Programs & Examples On #Configparser

ConfigParser is a Python module for reading and writing configuration files that have a structure similar to those of INI files in Microsoft Windows.

Python extending with - using super() Python 3 vs Python 2

  • super() (without arguments) was introduced in Python 3 (along with __class__):

    super() -> same as super(__class__, self)

    so that would be the Python 2 equivalent for new-style classes:

    super(CurrentClass, self)
  • for old-style classes you can always use:

     class Classname(OldStyleParent):
        def __init__(self, *args, **kwargs):
            OldStyleParent.__init__(self, *args, **kwargs)

Lists in ConfigParser

I completed similar task in my project with section with keys without values:

import configparser

# allow_no_value param says that no value keys are ok
config = configparser.ConfigParser(allow_no_value=True)

# overwrite optionxform method for overriding default behaviour (I didn't want lowercased keys)
config.optionxform = lambda optionstr: optionstr'./app.config')

features = list(config['FEATURES'].keys())



['BIOtag', 'TextPosition', 'IsNoun', 'IsNomn']



Convert from MySQL datetime to another format with PHP

$valid_date = date( 'm/d/y g:i A', strtotime($date));


Convert array values from string to int?

An alternative shorter method could be:

$r = explode(',', $s);
foreach ($r as &$i) $i = (int) $i;

It has the same performance as Method 3.

Razor View Without Layout

I wanted to display the login page without the layout and this works pretty good for me.(this is the _ViewStart.cshtml file) You need to set the ViewBag.Title in the Controller.

    if (! (ViewContext.ViewBag.Title == "Login"))
        Layout = "~/Views/Shared/_Layout.cshtml";        

I know it's a little bit late but I hope this helps some body.

android - How to get view from context?

In your broadcast receiver you could access a view via inflation a root layout from XML resource and then find all your views from this root layout with findViewByid():

View view = View.inflate(context, R.layout.ROOT_LAYOUT, null);

Now you can access your views via 'view' and cast them to your view type:

myImage = (ImageView) view.findViewById(;

How return error message in spring mvc @Controller

Here is an alternative. Create a generic exception that takes a status code and a message. Then create an exception handler. Use the exception handler to retrieve the information out of the exception and return to the caller of the service.

public class ResourceException extends RuntimeException {

    private HttpStatus httpStatus = HttpStatus.INTERNAL_SERVER_ERROR;

    public HttpStatus getHttpStatus() {
        return httpStatus;

     * Constructs a new runtime exception with the specified detail message.
     * The cause is not initialized, and may subsequently be initialized by a
     * call to {@link #initCause}.
     * @param message the detail message. The detail message is saved for later retrieval by the {@link #getMessage()}
     *                method.
    public ResourceException(HttpStatus httpStatus, String message) {
        this.httpStatus = httpStatus;

Then use an exception handler to retrieve the information and return it to the service caller.

public class ExceptionHandlerAdvice { 

    public ResponseEntity handleException(ResourceException e) {
        // log exception 
        return ResponseEntity.status(e.getHttpStatus()).body(e.getMessage());

Then create an exception when you need to.

throw new ResourceException(HttpStatus.NOT_FOUND, "We were unable to find the specified resource.");

If statement in aspx page

Just use simple code


html code

<% } 
html code
<% } %>

Checking if sys.argv[x] is defined

It's an ordinary Python list. The exception that you would catch for this is IndexError, but you're better off just checking the length instead.

if len(sys.argv) >= 2:
  startingpoint = sys.argv[1]
  startingpoint = 'blah'

Output first 100 characters in a string

Most of previous examples will raise an exception in case your string is not long enough.

Another approach is to use 'yourstring'.ljust(100)[:100].strip().

This will give you first 100 chars. You might get a shorter string in case your string last chars are spaces.

join list of lists in python

If you're only going one level deep, a nested comprehension will also work:

>>> x = [["a","b"], ["c"]]
>>> [inner
...     for outer in x
...         for inner in outer]
['a', 'b', 'c']

On one line, that becomes:

>>> [j for i in x for j in i]
['a', 'b', 'c']

Content Security Policy: The page's settings blocked the loading of a resource

I got around this by upgrading both the version of Angular that I was using (from v8 -> v9) and the version of TypeScript (from 3.5.3 -> latest).

Call another rest api from my server in Spring-Boot

Modern Spring 5+ answer using WebClient instead of RestTemplate.

Configure WebClient for a specific web-service or resource as a bean (additional properties can be configured).

public WebClient localApiClient() {
    return WebClient.create("http://localhost:8080/api/v3");

Inject and use the bean from your service(s).

public class UserService {

    private static final Duration REQUEST_TIMEOUT = Duration.ofSeconds(3);

    private final WebClient localApiClient;

    public UserService(WebClient localApiClient) {
        this.localApiClient = localApiClient;

    public User getUser(long id) {
        return localApiClient
                .uri("/users/" + id)


Create a new database with MySQL Workbench

How to create database in MySQL Workbench 6.3

  1. In tab home (1) -> Right click on Local instance banner (2) -> Open Connection (3) enter image description here
  2. Right click on the empty space in schema window (1) -> Create schema (2) enter image description here
  3. Type name of database (1) -> Apply (2) enter image description here

C++/CLI Converting from System::String^ to std::string

I like to stay away from the marshaller.

Using CString newString(originalString);

Seems much cleaner and faster to me. No need to worry about creating and deleting a context.

How to display Oracle schema size with SQL query?


I want to exception handle 'list index out of range.'

for i in range (1, len(list))
        print (list[i])

    except ValueError:
        print("Error Value.")
    except indexError:
        print("Erorr index")
    except :
        print('error ')

What is the '.well' equivalent class in Bootstrap 4

Card seems to be "discarded" LOL, I found the "well" not working with bootstrap 4.3.1 and jQuery v3.4.1, just working fine with bootstrap 4.3.1 and jQuery v3.3.1. Hope it helps.

Bootstrap-select - how to fire event on change

Simplest solution would be -


How to add a touch event to a UIView?

Gesture Recognizers

There are a number of commonly used touch events (or gestures) that you can be notified of when you add a Gesture Recognizer to your view. They following gesture types are supported by default:

  • UITapGestureRecognizer Tap (touching the screen briefly one or more times)
  • UILongPressGestureRecognizer Long touch (touching the screen for a long time)
  • UIPanGestureRecognizer Pan (moving your finger across the screen)
  • UISwipeGestureRecognizer Swipe (moving finger quickly)
  • UIPinchGestureRecognizer Pinch (moving two fingers together or apart - usually to zoom)
  • UIRotationGestureRecognizer Rotate (moving two fingers in a circular direction)

In addition to these, you can also make your own custom gesture recognizer.

Adding a Gesture in the Interface Builder

Drag a gesture recognizer from the object library onto your view.

enter image description here

Control drag from the gesture in the Document Outline to your View Controller code in order to make an Outlet and an Action.

enter image description here

This should be set by default, but also make sure that User Action Enabled is set to true for your view.

enter image description here

Adding a Gesture Programmatically

To add a gesture programmatically, you (1) create a gesture recognizer, (2) add it to a view, and (3) make a method that is called when the gesture is recognized.

import UIKit
class ViewController: UIViewController {

    @IBOutlet weak var myView: UIView!
    override func viewDidLoad() {
        // 1. create a gesture recognizer (tap gesture)
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(sender:)))
        // 2. add the gesture recognizer to a view
    // 3. this method is called when a tap is recognized
    @objc func handleTap(sender: UITapGestureRecognizer) {


  • The sender parameter is optional. If you don't need a reference to the gesture then you can leave it out. If you do so, though, remove the (sender:) after the action method name.
  • The naming of the handleTap method was arbitrary. Name it whatever you want using action: #selector(someMethodName(sender:)).

More Examples

You can study the gesture recognizers that I added to these views to see how they work.

enter image description here

Here is the code for that project:

import UIKit
class ViewController: UIViewController {
    @IBOutlet weak var tapView: UIView!
    @IBOutlet weak var doubleTapView: UIView!
    @IBOutlet weak var longPressView: UIView!
    @IBOutlet weak var panView: UIView!
    @IBOutlet weak var swipeView: UIView!
    @IBOutlet weak var pinchView: UIView!
    @IBOutlet weak var rotateView: UIView!
    @IBOutlet weak var label: UILabel!
    override func viewDidLoad() {
        // Tap
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap))
        // Double Tap
        let doubleTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTap))
        doubleTapGesture.numberOfTapsRequired = 2
        // Long Press
        let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(handleLongPress(gesture:)))
        // Pan
        let panGesture = UIPanGestureRecognizer(target: self, action: #selector(handlePan(gesture:)))
        // Swipe (right and left)
        let swipeRightGesture = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipe(gesture:)))
        let swipeLeftGesture = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipe(gesture:)))
        swipeRightGesture.direction = UISwipeGestureRecognizerDirection.right
        swipeLeftGesture.direction = UISwipeGestureRecognizerDirection.left
        // Pinch
        let pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(handlePinch(gesture:)))
        // Rotate
        let rotateGesture = UIRotationGestureRecognizer(target: self, action: #selector(handleRotate(gesture:)))
    // Tap action
    @objc func handleTap() {
        label.text = "Tap recognized"
        // example task: change background color
        if tapView.backgroundColor == {
            tapView.backgroundColor =
        } else {
            tapView.backgroundColor =
    // Double tap action
    @objc func handleDoubleTap() {
        label.text = "Double tap recognized"
        // example task: change background color
        if doubleTapView.backgroundColor == UIColor.yellow {
            doubleTapView.backgroundColor =
        } else {
            doubleTapView.backgroundColor = UIColor.yellow
    // Long press action
    @objc func handleLongPress(gesture: UILongPressGestureRecognizer) {
        label.text = "Long press recognized"
        // example task: show an alert
        if gesture.state == UIGestureRecognizerState.began {
            let alert = UIAlertController(title: "Long Press", message: "Can I help you?", preferredStyle: UIAlertControllerStyle.alert)
            alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
            self.present(alert, animated: true, completion: nil)
    // Pan action
    @objc func handlePan(gesture: UIPanGestureRecognizer) {
        label.text = "Pan recognized"
        // example task: drag view
        let location = gesture.location(in: view) // root view = location
    // Swipe action
    @objc func handleSwipe(gesture: UISwipeGestureRecognizer) {
        label.text = "Swipe recognized"
        // example task: animate view off screen
        let originalLocation =
        if gesture.direction == UISwipeGestureRecognizerDirection.right {
            UIView.animate(withDuration: 0.5, animations: {
       += self.view.bounds.width
            }, completion: { (value: Bool) in
       = originalLocation
        } else if gesture.direction == UISwipeGestureRecognizerDirection.left {
            UIView.animate(withDuration: 0.5, animations: {
       -= self.view.bounds.width
            }, completion: { (value: Bool) in
       = originalLocation
    // Pinch action
    @objc func handlePinch(gesture: UIPinchGestureRecognizer) {
        label.text = "Pinch recognized"
        if gesture.state == UIGestureRecognizerState.changed {
            let transform = CGAffineTransform(scaleX: gesture.scale, y: gesture.scale)
            pinchView.transform = transform
    // Rotate action
    @objc func handleRotate(gesture: UIRotationGestureRecognizer) {
        label.text = "Rotate recognized"
        if gesture.state == UIGestureRecognizerState.changed {
            let transform = CGAffineTransform(rotationAngle: gesture.rotation)
            rotateView.transform = transform


  • You can add multiple gesture recognizers to a single view. For the sake of simplicity, though, I didn't do that (except for the swipe gesture). If you need to for your project, you should read the gesture recognizer documentation. It is fairly understandable and helpful.
  • Known issues with my examples above: (1) Pan view resets its frame on next gesture event. (2) Swipe view comes from the wrong direction on the first swipe. (These bugs in my examples should not affect your understanding of how Gestures Recognizers work, though.)

How do I execute a stored procedure once for each row returned by query?

You can do it with a dynamic query.

declare @cadena varchar(max) = ''
select @cadena = @cadena + 'exec spAPI ' + ltrim(id) + ';'
from sysobjects;

get current page from url


Another option.

How would I create a UIAlertView in Swift?

try This. Put Bellow Code In Button.

let alert = UIAlertController(title: "Your_Title_Text", message: "Your_MSG", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Your_Text", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated:true, completion: nil)

How do you display code snippets in MS Word preserving format and syntax highlighting?

When I've done this, I've made extensive use of styles. It helps a lot.

What I do is create a paragraph style (perhaps called "Code Example" or something like that) which uses a monospaced font, carefully chosen tabs, a very light grey background, a thin black border above and below (that helps visibility a lot) and with spelling turned off. I also make sure that inter-line and inter-paragraph spacing are set right. I then create additional character styles on top (e.g., "Comment", "String", "Keyword", "Function Name Decl", "Variable Name Decl") which I layer on top; those set the color and whether the text is bold/italic. It's then pretty simple to go through and mark up a pasted example as being code and have it come out looking really good, and this is works well for short snippets. Long chunks of code probably should not normally be in something that's going to go on a dead tree. :-)

An advantage of doing it this way is that it is easy to adapt to whatever code you're doing; you don't have to rely on some IDE to figure out whatever is going on for you. (The main problem? Printed pages typically aren't as wide as editor windows so wrapping will suck...)

How to group subarrays by a column value?

This array_group_by function achieves what you are looking for:

$grouped = array_group_by($arr, 'id');

It even supports multi-level groupings:

$grouped = array_group_by($arr, 'id', 'part_no');

Find TODO tags in Eclipse

Tasks view, under Window -> Show View -> Tasks

Different names of JSON property during serialization and deserialization

Just tested and this works:

public class Coordinates {
    byte red;

    public byte getR() {
      return red;

    public void setRed(byte red) { = red;

The idea is that method names should be different, so jackson parses it as different fields, not as one field.

Here is test code:

Coordinates c = new Coordinates();
c.setRed((byte) 5);

ObjectMapper mapper = new ObjectMapper();
System.out.println("Serialization: " + mapper.writeValueAsString(c));

Coordinates r = mapper.readValue("{\"red\":25}",Coordinates.class);
System.out.println("Deserialization: " + r.getR());


Serialization: {"r":5}
Deserialization: 25

Is it wrong to place the <script> tag after the </body> tag?

IE doesn't allow this anymore (since Version 10, I believe) and will ignore such scripts. FF and Chrome still tolerate them, but there are chances that some day they will drop this as non-standard.

Convert java.time.LocalDate into java.util.Date type

You can use java.sql.Date.valueOf() method as:

Date date = java.sql.Date.valueOf(localDate);

No need to add time and time zone info here because they are taken implicitly.
See LocalDate to java.util.Date and vice versa simpliest conversion?

How do you use $sce.trustAsHtml(string) to replicate ng-bind-html-unsafe in Angular 1.2+

var line = "<label onclick="alert(1)">aaa</label>";

1. use filter

app.filter('unsafe', function($sce) { return $sce.trustAsHtml; });

using (html):

<span ng-bind-html="line | unsafe"></span>
==>click `aaa` show alert box

2. use ngSanitize : safer

include angular-sanitize.js

<script src="bower_components/angular-sanitize/angular-sanitize.js"></script>

add ngSanitize in root angular app

var app = angular.module("app", ["ngSanitize"]);

using (html):

<span ng-bind-html="line"></span>
==>click `aaa` nothing happen

$rootScope.$broadcast vs. $scope.$emit

Use RxJS in a Service

What about in a situation where you have a Service that's holding state for example. How could I push changes to that Service, and other random components on the page be aware of such a change? Been struggling with tackling this problem lately

Build a service with RxJS Extensions for Angular.

<script src="//"></script>
<script src="//"></script>
<script src="//"></script>
var app = angular.module('myApp', ['rx']);

app.factory("DataService", function(rx) {
  var subject = new rx.Subject(); 
  var data = "Initial";

  return {
      set: function set(d){
        data = d;
      get: function get() {
        return data;
      subscribe: function (o) {
         return subject.subscribe(o);

Then simply subscribe to the changes.

app.controller('displayCtrl', function(DataService) {
  var $ctrl = this;

  $ = DataService.get();
  var subscription = DataService.subscribe(function onNext(d) {
      $ = d;

  this.$onDestroy = function() {

Clients can subscribe to changes with DataService.subscribe and producers can push changes with DataService.set.


Android Device not recognized by adb

Generally, I think your USB connection should be set to use MTP (Media Transfer), however, I couldn't get my computer to recognize my device (Nexus 4). Oddly, setting the USB connection to Camera got it working for me.

How do you clear a stringstream variable?

You can clear the error state and empty the stringstream all in one line

std::stringstream().swap(m); // swap m with a default constructed stringstream

This effectively resets m to a default constructed state

Linker Error C++ "undefined reference "

Your error shows you are not compiling file with the definition of the insert function. Update your command to include the file which contains the definition of that function and it should work.

Extract a part of the filepath (a directory) in Python

import os

directory = os.path.abspath('\\') # root directory
print(directory) # e.g. 'C:\'

directory = os.path.abspath('.') # current directory
print(directory) # e.g. 'C:\Users\User\Desktop'

parent_directory, directory_name = os.path.split(directory)
print(directory_name) # e.g. 'Desktop'
parent_parent_directory, parent_directory_name = os.path.split(parent_directory)
print(parent_directory_name) # e.g. 'User'

This should also do the trick.

Show all current locks from get_lock

Starting with MySQL 5.7, the performance schema exposes all metadata locks, including locks related to the GET_LOCK() function.


Passing ArrayList through Intent

if you using Generic Array List with Class instead of specific type like


private ArrayList<Model> aListModel = new ArrayList<Model>();

Here, Model = Class

Receiving Intent Like :

aListModel = (ArrayList<Model>) getIntent().getSerializableExtra(KEY);


Here Model-class must be implemented like: ModelClass implements Serializable

PHP how to get value from array if key is in a variable

Your code seems to be fine, make sure that key you specify really exists in the array or such key has a value in your array eg:

$array = array(4 => 'Hello There');
// or better


    [0] => 4


$key = 4;
$value = $array[$key];
print $value;


Hello There

How do I remove packages installed with Python's easy_install?

If the problem is a serious-enough annoyance to you, you might consider virtualenv. It allows you to create an environment that encapsulates python libraries. You install packages there rather than in the global site-packages directory. Any scripts you run in that environment have access to those packages (and optionally, your global ones as well). I use this a lot when evaluating packages that I am not sure I want/need to install globally. If you decide you don't need the package, it's easy enough to just blow that virtual environment away. It's pretty easy to use. Make a new env:

$>virtualenv /path/to/your/new/ENV

virtual_envt installs setuptools for you in the new environment, so you can do:


You can even create your own boostrap scripts that setup your new environment. So, with one command, you can create a new virtual env with, say, python 2.6, psycopg2 and django installed by default (you can can install an env-specific version of python if you want).

Local package.json exists, but node_modules missing

Just had the same error message, but when I was running a package.json with:

"scripts": {
    "build": "tsc -p ./src",

tsc is the command to run the TypeScript compiler.

I never had any issues with this project because I had TypeScript installed as a global module. As this project didn't include TypeScript as a dev dependency (and expected it to be installed as global), I had the error when testing in another machine (without TypeScript) and running npm install didn't fix the problem. So I had to include TypeScript as a dev dependency (npm install typescript --save-dev) to solve the problem.

How to access the php.ini file in godaddy shared hosting linux

As pointed out by @Jason, for most shared hosting environments, having a copy of php.ini file in your public_html directory works to override the system default settings. A great way to do this is by copying the hosting company's copy. Put this in a file, say copyini.php

  system("cp /path/to/php/conf/file/php.ini  /home/yourusername/public_html/php.ini");

Get /path/to/php/conf/file/php.ini from the output of phpinfo(); in a file. Then in your ini file, make your amendments Delete all files created during this process (Apart from php.ini of course :-) )

How to validate date with format "mm/dd/yyyy" in JavaScript?

I pulled most of this code from another post found here. I have modified it for my purposes. This works well for what I need. It may help with your situation.

$(window).load(function() {
  function checkDate() {
    var dateFormat = /^(0?[1-9]|[12][0-9]|3[01])[\/\-](0?[1-9]|1[012])[\/\-]\d{4}$/;
    var valDate = $(this).val();
    if ( valDate.match( dateFormat )) {
      $(this).css("border","1px solid #cccccc","color", "#555555", "font-weight", "normal");
      var seperator1 = valDate.split('/');
      var seperator2 = valDate.split('-');

      if ( seperator1.length > 1 ) {
        var splitdate = valDate.split('/');
      } else if ( seperator2.length > 1 ) {
        var splitdate = valDate.split('-');

      var dd = parseInt(splitdate[0]);
      var mm = parseInt(splitdate[1]);
      var yy = parseInt(splitdate[2]);
      var ListofDays = [31,28,31,30,31,30,31,31,30,31,30,31];

      if ( mm == 1 || mm > 2 ) {
        if ( dd > ListofDays[mm - 1] ) {
          $(this).css("border","solid red 1px","color", "red", "font-weight", "bold");
          alert('Invalid Date! You used a date which does not exist in the known calender.');
          return false;

      if ( mm == 2 ) {
       var lyear = false;
        if ( (!(yy % 4) && yy % 100) || !(yy % 400) ){
          lyear = true;

        if ( (lyear==false) && (dd>=29) ) {
          $(this).css("border","solid red 1px","color", "red", "font-weight", "bold");
          alert('Invalid Date! You used Feb 29th for an invalid leap year');
          return false;

        if ( (lyear==true) && (dd>29) ) {
          $(this).css("border","solid red 1px","color", "red", "font-weight", "bold");
          alert('Invalid Date! You used a date greater than Feb 29th in a valid leap year');
          return false;
    } else {
      $(this).css("border","solid red 1px","color", "red", "font-weight", "bold");
      alert('Date format was invalid! Please use format mm/dd/yyyy');
      return false;

  $('#from_date').change( checkDate );
  $('#to_date').change( checkDate );

What is the default Precision and Scale for a Number in Oracle?

Oracle stores numbers in the following way: 1 byte for power, 1 byte for the first significand digit (that is one before the separator), the rest for the other digits.

By digits here Oracle means centesimal digits (i. e. base 100)

SQL> INSERT INTO t_numtest VALUES (LPAD('9', 125, '9'))
  2  /

1 row inserted

SQL> INSERT INTO t_numtest VALUES (LPAD('7', 125, '7'))
  2  /

1 row inserted

SQL> INSERT INTO t_numtest VALUES (LPAD('9', 126, '9'))
  2  /

INSERT INTO t_numtest VALUES (LPAD('9', 126, '9'))

ORA-01426: numeric overflow

SQL> SELECT DUMP(num) FROM t_numtest;

Typ=2 Len=2: 255,11
Typ=2 Len=21: 255,8,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,79

As we can see, the maximal number here is 7.(7) * 10^124, and he have 19 centesimal digits for precision, or 38 decimal digits.

Download files from server php

Here is the code that will not download courpt files

$filename = "myfile.jpg";
$file = "/uploads/images/".$filename;

header('Content-type: application/octet-stream');
header("Content-Type: ".mime_content_type($file));
header("Content-Disposition: attachment; filename=".$filename);
while (ob_get_level()) {

I have included mime_content_type which will return content type of file .

To prevent from corrupt file download i have added ob_get_level() and ob_end_clean();

JQuery - how to select dropdown item based on value

You can simply use:


Array initializing in Scala

If you know Array's length but you don't know its content, you can use

val length = 5
val temp = Array.ofDim[String](length)

If you want to have two dimensions array but you don't know its content, you can use

val row = 5
val column = 3
val temp = Array.ofDim[String](row, column)

Of course, you can change String to other type.

If you already know its content, you can use

val temp = Array("a", "b")

Bootstrap 3: How to get two form inputs on one line and other inputs on individual lines?

I resorted to creating 2 style cascades using inline-block for input that pretty much override the field:

.input-sm {
    height: 2.1em;
    display: inline-block;

and a series of fixed sizes as opposed to %

.input-10 {
    width: 10em;

.input-32 {
    width: 32em;

Why is the apt-get function not working in the terminal on Mac OS X v10.9 (Mavericks)?

Alternatively You can use the brew or curl command for installing things, wherever apt-get is mentioned with a URL...

For example,

curl -O

Using reCAPTCHA on localhost

Google has recently changed stopped allowing localhost being allowed by default. (as touched upon by @Artur Cesar De Melo)This is under their FAQ's:

I'm getting an error "Localhost is not in the list of supported domains". This was working before, what should I do?

localhost domains are no longer supported by default. If you wish to continue supporting them for development you can add them to the list of supported domains for your site key. Go to the admin console to update your list of supported domains. We advise to use a separate key for development and production and to not allow localhost on your production site key.

1: Create a separate key for your development environment

2: Add to the list of allowed domains

3: Save changes and allow up to 30 mins for changes to take affect

How can I write to the console in PHP?

Here is my solution, the good thing about this one is that you can pass as many params as you like.

function console_log()
    $js_code = 'console.log(' . json_encode(func_get_args(), JSON_HEX_TAG) .
    $js_code = '<script>' . $js_code . '</script>';
    echo $js_code;

Call it this way

console_log('DEBUG>>', 'Param 1', 'Param 2');
console_log('Console DEBUG:', $someRealVar1, $someVar, $someArray, $someObj);

Now you should be able to see output in your console, happy coding :)

What is the apply function in Scala?

TLDR for people comming from c++

It's just overloaded operator of ( ) parentheses

So in scala:

class X {
   def apply(param1: Int, param2: Int, param3: Int) : Int = {
     // Do something

Is same as this in c++:

class X {
   int operator()(int param1, int param2, int param3) {
      // do something

getOutputStream() has already been called for this response

I got the same problem, and I solved just adding "return;" at the end of the FileInputStream.

Here is my JSP

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"_x000D_
<%@ page import="*"%>_x000D_
<%@ page trimDirectiveWhitespaces="true"%>_x000D_
 try {_x000D_
  FileInputStream ficheroInput = new FileInputStream("C:\\export_x_web.pdf");_x000D_
  int tamanoInput = ficheroInput.available();_x000D_
  byte[] datosPDF = new byte[tamanoInput];_x000D_, 0, tamanoInput);_x000D_
  response.setHeader("Content-disposition", "inline; filename=export_sise_web.pdf");_x000D_
 } catch (Exception e) {_x000D_

Create a symbolic link of directory in Ubuntu

In script is usefull something like this:

if [ ! -d /etc/nginx ]; then ln -s /usr/local/nginx/conf/ /etc/nginx > /dev/null 2>&1; fi

it prevents before re-create "bad" looped symlink after re-run script

Length of string in bash

If you want to use this with command line or function arguments, make sure you use size=${#1} instead of size=${#$1}. The second one may be more instinctual but is incorrect syntax.

Unable to begin a distributed transaction

If the servers are clustered and there is a clustered DTC you have to disable security on the clustered DTC not the local DTC.

Find MongoDB records where array field is not empty

You can use any of the following to achieve this.
Both also take care of not returning a result for objects that don't have the requested key in them:{pictures: {$exists: true, $gt: {$size: 0}}}){comments: {$exists: true, $not: {$size: 0}}})

How do I open phone settings when a button is clicked?

The first response from App-Specific URL Schemes worked for me on iOS 10.3.

if let appSettings = URL(string: UIApplicationOpenSettingsURLString + Bundle.main.bundleIdentifier!) {
    if UIApplication.shared.canOpenURL(appSettings) {

How should I pass an int into stringWithFormat?

And for comedic value:

label.text = [NSString stringWithFormat:@"%@", [NSNumber numberWithInt:count]];

(Though it could be useful if one day you're dealing with NSNumber's)

Why did I get the compile error "Use of unassigned local variable"?

Default assignments apply to class members, but not to local variables. As Eric Lippert explained it in this answer, Microsoft could have initialized locals by default, but they choose not to do it because using an unassigned local is almost certainly a bug.

How to return a file using Web API?

Better to return HttpResponseMessage with StreamContent inside of it.

Here is example:

public HttpResponseMessage GetFile(string id)
    if (String.IsNullOrEmpty(id))
        return Request.CreateResponse(HttpStatusCode.BadRequest);

    string fileName;
    string localFilePath;
    int fileSize;

    localFilePath = getFileFromID(id, out fileName, out fileSize);

    HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
    response.Content = new StreamContent(new FileStream(localFilePath, FileMode.Open, FileAccess.Read));
    response.Content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment");
    response.Content.Headers.ContentDisposition.FileName = fileName;
    response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/pdf");

    return response;

UPD from comment by patridge: Should anyone else get here looking to send out a response from a byte array instead of an actual file, you're going to want to use new ByteArrayContent(someData) instead of StreamContent (see here).

java SSL and cert keystore

Just a word of caution. If you are trying to open an existing JKS keystore in Java 9 onwards, you need to make sure you mention the following properties too with value as "JKS":

The reason being that the default keystore type as prescribed in file has been changed to pkcs12 from jks from Java 9 onwards.

Error starting Tomcat from NetBeans - '*' is not recognized as an internal or external command

I didnt try Sumama Waheed's answer but what worked for me was replacing the bin/catalina.jar with a working jar (I disposed of an older tomcat) and after adding in NetBeans, I put the original catalina.jar again.

How to calculate the IP range when the IP address and the netmask is given?

I know this is an older question, but I found this nifty library on nuget that seems to do just the trick for me:

Netbeans installation doesn't find JDK

Set JAVA_HOME in environment variable.

set JAVA_HOME to only JDK1.6.0_23 or whatever jdk folder you have. dont include bin folder in path.

How to select from subquery using Laravel Query Builder?

Laravel v5.6.12 (2018-03-14) added fromSub() and fromRaw() methods to query builder (#23476).

The accepted answer is correct but can be simplified into:

DB::query()->fromSub(function ($query) {
}, 'a')->count();

The above snippet produces the following SQL:

select count(*) as aggregate from (select * from `abc` group by `col1`) as `a`

MySQL SELECT query string matching


SELECT * FROM customers WHERE name LIKE '%Bob Smith%';


select count(*)
from rearp.customers c
where  LIKE '%Bob smith.8%';

select count will just query (totals)

C will link the db.table to the names row you need this to index

LIKE should be obvs

8 will call all references in DB 8 or less (not really needed but i like neatness)

How to mark a method as obsolete or deprecated?

With ObsoleteAttribute you can to show the deprecated method. Obsolete attribute has three constructor:

  1. [Obsolete]: is a no parameter constructor and is a default using this attribute.
  2. [Obsolete(string message)]: in this format you can get message of why this method is deprecated.
  3. [Obsolete(string message, bool error)]: in this format message is very explicit but error means, in compilation time, compiler must be showing error and cause to fail compiling or not.

enter image description here

Visual Studio Code includePath

This answer maybe late but I just happened to fix the issue. Here is my c_cpp_properties.json file:

"configurations": [
        "name": "Linux",
        "includePath": [
        "defines": [],
        "compilerPath": "/usr/bin/gcc",
        "cStandard": "c11",
        "cppStandard": "c++14",
        "intelliSenseMode": "clang-x64"
"version": 4


Python - Using regex to find multiple matches and print them out

Do not use regular expressions to parse HTML.

But if you ever need to find all regexp matches in a string, use the findall function.

import re
line = 'bla bla bla<form>Form 1</form> some text...<form>Form 2</form> more text?'
matches = re.findall('<form>(.*?)</form>', line, re.DOTALL)

# Output: ['Form 1', 'Form 2']

Open a workbook using FileDialog and manipulate it in Excel VBA

Thankyou Frank.i got the idea. Here is the working code.

Option Explicit
Private Sub CommandButton1_Click()

  Dim directory As String, fileName As String, sheet As Worksheet, total As Integer
  Dim fd As Office.FileDialog

  Set fd = Application.FileDialog(msoFileDialogFilePicker)

  With fd
    .AllowMultiSelect = False
    .Title = "Please select the file."
    .Filters.Add "Excel 2003", "*.xls?"

    If .Show = True Then
      fileName = Dir(.SelectedItems(1))

    End If
  End With

  Application.ScreenUpdating = False
  Application.DisplayAlerts = False

  Workbooks.Open (fileName)

  For Each sheet In Workbooks(fileName).Worksheets
    total = Workbooks("import-sheets.xlsm").Worksheets.Count
    Workbooks(fileName).Worksheets(sheet.Name).Copy _
  Next sheet


  Application.ScreenUpdating = True
  Application.DisplayAlerts = True

End Sub

How do I declare and assign a variable on a single line in SQL

on sql 2008 this is valid

DECLARE @myVariable nvarchar(Max) = 'John said to Emily "Hey there Emily"'
select @myVariable

on sql server 2005, you need to do this

DECLARE @myVariable nvarchar(Max) 
select @myVariable = 'John said to Emily "Hey there Emily"'
select @myVariable

Persistent invalid graphics state error when using ggplot2

The solution is to simply reinstall ggplot2. Maybe there is an incompatibility between the R version you are using, and your installed version of ggplot2. Alternatively, something might have gone wrong while installing ggplot2 earlier, causing the issue you see.

JWT (Json Web Token) Audience "aud" versus Client_Id - What's the difference?

As it turns out, my suspicions were right. The audience aud claim in a JWT is meant to refer to the Resource Servers that should accept the token.

As this post simply puts it:

The audience of a token is the intended recipient of the token.

The audience value is a string -- typically, the base address of the resource being accessed, such as

The client_id in OAuth refers to the client application that will be requesting resources from the Resource Server.

The Client app (e.g. your iOS app) will request a JWT from your Authentication Server. In doing so, it passes it's client_id and client_secret along with any user credentials that may be required. The Authorization Server validates the client using the client_id and client_secret and returns a JWT.

The JWT will contain an aud claim that specifies which Resource Servers the JWT is valid for. If the aud contains, but the client app tries to use the JWT on, then access will be denied because that Resource Server will see that the JWT was not meant for it.

How to get the Mongo database specified in connection string in C#


MongoServer.Create is obsolete now (thanks to @aknuds1). Instead this use following code:

var _server = new MongoClient(connectionString).GetServer();

It's easy. You should first take database name from connection string and then get database by name. Complete example:

var connectionString = "mongodb://localhost:27020/mydb";

//take database name from connection string
var _databaseName = MongoUrl.Create(connectionString).DatabaseName;
var _server = MongoServer.Create(connectionString);

//and then get database by database name:

Important: If your database and auth database are different, you can add a authSource= query parameter to specify a different auth database. (thank you to @chrisdrobison)

From docs:

NOTE If you are using the database segment as the initial database to use, but the username and password specified are defined in a different database, you can use the authSource option to specify the database in which the credential is defined. For example, mongodb://user:pass@hostname/db1?authSource=userDb would authenticate the credential against the userDb database instead of db1.

How can I change the app display name build with Flutter?

There is a plugin, flutter_launcher_name.

Write file pubspec.yaml:

  flutter_launcher_name: "^0.0.1"

  name: "yourNewAppLauncherName"

And run:

flutter pub get
flutter pub run flutter_launcher_name:main

You can get the same result as editing AndroidManifes.xml and Info.plist.

Regex doesn't work in String.matches()

Your regular expression [a-z] doesn't match dkoe since it only matches Strings of lenght 1. Use something like [a-z]+.

Android: Background Image Size (in Pixel) which Support All Devices

Check this. This image will show for all icon size for different screen sizes


How to unmount, unrender or remove a component, from itself in a React/Redux/Typescript notification message

instead of using


try using


How to get the index of an element in an IEnumerable?

This can get really cool with an extension (functioning as a proxy), for example:

// vs. 
collection.Select((item, index) => item);

Which will automagically assign indexes to the collection accessible via this Index property.


public interface IIndexable
    int Index { get; set; }

Custom extension (probably most useful for working with EF and DbContext):

public static class EnumerableXtensions
    public static IEnumerable<TModel> SelectWithIndex<TModel>(
        this IEnumerable<TModel> collection) where TModel : class, IIndexable
        return collection.Select((item, index) =>
            item.Index = index;
            return item;

public class SomeModelDTO : IIndexable
    public Guid Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }

    public int Index { get; set; }

// In a method
var items = from a in db.SomeTable
            where a.Id == someValue
            select new SomeModelDTO
                Id = a.Id,
                Name = a.Name,
                Price = a.Price

return items.SelectWithIndex()
            .OrderBy(m => m.Name)

Skipping Incompatible Libraries at compile

Normally, that is not an error per se; it is a warning that the first file it found that matches the -lPI-Http argument to the compiler/linker is not valid. The error occurs when no other library can be found with the right content.

So, you need to look to see whether /dvlpmnt/libPI-Http.a is a library of 32-bit object files or of 64-bit object files - it will likely be 64-bit if you are compiling with the -m32 option. Then you need to establish whether there is an alternative libPI-Http.a or file somewhere else that is 32-bit. If so, ensure that the directory that contains it is listed in a -L/some/where argument to the linker. If not, then you will need to obtain or build a 32-bit version of the library from somewhere.

To establish what is in that library, you may need to do:

mkdir junk
cd junk
ar x /dvlpmnt/libPI-Http.a
file *.o
cd ..
rm -fr junk

The 'file' step tells you what type of object files are in the archive. The rest just makes sure you don't make a mess that can't be easily cleaned up.

Oracle "ORA-01008: not all variables bound" Error w/ Parameters

It seems daft, but I think when you use the same bind variable twice you have to set it twice:

cmd.Parameters.Add("VarA", "24");
cmd.Parameters.Add("VarB", "test");
cmd.Parameters.Add("VarB", "test");
cmd.Parameters.Add("VarC", "1234");
cmd.Parameters.Add("VarC", "1234");

Certainly that's true with Native Dynamic SQL in PL/SQL:

SQL> begin
  2     execute immediate 'select * from emp where ename=:name and ename=:name'
  3     using 'KING';
  4  end;
  5  /
ERROR at line 1:
ORA-01008: not all variables bound

SQL> begin
  2     execute immediate 'select * from emp where ename=:name and ename=:name' 
  3     using 'KING', 'KING';
  4  end;
  5  /

PL/SQL procedure successfully completed.

Gradle sync failed: failed to find Build Tools revision 24.0.0 rc1

Go to Build Gradle (Module:app) Change the following. In my case, I choose 25.0.3

android {

    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.example.cesarhcq.viisolutions"
        minSdkVersion 15
        targetSdkVersion 25

After that, it works fine!

How do I get the current time only in JavaScript

function getCurrentTime(){
    var date = new Date();
    var hh = date.getHours();
    var mm = date.getMinutes();

    hh = hh < 10 ? '0'+hh : hh; 
    mm = mm < 10 ? '0'+mm : mm;

    curr_time = hh+':'+mm;
    return curr_time;

cordova run with ios error .. Error code 65 for command: xcodebuild with args:

In my case it was the app icon PNG file... I mean, it took 1 day to go from the provided error

Error code 65 for command: xcodebuild with args:

to the human-readable one:

"the PNG file icon is no good for the picky Apple Xcode"

Validate date in dd/mm/yyyy format using JQuery Validate

You don't need the date validator. It doesn't support dd/mm/yyyy format, and that's why you are getting "Please enter a valid date" message for input like 13/01/2014. You already have the dateITA validator, which uses dd/mm/yyyy format as you need.

Just like the date validator, your code for dateGreaterThan and dateLessThan calls new Date for input string and has the same issue parsing dates. You can use a function like this to parse the date:

function parseDMY(value) {
    var date = value.split("/");
    var d = parseInt(date[0], 10),
        m = parseInt(date[1], 10),
        y = parseInt(date[2], 10);
    return new Date(y, m - 1, d);

is there a require for json in node.js

You can import json files by using the node.js v14 experimental json modules flag. More details here


import data from './folder/file.json'

export default {
  foo () {

And you call it with node --experimental-json-modules file.js

How to validate domain credentials?

using System;
using System.Collections.Generic;
using System.Text;
using System.DirectoryServices.AccountManagement;

class WindowsCred
    private const string SPLIT_1 = "\\";

    public static bool ValidateW(string UserName, string Password)
        bool valid = false;
        string Domain = "";

        if (UserName.IndexOf("\\") != -1)
            string[] arrT = UserName.Split(SPLIT_1[0]);
            Domain = arrT[0];
            UserName = arrT[1];

        if (Domain.Length == 0)
            Domain = System.Environment.MachineName;

        using (PrincipalContext context = new PrincipalContext(ContextType.Domain, Domain)) 
            valid = context.ValidateCredentials(UserName, Password);

        return valid;

Kashif Mushtaq Ottawa, Canada

Launch Image does not show up in my iOS App

Xcode 8:

Images used in LaunchScreen.xib should not be on a .xcassets, try dropping them in the bundle.

Looks like that by the time that the .xib gets loaded, the images in the .xcassets are not yet available.

EDIT: For some opaque reason after adding some localizations, launch screen stopped working, now it works with an image from the assets, extremely weird.

How to convert vector to array

What for? You need to clarify: Do you need a pointer to the first element of an array, or an array?

If you're calling an API function that expects the former, you can do do_something(&v[0], v.size()), where v is a vector of doubles. The elements of a vector are contiguous.

Otherwise, you just have to copy each element:

double arr[100];
std::copy(v.begin(), v.end(), arr);

Ensure not only thar arr is big enough, but that arr gets filled up, or you have uninitialized values.

Should I use JSLint or JSHint JavaScript validation?

There is an another mature and actively developed "player" on the javascript linting front - ESLint:

ESLint is a tool for identifying and reporting on patterns found in ECMAScript/JavaScript code. In many ways, it is similar to JSLint and JSHint with a few exceptions:

  • ESLint uses Esprima for JavaScript parsing.
  • ESLint uses an AST to evaluate patterns in code.
  • ESLint is completely pluggable, every single rule is a plugin and you can add more at runtime.

What really matters here is that it is extendable via custom plugins/rules. There are already multiple plugins written for different purposes. Among others, there are:

And, of course, you can use your build tool of choice to run ESLint:

How to check a string for a special character?

You can use string.punctuation and any function like this

import string
invalidChars = set(string.punctuation.replace("_", ""))
if any(char in invalidChars for char in word):
    print "Invalid"
    print "Valid"

With this line

invalidChars = set(string.punctuation.replace("_", ""))

we are preparing a list of punctuation characters which are not allowed. As you want _ to be allowed, we are removing _ from the list and preparing new set as invalidChars. Because lookups are faster in sets.

any function will return True if atleast one of the characters is in invalidChars.

Edit: As asked in the comments, this is the regular expression solution. Regular expression taken from

word = "Welcome"
import re
print "Valid" if re.match("^[a-zA-Z0-9_]*$", word) else "Invalid"

React - How to get parameter value from query string?

React Router 5.1+

5.1 introduced various hooks like useLocation and useParams that could be of use here.


<Route path="/test/:slug" component={Dashboard} />

Then if we visited say


You could retrieve it like

import { useLocation } from 'react-router';
import queryString from 'query-string';

const Dashboard: React.FC = React.memo((props) => {
    const location = useLocation();


    // {__firebase_request_key: "blablabla", _k: "v9ifuf"}


    return <p>Example</p>;

How to submit form on change of dropdown list?

other than using this.form.submit() you also submiting by id or name. example i have form like this : <form action="" name="PostName" id="IdName">

  1. By Name : <select onchange="PostName.submit()">

  2. By Id : <select onchange="IdName.submit()">

How to center content in a bootstrap column?

Bootstrap 4, horizontal and vertical align contents using flex box

<div class="page-hero d-flex align-items-center justify-content-center">
 <h1>Some text </h1>

Use bootstrap class align-items-center and justify-content-center

Vertically and horizontally center aligned text

.page-hero {
  height: 200px;
  background-color: grey;
<link rel="stylesheet" href="" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">

<div class="page-hero d-flex align-items-center justify-content-center">
  <h1>Some text </h1>

How to print current date on python3?

I use this which is standard for every time

import datetime
now =
print ("Current date and time : ")
print (now.strftime("%Y-%m-%d %H:%M:%S"))

Finding local IP addresses using Python's stdlib

I settled for using the service and/or API of ipfy:

#!/usr/bin/env python3
from urllib.request import urlopen

def public_ip():
    data = urlopen('').read()
    return str(data, encoding='utf-8')


The response can also be obtained in JSON and JSONP formats.

There's an ipify Python library on Github.

Encrypt and Decrypt in Java

Here is a solution using the javax.crypto library and the apache commons codec library for encoding and decoding in Base64 that I was looking for:

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import org.apache.commons.codec.binary.Base64;

public class TrippleDes {

    private static final String UNICODE_FORMAT = "UTF8";
    public static final String DESEDE_ENCRYPTION_SCHEME = "DESede";
    private KeySpec ks;
    private SecretKeyFactory skf;
    private Cipher cipher;
    byte[] arrayBytes;
    private String myEncryptionKey;
    private String myEncryptionScheme;
    SecretKey key;

    public TrippleDes() throws Exception {
        myEncryptionKey = "ThisIsSpartaThisIsSparta";
        myEncryptionScheme = DESEDE_ENCRYPTION_SCHEME;
        arrayBytes = myEncryptionKey.getBytes(UNICODE_FORMAT);
        ks = new DESedeKeySpec(arrayBytes);
        skf = SecretKeyFactory.getInstance(myEncryptionScheme);
        cipher = Cipher.getInstance(myEncryptionScheme);
        key = skf.generateSecret(ks);

    public String encrypt(String unencryptedString) {
        String encryptedString = null;
        try {
            cipher.init(Cipher.ENCRYPT_MODE, key);
            byte[] plainText = unencryptedString.getBytes(UNICODE_FORMAT);
            byte[] encryptedText = cipher.doFinal(plainText);
            encryptedString = new String(Base64.encodeBase64(encryptedText));
        } catch (Exception e) {
        return encryptedString;

    public String decrypt(String encryptedString) {
        String decryptedText=null;
        try {
            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] encryptedText = Base64.decodeBase64(encryptedString);
            byte[] plainText = cipher.doFinal(encryptedText);
            decryptedText= new String(plainText);
        } catch (Exception e) {
        return decryptedText;

    public static void main(String args []) throws Exception
        TrippleDes td= new TrippleDes();

        String target="imparator";
        String encrypted=td.encrypt(target);
        String decrypted=td.decrypt(encrypted);

        System.out.println("String To Encrypt: "+ target);
        System.out.println("Encrypted String:" + encrypted);
        System.out.println("Decrypted String:" + decrypted);



Running the above program results with the following output:

String To Encrypt: imparator
Encrypted String:FdBNaYWfjpWN9eYghMpbRA==
Decrypted String:imparator

Printing Lists as Tabular Data

To create a simple table using terminaltables

Open the terminal or your command prompt and run pip install terminaltables You can print and python list as the following

from terminaltables import AsciiTable

l = [
  ['Head', 'Head'],
  ['R1 C1', 'R1 C2'],
  ['R2 C1', 'R2 C2'],
  ['R3 C1', 'R3 C2']

table = AsciiTable(l)


They have other cool tables don't forget to check them out. Just google their library.

Hope that helps :100:!

How to redirect to the same page in PHP

I use correctly in localhost:


HTML form with side by side input fields

I would go with Larry K's solution, but you can also set the display to inline-block if you want the benefits of both block and inline elements.

You can do this in the div tag by inserting:


Or in a CSS stylesheet with this method:

div { display:inline-block; }

Hope it helps, but as earlier mentioned, I would personally go for Larry K's solution ;-)

How to get the python.exe location programmatically?

This works in Linux & Windows:

Python 3.x

>>> import sys
>>> print(sys.executable)

Python 2.x

>>> import sys
>>> print sys.executable

Rewrite URL after redirecting 404 error htaccess

Try this in your .htaccess:


ErrorDocument 404
ErrorDocument 500
# or map them to one error document:
# ErrorDocument 404 /pages/errors/error_redirect.php
# ErrorDocument 500 /pages/errors/error_redirect.php

RewriteEngine On
RewriteBase /

RewriteCond %{REQUEST_URI} ^/404/$
RewriteRule ^(.*)$ /pages/errors/404.php [L]

RewriteCond %{REQUEST_URI} ^/500/$
RewriteRule ^(.*)$ /pages/errors/500.php [L]

# or map them to one error document:
#RewriteCond %{REQUEST_URI} ^/404/$ [OR]
#RewriteCond %{REQUEST_URI} ^/500/$
#RewriteRule ^(.*)$ /pages/errors/error_redirect.php [L]

The ErrorDocument redirects all 404s to a specific URL, all 500s to another url (replace with your domain).

The Rewrite rules map that URL to your actual 404.php script. The RewriteCond regular expressions can be made more generic if you want, but I think you have to explicitly define all ErrorDocument codes you want to override.

Local Redirect:

Change .htaccess ErrorDocument to a file that exists (must exist, or you'll get an error):

ErrorDocument 404 /pages/errors/404_redirect.php


   header('Location: /404/');

Redirect based on error number

Looks like you'll need to specify an ErrorDocument line in .htaccess for every error you want to redirect (see: Apache ErrorDocument and Apache Custom Error). The .htaccess example above has multiple examples in it. You can use the following as the generic redirect script to replace 404_redirect.php above.


   $error_url = $_SERVER["REDIRECT_STATUS"] . '/';
   $error_path = $error_url . '.php';

   if ( ! file_exists($error_path)) {
      // this is the default error if a specific error page is not found
      $error_url = '404/';

   header('Location: ' . $error_url);

YAML: Do I need quotes for strings in YAML?

After a brief review of the YAML cookbook cited in the question and some testing, here's my interpretation:

  • In general, you don't need quotes.
  • Use quotes to force a string, e.g. if your key or value is 10 but you want it to return a String and not a Fixnum, write '10' or "10".
  • Use quotes if your value includes special characters, (e.g. :, {, }, [, ], ,, &, *, #, ?, |, -, <, >, =, !, %, @, \).
  • Single quotes let you put almost any character in your string, and won't try to parse escape codes. '\n' would be returned as the string \n.
  • Double quotes parse escape codes. "\n" would be returned as a line feed character.
  • The exclamation mark introduces a method, e.g. !ruby/sym to return a Ruby symbol.

Seems to me that the best approach would be to not use quotes unless you have to, and then to use single quotes unless you specifically want to process escape codes.


"Yes" and "No" should be enclosed in quotes (single or double) or else they will be interpreted as TrueClass and FalseClass values:

    'yes': 'Yes'
    'no': 'No'

install beautiful soup using pip

The easy method that will work even in corrupted setup environment is :

To download and run it using command line



Extracting in c:\uu\uu\appdata\local\temp\tmpjxvil3 Now working in c:\u\u\appdata\local\temp\tmpjxvil3\setuptools-5.6 Installing Setuptools


pip install beautifulsoup4


Downloading/unpacking beautifulsoup4 Running ... egg_info for package Installing collected packages: beautifulsoup4 Running install for beautifulsoup4 Successfully installed beautifulsoup4 Cleaning up...

Bam ! |Done¬

Inserting HTML elements with JavaScript

In old school JavaScript, you could do this:

document.body.innerHTML = '<p id="foo">Some HTML</p>' + document.body.innerHTML;

In response to your comment:

[...] I was interested in declaring the source of a new element's attributes and events, not the innerHTML of an element.

You need to inject the new HTML into the DOM, though; that's why innerHTML is used in the old school JavaScript example. The innerHTML of the BODY element is prepended with the new HTML. We're not really touching the existing HTML inside the BODY.

I'll rewrite the abovementioned example to clarify this:

var newElement = '<p id="foo">This is some dynamically added HTML. Yay!</p>';
var bodyElement = document.body;
bodyElement.innerHTML = newElement + bodyElement.innerHTML;
// note that += cannot be used here; this would result in 'NaN'

Using a JavaScript framework would make this code much less verbose and improve readability. For example, jQuery allows you to do the following:

$('body').prepend('<p id="foo">Some HTML</p>');

Installation error: INSTALL_FAILED_OLDER_SDK

I am on Android Studio. I got this error when min/targetSDKVersion were set to 17. While looking thro this thread, I tried to change the minSDKVersion, voila..problem fixed. Go figure.. :(

    android:targetSdkVersion="17" />

How to install and run phpize

Under Redhat Enterprise / CentOS, use yum to install the php-devel module:

yum install php-devel

For PHP 7, you need:

yum install php70-php-devel

Find the division remainder of a number

Modulo would be the correct answer, but if you're doing it manually this should work.

num = input("Enter a number: ")
div = input("Enter a divisor: ")

while num >= div:
    num -= div
print num

SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

I had to reinstall Ruby. This should solve it if you are using Ubuntu & rbenv:

rbenv uninstall your_version

# install dependencies
sudo apt-get install autoconf bison build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev libgdbm3 libgdbm-dev

# install ruby with patch
curl -fsSL | \
  rbenv install --patch your_version

For more information, check out the rbenv Wiki on the matter.

Setting the User-Agent header for a WebClient request

You can also use that:

client.Headers.Add(HttpRequestHeader.UserAgent, "My app.");

Proper way to wait for one function to finish before continuing?

I wonder why no one have mentioned this simple pattern? :

(function(next) {
  //do something
}(function() {
  //do some more

Using timeouts just for blindly waiting is bad practice; and involving promises just adds more complexity to the code. In OP's case:

(function(next) {
    // do something
    if (i==x-1) next()
}(function() {
  // now wait for firstFunction to finish...
  // do something else

a small demo ->

Disabling and enabling a html input button

Stick to php...

Why not only allow the button to appear once an above criteria is met.

if (whatever == something) {
    $display = '<input id="Button" type="button" value="+" style="background-color:grey" onclick="Me();"/>';
    return $display;

What is the python keyword "with" used for?

Explanation from the Preshing on Programming blog:

It’s handy when you have two related operations which you’d like to execute as a pair, with a block of code in between. The classic example is opening a file, manipulating the file, then closing it:

 with open('output.txt', 'w') as f:
     f.write('Hi there!')

The above with statement will automatically close the file after the nested block of code. (Continue reading to see exactly how the close occurs.) The advantage of using a with statement is that it is guaranteed to close the file no matter how the nested block exits. If an exception occurs before the end of the block, it will close the file before the exception is caught by an outer exception handler. If the nested block were to contain a return statement, or a continue or break statement, the with statement would automatically close the file in those cases, too.

How to add a single item to a Pandas Series

You can use the append function to add another element to it. Only, make a series of the new element, before you append it:

test = test.append(pd.Series(200, index=[101]))

Export from pandas to_excel without row names (index)?

You need to set index=False in to_excel in order for it to not write the index column out, this semantic is followed in other Pandas IO tools, see and

How do I call Objective-C code from Swift?

Logans answer works fine except in latest Swift 5 it gives some compiler error. Here is the fix for people who are working on Swift 5.

Swift 5

import Foundation

class MySwiftObject : NSObject {

    var someProperty: AnyObject = "Some Initializer Val" as AnyObject

    override init() {}

    func someFunction(someArg:AnyObject) -> String {
        let returnVal = "You sent me \(someArg)"
        return returnVal

What is

When you download a package with open your Terminal (Mac,Linux) or Command Prompt (Windows). Using cd and helping you with Tab button set the path right to the folder where you have downloaded the file and where there is :

iMac:~ user $ cd path/pakagefolderwithsetupfile/

Press enter, you should see something like this:

iMac:pakagefolderwithsetupfile user$

Then type after this python install :

iMac:pakagefolderwithsetupfile user$ python install

Press enter. Done!

git with development, staging and production branches

one of the best things about git is that you can change the work flow that works best for you.. I do use most of the time but you can use any workflow that fits your needs

How do I get a file extension in PHP?

You can try also this (it works on PHP 5.* and 7):

$info = new SplFileInfo('');
echo $info->getExtension(); // ----- Output -----> zip

Tip: it returns an empty string if the file doesn't have an extension

Node.js - EJS - including a partial

In oficial documentation show that includes works like that:

<%- include('../partials/head') %>

What is the difference between a "line feed" and a "carriage return"?

Since I can not comment because of not having enough reward points I have to answer to correct answer given by @Burhan Khalid.
In very layman language Enter key press is combination of carriage return and line feed.
Carriage return points the cursor to the beginning of the line horizontly and Line feed shifts the cursor to the next line vertically.Combination of both gives you new line(\n) effect.
Reference -

c# .net change label text

When I had this problem I could see only a part of my text and this is the solution for that:

Be sure to set the AutoSize property to true.

output.AutoSize = true;

How to convert a string Date to long millseconds

Using SimpleDateFormat

String string_date = "12-December-2012";

SimpleDateFormat f = new SimpleDateFormat("dd-MMM-yyyy");
try {
    Date d = f.parse(string_date);
    long milliseconds = d.getTime();
} catch (ParseException e) {

SQL Stored Procedure set variables using SELECT

One advantage your current approach does have is that it will raise an error if multiple rows are returned by the predicate. To reproduce that you can use.

SELECT @currentTerm = currentterm,
       @termID = termid,
       @endDate = enddate
FROM   table1
WHERE  iscurrent = 1

IF( @@ROWCOUNT <> 1 )
      RAISERROR ('Unexpected number of matching rows',


Regex lookahead, lookbehind and atomic groups

Lookarounds are zero width assertions. They check for a regex (towards right or left of the current position - based on ahead or behind), succeeds or fails when a match is found (based on if it is positive or negative) and discards the matched portion. They don't consume any character - the matching for regex following them (if any), will start at the same cursor position.

Read for more details.

  • Positive lookahead:



Match only if REGEX_1 matches; after matching REGEX_1, the match is discarded and searching for REGEX_2 starts at the same position.



REGEX_1 is [a-z0-9]{4}$ which matches four alphanumeric chars followed by end of line.
REGEX_2 is [a-z]{1,2}[0-9]{2,3} which matches one or two letters followed by two or three digits.

REGEX_1 makes sure that the length of string is indeed 4, but doesn't consume any characters so that search for REGEX_2 starts at the same location. Now REGEX_2 makes sure that the string matches some other rules. Without look-ahead it would match strings of length three or five.

  • Negative lookahead



Match only if REGEX_1 does not match; after checking REGEX_1, the search for REGEX_2 starts at the same position.



The look-ahead part checks for the FWORD in the string and fails if it finds it. If it doesn't find FWORD, the look-ahead succeeds and the following part verifies that the string's length is between 10 and 30 and that it contains only word characters a-zA-Z0-9_

Look-behind is similar to look-ahead: it just looks behind the current cursor position. Some regex flavors like javascript doesn't support look-behind assertions. And most flavors that support it (PHP, Python etc) require that look-behind portion to have a fixed length.

  • Atomic groups basically discards/forgets the subsequent tokens in the group once a token matches. Check this page for examples of atomic groups

Change application's starting activity

Follow to below instructions:

1:) Open your AndroidManifest.xml file.

2:) Go to the activity code which you want to make your main activity like below.

such as i want to make SplashScreen as main activity

    android:label="City Retails">

3:) Now copy the below code in between activity tags same as:

    android:label="City Retails">
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />

and also check that newly added lines are not attached with other activity tags.

SQL Statement using Where clause with multiple values

SELECT PersonName, songName, status
FROM table
WHERE name IN ('Holly', 'Ryan')

If you are using parametrized Stored procedure:

  1. Pass in comma separated string
  2. Use special function to split comma separated string into table value variable
  3. Use INNER JOIN ON t.PersonName = newTable.PersonName using a table variable which contains passed in names

How to declare a type as nullable in TypeScript?

To be more C# like, define the Nullable type like this:

type Nullable<T> = T | null;

interface Employee{
   id: number;
   name: string;
   salary: Nullable<number>;


To make Nullable behave like a built in Typescript type, define it in a global.d.ts definition file in the root source folder. This path worked for me: /src/global.d.ts

How do I check if a string contains a specific word?

I'm a bit impressed that none of the answers here that used strpos, strstr and similar functions mentioned Multibyte String Functions yet (2015-05-08).

Basically, if you're having trouble finding words with characters specific to some languages, such as German, French, Portuguese, Spanish, etc. (e.g.: ä, é, ô, ç, º, ñ), you may want to precede the functions with mb_. Therefore, the accepted answer would use mb_strpos or mb_stripos (for case-insensitive matching) instead:

if (mb_strpos($a,'are') !== false) {
    echo 'true';

If you cannot guarantee that all your data is 100% in UTF-8, you may want to use the mb_ functions.

A good article to understand why is The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!) by Joel Spolsky.

Reading HTTP headers in a Spring REST controller

Instead of taking the HttpServletRequest object in every method, keep in controllers' context by auto-wiring via the constructor. Then you can access from all methods of the controller.

public class OAuth2ClientController {
    private OAuth2ClientService oAuth2ClientService;

    private HttpServletRequest request;

    public OAuth2ClientController(HttpServletRequest request) {
        this.request = request;

    @RequestMapping(method = RequestMethod.POST)
    public ResponseEntity<String> createClient(@RequestBody OAuth2Client client) {

        return ResponseEntity.ok();

Cross browser method to fit a child div to its parent's width

In case you want to use that padding space... then here's something:

All the colors are background colors.

Why doesn't calling a Python string method do anything unless you assign its output?

Example for String Methods

Given a list of filenames, we want to rename all the files with extension hpp to the extension h. To do this, we would like to generate a new list called newfilenames, consisting of the new filenames. Fill in the blanks in the code using any of the methods you’ve learned thus far, like a for loop or a list comprehension.

filenames = ["program.c", "stdio.hpp", "sample.hpp", "a.out", "math.hpp", "hpp.out"]
# Generate newfilenames as a list containing the new filenames
# using as many lines of code as your chosen method requires.
newfilenames = []
for i in filenames:
    if i.endswith(".hpp"):
        x = i.replace("hpp", "h")

# Should be ["program.c", "stdio.h", "sample.h", "a.out", "math.h", "hpp.out"]

Can you write virtual functions / methods in Java?

All functions in Java are virtual by default.

You have to go out of your way to write non-virtual functions by adding the "final" keyword.

This is the opposite of the C++/C# default. Class functions are non-virtual by default; you make them so by adding the "virtual" modifier.

How to prevent background scrolling when Bootstrap 3 modal open on mobile browsers?

Try this,

 body.modal-open {
    overflow: hidden;
    width: 100%;

LINQ to SQL: Multiple joins ON multiple Columns. Is this possible?

In LINQ2SQL you seldom need to join explicitly when using inner joins.

If you have proper foreign key relationships in your database you will automatically get a relation in the LINQ designer (if not you can create a relation manually in the designer, although you should really have proper relations in your database)

parent-child relation

Then you can just access related tables with the "dot-notation"

var q = from child in context.Childs
        where child.Parent.col2 == 4
        select new
            childCol1 = child.col1,
            parentCol1 = child.Parent.col1,

will generate the query

SELECT [t0].[col1] AS [childCol1], [t1].[col1] AS [parentCol1]
FROM [dbo].[Child] AS [t0]
INNER JOIN [dbo].[Parent] AS [t1] ON ([t1].[col1] = [t0].[col1]) AND ([t1].[col2] = [t0].[col2])
WHERE [t1].[col2] = @p0
-- @p0: Input Int (Size = -1; Prec = 0; Scale = 0) [4]
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1

In my opinion this is much more readable and lets you concentrate on your special conditions and not the actual mechanics of the join.

This is of course only applicable when you want to join in the line with our database model. If you want to join "outside the model" you need to resort to manual joins as in the answer from Quintin Robinson

coercing to Unicode: need string or buffer, NoneType found when rendering in django admin

This error might occur when you return an object instead of a string in your __unicode__ method. For example:

class Author(models.Model):
    . . . 
    name = models.CharField(...)

class Book(models.Model):
    . . .
    author = models.ForeignKey(Author, ...)
    . . .
    def __unicode__(self):
        return  # <<<<<<<< this causes problems

To avoid this error you can cast the author instance to unicode:

class Book(models.Model):
    . . . 
    def __unicode__(self):
        return unicode(  # <<<<<<<< this is OK

append option to select menu?

You can also use insertAdjacentHTML function:

const select = document.querySelector('select')
const value = 'bmw'
const label = 'BMW'

select.insertAdjacentHTML('beforeend', `
  <option value="${value}">${label}</option>

How can I populate a select dropdown list from a JSON feed with AngularJS?

<select name="selectedFacilityId" ng-model="selectedFacilityId">
         <option ng-repeat="facility in facilities" value="{{}}">{{}}</option>

This is an example on how to use it.

How to fetch the dropdown values from database and display in jsp

how to fetch the dropdown values from database and display in jsp:

Dynamically Fetch data from Mysql to (drop down) select option in Jsp. This post illustrates, to fetch the data from the mysql database and display in select option element in Jsp. You should know the following post before going through this post i.e :

How to Connect Mysql database to jsp.

How to create database in MySql and insert data into database. Following database is used, to illustrate ‘Dynamically Fetch data from Mysql to (drop down)

select option in Jsp’ :

id  City
1   London
2   Bangalore
3   Mumbai
4   Paris

Following codes are used to insert the data in the MySql database. Database used is “City” and username = “root” and password is also set as “root”.

Create Database city;
Use city;

Create table new(id int(4), city varchar(30));

insert into new values(1, 'LONDON');
insert into new values(2, 'MUMBAI');
insert into new values(3, 'PARIS');
insert into new values(4, 'BANGLORE');

Here is the code to Dynamically Fetch data from Mysql to (drop down) select option in Jsp:

<%@ page import="java.sql.*" %>
<%ResultSet resultset =null;%>

    <TITLE>Select element drop down box</TITLE>

<BODY BGCOLOR=##f89ggh>

Connection connection = 

       Statement statement = connection.createStatement() ;

       resultset =statement.executeQuery("select * from new") ;

    <h1> Drop down box or select element</h1>
        <%  while({ %>
            <option><%= resultset.getString(2)%></option>
        <% } %>

//**Should I input the codes here?**
        catch(Exception e)
             out.println("wrong entry"+e);


enter image description here

R - Markdown avoiding package loading messages

```{r results='hide', message=FALSE, warning=FALSE}

see Chunk Options in the Knitr docs

jQuery.ajax handling continue responses: "success:" vs ".done"?

From JQuery Documentation

The jqXHR objects returned by $.ajax() as of jQuery 1.5 implement the Promise interface, giving them all the properties, methods, and behavior of a Promise (see Deferred object for more information). These methods take one or more function arguments that are called when the $.ajax() request terminates. This allows you to assign multiple callbacks on a single request, and even to assign callbacks after the request may have completed. (If the request is already complete, the callback is fired immediately.) Available Promise methods of the jqXHR object include:

jqXHR.done(function( data, textStatus, jqXHR ) {});

An alternative construct to the success callback option, refer to deferred.done() for implementation details. jqXHR, textStatus, errorThrown ) {});

An alternative construct to the error callback option, the .fail() method replaces the deprecated .error() method. Refer to for implementation details.

jqXHR.always(function( data|jqXHR, textStatus, jqXHR|errorThrown ) { }); 

(added in jQuery 1.6) An alternative construct to the complete callback option, the .always() method replaces the deprecated .complete() method.

In response to a successful request, the function's arguments are the same as those of .done(): data, textStatus, and the jqXHR object. For failed requests the arguments are the same as those of .fail(): the jqXHR object, textStatus, and errorThrown. Refer to deferred.always() for implementation details.

jqXHR.then(function( data, textStatus, jqXHR ) {}, function( jqXHR, textStatus, errorThrown ) {});

Incorporates the functionality of the .done() and .fail() methods, allowing (as of jQuery 1.8) the underlying Promise to be manipulated. Refer to deferred.then() for implementation details.

Deprecation Notice: The jqXHR.success(), jqXHR.error(), and jqXHR.complete() callbacks are removed as of jQuery 3.0. You can use jqXHR.done(),, and jqXHR.always() instead.

How to wait for a process to terminate to execute another process in batch file

I liked the "START /W" answer, though for my situation I found something even more basic. My processes were console applications. And in my ignorance I thought I would need something special in BAT syntax to make sure that the 1st one completed before the 2nd one started. However BAT appears to make a distinction between console apps and windows apps, and it executes them a little differently. The OP shows that window apps will get launched as an asynchronous call from BAT. But for console apps, that are invoked synchronously, inside the same command window as the BAT itself is running in.

For me it was actually better not to use "START /W", because everything could run inside one command window. The annoying thing about "START /W" is that it will spawn a new command window to execute your console application in.

NoClassDefFoundError - Eclipse and Android

Sometimes it will happen due to not including jar, which you have dependency, with "uses-libary" tag in your AndroidManifest.xml.

Also, make sure it should be inside "application" tag.



Intel X86 emulator accelerator (HAXM installer) VT/NX not enabled

1.To install the virtualization driver:

Start the Android SDK Manager, select Extras and then select Intel Hardware Accelerated Execution Manager. After the download completes, execute /extras/intel/Hardware_Accelerated_Execution_Manager/IntelHAXM.exe. Follow the on-screen instructions to complete installation.

2.If it show any problem restart your computer and inter in BIOS an enable Virtualization Technology ...

3.To see your possessor is capable to virtualization go to the bellow link

Does Java SE 8 have Pairs or Tuples?

Eclipse Collections has Pair and all combinations of primitive/object Pairs (for all eight primitives).

The Tuples factory can create instances of Pair, and the PrimitiveTuples factory can be used to create all combinations of primitive/object pairs.

We added these before Java 8 was released. They were useful to implement key/value Iterators for our primitive maps, which we also support in all primitive/object combinations.

If you're willing to add the extra library overhead, you can use Stuart's accepted solution and collect the results into a primitive IntList to avoid boxing. We added new methods in Eclipse Collections 9.0 to allow for Int/Long/Double collections to be created from Int/Long/Double Streams.

IntList list = IntLists.mutable.withAll(intStream);

Note: I am a committer for Eclipse Collections.

Set focus and cursor to end of text input field / string w. Jquery

You can do this using Input.setSelectionRange, part of the Range API for interacting with text selections and the text cursor:

var searchInput = $('#Search');

// Multiply by 2 to ensure the cursor always ends up at the end;
// Opera sometimes sees a carriage return as 2 characters.
var strLength = searchInput.val().length * 2;

searchInput[0].setSelectionRange(strLength, strLength);

Demo: Fiddle

Class JavaLaunchHelper is implemented in both. One of the two will be used. Which one is undefined

From what I've found online, this is a bug introduced in JDK 1.7.0_45. It appears to also be present in JDK 1.7.0_60. A bug report on Oracle's website states that, while there was a fix, it was removed before the JDK was released. I do not know why the fix was removed, but it confirms what we've already suspected -- the JDK is still broken.

The bug report claims that the error is benign and should not cause any run-time problems, though one of the comments disagrees with that. In my own experience, I have been able to work without any problems using JDK 1.7.0_60 despite seeing the message.

If this issue is causing serious problems, here are a few things I would suggest:

  • Revert back to JDK 1.7.0_25 until a fix is added to the JDK.

  • Keep an eye on the bug report so that you are aware of any work being done on this issue. Maybe even add your own comment so Oracle is aware of the severity of the issue.

  • Try the JDK early releases as they come out. One of them might fix your problem.

Instructions for installing the JDK on Mac OS X are available at JDK 7 Installation for Mac OS X. It also contains instructions for removing the JDK.

PHP: Return all dates between two dates in an array

// will return dates array
function returnBetweenDates( $startDate, $endDate ){
    $startStamp = strtotime(  $startDate );
    $endStamp   = strtotime(  $endDate );

    if( $endStamp > $startStamp ){
        while( $endStamp >= $startStamp ){

            $dateArr[] = date( 'Y-m-d', $startStamp );

            $startStamp = strtotime( ' +1 day ', $startStamp );

        return $dateArr;    
        return $startDate;


returnBetweenDates( '2014-09-16', '2014-09-26' );

// print_r( returnBetweenDates( '2014-09-16', '2014-09-26' ) );

it will return array like below:

    [0] => 2014-09-16
    [1] => 2014-09-17
    [2] => 2014-09-18
    [3] => 2014-09-19
    [4] => 2014-09-20
    [5] => 2014-09-21
    [6] => 2014-09-22
    [7] => 2014-09-23
    [8] => 2014-09-24
    [9] => 2014-09-25
    [10] => 2014-09-26

How does one extract each folder name from a path?

I wrote the following method which works for me.

protected bool isDirectoryFound(string path, string pattern)
        bool success = false;

        DirectoryInfo directories = new DirectoryInfo(@path);
        DirectoryInfo[] folderList = directories.GetDirectories();

        Regex rx = new Regex(pattern);

        foreach (DirectoryInfo di in folderList)
            if (rx.IsMatch(di.Name))
                success = true;

        return success;

The lines most pertinent to your question being:

DirectoryInfo directories = new DirectoryInfo(@path); DirectoryInfo[] folderList = directories.GetDirectories();

Converting Varchar Value to Integer/Decimal Value in SQL Server

Table structure...very basic:

create table tabla(ID int, Stuff varchar (50));

insert into tabla values(1, '32.43');
insert into tabla values(2, '43.33');
insert into tabla values(3, '23.22');


SELECT SUM(cast(Stuff as decimal(4,2))) as result FROM tabla

Or, try this:

SELECT SUM(cast(isnull(Stuff,0) as decimal(12,2))) as result FROM tabla

Working on SQLServer 2008

Linux command to list all available commands and aliases

maybe i'm misunderstanding but what if you press Escape until you got the Display All X possibilities ?

'Microsoft.ACE.OLEDB.16.0' provider is not registered on the local machine. (System.Data)

An alternative that works for me is to simply convert to a CSV.

Pass in an enum as a method parameter

public string CreateFile(string id, string name, string description, SupportedPermissions supportedPermissions)
    file = new File
       Name = name,
        Id = id,
        Description = description,
        SupportedPermissions = supportedPermissions

    return file.Id;

When to use StringBuilder in Java

Some compilers may not replace any string concatenations with StringBuilder equivalents. Be sure to consider which compilers your source will use before relying on compile time optimizations.

jQuery issue - #<an Object> has no method

This problem can also arise if you include jQuery more than once.

$(form).ajaxSubmit is not a function

Ajax Submit form with out page refresh by using jquery ajax method first include library jquery.js and jquery-form.js then create form in html:

<form action="postpage.php" method="POST" id="postForm" >

<div id="flash_success"></div>

<input type="text" name="name" />
<input type="password" name="pass" />
<input type="text" name="email" />

<input type="submit" name="btn" value="Submit" />

  var options = { 
        target:        '#flash_success',  // your response show in this ID
        beforeSubmit:  callValidationFunction,
        success:       YourResponseFunction  
    // bind to the form's submit event
        jQuery('#postForm').submit(function() { 
            return false; 

function callValidationFunction()
 //  validation code for your form HERE

function YourResponseFunction(responseText, statusText, xhr, $form)
        $('#flash_success').html('Your Success Message Here!!!');
        $('body,html').animate({scrollTop: 0}, 800);

        $('#flash_success').html('Error Msg Here');


What is the difference between JDK and JRE?

One difference from a debugging perspective:

To debug into Java system classes such as String and ArrayList, you need a special version of the JRE which is compiled with "debug information". The JRE included inside the JDK provides this info, but the regular JRE does not. Regular JRE does not include this info to ensure better performance.

What is debugging information? Here is a quick explanation taken from this blog post:

Modern compilers do a pretty good job converting your high-level code, with its nicely indented and nested control structures and arbitrarily typed variables into a big pile of bits called machine code (or bytecode in case of Java), the sole purpose of which is to run as fast as possible on the target CPU (virtual CPU of your JVM). Java code gets converted into several machine code instructions. Variables are shoved all over the place – into the stack, into registers, or completely optimized away. Structures and objects don’t even exist in the resulting code – they’re merely an abstraction that gets translated to hard-coded offsets into memory buffers.

So how does a debugger know where to stop when you ask it to break at the entry to some function? How does it manage to find what to show you when you ask it for the value of a variable? The answer is – debugging information.

Debugging information is generated by the compiler together with the machine code. It is a representation of the relationship between the executable program and the original source code. This information is encoded into a pre-defined format and stored alongside the machine code. Many such formats were invented over the years for different platforms and executable files.

How do I get the current time zone of MySQL?

If you need the GMT difference as an integer:


Convert string with comma to integer

The following is another method that will work, although as with some of the other methods it will strip decimal places.

a = 1,112
b = a.scan(/\d+/).join().to_i => 1112

JavaScript adding decimal numbers issue

Use toFixed to convert it to a string with some decimal places shaved off, and then convert it back to a number.

+(0.1 + 0.2).toFixed(12) // 0.3

It looks like IE's toFixed has some weird behavior, so if you need to support IE something like this might be better:

Math.round((0.1 + 0.2) * 1e12) / 1e12

What is __future__ in Python used for and how/when to use it, and how it works

With __future__ module's inclusion, you can slowly be accustomed to incompatible changes or to such ones introducing new keywords.

E.g., for using context managers, you had to do from __future__ import with_statement in 2.5, as the with keyword was new and shouldn't be used as variable names any longer. In order to use with as a Python keyword in Python 2.5 or older, you will need to use the import from above.

Another example is

from __future__ import division
print 8/7  # prints 1.1428571428571428
print 8//7 # prints 1

Without the __future__ stuff, both print statements would print 1.

The internal difference is that without that import, / is mapped to the __div__() method, while with it, __truediv__() is used. (In any case, // calls __floordiv__().)

Apropos print: print becomes a function in 3.x, losing its special property as a keyword. So it is the other way round.

>>> print

>>> from __future__ import print_function
>>> print
<built-in function print>

ALTER TABLE on dependent column

you can drop the Constraint which is restricting you. If the column has access to other table. suppose a view is accessing the column which you are altering then it wont let you alter the column unless you drop the view. and after making changes you can recreate the view.

enter image description here

How to select true/false based on column value?

At least in Postgres you can use the following statement:

SELECT EntityID, EntityName, EntityProfile IS NOT NULL AS HasProfile FROM Entity

How do negative margins in CSS work and why is (margin-top:-5 != margin-bottom:5)?

Margin is the spacing outside your element, just as padding is the spacing inside your element.

Setting the bottom margin indicates what distance you want below the current block. Setting a negative top margin indicates that you want negative spacing above your block. Negative spacing may in itself be a confusing concept, but just the way positive top margin pushes content down, a negative top margin pulls content up.

How to pass a callback as a parameter into another function

Yes of course, function are objects and can be passed, but of course you must declare it:

function firstFunction(){
    //some code
    var callbackfunction = function(data){
       //do something with the data returned from the ajax request
    //a callback function is written for $.post() to execute

an interesting thing is that your callback function has also access to every variable you might have declared inside firstFunction() (variables in javascript have local scope).

How to add MVC5 to Visual Studio 2013?

Also, while installing Visual Studio 2013, ensure that you have checked "Web Developer Tools"

How do I get the value of text input field using JavaScript?

//creates a listener for when you press a key
window.onkeyup = keyup;

//creates a global Javascript variable
var inputTextValue;

function keyup(e) {
  //setting your input text to the global Javascript Variable for every key press
  inputTextValue =;

  //listens for you to press the ENTER key, at which point your web address will change to the one you have input in the search box
  if (e.keyCode == 13) {
    window.location = "" + inputTextValue;

See this functioning in codepen.

Simple way to change the position of UIView? = CGPointMake(150, 150); // set center


aView.frame = CGRectMake( 100, 200, aView.frame.size.width, aView.frame.size.height ); // set new position exactly


aView.frame = CGRectOffset( aView.frame, 10, 10 ); // offset by an amount


I didn't compile this yet, but it should work:

#define CGRectSetPos( r, x, y ) CGRectMake( x, y, r.size.width, r.size.height )

aView.frame = CGRectSetPos( aView.frame, 100, 200 );

jQuery UI Dialog Box - does not open after being closed

on the last line, don't use $(this).remove() use $(this).hide() instead.

EDIT: To clarify,on the close click event you're removing the #terms div from the DOM which is why its not coming back. You just need to hide it instead.

PNG transparency issue in IE8

I put this into a jQuery plugin to make it more modular (you supply the transparent gif):

$.fn.pngFix = function() {
  if (!$.browser.msie || $.browser.version >= 9) { return $(this); }

  return $(this).each(function() {
    var img = $(this),
        src = img.attr('src');

    img.attr('src', '/images/general/transparent.gif')
        .css('filter', "progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled='true',sizingMethod='crop',src='" + src + "')");



Note: It works also if your images are background images. Just apply the function on the div.

How to print color in console using System.out.println?


You can use colors for text as others mentioned in their answers.

But you can use emojis instead! for example you can use You can use ?? for warning messages and for error messages.

Or simply use these note books as a color:

: error message
: warning message
: ok status message
: action message
: canceled status message
: Or anything you like and want to recognize immediately by color


This method also helps you to quickly scan and find logs directly in the source code.

But linux and Windows CMD default emoji font is not colorful by default and you may want to make them colorful, first.

Fixed width buttons with Bootstrap

With BS 4, you can also use the sizing, and apply w-100 so that the button can occupy the complete width of the parent container.

<link href="" rel="stylesheet" />_x000D_
<script src=""></script>_x000D_
  Using btn-block_x000D_
<div class="container-fluid">_x000D_
  <div class="btn-group col" role="group" aria-label="Basic example">_x000D_
    <button type="button" class="btn btn-outline-secondary">Left</button>_x000D_
    <button type="button" class="btn btn-outline-secondary btn-block">Middle</button>_x000D_
    <button type="button" class="btn btn-outline-secondary">Right</button>_x000D_
  Using w-100_x000D_
<div class="container-fluid">_x000D_
  <div class="btn-group col" role="group" aria-label="Basic example">_x000D_
    <button type="button" class="btn btn-outline-secondary">Left</button>_x000D_
    <button type="button" class="btn btn-outline-secondary w-100">Middle</button>_x000D_
    <button type="button" class="btn btn-outline-secondary">Right</button>_x000D_

The Eclipse executable launcher was unable to locate its companion launcher jar windows

I got this error because on Windows the Zend Studio Icon in the Start Menu was still pointing at the previous version of Zend Studio. Once I changed the target to the new path, the error went away.

Get the second highest value in a MySQL table

A straight forward answer for second highest salary

SELECT name, salary
FROM employees ORDER BY `employees`.`salary` DESC LIMIT 1 , 1

another interesting solution

SELECT salary 
FROM emp 
WHERE salary = (SELECT DISTINCT(salary) 
                FROM emp as e1 
                WHERE (n) = (SELECT COUNT(DISTINCT(salary)) 
                             FROM emp as e2 
                             WHERE e1.salary <= e2.salary))

MongoDB - admin user not authorized

For MongoDB shell version v4.2.8 I've tried different ways to back-up my database with auth, my winner solution is

mongodump -h <your_hostname> -d <your_db_name> -u <your_db_username> -p <your_db_password> --authenticationDatabase admin -o /path/to/where/i/want

stringstream, string, and char* conversion confusion

The std::string object returned by ss.str() is a temporary object that will have a life time limited to the expression. So you cannot assign a pointer to a temporary object without getting trash.

Now, there is one exception: if you use a const reference to get the temporary object, it is legal to use it for a wider life time. For example you should do:

#include <string>
#include <sstream>
#include <iostream>

using namespace std;

int main()
    stringstream ss("this is a string\n");

    string str(ss.str());

    const char* cstr1 = str.c_str();

    const std::string& resultstr = ss.str();
    const char* cstr2 = resultstr.c_str();

    cout << cstr1       // Prints correctly
        << cstr2;       // No more error : cstr2 points to resultstr memory that is still alive as we used the const reference to keep it for a time.


    return 0;

That way you get the string for a longer time.

Now, you have to know that there is a kind of optimisation called RVO that say that if the compiler see an initialization via a function call and that function return a temporary, it will not do the copy but just make the assigned value be the temporary. That way you don't need to actually use a reference, it's only if you want to be sure that it will not copy that it's necessary. So doing:

 std::string resultstr = ss.str();
 const char* cstr2 = resultstr.c_str();

would be better and simpler.

2D Euclidean vector rotations

you should remove the vars from the function:

x = x * cs - y * sn; // now x is something different than original vector x
y = x * sn + y * cs;

create new coordinates becomes, to avoid calculation of x before it reaches the second line:

px = x * cs - y * sn; 
py = x * sn + y * cs;

Replace missing values with column mean

Go simply with Zoo, it will simply replace all NA values with mean of the column values:


How to send objects through bundle

The Parcelable interface is a good way to pass an object with an Intent.

How can I make my custom objects Parcelable? is a pretty good answer on how to use Parcelable

The official google docs also include an example

How can I delete a user in linux when the system says its currently used in a process

restart your computer and run $sudo deluser username... worked for me

How to insert text with single quotation sql server 2005

INSERT INTO Table1 (Column1) VALUES ('John''s')

Or you can use a stored procedure and pass the parameter as -

usp_Proc1 @Column1 = 'John''s'

If you are using an INSERT query and not a stored procedure, you'll have to escape the quote with two quotes, else its OK if you don't do it.

Form Submit jQuery does not work

Don't forget to close your form with a </form>. That stopped submit() working for me.

Use multiple custom fonts using @font-face?

If you are having a problem with the font working I have also had this in the past and the issue I found was down to the font-family: name. This had to match what font name was actually given.

The easiest way I found to find this out was to install the font and see what display name is given.

For example, I was using Gill Sans on one project, but the actual font was called Gill Sans MT. Spacing and capitlisation was also important to get right.

Hope that helps.

How to find the extension of a file in C#?

This solution also helps in cases of more than one extension like "Avishay.student.DB"

                FileInfo FileInf = new FileInfo(filePath);
                string strExtention = FileInf.Name.Replace(System.IO.Path.GetFileNameWithoutExtension(FileInf.Name), "");

How to create a connection string in c#

Add this in your web.config file

<add name="itmall" 
connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=D:\19-
02\ABCC\App_Data\abcc.mdf;Integrated Security=True;User Instance=True" />

How to select only 1 row from oracle sql?

The answer is:

You should use nested query as:


=> In PL/SQL "ROWNUM = 1" is NOT equal to "TOP 1" of TSQL.

So you can't use a query like this: "select * from any_table_x where rownum=1 order by any_column_x;" Because oracle gets first row then applies order by clause.

Method has the same erasure as another method in type

The problem is that Set<Integer> and Set<String> are actually treated as a Set from the JVM. Selecting a type for the Set (String or Integer in your case) is only syntactic sugar used by the compiler. The JVM can't distinguish between Set<String> and Set<Integer>.

show validation error messages on submit in angularjs

I found this fiddle which does a nifty trick to cause control validation.

Basically it declares a scope member submitted and sets it true when you click submit. The model error binding use this extra expression to show the error message like

submitted &&$error.required


As pointed out in @Hafez's comment (give him some upvotes!), the Angular 1.3+ solution is simply:

form.$submitted &&$error.required

How can I make a CSS glass/blur effect work for an overlay?

I was able to piece together information from everyone here and further Googling, and I came up with the following which works in Chrome and Firefox: I'm still working on making this work for IE and Opera.

The key is putting the content inside of the div to which the filter is applied:

<div id="mask">
    <p>Lorem ipsum ...</p>
    <img src="" />

And then the CSS:

body {
    background: #300000;
    background: linear-gradient(45deg, #300000, #000000, #300000, #000000);
    color: white;
#mask {
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    background-color: black;
    opacity: 0.5;
img {
    filter: blur(10px);
    -webkit-filter: blur(10px);
    -moz-filter: blur(10px);
    -o-filter: blur(10px);
    -ms-filter: blur(10px);
    position: absolute;
    left: 100px;
    top: 100px;
    height: 300px;
    width: auto;

So mask has the filters applied. Also, note the use of url() for a filter with an <svg> tag for the value -- that idea came from If you happen to minify your CSS, you might need to replace any spaces in the SVG filter markup with "%20".

So now, everything inside the mask div is blurred.

jQuery - hashchange event

I think Chris Coyier has solution for that hashing problem, have a look at his screencast:

Best Practices with Dynamic Content

Issue with background color in JavaFX 8

Try this one in your css document,

-fx-background-color : #ffaadd;


-fx-base : #ffaadd; 

Also, you can set background color on your object with this code directly.

yourPane.setBackground(new Background(new BackgroundFill(Color.DARKGREEN, CornerRadii.EMPTY, Insets.EMPTY)));

How to custom switch button?

You can use Android Material Components.

enter image description here


implementation ''



            android:text="One way trip" />

            android:text="Round trip" />


How to make Sonar ignore some classes for codeCoverage metric?

I am able to achieve the necessary code coverage exclusions by updating jacoco-maven-plugin configuration in pom.xml


this configuration excludes the and in the jacoco coverage.

And the following two lines does the same for sonar coverage .

    <sonar.exclusions> **/*GlobalExceptionHandler*.*, **/*ErrorResponse*.</sonar.exclusions>
        <sonar.coverage.exclusions> **/*GlobalExceptionHandler*.*, **/*ErrorResponse*.* </sonar.coverage.exclusions>

Can't push image to Amazon ECR - fails with "no basic auth credentials"

I ran into this issue as well running on OSX. I saw Oliver Salzburg's response and checked my ~/.docker/config.json. It had multiple authorization credentials inside it from the different AWS accounts I have. I deleted the file and after running get-login again it worked.

Java: How to convert String[] to List or Set

Whilst this isn't strictly an answer to this question I think it's useful.

Arrays and Collections can bother be converted to Iterable which can avoid the need for performing a hard conversion.

For instance I wrote this to join lists/arrays of stuff into a string with a seperator

public static <T> String join(Iterable<T> collection, String delimiter) {
    Iterator<T> iterator = collection.iterator();
    if (!iterator.hasNext())
        return "";

    StringBuilder builder = new StringBuilder();

    T thisVal =;
    builder.append(thisVal == null? "": thisVal.toString());

    while (iterator.hasNext()) {
        thisVal =;
        builder.append(thisVal == null? "": thisVal.toString());

    return builder.toString();

Using iterable means you can either feed in an ArrayList or similar aswell as using it with a String... parameter without having to convert either.

How to count occurrences of a column value efficiently in SQL?

This should work:

SELECT age, count(age) 
  FROM Students 
 GROUP by age

If you need the id as well you could include the above as a sub query like so:

SELECT, S.age, C.cnt
  FROM Students  S
       INNER JOIN (SELECT age, count(age) as cnt
                     FROM Students 
                    GROUP BY age) C ON S.age = C.age

How long do browsers cache HTTP 301s?

as answer of @thomasrutter

If you previously issued a 301 redirect but want to un-do that

If people still have the cached 301 redirect in their browser they will continue to be taken to the target page regardless of whether the source page still has the redirect in place. Your options for fixing this include:

The simplest and best solution is to issue another 301 redirect back again.

The browser will realise it is being directed back to what it previously thought was a decommissioned URL, and this should cause it re-fetch that URL again to confirm that the old redirect isn't still there.

If you don't have control over the site where the previous redirect target went to, then you are outta luck. Try and beg the site owner to redirect back to you.

In fact, this means:

  1. 301 to

  2. delete 's 301

  3. add 301 to

Then it works.

Deploying just HTML, CSS webpage to Tomcat

If you want to create a .war file you can deploy to a Tomcat instance using the Manager app, create a folder, put all your files in that folder (including an index.html file) move your terminal window into that folder, and execute the following command:

zip -r <AppName>.war *

I've tested it with Tomcat 8 on the Mac, but it should work anywhere

How can I get dictionary key as variable directly in Python (not by searching from value)?

You can do this by casting the dict keys and values to list. It can also be be done for items.


f = {'one': 'police', 'two': 'oranges', 'three': 'car'}
list(f.keys())[0] = 'one'
list(f.keys())[1] = 'two'

list(f.values())[0] = 'police'
list(f.values())[1] = 'oranges'

Node.js: Difference between req.query[] and req.params

Given this route

app.get('/hi/:param1', function(req,res){} );

and given this URL

You will have:


  qs1: 'you',
  qs2: 'tube'


  param1: 'there'

Express req.params >>