Programs & Examples On #Console.out.writeline

Where can I read the Console output in Visual Studio 2015

My problem was that I needed to Reset Window Layout.

Reset Window Layout

How do I make calls to a REST API using C#?

Calling a REST API when using .NET 4.5 or .NET Core

I would suggest DalSoft.RestClient (caveat: I created it). The reason being, because it uses dynamic typing, you can wrap everything up in one fluent call including serialization/de-serialization. Below is a working PUT example:

dynamic client = new RestClient("");

var post = new Post { title = "foo", body = "bar", userId = 10 };

var result = await client.Posts(1).Put(post);

Why am I getting "(304) Not Modified" error on some links when using HttpWebRequest?

I think you have not installed these features. see below in picture.

enter image description here

I also suffered from this problem some days ago. After installing this feature then I solved it. If you have not installed this feature then installed it.

Install Process:

  1. go to android studio
  2. Tools
  3. Android
  4. SDK Manager
  5. Appearance & Behavior
  6. Android SDK

Is gcc's __attribute__((packed)) / #pragma pack unsafe?

It's perfectly safe as long as you always access the values through the struct via the . (dot) or -> notation.

What's not safe is taking the pointer of unaligned data and then accessing it without taking that into account.

Also, even though each item in the struct is known to be unaligned, it's known to be unaligned in a particular way, so the struct as a whole must be aligned as the compiler expects or there'll be trouble (on some platforms, or in future if a new way is invented to optimise unaligned accesses).

Create sequence of repeated values, in sequence?

You missed the each= argument to rep():

R> n <- 3
R> rep(1:5, each=n)
 [1] 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5

so your example can be done with a simple

R> rep(1:8, each=20)

VSCode single to double quote automatic replace

quote_type = single

add this inside .editorconfig

# EditorConfig is awesome:

# top-most EditorConfig file
root = true

indent_style = space
indent_size = 2
end_of_line = lf
charset = utf-8
trim_trailing_whitespace = false
insert_final_newline = false
quote_type = single

What is difference between Errors and Exceptions?

Error is something that most of the time you cannot handle it.

Exception was meant to give you an opportunity to do something with it. like try something else or write to the log.

  //connect to database 1
catch(DatabaseConnctionException err){
  //connect to database 2
  //write the err to log

How to switch to the new browser window, which opens after click on the button?

Just to add to the content ...

To go back to the main window(default window) .

use driver.switchTo().defaultContent();

Create a dropdown component

Hope this will help to someone. Works fine in Angular 6 with reactive forms. Can operate by keyboard too.


<div class="dropdown-wrapper {{className}} {{isFocused ? 'focus':''}}" [ngClass]="{'is-open':isOpen, 'disabled':isReadOnly}" *ngIf="options" (contextmenu)="$event.stopPropagation();">
  <div class="box" (click)="toggle($event)">
      <div class="dropdown-selected" *ngIf="isSelectedValue" l10nTranslate><span>{{options[selected]}}</span></div>
      <div class="dropdown-selected" *ngIf="!isSelectedValue" l10nTranslate><span>{{placeholder}}</span></div>

  <ul class="dropdown-options" *ngIf="options">
    <li *ngIf="placeholder" (click)="$event.stopPropagation()">{{placeholder}}</li>
      <li id="li{{i}}"
        *ngFor="let option of options; let i = index"
        []="selected === i"
        (click)="optionSelect(option, i, $event)"



@import "../../../assets/scss/variables";

.dropdown-wrapper {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    border: 1px solid #DDDDDD;
    border-radius: 3px;
    cursor: pointer;
    position: relative;
        border: 1px solid #a8a8a8;
    .box {
        display: -webkit-box;
        display: -ms-flexbox;
        display: flex;
        width: 100%;

    .dropdown-selected {
        height: 30px;
        position: relative;
        padding: 10px 30px 10px 10px;
        display: -webkit-box;
        display: -ms-flexbox;
        display: flex;
        -webkit-box-align: center;
            -ms-flex-align: center;
                align-items: center;
        width: 100%;
        font-size: 12px;
        color: #666666;
        overflow: hidden;
        background-color: #fff;
        &::before {
            content: "";
            position: absolute;
            top: 50%;
            right: 5px;
            -webkit-transform: translateY(-50%);
                    transform: translateY(-50%);
            width: 22px;
            height: 22px;
            background: url('/assets/i/dropdown-open-selector.svg');
            background-size: 22px 22px;
        span {
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;

    .dropdown-options {
        display: none;
        position: absolute;
        padding: 8px 6px 9px 5px;
        max-height: 261px;
        overflow-y: auto;
        z-index: 999;
        li {
            padding: 10px 25px 10px 10px;
            font-size: $regular-font-size;
            color: $content-text-black;
            position: relative;
            line-height: 10px;
            &:last-child {
                border-bottom: none;
            &:hover {
                background-color: #245A88;
                border-radius: 3px;
                color: #fff;
                border-bottom-color: transparent;
                background-color: #245A88;
                border-radius: 3px;
                color: #fff;
            &.active {
                background-color: #245A88;
                border-radius: 3px;
                color: #fff;
                border-bottom-color: transparent;
            &:hover {
                background-color: #7898B3
            &.active {
                font-weight: 600;
    &.is-open {
        .dropdown-selected {
            &::before {
                content: "";
                position: absolute;
                top: 50%;
                right: 5px;
                -webkit-transform: translateY(-50%);
                        transform: translateY(-50%);
                width: 22px;
                height: 22px;
                background: url('/assets/i/dropdown-close-selector.svg');
                background-size: 22px 22px;
        .dropdown-options {
            display: -webkit-box;
            display: -ms-flexbox;
            display: flex;
            -webkit-box-orient: vertical;
            -webkit-box-direction: normal;
                -ms-flex-direction: column;
                    flex-direction: column;
            width: 100%;
            top: 32px;
            border-radius: 3px;
            background-color: #ffffff;
            border: 1px solid #DDDDDD;
            -webkit-box-shadow: 0px 3px 11px 0 rgba(1, 2, 2, 0.14);
                    box-shadow: 0px 3px 11px 0 rgba(1, 2, 2, 0.14);
    &.data-input-fields {
        .box {
            height: 35px;
    &.send-email-table-select {
        min-width: 140px;
        border: none;
    &.persoanal-settings {
        width: 80px;

  pointer-events: none;
  background-color: #F1F1F1;
  opacity: 0.7;


import { Component, OnInit, Input, Output, EventEmitter, HostListener, forwardRef } from '@angular/core';
import { ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms';

const noop = () => {

  useExisting: forwardRef(() => DropdownComponent),
  multi: true

  selector: 'app-dropdown',
  templateUrl: './dropdown.component.html',
  styleUrls: ['./dropdown.component.scss'],
export class DropdownComponent implements OnInit, ControlValueAccessor {

  @Input() options: Array<string>;
  @Input() selected: number;
  @Input() className: string;
  @Input() placeholder: string;
  @Input() isReadOnly = false;
  @Output() optSelect = new EventEmitter();
  isOpen = false;

  private onTouchedCallback: () => void = noop;
  private onChangeCallback: (_: any) => void = noop;
  isSelectedValue: boolean;
  key: string;
  isFocused: boolean;

   *Creates an instance of DropdownComponent.
   * @memberof DropdownComponent

  ngOnInit() {
    // Place default value in dropdown
    if (this.selected) {
      this.placeholder = '';
      this.isOpen = false;

  focusHandler() {
    this.selected = 0;
    this.isFocused = true;

  focusOutHandler() {
    this.isFocused = false;

  @HostListener('document:keydown', ['$event'])
  keyPressHandle(event: KeyboardEvent) {

    if (this.isFocused) {
      this.key = event.code;
      switch (this.key) {
        case 'Space':
          this.isOpen = true;
        case 'ArrowDown':
          if (this.options.length - 1 > this.selected) {
            this.selected = this.selected + 1;
        case 'ArrowUp':
          if (this.selected > 0) {
            this.selected = this.selected - 1;
        case 'Enter':
          if (this.selected > 0) {
            this.isSelectedValue = true;
            this.isOpen = false;


  * option selection
  * @param {string} selectedOption - text
  * @param {number} idx - current index of item
  * @param {any} event - object
  optionSelect(selectedOption: string, idx, e: any) {
    this.selected = idx;
    this.isSelectedValue = true;
    // this.placeholder = '';
    this.isOpen = false;

  * toggle the dropdown
  * @param {any} event object
  toggle(e: any) {
    // close all previously opened dropdowns, before open
    const allElems = document.querySelectorAll('.dropdown-wrapper');
    for (let i = 0; i < allElems.length; i++) {
    this.isOpen = !this.isOpen;
    if (this.selected >= 0) {
      document.querySelector('#li' + this.selected).scrollIntoView(true);

  * dropdown click on outside
  @HostListener('document: click', ['$event'])
  onClick() {
    this.isOpen = false;

   * Method implemented from ControlValueAccessor and set default selected value
   * @param {*} obj
   * @memberof DropdownComponent
  writeValue(obj: any): void {
    if (obj && obj !== '') {
      this.isSelectedValue = true;
      this.selected = obj;
    } else {
      this.isSelectedValue = false;

  // From ControlValueAccessor interface
  registerOnChange(fn: any) {
    this.onChangeCallback = fn;

  // From ControlValueAccessor interface
  registerOnTouched(fn: any) {
    this.onTouchedCallback = fn;

  setDisabledState?(isDisabled: boolean): void {




<app-dropdown formControlName="type" [options]="types" [placeholder]="captureData.type" [isReadOnly]="isReadOnly">

Options must bind an array as follows. It can change based on the requirement.

types= [
            "id": "1",
            "value": "Type 1"
             "id": "2",
             "value": "Type 2"
              "id": "3",
              "value": "Type 3"

Replace non ASCII character from string

[Updated solution]

can be used with "Normalize" (Canonical decomposition) and "replaceAll", to replace it with the appropriate characters.

import java.text.Normalizer;
import java.text.Normalizer.Form;
import java.util.regex.Pattern;

public final class NormalizeUtils {

    public static String normalizeASCII(final String string) {
        final String normalize = Normalizer.normalize(string, Form.NFD);

        return Pattern.compile("\\p{InCombiningDiacriticalMarks}+")
    } ...

What is a good alternative to using an image map generator?

This service is the best in online image map editing I found so far :

... but it is in fact a bit weak and I personnaly don't use it anymore. I switched to GIMP and it is indeed pretty good.

The answer from mobius is not wrong but in some cases you must use imagemaps even if it seems a bit old and rusty. For instance, in a newsletter, where you can't use HTML/CSS to do what you want.

Go to beginning of line without opening new line in VI

Try this Vi/Vim cheatsheet solution to many problems.

For normal mode :
0 - [zero] to beginning of line, first column.
$ - to end of line

Difference between EXISTS and IN in SQL?

As per my knowledge when a subquery returns a NULL value then the whole statement becomes NULL. In that cases we are using the EXITS keyword. If we want to compare particular values in subqueries then we are using the IN keyword.

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

That's called rounding to even (or banker's rounding), which is a valid rounding strategy for minimizing accrued errors in sums (MidpointRounding.ToEven). The theory is that, if you always round a 0.5 number in the same direction, the errors will accrue faster (round-to-even is supposed to minimize that) (a).

Follow these links for the MSDN descriptions of:

  • Math.Floor, which rounds down towards negative infinity.
  • Math.Ceiling, which rounds up towards positive infinity.
  • Math.Truncate, which rounds up or down towards zero.
  • Math.Round, which rounds to the nearest integer or specified number of decimal places. You can specify the behavior if it's exactly equidistant between two possibilities, such as rounding so that the final digit is even ("Round(2.5,MidpointRounding.ToEven)" becoming 2) or so that it's further away from zero ("Round(2.5,MidpointRounding.AwayFromZero)" becoming 3).

The following diagram and table may help:

-3        -2        -1         0         1         2         3
    a                     b       c           d            e

                       a=-2.7  b=-0.5  c=0.3  d=1.5  e=2.8
                       ======  ======  =====  =====  =====
Floor                    -3      -1      0      1      2
Ceiling                  -2       0      1      2      3
Truncate                 -2       0      0      1      2
Round(ToEven)            -3       0      0      2      3
Round(AwayFromZero)      -3      -1      0      2      3

Note that Round is a lot more powerful than it seems, simply because it can round to a specific number of decimal places. All the others round to zero decimals always. For example:

n = 3.145;
a = System.Math.Round (n, 2, MidpointRounding.ToEven);       // 3.14
b = System.Math.Round (n, 2, MidpointRounding.AwayFromZero); // 3.15

With the other functions, you have to use multiply/divide trickery to achieve the same effect:

c = System.Math.Truncate (n * 100) / 100;                    // 3.14
d = System.Math.Ceiling (n * 100) / 100;                     // 3.15

(a) Of course, that theory depends on the fact that your data has an fairly even spread of values across the even halves (0.5, 2.5, 4.5, ...) and odd halves (1.5, 3.5, ...).

If all the "half-values" are evens (for example), the errors will accumulate just as fast as if you always rounded up.

Live-stream video from one android phone to another over WiFi

I did work on something like this once, but sending a video and playing it in real time is a really complex thing. I suggest you work with PNG's only. In my implementation What i did was capture PNGs using the host camera and then sending them over the network to the client, Which will display the image as soon as received and request the next image from the host. Since you are on wifi that communication will be fast enough to get around 8-10 images per-second(approximation only, i worked on Bluetooth). So this will look like a continuous video but with much less effort. For communication you may use UDP sockets(Faster and less complex) or DLNA (Not sure how that works).

Already defined in .obj - no double inclusions

This is one of the method to overcome this issue.

  • Just put the prototype in the header files and include the header files in the .cpp files as shown below.


#include <boost/asio.hpp>

class SocketClient // Or whatever the name is... {

// ...

    bool read(int, char*); // Or whatever the name is...

//  ... };



bool SocketClient::read(int, char*)
    // Implementation  goes here...


#include <iostream>
#include <string>
#include <sstream>
#include <boost/asio.hpp>
#include <boost/thread/thread.hpp>
#include "client.h"
//              ^^ Notice this!


int main()

How to tell which disk Windows Used to Boot

There is no boot.ini on a machine with just Vista installed.

How do you want to identify the drive/partition: by the windows drive letter it is mapped to (eg. c:\, d:) or by how its hardware signature (which bus, etc).

For the simple case check out GetSystemDirectory

Access 2013 - Cannot open a database created with a previous version of your application

NO, it does NOT work in Access 2013, only 2007/2010. There is no way to really convert an MDB to ACCDB in Access 2013.

How do I find files with a path length greater than 260 characters in Windows?

TLPD ("too long path directory") is the program that saved me. Very easy to use:

Returning a file to View/Download in ASP.NET MVC

Below code worked for me for getting a pdf file from an API service and response it out to the browser - hope it helps;

public async Task<FileResult> PrintPdfStatements(string fileName)
         var fileContent = await GetFileStreamAsync(fileName);
         var fileContentBytes = ((MemoryStream)fileContent).ToArray();
         return File(fileContentBytes, System.Net.Mime.MediaTypeNames.Application.Pdf);

How can I post data as form data instead of a request payload?

As a workaround you can simply make the code receiving the POST respond to application/json data. For PHP I added the code below, allowing me to POST to it in either form-encoded or JSON.

//handles JSON posted arguments and stuffs them into $_POST
//angular's $http makes JSON posts (not normal "form encoded")
$content_type_args = explode(';', $_SERVER['CONTENT_TYPE']); //parse content_type string
if ($content_type_args[0] == 'application/json')
  $_POST = json_decode(file_get_contents('php://input'),true);

//now continue to reference $_POST vars as usual

How to call a method in another class in Java?

Instead of using this in your current class setClassRoomName("aClassName"); you have to use classroom.setClassRoomName("aClassName");

You have to add the class' and at a point like


I know it's a really late answer but if someone starts learning Java and randomly sees this post he knows what to do.

android fragment- How to save states of views in a fragment when another fragment is pushed on top of it

In fragment guide FragmentList example you can find:

public void onSaveInstanceState(Bundle outState) {
    outState.putInt("curChoice", mCurCheckPosition);

Which you can use later like this:

public void onActivityCreated(Bundle savedInstanceState) {
    if (savedInstanceState != null) {
        // Restore last state for checked position.
        mCurCheckPosition = savedInstanceState.getInt("curChoice", 0);

I'm a beginner in Fragments but it seems like solution of your problem ;) OnActivityCreated is invoked after fragment returns from back stack.

How to get a pixel's x,y coordinate color from an image?

The two previous answers demonstrate how to use Canvas and ImageData. I would like to propose an answer with runnable example and using an image processing framework, so you don't need to handle the pixel data manually.

MarvinJ provides the method image.getAlphaComponent(x,y) which simply returns the transparency value for the pixel in x,y coordinate. If this value is 0, pixel is totally transparent, values between 1 and 254 are transparency levels, finally 255 is opaque.

For demonstrating I've used the image below (300x300) with transparent background and two pixels at coordinates (0,0) and (150,150).

enter image description here

Console output:


image = new MarvinImage();_x000D_
image.load("", imageLoaded);_x000D_
function imageLoaded(){_x000D_
  console.log("(0,0): "+(image.getAlphaComponent(0,0) > 0 ? "NOT_TRANSPARENT" : "TRANSPARENT"));_x000D_
  console.log("(150,150): "+(image.getAlphaComponent(150,150) > 0 ? "NOT_TRANSPARENT" : "TRANSPARENT"));_x000D_
<script src=""></script>

How to solve “Microsoft Visual Studio (VS)” error “Unable to connect to the configured development Web server”

I tried almost all the options above, none of them worked for my scenario. Finally I was forced to uninstall IIS Express, re-start the machine, and install the same version again from Microsoft.

Anyway thanks for all the suggestions above.

How do I get the fragment identifier (value after hash #) from a URL?

var url ='';
var type = url.split('#');
var hash = '';
if(type.length > 1)
  hash = type[1];

Working demo on jsfiddle

PHP CURL Enable Linux

if you have used curl above the page and below your html is present and unfortunately your html page is not able to view then just enable your curl. But in order to check CURL is enable or not in php you need to write following code:

echo 'Curl: ', function_exists('curl_version') ? 'Enabled' : 'Disabled';

How do I get indices of N maximum values in a NumPy array?

Here's a more complicated way that increases n if the nth value has ties:

>>>> def get_top_n_plus_ties(arr,n):
>>>>     sorted_args = np.argsort(-arr)
>>>>     thresh = arr[sorted_args[n]]
>>>>     n_ = np.sum(arr >= thresh)
>>>>     return sorted_args[:n_]
>>>> get_top_n_plus_ties(np.array([2,9,8,3,0,2,8,3,1,9,5]),3)
array([1, 9, 2, 6])

Is there a JavaScript function that can pad a string to get to a determined length?

Pad a string to pad_length fillig it with pad_char.
By default the function performs a left pad, unless pad_right is set to true.

If the value of pad_length is negative, less than, or equal to the length of the input string, no padding takes place.
String.prototype.pad = function(pad_char, pad_length, pad_right) 
   var result = this;
   if( (typeof pad_char === 'string') && (pad_char.length === 1) && (pad_length > this.length) )
      var padding = new Array(pad_length - this.length + 1).join(pad_char); //thanks to
      result = (pad_right ? result + padding : padding + result);
   return result;

And then you can do:

alert( "3".pad("0", 3) ); //shows "003"
alert( "hi".pad(" ", 3) ); //shows " hi"
alert( "hi".pad(" ", 3, true) ); //shows "hi "

How to enable LogCat/Console in Eclipse for Android?

Go to your desired perspective. Go to 'Window->show view' menu.

If you see logcat there, click it and you are done.

Else, click on 'other' (at the bottom), chose 'Android'->logcat.

Hope that helps :-)

Use of ~ (tilde) in R programming Language

R defines a ~ (tilde) operator for use in formulas. Formulas have all sorts of uses, but perhaps the most common is for regression:

lm( myFormula, data=iris)

help("~") or help("formula") will teach you more.

@Spacedman has covered the basics. Let's discuss how it works.

First, being an operator, note that it is essentially a shortcut to a function (with two arguments):

> `~`(lhs,rhs)
lhs ~ rhs
> lhs ~ rhs
lhs ~ rhs

That can be helpful to know for use in e.g. apply family commands.

Second, you can manipulate the formula as text:

oldform <- as.character(myFormula) # Get components
myFormula <- as.formula( paste( oldform[2], "Sepal.Length", sep="~" ) )

Third, you can manipulate it as a list:


Finally, there are some helpful tricks with formulae (see help("formula") for more):

myFormula <- Species ~ . 

For example, the version above is the same as the original version, since the dot means "all variables not yet used." This looks at the data.frame you use in your eventual model call, sees which variables exist in the data.frame but aren't explicitly mentioned in your formula, and replaces the dot with those missing variables.

How to make a round button?

You can use a MaterialButton:


and apply a circular ShapeAppearanceOverlay with:

<style name="ShapeAppearanceOverlay.App.rounded" parent="">
    <item name="cornerSize">50%</item>

enter image description here

How to manage local vs production settings in Django?

I use a slightly modified version of the "if DEBUG" style of settings that Harper Shelby posted. Obviously depending on the environment (win/linux/etc.) the code might need to be tweaked a bit.

I was in the past using the "if DEBUG" but I found that occasionally I needed to do testing with DEUBG set to False. What I really wanted to distinguish if the environment was production or development, which gave me the freedom to choose the DEBUG level.

    PRODUCTION = False


# ...

    DATABASE_HOST = 'localhost'

I'd still consider this way of settings a work in progress. I haven't seen any one way to handling Django settings that covered all the bases and at the same time wasn't a total hassle to setup (I'm not down with the 5x settings files methods).

How to easily import multiple sql files into a MySQL database?

You could also a for loop to do so:

for i in *.sql
    echo "Importing: $i"
    mysql your_db_name < $i


How do I set bold and italic on UILabel of iPhone/iPad?

Swift 3


let bondFont = UIFont.boldSystemFont(ofSize:UIFont.labelFontSize)


let italicFont = UIFont.italicSystemFont(ofSize:UIFont.labelFontSize)

Parse String date in (yyyy-MM-dd) format

You may need to format the out put as follows.

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date convertedCurrentDate = sdf.parse("2013-09-18");
String date=sdf.format(convertedCurrentDate );


String convertedCurrentDate =sdf.format(sdf.parse("2013-09-18"));



How to use MySQLdb with Python and Django in OSX 10.6?

mysql_config must be on the path. On Mac, do

export PATH=$PATH:/usr/local/mysql/bin/
pip install MySQL-python

No newline at end of file

Source files are often concatenated by tools (C, C++: header files, Javascript: bundlers). If you omit the newline character, you could introduce nasty bugs (where the last line of one source is concatenated with the first line of the next source file). Hopefully all the source code concat tools out there insert a newline between concatenated files anyway but that doesn't always seem to be the case.

The crux of the issue is - in most languages, newlines have semantic meaning and end-of-file is not a language defined alternative for the newline character. So you ought to terminate every statement/expression with a newline character -- including the last one.

Why isn't my Pandas 'apply' function referencing multiple columns working?

If you just want to compute (column a) % (column b), you don't need apply, just do it directly:

In [7]: df['a'] % df['c']                                                                                                                                                        
0   -1.132022                                                                                                                                                                    
1   -0.939493                                                                                                                                                                    
2    0.201931                                                                                                                                                                    
3    0.511374                                                                                                                                                                    
4   -0.694647                                                                                                                                                                    
5   -0.023486                                                                                                                                                                    
Name: a

How can I find the last element in a List<>?

Use the Count property. The last index will be Count - 1.

for (int cnt3 = 0 ; cnt3 < integerList.Count; cnt3++)

JQuery confirm dialog

Try this one

  .html('<div><h6>Yes or No?</h6></div>')
      modal: true, title: 'message', zIndex: 10000, autoOpen: true,
      width: 'auto', resizable: false,
      buttons: {
          Yes: function () {
          No: function () {
      close: function (event, ui) {


What should I use to open a url instead of urlopen in urllib3

With gazpacho you could pipeline the page straight into a parse-able soup object:

from gazpacho import Soup
url = ""
soup = Soup.get(url)

And run finds on top of it:


How to Update Multiple Array Elements in mongodb

What worked for me was this:

db.collection.find({ _id: ObjectId('4d2d8deff4e6c1d71fc29a07') })
  .forEach(function (doc) { (event) {
      if (event.profile === 10) {

I think it's clearer for mongo newbies and anyone familiar with JQuery & friends.

How do you get an iPhone's device name

To get an iPhone's device name programmatically

 UIDevice *deviceInfo = [UIDevice currentDevice];

 NSLog(@"Device name:  %@",; 

// Device name: my iPod

Can you recommend a free light-weight MySQL GUI for Linux?

RazorSQL vote here too. It is not free, but it's not expensive ($70 for a perpetual license and 1 year of free upgrades).

If you use it for work, it will pay for itself quickly. I was jumping between MySQL GUI tools, SQL Server and Informix DBAccess, some of them through VMs because I use a Mac for development. Having a single tool to connect to any database out there is pretty nice. It is also highly customizable, and very reliable.

How do I get information about an index and table owner in Oracle?

According to the docs, you can just do:




if you want all indexes...

JavaScript listener, "keypress" doesn't detect backspace?

Something I wrote up incase anyone comes across an issue with people hitting backspace while thinking they are in a form field

window.addEventListener("keydown", function(e){
     * keyCode: 8
     * keyIdentifier: "U+0008"
    if(e.keyCode === 8 && document.activeElement !== 'text') {
        alert('Prevent page from going back');

ASP.NET MVC JsonResult Date Format

I had a number of issues come up with JSON dates and decided to just get rid of the problem by addressing the date issue in the SQL. Change the date format to a string format

select flddate from tblName

select flddate, convert(varchar(12), flddate, 113) as fldDateStr from tblName

By using the fldDateStr the problem dissappeared and I could still use the date field for sorting or other purposes.

Docker error cannot delete docker container, conflict: unable to remove repository reference

If you have multiples docker containers launched, use this

$ docker rm $(docker ps -aq)

It will remove all the current dockers listed in the "ps -aq" command.

Source : aaam on

Unix ls command: show full path when using options

You can combine the find command and the ls command. Use the path (.) and selector (*) to narrow down the files you're after. Surround the find command in back quotes. The argument to -name is doublequote star doublequote in case you can't read it.

ls -lart `find . -type f -name "*" `

Suppress/ print without b' prefix for bytes in Python 3

If the bytes use an appropriate character encoding already; you could print them directly:



nwritten = os.write(sys.stdout.fileno(), data)  # NOTE: it may write less than len(data) bytes

numbers not allowed (0-9) - Regex Expression in javascript



That pattern matches any number of characters that is not 0 through 9.

I recommend checking out It will let you easily test out a regex.

Deserialize JSON with Jackson into Polymorphic Types - A Complete Example is giving me a compile error

A simple way to enable polymorphic serialization / deserialization via Jackson library is to globally configure the Jackson object mapper (jackson.databind.ObjectMapper) to add information, such as the concrete class type, for certain kinds of classes, such as abstract classes.

To do that, just make sure your mapper is configured correctly. For example:

Option 1: Support polymorphic serialization / deserialization for abstract classes (and Object typed classes)


Option 2: Support polymorphic serialization / deserialization for abstract classes (and Object typed classes), and arrays of those types.



How do I parse a string to a float or int?

float("545.2222") and int(float("545.2222"))

LINQ Where with AND OR condition

from item in db.vw_Dropship_OrderItems
    where (listStatus != null ? listStatus.Contains(item.StatusCode) : true) &&
    (listMerchants != null ? listMerchants.Contains(item.MerchantId) : true)
    select item;

Might give strange behavior if both listMerchants and listStatus are both null.

MongoDB vs Firebase

Firebase provides some good features like real time change reflection , easy integration of authentication mechanism , and lots of other built-in features for rapid web development. Firebase, really makes Web development so simple that never exists. Firebase database is a fork of MongoDB.

What's the advantage of using Firebase over MongoDB?

You can take advantage of all built-in features of Firebase over MongoDB.

What are best practices for REST nested resources?

Rails provides a solution to this: shallow nesting.

I think this is a good because when you deal directly with a known resource, there's no need to use nested routes, as has been discussed in other answers here.

How to select element using XPATH syntax on Selenium for Python?


<div id='a'>
    <a class='click'>abc</a>

You could use the XPATH as :



<a class="click">abc</a>

That said your Python code should be as :


Markdown: continue numbered list

Note that there are also a number of extensions available that will fix this behaviour for specific contexts of Markdown use.

For example, sane_lists extension of python-markdown (used in mkdocs, for example), will recognize numbers used in Markdown lists. You just need to enable this extension arkdown.markdown(some_text, extensions=['sane_lists'])

How can I get the current page name in WordPress?

I have come up with a simpler solution.

Get the returned value of the page name from wp_title(). If empty, print homepage name, otherwise echo the wp_title() value.

<?php $title = wp_title('', false); ?>

Remember to remove the separation with the first argument and then set display to false to use as an input to the variable. Then just bung the code between your heading, etc. tags.

<?php if ( $title == "" ) : echo "Home"; else : echo $title; endif; ?>

It worked a treat for me and ensuring that the first is declared in the section where you wish to extract the $title, this can be tuned to return different variables.

How to insert logo with the title of a HTML page?

It's called a favicon. It is inserted like this:

<link rel="shortcut icon" href="favicon.ico" />

Default session timeout for Apache Tomcat applications

Open $CATALINA_BASE/conf/web.xml and find this

<!-- ==================== Default Session Configuration ================= -->
<!-- You can set the default session timeout (in minutes) for all newly   -->
<!-- created sessions by modifying the value below.                       -->


all webapps implicitly inherit from this default web descriptor. You can override session-config as well as other settings defined there in your web.xml.

This is actually from my Tomcat 7 (Windows) but I think 5.5 conf is not very different

How to set null value to int in c#?

Declare you integer variable as nullable eg: int? variable=0; variable=null;

Increase JVM max heap size for Eclipse



Try to bump that value up!

Description Box using "onmouseover"

I'd try doing this with jQuery's .hover() event handler system, it makes it easy to show a div with the tooltip when the mouse is over the text, and hide it once it's gone.

Here's a simple example.


?<p id="testText">Some Text</p>
<div id="tooltip">Tooltip Hint Text</div>???????????????????????????????????????????

Basic CSS:

?#?tooltip {
border:1px solid #F00;



console.log(result) returns [object Object]. How do I get

Try adding JSON.stringify(result) to convert the JS Object into a JSON string.

From your code I can see you are logging the result in error which is called if the AJAX request fails, so I'm not sure how you'd go about accessing the id/name/etc. then (you are checking for success inside the error condition!).

Note that if you use Chrome's console you should be able to browse through the object without having to stringify the JSON, which makes it easier to debug.

How to get option text value using AngularJS?

<div ng-controller="ExampleController">
  <form name="myForm">
    <label for="repeatSelect"> Repeat select: </label>
    <select name="repeatSelect" id="repeatSelect" ng-model="data.model">
      <option ng-repeat="option in data.availableOptions" value="{{}}">{{}}</option>
  <tt>model = {{data.model}}</tt><br/>


angular.module('ngrepeatSelect', [])
 .controller('ExampleController', ['$scope', function($scope) {
   $ = {
    model: null,
    availableOptions: [
      {id: '1', name: 'Option A'},
      {id: '2', name: 'Option B'},
      {id: '3', name: 'Option C'}

taken from AngularJS docs

Spring Boot java.lang.NoClassDefFoundError: javax/servlet/Filter

That looks like you tried to add the libraries servlet.jar or servlet-api.jar into your project /lib/ folder, but Tomcat already should provide you with those libraries. Remove them from your project and classpath. Search for that anywhere in your project or classpath and remove it.

Select multiple columns by labels in pandas

How do I select multiple columns by labels in pandas?

Multiple label-based range slicing is not easily supported with pandas, but position-based slicing is, so let's try that instead:

loc = df.columns.get_loc
df.iloc[:, np.r_[loc('A'):loc('C')+1, loc('E'), loc('G'):loc('I')+1]]

          A         B         C         E         G         H         I
0 -1.666330  0.321260 -1.768185 -0.034774  0.023294  0.533451 -0.241990
1  0.911498  3.408758  0.419618 -0.462590  0.739092  1.103940  0.116119
2  1.243001 -0.867370  1.058194  0.314196  0.887469  0.471137 -1.361059
3 -0.525165  0.676371  0.325831 -1.152202  0.606079  1.002880  2.032663
4  0.706609 -0.424726  0.308808  1.994626  0.626522 -0.033057  1.725315
5  0.879802 -1.961398  0.131694 -0.931951 -0.242822 -1.056038  0.550346
6  0.199072  0.969283  0.347008 -2.611489  0.282920 -0.334618  0.243583
7  1.234059  1.000687  0.863572  0.412544  0.569687 -0.684413 -0.357968
8 -0.299185  0.566009 -0.859453 -0.564557 -0.562524  0.233489 -0.039145
9  0.937637 -2.171174 -1.940916 -1.553634  0.619965 -0.664284 -0.151388

Note that the +1 is added because when using iloc the rightmost index is exclusive.

Comments on Other Solutions

  • filter is a nice and simple method for OP's headers, but this might not generalise well to arbitrary column names.

  • The "location-based" solution with loc is a little closer to the ideal, but you cannot avoid creating intermediate DataFrames (that are eventually thrown out and garbage collected) to compute the final result range -- something that we would ideally like to avoid.

  • Lastly, "pick your columns directly" is good advice as long as you have a manageably small number of columns to pick. It will, however not be applicable in some cases where ranges span dozens (or possibly hundreds) of columns.

Bootstrap: Collapse other sections when one is expanded

If you are using Bootstrap 4, and you don't want to change your markup:

var $myGroup = $('#myGroup');
$myGroup.on('','.collapse', function() {

event.preventDefault() vs. return false

From my experience event.stopPropagation() is mostly used in CSS effect or animation works, for instance when you have hover effect for both card and button element, when you hover on the button both card and buttons hover effect will be triggered in this case, you can use event.stopPropagation() stop bubbling actions, and event.preventDefault() is for prevent default behaviour of browser actions. For instance, you have form but you only defined click event for the submit action, if the user submits the form by pressing enter, the browser triggered by keypress event, not your click event here you should use event.preventDefault() to avoid inappropriate behavior. I don't know what the hell is return false; sorry.For more clarification visit this link and play around with line #33

How to insert data into elasticsearch

To test and try curl requests from Windows, you can make use of Postman client Chrome extension. It is very simple to use and quite powerful.

Or as suggested you can install the cURL util.

A sample curl request is as follows.

curl -X POST -H "Content-Type: application/json" -H "Cache-Control: no-cache" -d '{
"user" : "Arun Thundyill Saseendran",
"post_date" : "2009-03-23T12:30:00",
"message" : "trying out Elasticsearch"
}' ""

I am also getting started with and exploring ES in vast. So please let me know if you have any other doubts.

EDIT: Updated the index name and type name to be fully lowercase to avoid errors and follow convention.

Ajax Upload image

first in your ajax call include success & error function and then check if it gives you error or what?

your code should be like this

$(document).ready(function (e) {
    $('#imageUploadForm').on('submit',(function(e) {
        var formData = new FormData(this);

            url: $(this).attr('action'),
            contentType: false,
            processData: false,
            error: function(data){

    $("#ImageBrowse").on("change", function() {

Add new line in text file with Windows batch file

DISCLAIMER: The below solution does not preserve trailing tabs.

If you know the exact number of lines in the text file, try the following method:

SET origfile=original file
SET tempfile=temporary file
SET insertbefore=4
SET totallines=200
<%origfile% (FOR /L %%i IN (1,1,%totallines%) DO (
  SETLOCAL EnableDelayedExpansion
  SET /P L=
  IF %%i==%insertbefore% ECHO(
) >%tempfile%
COPY /Y %tempfile% %origfile% >NUL
DEL %tempfile%

The loop reads lines from the original file one by one and outputs them. The output is redirected to a temporary file. When a certain line is reached, an empty line is output before it.

After finishing, the original file is deleted and the temporary one gets assigned the original name.


If the number of lines is unknown beforehand, you can use the following method to obtain it:

FOR /F %%C IN ('FIND /C /V "" ^<%origfile%') DO SET totallines=%%C

(This line simply replaces the SET totallines=200 line in the above script.)

The method has one tiny flaw: if the file ends with an empty line, the result will be the actual number of lines minus one. If you need a workaround (or just want to play safe), you can use the method described in this answer.

Python Pandas User Warning: Sorting because non-concatenation axis is not aligned


concat and append currently sort the non-concatenation index (e.g. columns if you're adding rows) if the columns don't match. In pandas 0.23 this started generating a warning; pass the parameter sort=True to silence it. In the future the default will change to not sort, so it's best to specify either sort=True or False now, or better yet ensure that your non-concatenation indices match.

The warning is new in pandas 0.23.0:

In a future version of pandas pandas.concat() and DataFrame.append() will no longer sort the non-concatenation axis when it is not already aligned. The current behavior is the same as the previous (sorting), but now a warning is issued when sort is not specified and the non-concatenation axis is not aligned, link.

More information from linked very old github issue, comment by smcinerney :

When concat'ing DataFrames, the column names get alphanumerically sorted if there are any differences between them. If they're identical across DataFrames, they don't get sorted.

This sort is undocumented and unwanted. Certainly the default behavior should be no-sort.

After some time the parameter sort was implemented in pandas.concat and DataFrame.append:

sort : boolean, default None

Sort non-concatenation axis if it is not already aligned when join is 'outer'. The current default of sorting is deprecated and will change to not-sorting in a future version of pandas.

Explicitly pass sort=True to silence the warning and sort. Explicitly pass sort=False to silence the warning and not sort.

This has no effect when join='inner', which already preserves the order of the non-concatenation axis.

So if both DataFrames have the same columns in the same order, there is no warning and no sorting:

df1 = pd.DataFrame({"a": [1, 2], "b": [0, 8]}, columns=['a', 'b'])
df2 = pd.DataFrame({"a": [4, 5], "b": [7, 3]}, columns=['a', 'b'])

print (pd.concat([df1, df2]))
   a  b
0  1  0
1  2  8
0  4  7
1  5  3

df1 = pd.DataFrame({"a": [1, 2], "b": [0, 8]}, columns=['b', 'a'])
df2 = pd.DataFrame({"a": [4, 5], "b": [7, 3]}, columns=['b', 'a'])

print (pd.concat([df1, df2]))
   b  a
0  0  1
1  8  2
0  7  4
1  3  5

But if the DataFrames have different columns, or the same columns in a different order, pandas returns a warning if no parameter sort is explicitly set (sort=None is the default value):

df1 = pd.DataFrame({"a": [1, 2], "b": [0, 8]}, columns=['b', 'a'])
df2 = pd.DataFrame({"a": [4, 5], "b": [7, 3]}, columns=['a', 'b'])

print (pd.concat([df1, df2]))

FutureWarning: Sorting because non-concatenation axis is not aligned.

   a  b
0  1  0
1  2  8
0  4  7
1  5  3

print (pd.concat([df1, df2], sort=True))
   a  b
0  1  0
1  2  8
0  4  7
1  5  3

print (pd.concat([df1, df2], sort=False))
   b  a
0  0  1
1  8  2
0  7  4
1  3  5

If the DataFrames have different columns, but the first columns are aligned - they will be correctly assigned to each other (columns a and b from df1 with a and b from df2 in the example below) because they exist in both. For other columns that exist in one but not both DataFrames, missing values are created.

Lastly, if you pass sort=True, columns are sorted alphanumerically. If sort=False and the second DafaFrame has columns that are not in the first, they are appended to the end with no sorting:

df1 = pd.DataFrame({"a": [1, 2], "b": [0, 8], 'e':[5, 0]}, 
                    columns=['b', 'a','e'])
df2 = pd.DataFrame({"a": [4, 5], "b": [7, 3], 'c':[2, 8], 'd':[7, 0]}, 

print (pd.concat([df1, df2]))

FutureWarning: Sorting because non-concatenation axis is not aligned.

   a  b    c    d    e
0  1  0  NaN  NaN  5.0
1  2  8  NaN  NaN  0.0
0  4  7  2.0  7.0  NaN
1  5  3  8.0  0.0  NaN

print (pd.concat([df1, df2], sort=True))
   a  b    c    d    e
0  1  0  NaN  NaN  5.0
1  2  8  NaN  NaN  0.0
0  4  7  2.0  7.0  NaN
1  5  3  8.0  0.0  NaN

print (pd.concat([df1, df2], sort=False))

   b  a    e    c    d
0  0  1  5.0  NaN  NaN
1  8  2  0.0  NaN  NaN
0  7  4  NaN  2.0  7.0
1  3  5  NaN  8.0  0.0

In your code:

placement_by_video_summary = placement_by_video_summary.drop(placement_by_video_summary_new.index)
                                                       .append(placement_by_video_summary_new, sort=True)

Android checkbox style

The correct way to do it for Material design is :

Style :

<style name="MyCheckBox" parent="Theme.AppCompat.Light">  
    <item name="colorControlNormal">@color/foo</item>
    <item name="colorControlActivated">@color/bar</item>

Layout :

    android:text="Check Box"

It will preserve Material animations on Lollipop+.

What is the difference between varchar and nvarchar?

My two cents

  1. Indexes can fail when not using the correct datatypes:
    In SQL Server: When you have an index over a VARCHAR column and present it a Unicode String, SQL Server does not make use of the index. The same thing happens when you present a BigInt to a indexed-column containing SmallInt. Even if the BigInt is small enough to be a SmallInt, SQL Server is not able to use the index. The other way around you do not have this problem (when providing SmallInt or Ansi-Code to an indexed BigInt ot NVARCHAR column).

  2. Datatypes can vary between different DBMS's (DataBase Management System):
    Know that every database has slightly different datatypes and VARCHAR does not means the same everywhere. While SQL Server has VARCHAR and NVARCHAR, an Apache/Derby database has only VARCHAR and there VARCHAR is in Unicode.

Renaming branches remotely in Git

You just have to create a new local branch with the desired name, push it to your remote, and then delete the old remote branch:

$ git branch new-branch-name origin/old-branch-name
$ git push origin --set-upstream new-branch-name
$ git push origin :old-branch-name

Then, to see the old branch name, each client of the repository would have to do:

$ git fetch origin
$ git remote prune origin

NOTE: If your old branch is your main branch, you should change your main branch settings. Otherwise, when you run $ git push origin :old-branch-name, you'll get the error "deletion of the current branch prohibited".

How to run ~/.bash_profile in mac terminal

If you change .bash_profile, it only applies to new Terminal sessions.

To apply it to an existing session, run source ~/.bash_profile. You can run any Bash script this way - think of executing source as the same as typing commands in the Terminal window (from the specified script).

More info: How to reload .bash_profile from the command line?

Bonus: You can make environment variables available to OSX applications - not just the current Bash session but apps like Visual Studio Code or IntelliJ - using launchctl setenv GOPATH "${GOPATH:-}"

Android get image path from drawable as string

If you are planning to get the image from its path, it's better to use Assets instead of trying to figure out the path of the drawable folder.

    InputStream stream = getAssets().open("image.png");
    Drawable d = Drawable.createFromStream(stream, null);

Difference between Role and GrantedAuthority in Spring Security

Another way to understand the relationship between these concepts is to interpret a ROLE as a container of Authorities.

Authorities are fine-grained permissions targeting a specific action coupled sometimes with specific data scope or context. For instance, Read, Write, Manage, can represent various levels of permissions to a given scope of information.

Also, authorities are enforced deep in the processing flow of a request while ROLE are filtered by request filter way before reaching the Controller. Best practices prescribe implementing the authorities enforcement past the Controller in the business layer.

On the other hand, ROLES are coarse grained representation of an set of permissions. A ROLE_READER would only have Read or View authority while a ROLE_EDITOR would have both Read and Write. Roles are mainly used for a first screening at the outskirt of the request processing such as http. ... .antMatcher(...).hasRole(ROLE_MANAGER)

The Authorities being enforced deep in the request's process flow allows a finer grained application of the permission. For instance, a user may have Read Write permission to first level a resource but only Read to a sub-resource. Having a ROLE_READER would restrain his right to edit the first level resource as he needs the Write permission to edit this resource but a @PreAuthorize interceptor could block his tentative to edit the sub-resource.


How can I get a process handle by its name in C++?

The following code shows how you can use toolhelp and OpenProcess to get a handle to the process. Error handling removed for brevity.

HANDLE GetProcessByName(PCSTR name)
    DWORD pid = 0;

    // Create toolhelp snapshot.
    HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    PROCESSENTRY32 process;
    ZeroMemory(&process, sizeof(process));
    process.dwSize = sizeof(process);

    // Walkthrough all processes.
    if (Process32First(snapshot, &process))
            // Compare process.szExeFile based on format of name, i.e., trim file path
            // trim .exe if necessary, etc.
            if (string(process.szExeFile) == string(name))
               pid = process.th32ProcessID;
        } while (Process32Next(snapshot, &process));


    if (pid != 0)
         return OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid);

    // Not found

       return NULL;

How to convert string to double with proper cultureinfo

I have this function in my toolbelt since years ago (all the function and variable names are messy and mixing Spanish and English, sorry for that).

It lets the user use , and . to separate the decimals and will try to do the best if both symbols are used.

    Public Shared Function TryCDec(ByVal texto As String, Optional ByVal DefaultValue As Decimal = 0) As Decimal

        If String.IsNullOrEmpty(texto) Then
            Return DefaultValue
        End If

        Dim CurAsTexto As String = texto.Trim.Replace("$", "").Replace(" ", "")

        ''// You can probably use a more modern way to find out the
        ''// System current locale, this function was done long time ago
        Dim SepDecimal As String, SepMiles As String
        If CDbl("3,24") = 324 Then
            SepDecimal = "."
            SepMiles = ","
            SepDecimal = ","
            SepMiles = "."
        End If

        If InStr(CurAsTexto, SepDecimal) > 0 Then
            If InStr(CurAsTexto, SepMiles) > 0 Then
                ''//both symbols was used find out what was correct
                If InStr(CurAsTexto, SepDecimal) > InStr(CurAsTexto, SepMiles) Then
                    ''// The usage was correct, but get rid of thousand separator
                    CurAsTexto = Replace(CurAsTexto, SepMiles, "")
                    ''// The usage was incorrect, but get rid of decimal separator and then replace it
                    CurAsTexto = Replace(CurAsTexto, SepDecimal, "")
                    CurAsTexto = Replace(CurAsTexto, SepMiles, SepDecimal)
                End If
            End If
            CurAsTexto = Replace(CurAsTexto, SepMiles, SepDecimal)
        End If
        ''// At last we try to tryParse, just in case
        Dim retval As Decimal = DefaultValue
        Decimal.TryParse(CurAsTexto, retval)
        Return retval
    End Function

Visual Studio can't build due to rc.exe

I was able to make it work for me also this way in windows

  1. Set your environment variable to point to the location of your rc.exe assuming you're using x86 version

C:\Program Files (x86)\Windows Kits\10\bin\10.0.18362.0\x86

You can easily set your environment variable using

C:> setx path "%path%;C:\Program Files (x86)\Windows Kits\10\bin\10.0.18362.0\x86"

  1. Restart your Qt Creator
  2. Clean and Rebuild

php string to int

Use str_replace to remove the spaces first ?

Adobe Acrobat Pro make all pages the same dimension

With Mac OS X and the more recent versions of Acrobat Pro, the PDF printer option does not work. What does work is doing basically the same thing in Preview App. Open the multi page file in Preview, select File>Print. In the Print dialog set your sheet size as if you are using a printer. You may want to select "Auto Rotate", "Scale to Fit" and "Print Entire Image". Then in the lower left corner is the drop button "PDF" and in that menu select "Save as PDF". Give it a new file name, click Save and then you can open the resulting file in whatever PDF app you want and the sheet sizes are the same.

SQL to generate a list of numbers from 1 to 100


The above query is written in SQL in the database.

How do I change selected value of select2 dropdown with JqGrid?

For V4 Select2 if you want to change both the value of the select2 and the text representation of the drop down.

var intValueOfFruit = 1;
var selectOption = new Option("Fruit", intValueOfFruit, true, true);

This will set not only the value behind the scenes but also the text display for the select2.

Pulled from

Postgres where clause compare timestamp

Assuming you actually mean timestamp because there is no datetime in Postgres

Cast the timestamp column to a date, that will remove the time part:

select *
from the_table
where the_timestamp_column::date = date '2015-07-15';

This will return all rows from July, 15th.

Note that the above will not use an index on the_timestamp_column. If performance is critical, you need to either create an index on that expression or use a range condition:

select *
from the_table
where the_timestamp_column >= timestamp '2015-07-15 00:00:00'
  and the_timestamp_column < timestamp '2015-07-16 00:00:00';

HTML CSS Button Positioning

try changing that line-height change to a margin-top or padding-top change instead

margin-top : 25px;

Edit: You could also try adding a span inside the button

<div id="header">           
    <button id="btnhome"><span>Home</span></button>          
    <button id="btnabout">About</button>
    <button id="btncontact">Contact</button>
    <button id="btnsup">Help Us</button>           

Then style that

#btnhome span:active { padding-top:25px;}

Setting DIV width and height in JavaScript

These are several ways to apply style to an element. Try any one of the examples below:

1. document.getElementById('div_register').className = 'wide';
  /* CSS */ .wide{width:500px;}
2. document.getElementById('div_register').setAttribute('class','wide');
3. document.getElementById('div_register').style.width = '500px';

Validating IPv4 addresses with regexp

I was in search of something similar for IPv4 addresses - a regex that also stopped commonly used private ip addresses from being validated (192.168.x.y, 10.x.y.z, 172.16.x.y) so used negative look aheads to accomplish this:


(These should be on one line of course, formatted for readability purposes on 3 separate lines) Regular expression visualization

Debuggex Demo

It may not be optimised for speed, but works well when only looking for 'real' internet addresses.

Things that will (and should) fail:         ( is reserved for some broadcasts)        ( is considered private)      ( is considered private)      (same as previous, but near the end of that range)     ( is considered private) (reserved broadcast is not an IP)

IPs that will (and should) work:         (China)         (Google DNS in USA)       (USA)      (USA)      (USA)     (Italy)

Provided in case anybody else is looking for validating 'Internet IP addresses not including the common private addresses'

How to remove an element from a list by index

Use del and specify the index of the element you want to delete:

>>> a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> del a[-1]
>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8]

Also supports slices:

>>> del a[2:4]
>>> a
[0, 1, 4, 5, 6, 7, 8, 9]

Here is the section from the tutorial.

KeyListener, keyPressed versus keyTyped

You should use keyPressed if you want an immediate effect, and keyReleased if you want the effect after you release the key. You cannot use keyTyped because F5 is not a character. keyTyped is activated only when an character is pressed.

How to update a menu item shown in the ActionBar?

I have used this code:

public boolean onPrepareOptionsMenu (Menu menu) {       
    MenuInflater inflater = getMenuInflater();
    TextView title  = (TextView) findViewById(;
        getString(R.string.payFor) + " " + title.getText().toString());
    menu.getItem(1).setTitle(getString(R.string.payFor) + "...");
    return true;        

And worked like a charm to me you can find OnPrepareOptionsMenu here

Dump Mongo Collection into JSON format

Mongo includes a mongoexport utility (see docs) which can dump a collection. This utility uses the native libmongoclient and is likely the fastest method.

mongoexport -d <database> -c <collection_name>

Also helpful:

-o: write the output to file, otherwise standard output is used (docs)

--jsonArray: generates a valid json document, instead of one json object per line (docs)

--pretty: outputs formatted json (docs)

Check if TextBox is empty and return MessageBox?

Well, you are clearing the textbox right before you check if it's empty

/* !! This clears the textbox BEFORE you check if it's empty */

HoursNumericUpDown.Value = HoursNumericUpDown.Minimum;
MarkNumericUpDown.Value = MarkNumericUpDown.Minimum;

if (String.IsNullOrEmpty(MaterialTextBox.Text))
        MessageBox.Show("Enter Material Name Please.", "Error", MessageBoxButtons.OK,    MessageBoxIcon.Warning);

Getting assembly name


Pass multiple optional parameters to a C# function

C# 4.0 also supports optional parameters, which could be useful in some other situations. See this article.

Using the grep and cut delimiter command (in bash shell scripting UNIX) - and kind of "reversing" it?

You don't need to change the delimiter to display the right part of the string with cut.

The -f switch of the cut command is the n-TH element separated by your delimiter : :, so you can just type :

 grep puddle2_1557936 | cut -d ":" -f2

Another solutions (adapt it a bit) if you want fun :

Using :

grep -oP 'puddle2_1557936:\K.*' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                                        

or still with look around

grep -oP '(?<=puddle2_1557936:).*' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                                    

or with :

perl -lne '/puddle2_1557936:(.*)/ and print $1' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                      

or using (thanks to glenn jackman)

ruby -F: -ane '/puddle2_1557936/ and puts $F[1]' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'

or with :

awk -F'puddle2_1557936:' '{print $2}'  <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'

or with :

python -c 'import sys; print(sys.argv[1].split("puddle2_1557936:")[1])' 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'

or using only :

IFS=: read _ a <<< "puddle2_1557936:/home/rogers.williams/folderz/puddle2"
echo "$a"

or using in a :

var x = 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'

or using in a :

php -r 'preg_match("/puddle2_1557936:(.*)/", $argv[1], $m); echo "$m[1]\n";' 'puddle2_1557936:/home/rogers.williams/folderz/puddle2' 

Can I dynamically add HTML within a div tag from C# on load event?

You can add a div with runat="server" to the page:

<div runat="server" id="myDiv">

and then set its InnerHtml property from the code-behind:

myDiv.InnerHtml = "your html here";

If you want to modify the DIV's contents on the client side, then you can use javascript code similar to this:

<script type="text/javascript">
    function MyLoad(sender) {
        $get('<%= div.ClientID %>').innerHTML += " - text added on client";

jQuery send HTML data through POST

If you want to send an arbitrary amount of data to your server, POST is the only reliable method to do that. GET would also be possible but clients and servers allow just a limited URL length (something like 2048 characters).

In C, how should I read a text file and print all strings

Instead just directly print the characters onto the console because the text file maybe very large and you may require a lot of memory.

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

int main() {

    FILE *f;
    char c;


    return 0;

Checkbox value true/false

Use Checked = true

$("#checkbox1").prop('checked', true);

Note: I am not clear whether you want to onclick/onchange event on checkbox. is(":checked", function(){}) is a wrong in the question.

Styling the arrow on bootstrap tooltips

I have created fiddle for you.

Take a look at here

    <a class="tooltip" href="#">Tooltip
            <img alt="CSS Tooltip callout"
                 src="" class="callout">
            <strong>Most Light-weight Tooltip</strong><br>
            This is the easy-to-use Tooltip driven purely by CSS.


a.tooltip {
    outline: none;

a.tooltip strong {
    line-height: 30px;

a.tooltip:hover {
    text-decoration: none;

a.tooltip span {
    z-index: 10;
    display: none;
    padding: 14px 20px;
    margin-top: -30px;
    margin-left: 28px;
    width: 240px;
    line-height: 16px;

a.tooltip:hover span {
    display: inline;
    position: absolute;
    color: #111;
    border: 1px solid #DCA;
    background: #fffAF0;

.callout {
    z-index: 20;
    position: absolute;
    top: 30px;
    border: 0;
    left: -12px;
/*CSS3 extras*/
a.tooltip span {
    border-radius: 4px;
    -moz-border-radius: 4px;
    -webkit-border-radius: 4px;
    -moz-box-shadow: 5px 5px 8px #CCC;
    -webkit-box-shadow: 5px 5px 8px #CCC;
    box-shadow: 5px 5px 8px #CCC;

How to solve error message: "Failed to map the path '/'."

I ran into the same issue when trying to run the ASP.Net precompiler, it turned out that I was not opening the command prompt as administrator. Once I did, I was able to run the compiler successfully.

What is SELF JOIN and when would you use it?

A self join is simply when you join a table with itself. There is no SELF JOIN keyword, you just write an ordinary join where both tables involved in the join are the same table. One thing to notice is that when you are self joining it is necessary to use an alias for the table otherwise the table name would be ambiguous.

It is useful when you want to correlate pairs of rows from the same table, for example a parent - child relationship. The following query returns the names of all immediate subcategories of the category 'Kitchen'.

FROM category T1
JOIN category T2
ON T2.parent =
WHERE = 'Kitchen'

References with text in LaTeX

Using the hyperref package, you could also declare a new command by using \newcommand{\secref}[1]{\autoref{#1}. \nameref{#1}} in the pre-amble. Placing \secref{section:my} in the text generates: 1. My section.

How to set the Default Page in ASP.NET?

I had done all the above solutions but it did not work.

My default page wasn't an aspx page, it was an html page.

This article solved the problem.

Basically, in my \App_Start\RouteConfig.cs file, I had to add a line:

public static void RegisterRoutes(RouteCollection routes)
    routes.IgnoreRoute("");   // This was the line I had to add here!

        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }

Hope this helps someone, it took me a goodly while to find the answer.

Casting a number to a string in TypeScript

Use the "+" symbol to cast a string to a number.

window.location.hash = +page_number;

Add a CSS border on hover without moving the element

add margin:-1px; which reduces 1px to each side. or if you need only for side you can do margin-left:-1px etc.

How to get overall CPU usage (e.g. 57%) on Linux

EDITED: I noticed that in another user's reply %idle was field 12 instead of field 11. The awk has been updated to account for the %idle field being variable.

This should get you the desired output:

mpstat | awk '$3 ~ /CPU/ { for(i=1;i<=NF;i++) { if ($i ~ /%idle/) field=i } } $3 ~ /all/ { print 100 - $field }'

If you want a simple integer rounding, you can use printf:

mpstat | awk '$3 ~ /CPU/ { for(i=1;i<=NF;i++) { if ($i ~ /%idle/) field=i } } $3 ~ /all/ { printf("%d%%",100 - $field) }'

Create an application setup in visual studio 2013

I will tell , how i solved almost similar problem. I developed a application using VS 2013 and tried to create wizard for it failed to do. Later i installed premium VS and tried and failed.

at last i used "ClickOnce" and it worked fine.

So i believe here also , "CLICKONCE" would help you.

Maven compile: package does not exist

Not sure if there was file corruption or what, but after confirming proper pom configuration I was able to resolve this issue by deleting the jar from my local m2 repository, forcing Maven to download it again when I ran the tests.

Find all storage devices attached to a Linux machine

/proc/partitions will list all the block devices and partitions that the system recognizes. You can then try using file -s <device> to determine what kind of filesystem is present on the partition, if any.

Difference between IsNullOrEmpty and IsNullOrWhiteSpace in C#

string.isNullOrWhiteSpace(text) should be used in most cases as it also includes a blank string.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
namespace Rextester
    public class Program
        public static void Main(string[] args)
            //Your code goes here
            var str = "";



It returns True!

Simple IEnumerator use (with example)

Also you can use LINQ's Select Method:

var source = new[] { "Line 1", "Line 2" };

var result = source.Select(s => s + " roxxors");

Read more here Enumerable.Select Method

Find object by id in an array of JavaScript objects

Recently, I have to face the same thing in which I need to search the string from a huge array.

After some search I found It'll be easy to handle with simple code:


var items = mydata.filter(function(item){
    return item.word.toLowerCase().startsWith( 'gk );


Serach from 20k strings

What exactly are DLL files, and how do they work?

DLL files contain an Export Table which is a list of symbols which can be looked up by the calling program. The symbols are typically functions with the C calling convention (__stcall). The export table also contains the address of the function.

With this information, the calling program can then call the functions within the DLL even though it did not have access to the DLL at compile time.

Introducing Dynamic Link Libraries has some more information.

Recursively find all files newer than a given time

Given a unix timestamp (seconds since epoch) of 1494500000, do:

find . -type f -newermt "$(date '+%Y-%m-%d %H:%M:%S' -d @1494500000)"

To grep those files for "foo":

find . -type f -newermt "$(date '+%Y-%m-%d %H:%M:%S' -d @1494500000)" -exec grep -H 'foo' '{}' \;

Are HTTP cookies port specific?

The current cookie specification is RFC 6265, which replaces RFC 2109 and RFC 2965 (both RFCs are now marked as "Historic") and formalizes the syntax for real-world usages of cookies. It clearly states:

  1. Introduction


For historical reasons, cookies contain a number of security and privacy infelicities. For example, a server can indicate that a given cookie is intended for "secure" connections, but the Secure attribute does not provide integrity in the presence of an active network attacker. Similarly, cookies for a given host are shared across all the ports on that host, even though the usual "same-origin policy" used by web browsers isolates content retrieved via different ports.

And also:

8.5. Weak Confidentiality

Cookies do not provide isolation by port. If a cookie is readable by a service running on one port, the cookie is also readable by a service running on another port of the same server. If a cookie is writable by a service on one port, the cookie is also writable by a service running on another port of the same server. For this reason, servers SHOULD NOT both run mutually distrusting services on different ports of the same host and use cookies to store security sensitive information.

Get latest from Git branch

Although git pull origin yourbranch works, it's not really a good idea

You can alternatively do the following:

git fetch origin
git merge origin/yourbranch

The first line fetches all the branches from origin, but doesn't merge with your branches. This simply completes your copy of the repository.

The second line merges your current branch with that of yourbranch that you fetched from origin (which is one of your remotes).

This is assuming origin points to the repository at address ssh://

How do you sign a Certificate Signing Request with your Certification Authority?

1. Using the x509 module
openssl x509 ...

2 Using the ca module
openssl ca ...

You are missing the prelude to those commands.

This is a two-step process. First you set up your CA, and then you sign an end entity certificate (a.k.a server or user). Both of the two commands elide the two steps into one. And both assume you have a an OpenSSL configuration file already setup for both CAs and Server (end entity) certificates.

First, create a basic configuration file:

$ touch openssl-ca.cnf

Then, add the following to it:

HOME            = .
RANDFILE        = $ENV::HOME/.rnd

[ ca ]
default_ca    = CA_default      # The default ca section

[ CA_default ]

default_days     = 1000         # How long to certify for
default_crl_days = 30           # How long before next CRL
default_md       = sha256       # Use public key default MD
preserve         = no           # Keep passed DN ordering

x509_extensions = ca_extensions # The extensions to add to the cert

email_in_dn     = no            # Don't concat the email in the DN
copy_extensions = copy          # Required to copy SANs from CSR to cert

[ req ]
default_bits       = 4096
default_keyfile    = cakey.pem
distinguished_name = ca_distinguished_name
x509_extensions    = ca_extensions
string_mask        = utf8only

[ ca_distinguished_name ]
countryName         = Country Name (2 letter code)
countryName_default = US

stateOrProvinceName         = State or Province Name (full name)
stateOrProvinceName_default = Maryland

localityName                = Locality Name (eg, city)
localityName_default        = Baltimore

organizationName            = Organization Name (eg, company)
organizationName_default    = Test CA, Limited

organizationalUnitName         = Organizational Unit (eg, division)
organizationalUnitName_default = Server Research Department

commonName         = Common Name (e.g. server FQDN or YOUR name)
commonName_default = Test CA

emailAddress         = Email Address
emailAddress_default = [email protected]

[ ca_extensions ]

subjectKeyIdentifier   = hash
authorityKeyIdentifier = keyid:always, issuer
basicConstraints       = critical, CA:true
keyUsage               = keyCertSign, cRLSign

The fields above are taken from a more complex openssl.cnf (you can find it in /usr/lib/openssl.cnf), but I think they are the essentials for creating the CA certificate and private key.

Tweak the fields above to suit your taste. The defaults save you the time from entering the same information while experimenting with configuration file and command options.

I omitted the CRL-relevant stuff, but your CA operations should have them. See openssl.cnf and the related crl_ext section.

Then, execute the following. The -nodes omits the password or passphrase so you can examine the certificate. It's a really bad idea to omit the password or passphrase.

$ openssl req -x509 -config openssl-ca.cnf -newkey rsa:4096 -sha256 -nodes -out cacert.pem -outform PEM

After the command executes, cacert.pem will be your certificate for CA operations, and cakey.pem will be the private key. Recall the private key does not have a password or passphrase.

You can dump the certificate with the following.

$ openssl x509 -in cacert.pem -text -noout
        Version: 3 (0x2)
        Serial Number: 11485830970703032316 (0x9f65de69ceef2ffc)
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=US, ST=MD, L=Baltimore, CN=Test CA/[email protected]
            Not Before: Jan 24 14:24:11 2014 GMT
            Not After : Feb 23 14:24:11 2014 GMT
        Subject: C=US, ST=MD, L=Baltimore, CN=Test CA/[email protected]
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (4096 bit)
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Subject Key Identifier:
            X509v3 Authority Key Identifier:

            X509v3 Basic Constraints: critical
            X509v3 Key Usage:
                Certificate Sign, CRL Sign
    Signature Algorithm: sha256WithRSAEncryption

And test its purpose with the following (don't worry about the Any Purpose: Yes; see "critical,CA:FALSE" but "Any Purpose CA : Yes").

$ openssl x509 -purpose -in cacert.pem -inform PEM
Certificate purposes:
SSL client : No
SSL client CA : Yes
SSL server : No
SSL server CA : Yes
Netscape SSL server : No
Netscape SSL server CA : Yes
S/MIME signing : No
S/MIME signing CA : Yes
S/MIME encryption : No
S/MIME encryption CA : Yes
CRL signing : Yes
CRL signing CA : Yes
Any Purpose : Yes
Any Purpose CA : Yes
OCSP helper : Yes
OCSP helper CA : Yes
Time Stamp signing : No
Time Stamp signing CA : Yes

For part two, I'm going to create another configuration file that's easily digestible. First, touch the openssl-server.cnf (you can make one of these for user certificates also).

$ touch openssl-server.cnf

Then open it, and add the following.

HOME            = .
RANDFILE        = $ENV::HOME/.rnd

[ req ]
default_bits       = 2048
default_keyfile    = serverkey.pem
distinguished_name = server_distinguished_name
req_extensions     = server_req_extensions
string_mask        = utf8only

[ server_distinguished_name ]
countryName         = Country Name (2 letter code)
countryName_default = US

stateOrProvinceName         = State or Province Name (full name)
stateOrProvinceName_default = MD

localityName         = Locality Name (eg, city)
localityName_default = Baltimore

organizationName            = Organization Name (eg, company)
organizationName_default    = Test Server, Limited

commonName           = Common Name (e.g. server FQDN or YOUR name)
commonName_default   = Test Server

emailAddress         = Email Address
emailAddress_default = [email protected]

[ server_req_extensions ]

subjectKeyIdentifier = hash
basicConstraints     = CA:FALSE
keyUsage             = digitalSignature, keyEncipherment
subjectAltName       = @alternate_names
nsComment            = "OpenSSL Generated Certificate"

[ alternate_names ]

DNS.1  =
DNS.2  =
DNS.3  =
DNS.4  =

If you are developing and need to use your workstation as a server, then you may need to do the following for Chrome. Otherwise Chrome may complain a Common Name is invalid (ERR_CERT_COMMON_NAME_INVALID). I'm not sure what the relationship is between an IP address in the SAN and a CN in this instance.

# IPv4 localhost
IP.1     =

# IPv6 localhost
IP.2     = ::1

Then, create the server certificate request. Be sure to omit -x509*. Adding -x509 will create a certificate, and not a request.

$ openssl req -config openssl-server.cnf -newkey rsa:2048 -sha256 -nodes -out servercert.csr -outform PEM

After this command executes, you will have a request in servercert.csr and a private key in serverkey.pem.

And you can inspect it again.

$ openssl req -text -noout -verify -in servercert.csr
    verify OK
    Certificate Request:
        Version: 0 (0x0)
        Subject: C=US, ST=MD, L=Baltimore, CN=Test Server/[email protected]
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Exponent: 65537 (0x10001)
        Requested Extensions:
            X509v3 Subject Key Identifier:
            X509v3 Basic Constraints:
            X509v3 Key Usage:
                Digital Signature, Key Encipherment
            X509v3 Subject Alternative Name:
            Netscape Comment:
                OpenSSL Generated Certificate
    Signature Algorithm: sha256WithRSAEncryption

Next, you have to sign it with your CA.

You are almost ready to sign the server's certificate by your CA. The CA's openssl-ca.cnf needs two more sections before issuing the command.

First, open openssl-ca.cnf and add the following two sections.

[ signing_policy ]
countryName            = optional
stateOrProvinceName    = optional
localityName           = optional
organizationName       = optional
organizationalUnitName = optional
commonName             = supplied
emailAddress           = optional

[ signing_req ]
subjectKeyIdentifier   = hash
authorityKeyIdentifier = keyid,issuer
basicConstraints       = CA:FALSE
keyUsage               = digitalSignature, keyEncipherment

Second, add the following to the [ CA_default ] section of openssl-ca.cnf. I left them out earlier, because they can complicate things (they were unused at the time). Now you'll see how they are used, so hopefully they will make sense.

base_dir      = .
certificate   = $base_dir/cacert.pem   # The CA certifcate
private_key   = $base_dir/cakey.pem    # The CA private key
new_certs_dir = $base_dir              # Location for new certs after signing
database      = $base_dir/index.txt    # Database index file
serial        = $base_dir/serial.txt   # The current serial number

unique_subject = no  # Set to 'no' to allow creation of
                     # several certificates with same subject.

Third, touch index.txt and serial.txt:

$ touch index.txt
$ echo '01' > serial.txt

Then, perform the following:

$ openssl ca -config openssl-ca.cnf -policy signing_policy -extensions signing_req -out servercert.pem -infiles servercert.csr

You should see similar to the following:

Using configuration from openssl-ca.cnf
Check that the request matches the signature
Signature ok
The Subject's Distinguished Name is as follows
countryName           :PRINTABLE:'US'
stateOrProvinceName   :ASN.1 12:'MD'
localityName          :ASN.1 12:'Baltimore'
commonName            :ASN.1 12:'Test CA'
emailAddress          :IA5STRING:'[email protected]'
Certificate is to be certified until Oct 20 16:12:39 2016 GMT (1000 days)
Sign the certificate? [y/n]:Y

1 out of 1 certificate requests certified, commit? [y/n]Y
Write out database with 1 new entries
Data Base Updated

After the command executes, you will have a freshly minted server certificate in servercert.pem. The private key was created earlier and is available in serverkey.pem.

Finally, you can inspect your freshly minted certificate with the following:

$ openssl x509 -in servercert.pem -text -noout
        Version: 3 (0x2)
        Serial Number: 9 (0x9)
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=US, ST=MD, L=Baltimore, CN=Test CA/[email protected]
            Not Before: Jan 24 19:07:36 2014 GMT
            Not After : Oct 20 19:07:36 2016 GMT
        Subject: C=US, ST=MD, L=Baltimore, CN=Test Server
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Subject Key Identifier:
            X509v3 Authority Key Identifier:

            X509v3 Basic Constraints:
            X509v3 Key Usage:
                Digital Signature, Key Encipherment
            X509v3 Subject Alternative Name:
            Netscape Comment:
                OpenSSL Generated Certificate
    Signature Algorithm: sha256WithRSAEncryption

Earlier, you added the following to CA_default: copy_extensions = copy. This copies extension provided by the person making the request.

If you omit copy_extensions = copy, then your server certificate will lack the Subject Alternate Names (SANs) like and

If you use copy_extensions = copy, but don't look over the request, then the requester might be able to trick you into signing something like a subordinate root (rather than a server or user certificate). Which means he/she will be able to mint certificates that chain back to your trusted root. Be sure to verify the request with openssl req -verify before signing.

If you omit unique_subject or set it to yes, then you will only be allowed to create one certificate under the subject's distinguished name.

unique_subject = yes            # Set to 'no' to allow creation of
                                # several ctificates with same subject.

Trying to create a second certificate while experimenting will result in the following when signing your server's certificate with the CA's private key:

Sign the certificate? [y/n]:Y
failed to update database
TXT_DB error number 2

So unique_subject = no is perfect for testing.

If you want to ensure the Organizational Name is consistent between self-signed CAs, Subordinate CA and End-Entity certificates, then add the following to your CA configuration files:

[ policy_match ]
organizationName = match

If you want to allow the Organizational Name to change, then use:

[ policy_match ]
organizationName = supplied

There are other rules concerning the handling of DNS names in X.509/PKIX certificates. Refer to these documents for the rules:

RFC 6797 and RFC 7469 are listed, because they are more restrictive than the other RFCs and CA/B documents. RFC's 6797 and 7469 do not allow an IP address, either.

Parsing json and searching through it

You can use jsonpipe if you just need the output (and more comfortable with command line):

cat bookmarks.json | jsonpipe |grep uri

How to redirect output of systemd service to a file

I think there's a more elegant way to solve the problem: send the stdout/stderr to syslog with an identifier and instruct your syslog manager to split its output by program name.

Use the following properties in your systemd service unit file:

SyslogIdentifier=<your program identifier> # without any quote

Then, assuming your distribution is using rsyslog to manage syslogs, create a file in /etc/rsyslog.d/<new_file>.conf with the following content:

if $programname == '<your program identifier>' then /path/to/log/file.log
& stop

Now make the log file writable by syslog:

# ls -alth /var/log/syslog 
-rw-r----- 1 syslog adm 439K Mar  5 19:35 /var/log/syslog
# chown syslog:adm /path/to/log/file.log

Restart rsyslog (sudo systemctl restart rsyslog) and enjoy! Your program stdout/stderr will still be available through journalctl (sudo journalctl -u <your program identifier>) but they will also be available in your file of choice.

Source via

NSString with \n or line break

I just ran into the same issue when overloading -description for a subclass of NSObject. In this situation I was able to use carriage return (\r) instead of newline (\n) to create a line break.

[NSString stringWithFormat:@"%@\r%@", mystring1,mystring2];

Calling jQuery method from onClick attribute in HTML

you forgot to add this in your function : change to this :

<input type="button" value="ahaha"  onclick="$(this).MessageBox('msg');" />

Finding last occurrence of substring in string, replacing that

A one liner would be :


Get multiple elements by Id

Here is a function I came up with

function getElementsById(elementID){
    var elementCollection = new Array();
    var allElements = document.getElementsByTagName("*");
    for(i = 0; i < allElements.length; i++){
        if(allElements[i].id == elementID)

    return elementCollection;

Apparently there is a convention supported by prototype, and probably other major JavaScript libraries.

However, I have come to discover that dollar sign function has become the more-or-less de facto shortcut to document.getElementById(). Let’s face it, we all use document.getElementById() a lot. Not only does it take time to type, but it adds bytes to your code as well.

here is the function from prototype:

function $(element) {
  if (arguments.length > 1) {
    for (var i = 0, elements = [], length = arguments.length; i < length; i++)
    return elements;
  if (Object.isString(element))
    element = document.getElementById(element);
  return Element.extend(element);


How to create a Java cron job

If you are using unix, you need to write a shellscript to run you java batch first.

After that, in unix, you run this command "crontab -e" to edit crontab script. In order to configure crontab, please refer to this article

Save your crontab setting. Then wait for the time to come, program will run automatically.

How to send list of file in a folder to a txt file in Linux

you can just use

ls > filenames.txt

(usually, start a shell by using "Terminal", or "shell", or "Bash".) You may need to use cd to go to that folder first, or you can ls ~/docs > filenames.txt

What does "for" attribute do in HTML <label> tag?

It labels whatever input is the parameter for the for attribute.

<input id='myInput' type='radio'>_x000D_
<label for='myInput'>My 1st Radio Label</label>_x000D_
<input id='input2' type='radio'>_x000D_
<label for='input2'>My 2nd Radio Label</label>_x000D_
<input id='input3' type='radio'>_x000D_
<label for='input3'>My 3rd Radio Label</label>

How can I concatenate two arrays in Java?

You could try converting it into a Arraylist and use the addAll method then convert back to an array.

List list = new ArrayList(Arrays.asList(first));
  String[] both = list.toArray();

How to install php-curl in Ubuntu 16.04

For Ubuntu 18.04 or PHP 7.2 users you can do:

apt-get install php7.2-curl

You can check your PHP version by running php -v to verify your PHP version and get the right curl version.

Hexadecimal value 0x00 is a invalid character

To add to Sonz's answer above, following worked for us.

//Instead of 
XmlString.Replace("&#x0;", "[0x00]");
// use this
XmlString.Replace("\x00", "[0x00]");

Is there a Mutex in Java?

Any object in Java can be used as a lock using a synchronized block. This will also automatically take care of releasing the lock when an exception occurs.

Object someObject = ...;

synchronized (someObject) {

You can read more about this here: Intrinsic Locks and Synchronization

Conditional logic in AngularJS template

Angular 1.1.5 introduced the ng-if directive. That's the best solution for this particular problem. If you are using an older version of Angular, consider using angular-ui's ui-if directive.

If you arrived here looking for answers to the general question of "conditional logic in templates" also consider:

Original answer:

Here is a not-so-great "ng-if" directive:

myApp.directive('ngIf', function() {
    return {
        link: function(scope, element, attrs) {
            if(scope.$eval(attrs.ngIf)) {
                // remove '<div ng-if...></div>'
            } else {
                element.replaceWith(' ')

that allows for this HTML syntax:

<div ng-repeat="message in data.messages" ng-class="message.type">
   <div ng-if="showFrom(message)">
       <div>From: {{}}</div>
   <div ng-if="showCreatedBy(message)">
      <div>Created by: {{}}</div>
   <div ng-if="showTo(message)">
      <div>To: {{}}</div>


replaceWith() is used to remove unneeded content from the DOM.

Also, as I mentioned on Google+, ng-style can probably be used to conditionally load background images, should you want to use ng-show instead of a custom directive. (For the benefit of other readers, Jon stated on Google+: "both methods use ng-show which I'm trying to avoid because it uses display:none and leaves extra markup in the DOM. This is a particular problem in this scenario because the hidden element will have a background image which will still be loaded in most browsers.").
See also How do I conditionally apply CSS styles in AngularJS?

The angular-ui ui-if directive watches for changes to the if condition/expression. Mine doesn't. So, while my simple implementation will update the view correctly if the model changes such that it only affects the template output, it won't update the view correctly if the condition/expression answer changes.

E.g., if the value of a changes in the model, the view will update. But if you delete $[0].from, the from name will be removed from the view, but the template will not be removed from the view because the if-condition/expression is not being watched.

How to set TextView textStyle such as bold, italic

TextView text = (TextView)findViewById(R.layout.textName);

How to write to Console.Out during execution of an MSTest test

The Console output is not appearing is because the backend code is not running in the context of the test.

You're probably better off using Trace.WriteLine (In System.Diagnostics) and then adding a trace listener which writes to a file.

This topic from MSDN shows a way of doing this.

According to Marty Neal's and Dave Anderson's comments:

using System;
using System.Diagnostics;


Trace.Listeners.Add(new TextWriterTraceListener(Console.Out));
// or Trace.Listeners.Add(new ConsoleTraceListener());
Trace.WriteLine("Hello World");

How to change the type of a field?

db.coll.find().forEach(function(data) {

HTML character codes for this ? or this ?

Check this page, first is "9650 ? 25B2 BLACK UP-POINTING TRIANGLE (present in WGL4)" and 2nd "9660 ? 25BC BLACK DOWN-POINTING TRIANGLE (present in WGL4)".

Create line after text with css

Here is how I do this:

I use a background instead of after and use my H1 or H2 to cover the background. Not quite your method above but does work well for me.


.title-box { background: #fff url('images/bar-orange.jpg') repeat-x left; text-align: left; margin-bottom: 20px;}
.title-box h1 { color: #000; background-color: #fff; display: inline; padding: 0 50px 0 50px; }


<div class="title-box"><h1>Title can go here</h1></div>
<div class="title-box"><h1>Title can go here this one is really really long</h1></div>

Add line break to 'git commit -m' from the command line

I don't see anyone mentioning that if you don't provide a message it will open nano for you (at least in Linux) where you can write multiple lines...

Only this is needed:

git commit

Changing Underline color

No. The best you can do is to use a border-bottom with a different color, but that isn't really underlining.

Ineligible Devices section appeared in Xcode 6.x.x

Upgrade XCode to ensure that it supports your current iOS version on device.

(In my case, my phone was on iOS 9.1.x) `but XCode version was 7, which supported iOS 9.0 devices)

WebAPI to Return XML

You should simply return your object, and shouldn't be concerned about whether its XML or JSON. It is the client responsibility to request JSON or XML from the web api. For example, If you make a call using Internet explorer then the default format requested will be Json and the Web API will return Json. But if you make the request through google chrome, the default request format is XML and you will get XML back.

If you make a request using Fiddler then you can specify the Accept header to be either Json or XML.

Accept: application/xml

You may wanna see this article: Content Negotiation in ASP.NET MVC4 Web API Beta – Part 1

EDIT: based on your edited question with code:

Simple return list of string, instead of converting it to XML. try it using Fiddler.

public List<string> Get(int tenantID, string dataType, string ActionName)
       List<string> SQLResult = MyWebSite_DataProvidor.DB.spReturnXMLData("SELECT * FROM vwContactListing FOR XML AUTO, ELEMENTS").ToList();
       return SQLResult;

For example if your list is like:

List<string> list = new List<string>();
return list;

and you specify Accept: application/xml the output will be:

<ArrayOfstring xmlns:i="" xmlns="">

and if you specify 'Accept: application/json' in the request then the output will be:


So let the client request the content type, instead of you sending the customized xml.

Bootstrap Accordion button toggle "data-parent" not working

I got the same problem when toggling the accordion. But when I try to put the script block in the header block, it works for my case!!

<link rel="stylesheet" href="../assets/css/bootstrap.css" />       
<script src="../assets/js/jquery-1.9.1.min.js" ></script>   
<script src="../assets/js/bootstrap.js" ></script> 

Removing a list of characters in string

If you're using python2 and your inputs are strings (not unicodes), the absolutely best method is str.translate:

>>> chars_to_remove = ['.', '!', '?']
>>> subj = 'A.B!C?'
>>> subj.translate(None, ''.join(chars_to_remove))

Otherwise, there are following options to consider:

A. Iterate the subject char by char, omit unwanted characters and join the resulting list:

>>> sc = set(chars_to_remove)
>>> ''.join([c for c in subj if c not in sc])

(Note that the generator version ''.join(c for c ...) will be less efficient).

B. Create a regular expression on the fly and re.sub with an empty string:

>>> import re
>>> rx = '[' + re.escape(''.join(chars_to_remove)) + ']'
>>> re.sub(rx, '', subj)

(re.escape ensures that characters like ^ or ] won't break the regular expression).

C. Use the mapping variant of translate:

>>> chars_to_remove = [u'd', u'G', u'?']
>>> subj = u'A?BdCG'
>>> dd = {ord(c):None for c in chars_to_remove}
>>> subj.translate(dd)

Full testing code and timings:


import re

def remove_chars_iter(subj, chars):
    sc = set(chars)
    return ''.join([c for c in subj if c not in sc])

def remove_chars_re(subj, chars):
    return re.sub('[' + re.escape(''.join(chars)) + ']', '', subj)

def remove_chars_re_unicode(subj, chars):
    return re.sub(u'(?u)[' + re.escape(''.join(chars)) + ']', '', subj)

def remove_chars_translate_bytes(subj, chars):
    return subj.translate(None, ''.join(chars))

def remove_chars_translate_unicode(subj, chars):
    d = {ord(c):None for c in chars}
    return subj.translate(d)

import timeit, sys

def profile(f):
    assert f(subj, chars_to_remove) == test
    t = timeit.timeit(lambda: f(subj, chars_to_remove), number=1000)
    print ('{0:.3f} {1}'.format(t, f.__name__))

print (sys.version)
PYTHON2 = sys.version_info[0] == 2

print ('\n"plain" string:\n')

chars_to_remove = ['.', '!', '?']
subj = 'A.B!C?' * 1000
test = 'ABC' * 1000



print ('\nunicode string:\n')

    chars_to_remove = [u'd', u'G', u'?']
    subj = u'A?BdCG'
    chars_to_remove = ['d', 'G', '?']
    subj = 'A?BdCG'

subj = subj * 1000
test = 'ABC' * 1000





2.7.5 (default, Mar  9 2014, 22:15:05) 
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)]

"plain" string:

0.637 remove_chars_iter
0.649 remove_chars_re
0.010 remove_chars_translate_bytes

unicode string:

0.866 remove_chars_iter
0.680 remove_chars_re_unicode
1.373 remove_chars_translate_unicode


3.4.2 (v3.4.2:ab2c023a9432, Oct  5 2014, 20:42:22) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]

"plain" string:

0.512 remove_chars_iter
0.574 remove_chars_re
0.765 remove_chars_translate_unicode

unicode string:

0.817 remove_chars_iter
0.686 remove_chars_re
0.876 remove_chars_translate_unicode

(As a side note, the figure for remove_chars_translate_bytes might give us a clue why the industry was reluctant to adopt Unicode for such a long time).

What range of values can integer types store in C++

Other folks here will post links to data_sizes and precisions etc.
I'm going to tell you how to figure it out yourself.
Write a small app that will do the following.

unsigned int ui;
std::cout <<  sizeof(ui));

this will (depending on compiler and archicture) print 2, 4 or 8, saying 2 bytes long, 4 bytes long etc.

Lets assume it's 4.

You now want the maximum value 4 bytes can store, the max value for one byte is (in hex)0xFF. The max value of four bytes is 0x followed by 8 f's (one pair of f's for each byte, the 0x tells the compiler that the following string is a hex number). Now change your program to assign that value and print the result

unsigned int ui = 0xFFFFFFFF;
std::cout <<  ui;

Thats the max value an unsigned int can hold, shown in base 10 representation.

Now do that for long's, shorts and any other INTEGER value you're curious about.

NB: This approach will not work for floating point numbers (i.e. double or float).

Hope this helps

Remove a modified file from pull request

Removing a file from pull request but not from your local repository.

  1. Go to your branch from where you created the request use the following commands

git checkout -- c:\temp..... next git checkout origin/master -- c:\temp... u replace origin/master with any other branch. Next git commit -m c:\temp..... Next git push origin

Note : no single quote or double quotes for the filepath

Django Multiple Choice Field / Checkbox Select Multiple

The models.CharField is a CharField representation of one of the choices. What you want is a set of choices. This doesn't seem to be implemented in django (yet).

You could use a many to many field for it, but that has the disadvantage that the choices have to be put in a database. If you want to use hard coded choices, this is probably not what you want.

There is a django snippet at that does seem to solve your problem, by implementing a ModelField MultipleChoiceField.

CSS submit button weird rendering on iPad/iPhone

Add this code into the css file:

input {
-webkit-appearance: none;
-moz-appearance: none;
appearance: none;

This will help.

how to get right offset of an element? - jQuery

Actually these only work when the window isn't scrolled at all from the top left position.
You have to subtract the window scroll values to get an offset that's useful for repositioning elements so they stay on the page:

var offset = $('#whatever').offset();

offset.right = ($(window).width() + $(window).scrollLeft()) - (offset.left + $('#whatever').outerWidth(true));
offset.bottom = ($(window).height() + $(window).scrollTop()) - ( + $('#whatever').outerHeight(true));

How to install crontab on Centos

As seen in Install crontab on CentOS, the crontab package in CentOS is vixie-cron. Hence, do install it with:

yum install vixie-cron

And then start it with:

service crond start

To make it persistent, so that it starts on boot, use:

chkconfig crond on

On CentOS 7 you need to use cronie:

yum install cronie

On CentOS 6 you can install vixie-cron, but the real package is cronie:

yum install vixie-cron


yum install cronie

In both cases you get the same output:

 Package         Arch       Version         Repository      Size
 cronie          x86_64     1.4.4-12.el6    base             73 k
Installing for dependencies:
 cronie-anacron  x86_64     1.4.4-12.el6    base             30 k
 crontabs        noarch     1.10-33.el6     base             10 k
 exim            x86_64     4.72-6.el6      epel            1.2 M

Transaction Summary
Install       4 Package(s)

Is there a difference between "throw" and "throw ex"?

Yes, there is a difference;

  • throw ex resets the stack trace (so your errors would appear to originate from HandleException)
  • throw doesn't - the original offender would be preserved.

    static void Main(string[] args)
        catch (Exception ex)
    private static void Method2()
        catch (Exception ex)
            //throw ex resets the stack trace Coming from Method 1 and propogates it to the caller(Main)
            throw ex;
    private static void Method1()
            throw new Exception("Inside Method1");
        catch (Exception)

What is the most efficient way to get first and last line of a text file?

Can you use unix commands? I think using head -1 and tail -n 1 are probably the most efficient methods. Alternatively, you could use a simple fid.readline() to get the first line and fid.readlines()[-1], but that may take too much memory.

How to flatten only some dimensions of a numpy array

An alternative approach is to use numpy.resize() as in:

In [37]: shp = (50,100,25)
In [38]: arr = np.random.random_sample(shp)
In [45]: resized_arr = np.resize(arr, ([:2]), shp[-1]))
In [46]: resized_arr.shape
Out[46]: (5000, 25)

# sanity check with other solutions
In [47]: resized = np.reshape(arr, (-1, shp[-1]))
In [48]: np.allclose(resized_arr, resized)
Out[48]: True

Why does CreateProcess give error 193 (%1 is not a valid Win32 app)

Let me add an example here:

I'm trying to build Alluxio on windows platform and got the same issue, it's because the pom.xml contains below step:

            <id>Check that there are no Windows line endings</id>

The .sh file is not executable on windows so the error throws.

Comment it out if you do want build Alluxio on windows.

How to concatenate multiple lines of output to one line?

Piping output to xargs will concatenate each line of output to a single line with spaces:

grep pattern file | xargs

Or any command, eg. ls | xargs. The default limit of xargs output is ~4096 characters, but can be increased with eg. xargs -s 8192.

Cannot execute RUN mkdir in a Dockerfile

When creating subdirectories hanging off from a non-existing parent directory(s) you must pass the -p flag to mkdir ... Please update your Dockerfile with

RUN mkdir -p ... 

I tested this and it's correct.

How to uncommit my last commit in Git

To keep the changes from the commit you want to undo

git reset --soft HEAD^

To destroy the changes from the commit you want to undo

git reset --hard HEAD^

You can also say

git reset --soft HEAD~2

to go back 2 commits.

Edit: As charsi mentioned, if you are on Windows you will need to put HEAD or commit hash in quotes.

git reset --soft "HEAD^"
git reset --soft "asdf"

.NET - How do I retrieve specific items out of a Dataset?

The DataSet object has a Tables array. If you know the table you want, it will have a Row array, each object of which has an ItemArray array. In your case the code would most likely be

int var1 = int.Parse(ds.Tables[0].Rows[0].ItemArray[4].ToString());

and so forth. This would give you the 4th item in the first row. You can also use Columns instead of ItemArray and specify the column name as a string instead of remembering it's index. That approach can be easier to keep up with if the table structure changes. So that would be

int var1 = int.Parse(ds.Tables[0].Rows[0]["MyColumnName"].ToString());

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

function realtime() {_x000D_
  let time = moment().format('h:mm:ss a');_x000D_
  document.getElementById('time').innerHTML = time;_x000D_
  setInterval(() => {_x000D_
    time = moment().format('h:mm:ss a');_x000D_
    document.getElementById('time').innerHTML = time;_x000D_
  }, 1000)_x000D_
<script src=""></script>_x000D_
<div id="time"></div>

A very simple way using moment.js and setInterval.

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

Sample output

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

3:25:50 pm

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

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

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

Is setInterval CPU intensive?

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

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

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

Operation is not valid due to the current state of the object, when I select a dropdown list

This can happen if you call


on an IEnumerable with 2 or more elements.

How to compare binary files to check if they are the same?

Use cmp command. Refer to Binary Files and Forcing Text Comparisons for more information.

cmp -b file1 file2

Xcode 4: How do you view the console?

Here' an alternative

In Xcode 4 short cut to display and hide console is (command-shift-Y) , this will show the console and debugger below ur text edior in the same window.

Need a query that returns every field that contains a specified letter

There's most likely a more elegant way, but this does find every record with a letter in it, both upper or lower case:

select * from your_table
where UPPER(your_field) like '%A%'
or UPPER(your_field) like '%B%'
or UPPER(your_field) like '%C%'
or UPPER(your_field) like '%D%'
or UPPER(your_field) like '%E%'
or UPPER(your_field) like '%F%'
or UPPER(your_field) like '%G%'
or UPPER(your_field) like '%H%'
or UPPER(your_field) like '%I%'
or UPPER(your_field) like '%J%'
or UPPER(your_field) like '%K%'
or UPPER(your_field) like '%L%'
or UPPER(your_field) like '%M%'
or UPPER(your_field) like '%N%'
or UPPER(your_field) like '%O%'
or UPPER(your_field) like '%P%'
or UPPER(your_field) like '%Q%'
or UPPER(your_field) like '%R%'
or UPPER(your_field) like '%S%'
or UPPER(your_field) like '%T%'
or UPPER(your_field) like '%U%'
or UPPER(your_field) like '%V%'
or UPPER(your_field) like '%W%'
or UPPER(your_field) like '%X%'
or UPPER(your_field) like '%Y%'
or UPPER(your_field) like '%Z%'

NPM doesn't install module dependencies

It looks like you hit a bug that has existed for quite a while and doesn't have solution yet. There are several open issues for this case in the npm repository:

In the first one people list several workarounds that you may try.

An alternative solution may be (a little hackish) to explicitly list the dependencies as first level dependents. This requires you to maintain the list but practically it has to be done very infrequently.

Implementing two interfaces in a class with same method. Which interface method is overridden?

Try implementing the interface as anonymous.

public class MyClass extends MySuperClass implements MyInterface{

MyInterface myInterface = new MyInterface(){

/* Overrided method from interface */
public void method1(){



/* Overrided method from superclass*/
public void method1(){



How to make a smaller RatingBar?

I solve this issue the following: style="?android:attr/ratingBarStyleSmall"

Post form data using HttpWebRequest

Try this:

var request = (HttpWebRequest)WebRequest.Create("");

var postData = "thing1=hello";
    postData += "&thing2=world";
var data = Encoding.ASCII.GetBytes(postData);

request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = data.Length;

using (var stream = request.GetRequestStream())
    stream.Write(data, 0, data.Length);

var response = (HttpWebResponse)request.GetResponse();

var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();

Where to download Microsoft Visual c++ 2003 redistributable

Another way:

using Unofficial (Full Size: 26.1 MB) VC++ All in one that contained your needed files:

OR (Smallest 5.10 MB) Microsoft Visual Basic/C++ Runtimes 1.1.1 RePacked Here:

jQuery Validation using the class instead of the name value

Another way you can do it, is using addClassRules. It's specific for classes, while the option using selector and .rules is more a generic way.

Before calling


Use like this:

jQuery.validator.addClassRules('myClassName', {
        required: true /*,
        other rules */


I prefer this syntax for a case like this.

What is difference between arm64 and armhf?

armhf stands for "arm hard float", and is the name given to a debian port for arm processors (armv7+) that have hardware floating point support.

On the beaglebone black, for example:

:~$ dpkg --print-architecture

Although other commands (such as uname -a or arch) will just show armv7l

:~$ cat /proc/cpuinfo 
processor       : 0
model name      : ARMv7 Processor rev 2 (v7l)
BogoMIPS        : 995.32
Features        : half thumb fastmult vfp edsp thumbee neon vfpv3 tls

The vfpv3 listed under Features is what refers to the floating point support.

Incidentally, armhf, if your processor supports it, basically supersedes Raspbian, which if I understand correctly was mainly a rebuild of armhf with work arounds to deal with the lack of floating point support on the original raspberry pi's. Nowdays, of course, there's a whole ecosystem build up around Raspbian, so they're probably not going to abandon it. However, this is partly why the beaglebone runs straight debian, and that's ok even if you're used to Raspbian, unless you want some of the special included non-free software such as Mathematica.

I don't understand -Wl,-rpath -Wl,

The man page makes it pretty clear. If you want to pass two arguments (-rpath and .) to the linker you can write


or alternatively

-Wl,-rpath -Wl,.

The arguments -Wl,-rpath . you suggested do NOT make sense to my mind. How is gcc supposed to know that your second argument (.) is supposed to be passed to the linker instead of being interpreted normally? The only way it would be able to know that is if it had insider knowledge of all possible linker arguments so it knew that -rpath required an argument after it.

Android check internet connection

This is the another option to handle all situation:

public void isNetworkAvailable() {
    ConnectivityManager connectivityManager = (ConnectivityManager) ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
    if (activeNetworkInfo != null && activeNetworkInfo.isConnected()) {
    } else {
        Toast.makeText(ctx, "Internet Connection Is Required", Toast.LENGTH_LONG).show();


How do I configure IIS for URL Rewriting an AngularJS application in HTML5 mode?

I write out a rule in web.config after $locationProvider.html5Mode(true) is set in app.js.

Hope, helps someone out.

        <rule name="AngularJS Routes" stopProcessing="true">
          <match url=".*" />
          <conditions logicalGrouping="MatchAll">
            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
            <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
            <add input="{REQUEST_URI}" pattern="^/(api)" negate="true" />
          <action type="Rewrite" url="/" />

In my index.html I added this to <head>

<base href="/">

Don't forget to install IIS URL Rewrite on server.

Also if you use Web API and IIS, this will work if your API is at because of the third input (third line of condition).

Converting DateTime format using razor

Below code will help you

@Html.Label(@item.Date.Value.ToString("dd - M - yy"))

What does it mean to "call" a function in Python?

When you "call" a function you are basically just telling the program to execute that function. So if you had a function that added two numbers such as:

def add(a,b):
    return a + b

you would call the function like this:


which would return 8. You can put any two numbers in the parentheses in this case. You can also call a function like this:

answer = add(4,7)

Which would set the variable answer equal to 11 in this case.

How to float a div over Google Maps?

absolute positioning is evil... this solution doesn't take into account window size. If you resize the browser window, your div will be out of place!

Excel VBA App stops spontaneously with message "Code execution has been halted"

I found hitting ctrl+break while the macro wasn't running fixed the problem.

Share variables between files in Node.js?

Global variables are almost never a good thing (maybe an exception or two out there...). In this case, it looks like you really just want to export your "name" variable. E.g.,

// module.js
var name = "foobar";
// export it = name;

Then, in main.js...

// get a reference to your required module
var myModule = require('./module');

// name is a member of myModule due to the export above
var name =;

TypeError: ObjectId('') is not JSON serializable

I would like to provide an additional solution that improves the accepted answer. I have previously provided the answers in another thread here.

from flask import Flask
from flask.json import JSONEncoder

from bson import json_util

from . import resources

# define a custom encoder point to the json_util provided by pymongo (or its dependency bson)
class CustomJSONEncoder(JSONEncoder):
    def default(self, obj): return json_util.default(obj)

application = Flask(__name__)
application.json_encoder = CustomJSONEncoder

if __name__ == "__main__":

Inline CSS styles in React: how to implement a:hover?

Full CSS support is exactly the reason this huge amount of CSSinJS libraries, to do this efficiently, you need to generate actual CSS, not inline styles. Also inline styles are much slower in react in a bigger system. Disclaimer - I maintain JSS.

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

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

screenshot of console.table

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

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

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

screenshot of console.table

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

keycode and charcode

It is a conditional statement.

If browser supprts e.keyCode then take e.keyCode else e.charCode.

It is similar to

var code = event.keyCode || event.charCode

event.keyCode: Returns the Unicode value of a non-character key in a keypress event or any key in any other type of keyboard event.

event.charCode: Returns the Unicode value of a character key pressed during a keypress event.

Popup window in winform c#

Just create another form (let's call it formPopup) using Visual Studio. In a button handler write the following code:

var formPopup = new Form();
formPopup.Show(this); // if you need non-modal window

If you need a non-modal window use: formPopup.Show();. If you need a dialog (so your code will hang on this invocation until you close the opened form) use: formPopup.ShowDialog()

linux execute command remotely

I guess ssh is the best secured way for this, for example :

ssh -OPTIONS -p SSH_PORT user@remote_server "remote_command1; remote_command2;"  

where the OPTIONS have to be deployed according to your specific needs (for example, binding to ipv4 only) and your remote command could be starting your tomcat daemon.

If you do not want to be prompt at every ssh run, please also have a look to ssh-agent, and optionally to keychain if your system allows it. Key is... to understand the ssh keys exchange process. Please take a careful look to ssh_config (i.e. the ssh client config file) and sshd_config (i.e. the ssh server config file). Configuration filenames depend on your system, anyway you'll find them somewhere like /etc/sshd_config. Ideally, pls do not run ssh as root obviously but as a specific user on both sides, servers and client.

Some extra docs over the source project main pages :

ssh and ssh-agent
man ssh

an older tuto in French (by myself :-) but might be useful too :

ggplot legends - change labels, order and title

You need to do two things:

  1. Rename and re-order the factor levels before the plot
  2. Rename the title of each legend to the same title

The code:

dtt$model <- factor(dtt$model, levels=c("mb", "ma", "mc"), labels=c("MBB", "MAA", "MCC"))

ggplot(dtt, aes(x=year, y=V, group = model, colour = model, ymin = lower, ymax = upper)) +
  geom_ribbon(alpha = 0.35, linetype=0)+ 
  geom_line(aes(linetype=model), size = 1) +       
  geom_point(aes(shape=model), size=4)  +      
  theme(legend.position=c(.6,0.8)) +
  theme(legend.background = element_rect(colour = 'black', fill = 'grey90', size = 1, linetype='solid')) +
  scale_linetype_discrete("Model 1") +
  scale_shape_discrete("Model 1") +
  scale_colour_discrete("Model 1")

enter image description here

However, I think this is really ugly as well as difficult to interpret. It's far better to use facets:

ggplot(dtt, aes(x=year, y=V, group = model, colour = model, ymin = lower, ymax = upper)) +
  geom_ribbon(alpha=0.2, colour=NA)+ 
  geom_line() +       
  geom_point()  +      

enter image description here

How to pretty print XML from the command line?

xmllint --format yourxmlfile.xml

xmllint is a command line XML tool and is included in libxml2 (


Note: If you don't have libxml2 installed you can install it by doing the following:


cd /tmp
tar xzf libxml2-2.8.0.tar.gz
cd libxml2-2.8.0/
sudo make install


sudo apt-get install libxml2-utils


apt-cyg install libxml2


To install this on MacOS with Homebrew just do: brew install libxml2


Also available on Git if you want the code: git clone git://

Purpose of #!/usr/bin/python3 shebang

#!/usr/bin/python3 is a shebang line.

A shebang line defines where the interpreter is located. In this case, the python3 interpreter is located in /usr/bin/python3. A shebang line could also be a bash, ruby, perl or any other scripting languages' interpreter, for example: #!/bin/bash.

Without the shebang line, the operating system does not know it's a python script, even if you set the execution flag (chmod +x on the script and run it like ./ To make the script run by default in python3, either invoke it as python3 or set the shebang line.

You can use #!/usr/bin/env python3 for portability across different systems in case they have the language interpreter installed in different locations.

jQuery animate scroll

I just use:

$('body').animate({ 'scrollTop': '-=-'+<yourValueScroll>+'px' }, 2000);

.keyCode vs. .which

If you are staying in vanilla Javascript, please note keyCode is now deprecated and will be dropped:

This feature has been removed from the Web standards. Though some browsers may still support it, it is in the process of being dropped. Avoid using it and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any tim

Instead use either: .key or .code depending on what behavior you want:

Both are implemented on modern browsers.

Hide header in stack navigator React navigation

    options={{ headerShown: false }}

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

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

SQL: Two select statements in one query

select name, games, goals
from tblMadrid where name = 'ronaldo'
select name, games, goals
from tblBarcelona where name = 'messi'
ORDER  BY goals 

How to list files in an android directory?

I just discovered that:

new File("/sdcard/").listFiles() returns null if you do not have:

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

set in your AndroidManifest.xml file.

find path of current folder - cmd

for /f "delims=" %%i in ("%0") do set "curpath=%%~dpi"
echo "%curpath%"


echo "%cd%"

The double quotes are needed if the path contains any & characters.