x2

def determinant_of_2x2 (matrix):
  total = matrix[0][0] * matrix [1][1]
  return total - (matrix [1][0] * matrix [0][1])

def flip_signs (cofactor):
  sign_pos = True 
  # For each element in matrix...
  for row in range (3):
    for column in range (3):
      if sign_pos:
        sign_pos = False
        cofactor[row][column] *= -1
        sign_pos = True
  return cofactor

def transpose_cofactor (cofactor):
  new_cofactor = [[0,0,0],[0,0,0],[0,0,0]]
  for row in range (3):
    for column in range (3):
      new_cofactor[column][row] = cofactor[row][column]
  return new_cofactor

When tracing out variables in the console, How to create a new line?

Why not just use separate console.log() for each var, and separate with a comma rather than converting them all to strings? That would give you separate lines, AND give you the true value of each variable rather than the string representation of each (assuming they may not all be strings).


And I think it would be easier to read/maintain.

Auto-indent in Notepad++

There seems to be an option for auto-format of XML at least. It can be found at TextFX -> TextFX HTML Tidy -> Tidy: reindent XML.

How to sort a file, based on its numerical values for a field?

Well, most other answers here refer to

sort -n

However, I'm not sure this works for negative numbers. Here are the results I get with sort version 6.10 on Fedora 9.

Input file:




Which is obviously not ordered by numeric value.

Then, I guess that a more precise answer would be to use sort -n but only if all the values are positive.

P.S.: Using sort -g returns just the same results for this example


Looks like the locale settings affect how the minus sign affects the order (see here). In order to get proper results I just did:

LC_ALL=C sort -n filename.txt

CSS rounded corners in IE8

Internet Explorer (under version 9) does not natively support rounded corners.

There's an amazing script that will magically add it for you: CSS3 PIE.

I've used it a lot of times, with amazing results.

how to transfer a file through SFTP in java?

Try this code.

public void send (String fileName) {
    String SFTPHOST = "host:IP";
    int SFTPPORT = 22;
    String SFTPUSER = "username";
    String SFTPPASS = "password";
    String SFTPWORKINGDIR = "file/to/transfer";

    Session session = null;
    Channel channel = null;
    ChannelSftp channelSftp = null;
    System.out.println("preparing the host information for sftp.");

    try {
        JSch jsch = new JSch();
        session = jsch.getSession(SFTPUSER, SFTPHOST, SFTPPORT);
        java.util.Properties config = new java.util.Properties();
        config.put("StrictHostKeyChecking", "no");
        System.out.println("Host connected.");
        channel = session.openChannel("sftp");
        System.out.println("sftp channel opened and connected.");
        channelSftp = (ChannelSftp) channel;;
        File f = new File(fileName);
        channelSftp.put(new FileInputStream(f), f.getName());"File transfered successfully to host.");
    } catch (Exception ex) {
        System.out.println("Exception found while tranfer the response.");
    } finally {
        System.out.println("sftp Channel exited.");
        System.out.println("Channel disconnected.");
        System.out.println("Host Session disconnected.");

What is meant by the term "hook" in programming?

hooks can be executed when some condition is encountered. e.g. some variable changes or some action is called or some event happens. hooks can enter in the process and change things or react upon changes.

Executing <script> elements inserted with .innerHTML

scriptNode.innerHTML = code didn't work for IE. The only thing to do is replace with scriptNode.text = code and it work fine

How do I override nested NPM dependency versions?

I had an issue where one of the nested dependency had an npm audit vulnerability, but I still wanted to maintain the parent dependency version. the npm shrinkwrap solution didn't work for me, so what I did to override the nested dependency version:

  1. Remove the nested dependency under the 'requires' section in package-lock.json
  2. Add the updated dependency under DevDependencies in package.json, so that modules that require it will still be able to access it.
  3. npm i

Peak signal detection in realtime timeseries data

Here is a Groovy (Java) implementation of the smoothed z-score algorithm (see answer above).

 * "Smoothed zero-score alogrithm" shamelessly copied from
 *  Uses a rolling mean and a rolling deviation (separate) to identify peaks in a vector
 * @param y - The input vector to analyze
 * @param lag - The lag of the moving window (i.e. how big the window is)
 * @param threshold - The z-score at which the algorithm signals (i.e. how many standard deviations away from the moving mean a peak (or signal) is)
 * @param influence - The influence (between 0 and 1) of new signals on the mean and standard deviation (how much a peak (or signal) should affect other values near it)
 * @return - The calculated averages (avgFilter) and deviations (stdFilter), and the signals (signals)

public HashMap<String, List<Object>> thresholdingAlgo(List<Double> y, Long lag, Double threshold, Double influence) {
    //init stats instance
    SummaryStatistics stats = new SummaryStatistics()

    //the results (peaks, 1 or -1) of our algorithm
    List<Integer> signals = new ArrayList<Integer>(Collections.nCopies(y.size(), 0))
    //filter out the signals (peaks) from our original list (using influence arg)
    List<Double> filteredY = new ArrayList<Double>(y)
    //the current average of the rolling window
    List<Double> avgFilter = new ArrayList<Double>(Collections.nCopies(y.size(), 0.0d))
    //the current standard deviation of the rolling window
    List<Double> stdFilter = new ArrayList<Double>(Collections.nCopies(y.size(), 0.0d))
    //init avgFilter and stdFilter
    (0..lag-1).each { stats.addValue(y[it as int]) }
    avgFilter[lag - 1 as int] = stats.getMean()
    stdFilter[lag - 1 as int] = Math.sqrt(stats.getPopulationVariance()) //getStandardDeviation() uses sample variance (not what we want)
    //loop input starting at end of rolling window
    (lag..y.size()-1).each { i ->
        //if the distance between the current value and average is enough standard deviations (threshold) away
        if (Math.abs((y[i as int] - avgFilter[i - 1 as int]) as Double) > threshold * stdFilter[i - 1 as int]) {
            //this is a signal (i.e. peak), determine if it is a positive or negative signal
            signals[i as int] = (y[i as int] > avgFilter[i - 1 as int]) ? 1 : -1
            //filter this signal out using influence
            filteredY[i as int] = (influence * y[i as int]) + ((1-influence) * filteredY[i - 1 as int])
        } else {
            //ensure this signal remains a zero
            signals[i as int] = 0
            //ensure this value is not filtered
            filteredY[i as int] = y[i as int]
        //update rolling average and deviation
        (i - lag..i-1).each { stats.addValue(filteredY[it as int] as Double) }
        avgFilter[i as int] = stats.getMean()
        stdFilter[i as int] = Math.sqrt(stats.getPopulationVariance()) //getStandardDeviation() uses sample variance (not what we want)

    return [
        signals  : signals,
        avgFilter: avgFilter,
        stdFilter: stdFilter

Below is a test on the same dataset that yields the same results as the above Python / numpy implementation.

    // Data
    def y = [1d, 1d, 1.1d, 1d, 0.9d, 1d, 1d, 1.1d, 1d, 0.9d, 1d, 1.1d, 1d, 1d, 0.9d, 1d, 1d, 1.1d, 1d, 1d,
         1d, 1d, 1.1d, 0.9d, 1d, 1.1d, 1d, 1d, 0.9d, 1d, 1.1d, 1d, 1d, 1.1d, 1d, 0.8d, 0.9d, 1d, 1.2d, 0.9d, 1d,
         1d, 1.1d, 1.2d, 1d, 1.5d, 1d, 3d, 2d, 5d, 3d, 2d, 1d, 1d, 1d, 0.9d, 1d,
         1d, 3d, 2.6d, 4d, 3d, 3.2d, 2d, 1d, 1d, 0.8d, 4d, 4d, 2d, 2.5d, 1d, 1d, 1d]

    // Settings
    def lag = 30
    def threshold = 5
    def influence = 0

    def thresholdingResults = thresholdingAlgo((List<Double>) y, (Long) lag, (Double) threshold, (Double) influence)

    println y.size()
    println thresholdingResults.signals.size()
    println thresholdingResults.signals

    thresholdingResults.signals.eachWithIndex { x, idx ->
        if (x) {
            println y[idx]

How to extract numbers from a string in Python?

line2 = "hello 12 hi 89"
temp1 = re.findall(r'\d+', line2) # through regular expression
res2 = list(map(int, temp1))

Hi ,

you can search all the integers in the string through digit by using findall expression .

In the second step create a list res2 and add the digits found in string to this list

hope this helps

Regards, Diwakar Sharma

Controller not a function, got undefined, while defining controllers globally

I am a beginner with Angular and I did the basic mistake of not including the app name in the angular root element. So, changing the code from

<html data-ng-app> 


<html data-ng-app="myApp"> 

worked for me. @PSL, has covered this already in his answer above.

PreparedStatement IN clause alternatives?

Following Adam's idea. Make your prepared statement sort of select my_column from my_table where search_column in (#) Create a String x and fill it with a number of "?,?,?" depending on your list of values Then just change the # in the query for your new String x an populate

How to convert a timezone aware string to datetime in Python without dateutil?

You can convert like this.

date = datetime.datetime.strptime('2019-3-16T5-49-52-595Z','%Y-%m-%dT%H-%M-%S-%f%z')
date_time = date.strftime('%Y-%m-%dT%H:%M:%S.%fZ')

Do fragments really need an empty constructor?

Yes, as you can see the support-package instantiates the fragments too (when they get destroyed and re-opened). Your Fragment subclasses need a public empty constructor as this is what's being called by the framework.

force client disconnect from server with and nodejs

Any reason why you can't have the server emit a message to the client that makes it call the disconnect function?

On client:


On Server:

socket.on('forceDisconnect', function(){

How to run .sh on Windows Command Prompt?

New feature in Windows - run bash on ubuntu on windows - available in Windows 10 "Insiders" builds after the Build conference:

What are the differences between .so and .dylib on osx?

The difference between .dylib and .so on mac os x is how they are compiled. For .so files you use -shared and for .dylib you use -dynamiclib. Both .so and .dylib are interchangeable as dynamic library files and either have a type as DYLIB or BUNDLE. Heres the readout for different files showing this.

Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
MH_MAGIC_64  X86_64        ALL  0x00      BUNDLE    16       1696   NOUNDEFS DYLDLINK TWOLEVEL

The reason the two are equivalent on Mac OS X is for backwards compatibility with other UNIX OS programs that compile to the .so file type.

Compilation notes: whether you compile a .so file or a .dylib file you need to insert the correct path into the dynamic library during the linking step. You do this by adding -install_name and the file path to the linking command. If you dont do this you will run into the problem seen in this post: Mac Dynamic Library Craziness (May be Fortran Only).

css 100% width div not taking up full width of parent

html, body{ 

This tells the html to be 100% wide. But 100% refers to the whole browser window width, so no more than that.

You may want to set a min width instead.

html, body{ 

So it will be 100% as a minimum, bot more if needed.

UIImageView - How to get the file name of the image assigned?

No no no… in general these things are possible. It'll just make you feel like a dirty person. If you absolutely must, do this:

  • Create a category with your own implementation of +imageNamed:(NSString*)imageName that calls through to the existing implementation and uses the technique identified here (How do I use objc_setAssociatedObject/objc_getAssociatedObject inside an object?) to permanently associate imageName with the UIImage object that is returned.

  • Use Method Swizzling to swap the provided implementation of imageNamed: for your implementation in the method lookup table of the Objective-C runtime.

  • Access the name you associated with the UIImage instance (using objc_getAssociatedObject) anytime you want it.

I can verify that this works, with the caveat that you can't get the names of UIImage's loaded in NIBs. It appears that images loaded from NIBs are not created through any standard function calls, so it's really a mystery to me.

I'm leaving the implementation up to you. Copy-pasting code that screws with the Objective-C runtime is a very bad idea, so think carefully about your project's needs and implement this only if you must.

Apache HttpClient 4.0.3 - how do I set cookie with sessionID for POST request?

I did it by passing the cookie through the HttpContext:

HttpContext localContext = new BasicHttpContext();

localContext.setAttribute(ClientContext.COOKIE_STORE, cookieStore);

response = client.execute(httppost, localContext);

Event when window.location.href changes

There is a default onhashchange event that you can use.

Documented HERE

And can be used like this:

function locationHashChanged( e ) {
    console.log( location.hash );
    console.log( e.oldURL, e.newURL );
    if ( location.hash === "#pageX" ) {

window.onhashchange = locationHashChanged;

If the browser doesn't support oldURL and newURL you can bind it like this:

//let this snippet run before your hashChange event binding code
if( !window.HashChangeEvent )( function() {
    let lastURL = document.URL;
    window.addEventListener( "hashchange", function( event ) {
        Object.defineProperty( event, "oldURL", { enumerable: true, configurable: true, value: lastURL } );
        Object.defineProperty( event, "newURL", { enumerable: true, configurable: true, value: document.URL } );
        lastURL = document.URL;
    } );
} () );

how to convert string into dictionary in python 3.*?

  1. literal_eval, a somewhat safer version of eval (will only evaluate literals ie strings, lists etc):

    from ast import literal_eval
    python_dict = literal_eval("{'a': 1}")
  2. json.loads but it would require your string to use double quotes:

    import json
    python_dict = json.loads('{"a": 1}')

What is the most efficient way to create HTML elements using jQuery?

You don't need raw performance from an operation you will perform extremely infrequently from the point of view of the CPU.

What is AF_INET, and why do I need it?

AF_INET is an address family that is used to designate the type of addresses that your socket can communicate with (in this case, Internet Protocol v4 addresses). When you create a socket, you have to specify its address family, and then you can only use addresses of that type with the socket. The Linux kernel, for example, supports 29 other address families such as UNIX (AF_UNIX) sockets and IPX (AF_IPX), and also communications with IRDA and Bluetooth (AF_IRDA and AF_BLUETOOTH, but it is doubtful you'll use these at such a low level).

For the most part, sticking with AF_INET for socket programming over a network is the safest option. There is also AF_INET6 for Internet Protocol v6 addresses.

Hope this helps,

How to open maximized window with Javascript?

var params = [
    'fullscreen=yes' // only works in IE, but here for completeness
     // and any other options from

var popup ='', 'popup_window', params); 

Please refrain from opening the popup unless the user really wants it, otherwise they will curse you and blacklist your site. ;-)

edit: Oops, as Joren Van Severen points out in a comment, this may not take into account taskbars and window decorations (in a possibly browser-dependent way). Be aware. It seems that ignoring height and width (only param is fullscreen=yes) seems to work on Chrome and perhaps Firefox too; the original 'fullscreen' functionality has been disabled in Firefox for being obnoxious, but has been replaced with maximization. This directly contradicts information on the same page of which says that window-maximizing is impossible. This 'feature' may or may not be supported depending on the browser.

Insert into C# with SQLCommand

Try confirm the data type (SqlDbType) for each parameter in the database and do it this way;

 using(SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["connSpionshopString"].ConnectionString))
            string sql =  "INSERT INTO klant(klant_id,naam,voornaam) VALUES(@param1,@param2,@param3)";
            using(SqlCommand cmd = new SqlCommand(sql,connection)) 
                  cmd.Parameters.Add("@param1", SqlDbType.Int).value = klantId;  
                  cmd.Parameters.Add("@param2", SqlDbType.Varchar, 50).value = klantNaam;
                  cmd.Parameters.Add("@param3", SqlDbType.Varchar, 50).value = klantVoornaam;
                  cmd.CommandType = CommandType.Text;

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

.hover() function accepts two function arguments, one for mouseenter event and one for mouseleave event.

Text Progress Bar in the Console

Check this library: clint

it has a lot of features including a progress bar:

from time import sleep  
from random import random  
from clint.textui import progress  
if __name__ == '__main__':
    for i in
        sleep(random() * 0.2)

    for i in progress.dots(range(100)):
        sleep(random() * 0.2)

this link provides a quick overview of its features

How to echo shell commands as they are executed

For zsh, echo

setopt VERBOSE

And for debugging,

setopt XTRACE

Is it possible to declare two variables of different types in a for loop?

See "Is there a way to define variables of two types in for loop?" for another way involving nesting multiple for loops. The advantage of the other way over Georg's "struct trick" is that it (1) allows you to have a mixture of static and non-static local variables and (2) it allows you to have non-copyable variables. The downside is that it is far less readable and may be less efficient.

Twitter Bootstrap modal: How to remove Slide down effect

I solved this by overriding the default .modal.fade styles in my own LESS stylesheet:

.modal {
  &.fade {
    .transition(e('opacity .3s linear'));
    top: 50%;
  & { top: 50%; }

This keeps the fade in / fade out animation but removes the slide up / slide down animation.

docker: Error response from daemon: Get Service Unavailable. IN DOCKER , MAC

It's clearly a proxy issue: docker proxies https connections to the wrong place. Bear in mind that docker proxy settings may be different from the operating system (and curl) ones. Here's how I managed to solve the issue:

First of all, find out where are you proxying your docker https requests:

# docker info | grep Proxy
Http Proxy: http://<my.proxy.server>:8080
Https Proxy: https://<my.proxy.server>:8080
No Proxy: localhost,

and double check your https settings.

In my case, I realized that the "Https proxy" was set to https://... instead of http://..., so I corrected it in /etc/sysconfig/docker file (I'm using RHEL7) and, after a docker restart with:

# systemctl restart docker

the proxy variable shows up succesfully updated:

# docker info | grep Proxy
Http Proxy: http://<my.proxy.server>:8080
Https Proxy: http://<my.proxy.server>:8080
No Proxy: localhost,

and everything works fine :-)

Error:Unknown host You may need to adjust the proxy settings in Gradle

In my case issue occurred after following:

I selected proxy settings from Android Studio settings when I was working in a network behind a proxy. When I disconnected from that network and connected to home network which doesn't have a proxy, I removed the proxy settings from Android Studio, but gradle seemed to take the old proxy settings.

The problem was that gradle had also saved the proxy settings in following file when I set proxy settings in Android Studio, but it hasn't got removed when I removed proxy settings from Android Studio.


When I removed the proxy settings from this file, gradle sync worked again.

How to reference a file for variables using Bash?

The script containing variables can be executed imported using bash. Consider the


Consider the actual script where the variable will be used :

 bash path/to/
 echo "$scr-var"

Create a CSS rule / class with jQuery at runtime

Here is a jquery plugin that allows you to inject CSS:


    "#my-window": {
        "position": "fixed",
        "z-index": 102,
        "display": "none",
        "top": "50%",
        "left": "50%"

PHP PDO with foreach and fetch

foreach over a statement is just a syntax sugar for the regular one-way fetch() loop. If you want to loop over your data more than once, select it as a regular array first

$sql = "SELECT * FROM users";
$stm = $dbh->query($sql);
// here you go:
$users = $stm->fetchAll();

foreach ($users as $row) {
    print $row["name"] . "-" . $row["sex"] ."<br/>";
echo "<br/>";
foreach ($users as $row) {
    print $row["name"] . "-" . $row["sex"] ."<br/>";

Also quit that try..catch thing. Don't use it, but set the proper error reporting for PHP and PDO

how to check for null with a ng-if values in a view with angularjs?

You should check for !test, here is a fiddle showing that.

<span ng-if="!test">null</span>

Install tkinter for Python

If you are using Python 3 it might be because you are typing Tkinter not tkinter

How to fix the error; 'Error: Bootstrap tooltips require Tether ('

For webpack I resolved this with webpack.config.js:

new webpack.ProvidePlugin({
  $: 'jquery',
  jQuery: 'jquery',
  "window.jQuery": "jquery",
  Tether: 'tether'

How can I change the Bootstrap default font family using font from Google?

This is the best and easy way to import font from google and
this is also a standard method to import font

Paste this code on your index page or on header

<link href=',300,700' rel='stylesheet' type='text/css'>

other method is to import on css like this:

@import url(,300,700);

on your Css file as this code

body {
  font-family: 'Oswald', sans-serif !important;

Note : The @import code line will be the first lines in your css file (style.css, etc.css). They can be used in any of the .css files and should always be the first line in these files. The following is an example:

How to install SQL Server Management Studio 2008 component only

For any of you still having problems as of Sept. 2012, go here: ...and grab the SQLManagementStudio_x(32|64)_ENU.exe (if you've already installed SQL Server 2008 Express R2), or SQL Server 2008 Express R2 with Tools, i.e. SQLEXPRWT_x64_ENU.exe or SQLEXPRWT_x32_ENU.exe (if you haven't).

From there, follow similar instructions as above (i.e. use the "Perform new installation and add shared features" selection, as "Management Tools - Basic" is considered a "shared feature"), if you've already installed SQL Server Express 2008 R2 (as I had). And if you haven't done that yet, then of course you're going to follow this way as you need to install the new instance anyway.

This solved things for me, and hopefully it will for you, too!

Simulate Keypress With jQuery

I believe this is what you're looking for:

var press = jQuery.Event("keypress");
press.ctrlKey = false;
press.which = 40;

From here.

What is the difference between Builder Design pattern and Factory Design pattern?

I believe, the usage of and the difference between Factory & Builder patterns can be understood/clarified easier in a certain time period as you worked on the same code base and changing requirements.

From my experience, usually, you start with a Factory pattern including couple of static creator methods to primarily hide away relatively complex initialisation logic. As your object hierarchy gets more complex (or as you add more types, parameters), you probably end up having your methods populated with more parameters and not to mention you gonna have to recompile your Factory module. All those stuff, increases the complexity of your creator methods, decreases the readability and makes the creation module more fragile.

This point possibly will be the transition/extension point. By doing so, you create a wrapper module around the construction parameters and then you will be able represent new (similar) objects by adding some more abstractions(perhaps) and implementations without touching actual your creation logic. So you've had "less" complex logic.

Frankly, referring to something sort of "having an object created in one-step or multiple steps is the difference" as the sole diversity factor was not sufficient for me to distinguish them since I could use both ways for almost all cases I faced up to now without experiencing any benefit. So this is what I've finally thought about it.

How to convert List<Integer> to int[] in Java?

Using a lambda you could do this (compiles in jdk lambda):

public static void main(String ars[]) {
        TransformService transformService = (inputs) -> {
            int[] ints = new int[inputs.size()];
            int i = 0;
            for (Integer element : inputs) {
                ints[ i++ ] = element;
            return ints;

        List<Integer> inputs = new ArrayList<Integer>(5) { {add(10); add(10);} };

        int[] results = transformService.transform(inputs);

    public interface TransformService {
        int[] transform(List<Integer> inputs);

I need to get all the cookies from the browser

  1. You can't see cookies for other sites.
  2. You can't see HttpOnly cookies.
  3. All the cookies you can see are in the document.cookie property, which contains a semicolon separated list of name=value pairs.

How to track untracked content?

Had the same problem, but it was not solved in this discussion.

I hit also the submodule problem as described in the thread opening.

% git status          
# On branch master
# Changes not staged for commit:
#   modified:   bundle/taglist (untracked content)

Looking at the diff I recognized a -dirty appended to a hash: Reading the docs again, solved the problem for me. Look at section "Pitfalls with submodules"

Reason was, there were changes or untracked content within the submodule. I first had to got to the submodule directory, do a "git add" + "git commit" to get all content tracked within the submodule.

Then "git status" on the master stated
% git commit
# On branch master
# Changes not staged for commit:
#   modified:   bundle/taglist (new commits)

Now this new HEAD from the submodule could be commited to the master module.

ASP.NET Web API application gives 404 when deployed at IIS 7

You may need to install Hotfix KB980368.

This article describes a update that enables certain Internet Information Services (IIS) 7.0 or IIS 7.5 handlers to handle requests whose URLs do not end with a period. Specifically, these handlers are mapped to "." request paths. Currently, a handler that is mapped to a "." request path handles only requests whose URLs end with a period. For example, the handler handles only requests whose URLs resemble the following URL:

After you apply this update, handlers that are mapped to a "*." request path can handle requests whose URLs end with a period and requests whose URLs do not end with a period. For example, the handler can now handle requests that resemble the following URLs:

After this patch is applied, ASP.NET 4 applications can handle requests for extensionless URLs. Therefore, managed HttpModules that run prior to handler execution will run. In some cases, the HttpModules can return errors for extensionless URLs. For example, an HttpModule that was written to expect only .aspx requests may now return errors when it tries to access the HttpContext.Session property.

How to prevent custom views from losing state across screen orientation changes

To augment other answers - if you have multiple custom compound views with the same ID and they are all being restored with the state of the last view on a configuration change, all you need to do is tell the view to only dispatch save/restore events to itself by overriding a couple of methods.

class MyCompoundView : ViewGroup {


    override fun dispatchSaveInstanceState(container: SparseArray<Parcelable>) {

    override fun dispatchRestoreInstanceState(container: SparseArray<Parcelable>) {

For an explanation of what is happening and why this works, see this blog post. Basically your compound view's children's view IDs are shared by each compound view and state restoration gets confused. By only dispatching state for the compound view itself, we prevent their children from getting mixed messages from other compound views.

What is the maximum possible length of a .NET string?

200 megs... at which point your app grinds to a virtual halt, has about a gig working set memory, and the o/s starts to act like you'll need to reboot.

static void Main(string[] args)
    string s = "hello world";
        s = s + s.Substring(0, s.Length/10);


Golang append an item to a slice

Typical append usage is

a = append(a, x)

because append may either modify its argument in-place or return a copy of its argument with an additional entry, depending on the size and capacity of its input. Using a slice that was previously appended to may give unexpected results, e.g.

a := []int{1,2,3}
a = append(a, 4)
append(a[:3], 5)

may print

[1 2 3 4]
[1 2 3 5]

Limit on the WHERE col IN (...) condition

Why not do a where IN a sub-select...

Pre-query into a temp table or something...

    SELECT YourColumn
    FROM SomeTable
    WHERE UserPickedMultipleRecordsFromSomeListOrSomething


SELECT * FROM OtherTable
WHERE YourColumn IN ( SELECT YourColumn FROM SomeTempTable )

jQuery AJAX submit form

I find it surprising that no one mentions data as an object. For me it's the cleanest and easiest way to pass data:

$('form#foo').submit(function () {
        url: '',
        type: 'POST',
        dataType: 'json',
        data: {
            'foo': 'some-foo-value',
            'bar': $('#bar').val()
    }).always(function (response) {

    return false;

Then, in the backend:

// Example in PHP
$_POST['foo'] // some-foo-value
$_POST['bar'] // value in #bar

"could not find stored procedure"

make sure that your schema name is in the connection string?