Programs & Examples On #Textpad

TextPad is a general-purpose text editor.

Regular expression to search multiple strings (Textpad)

If I understand what you are asking, it is a regular expression like this:


This matches the three sets of digit strings at beginning of line only.

Objects inside objects in javascript

You may have as many levels of Object hierarchy as you want, as long you declare an Object as being a property of another parent Object. Pay attention to the commas on each level, that's the tricky part. Don't use commas after the last element on each level:

{el1, el2, {el31, el32, el33}, {el41, el42}}

var MainObj = {_x000D_
  prop1: "prop1MainObj",_x000D_
  Obj1: {_x000D_
    prop1: "prop1Obj1",_x000D_
    prop2: "prop2Obj1",    _x000D_
    Obj2: {_x000D_
      prop1: "hey you",_x000D_
      prop2: "prop2Obj2"_x000D_
  Obj3: {_x000D_
    prop1: "prop1Obj3",_x000D_
    prop2: "prop2Obj3"_x000D_
  Obj4: {_x000D_
    prop1: true,_x000D_
    prop2: 3_x000D_
  }  _x000D_

Error resolving template "index", template might not exist or might not be accessible by any of the configured Template Resolvers

If you are facing this issue and everything looks good, try invalidate cache/restart from your IDE. This will resolve the issue in most of the cases.

The most efficient way to implement an integer based power function pow(int, int)

In addition to the answer by Elias, which causes Undefined Behaviour when implemented with signed integers, and incorrect values for high input when implemented with unsigned integers,

here is a modified version of the Exponentiation by Squaring that also works with signed integer types, and doesn't give incorrect values:

#include <stdint.h>

#define SQRT_INT64_MAX (INT64_C(0xB504F333))

int64_t alx_pow_s64 (int64_t base, uint8_t exp)
    int_fast64_t    base_;
    int_fast64_t    result;

    base_   = base;

    if (base_ == 1)
        return  1;
    if (!exp)
        return  1;
    if (!base_)
        return  0;

    result  = 1;
    if (exp & 1)
        result *= base_;
    exp >>= 1;
    while (exp) {
        if (base_ > SQRT_INT64_MAX)
            return  0;
        base_ *= base_;
        if (exp & 1)
            result *= base_;
        exp >>= 1;

    return  result;

Considerations for this function:

(1 ** N) == 1
(N ** 0) == 1
(0 ** 0) == 1
(0 ** N) == 0

If any overflow or wrapping is going to take place, return 0;

I used int64_t, but any width (signed or unsigned) can be used with little modification. However, if you need to use a non-fixed-width integer type, you will need to change SQRT_INT64_MAX by (int)sqrt(INT_MAX) (in the case of using int) or something similar, which should be optimized, but it is uglier, and not a C constant expression. Also casting the result of sqrt() to an int is not very good because of floating point precission in case of a perfect square, but as I don't know of any implementation where INT_MAX -or the maximum of any type- is a perfect square, you can live with that.

String or binary data would be truncated. The statement has been terminated

The maximal length of the target column is shorter than the value you try to insert.

Rightclick the table in SQL manager and go to 'Design' to visualize your table structure and column definitions.


Try to set a length on your nvarchar inserts thats the same or shorter than whats defined in your table.

Difference between static class and singleton pattern?

Example with a static class

public class Any {

    private static Any instance = new Any();

    private Singleton() {

with singleton patterns only exist one instance:

public class Singleton {

    private static Singleton instance = new Singleton();

    private Singleton() {
        if (instance != null) {
            throw new RuntimeException("Imposible create a new instance ");

How can I adjust DIV width to contents

I'd like to add to the other answers this pretty new solution:

If you don't want the element to become inline-block, you can do this:

  width: min-content;

The support is increasing fast, so when edge decides to implement it, it will be really great:

Google Script to see if text contains a value

Google Apps Script is javascript, you can use all the string methods...

var grade = itemResponse.getResponse();
if(grade.indexOf("9th")>-1){do something }

You can find doc on many sites, this one for example.

What is JAVA_HOME? How does the JVM find the javac path stored in JAVA_HOME?

JVM does not find java.exe. It doesn't even call it. java.exe is called by the operating system (Windows in this case).

JAVA_HOME is just a convention, usually used by Tomcat, other Java EE app servers and build tools such as Gradle to find where Java lives.

The important thing from your point of view is that the Java /bin directory be on your PATH so Windows can find the .exe tools that ship with the JDK: javac.exe, java.exe, jar.exe, etc.

How to declare and use 1D and 2D byte arrays in Verilog?

In addition to Marty's excellent Answer, the SystemVerilog specification offers the byte data type. The following declares a 4x8-bit variable (4 bytes), assigns each byte a value, then displays all values:

module tb;

byte b [4];

initial begin
    foreach (b[i]) b[i] = 1 << i;
    foreach (b[i]) $display("Address = %0d, Data = %b", i, b[i]);


This prints out:

Address = 0, Data = 00000001
Address = 1, Data = 00000010
Address = 2, Data = 00000100
Address = 3, Data = 00001000

This is similar in concept to Marty's reg [7:0] a [0:3];. However, byte is a 2-state data type (0 and 1), but reg is 4-state (01xz). Using byte also requires your tool chain (simulator, synthesizer, etc.) to support this SystemVerilog syntax. Note also the more compact foreach (b[i]) loop syntax.

The SystemVerilog specification supports a wide variety of multi-dimensional array types. The LRM can explain them better than I can; refer to IEEE Std 1800-2005, chapter 5.

SQL Server - An expression of non-boolean type specified in a context where a condition is expected, near 'RETURN'

That is invalid syntax. You are mixing relational expressions with scalar operators (OR). Specifically you cannot combine expr IN (select ...) OR (select ...). You probably want expr IN (select ...) OR expr IN (select ...). Using union would also work: expr IN (select... UNION select...)

How can I hide the Adobe Reader toolbar when displaying a PDF in the .NET WebBrowser control?

It appears the default setting for Adobe Reader X is for the toolbars not to be shown by default unless they are explicitly turned on by the user. And even when I turn them back on during a session, they don't show up automatically next time. As such, I suspect you have a preference set contrary to the default.

The state you desire, with the top and left toolbars not shown, is called "Read Mode". If you right-click on the document itself, and then click "Page Display Preferences" in the context menu that is shown, you'll be presented with the Adobe Reader Preferences dialog. (This is the same dialog you can access by opening the Adobe Reader application, and selecting "Preferences" from the "Edit" menu.) In the list shown in the left-hand column of the Preferences dialog, select "Internet". Finally, on the right, ensure that you have the "Display in Read Mode by default" box checked:

   Adobe Reader Preferences dialog

You can also turn off the toolbars temporarily by clicking the button at the right of the top toolbar that depicts arrows pointing to opposing corners:

   Adobe Reader Read Mode toolbar button

Finally, if you have "Display in Read Mode by default" turned off, but want to instruct the page you're loading not to display the toolbars (i.e., override the user's current preferences), you can append the following to the URL:


So, for example, the following code will disable both the top toolbar (called "toolbar") and the left-hand toolbar (called "navpane"). However, if the user knows the keyboard combination (F8, and perhaps other methods as well), they will still be able to turn them back on.

string url = @"";

You can read more about the parameters that are available for customizing the way PDF files open here on Adobe's developer website.

trying to animate a constraint in swift

It's very important to point out that view.layoutIfNeeded() applies to the view subviews only.

Therefore to animate the view constraint, it is important to call it on the view-to-animate superview as follows:

    topConstraint.constant = heightShift

    UIView.animate(withDuration: 0.3) {

        // request layout on the *superview*

An example for a simple layout as follows:

class MyClass {

    /// Container view
    let container = UIView()
        /// View attached to container
        let view = UIView()

    /// Top constraint to animate
    var topConstraint = NSLayoutConstraint()

    /// Create the UI hierarchy and constraints
    func createUI() {

        // Create the top constraint
        topConstraint = view.topAnchor.constraint(equalTo: container.topAnchor, constant: 0)

        view.translatesAutoresizingMaskIntoConstraints = false

        // Activate constaint(s)

    /// Update view constraint with animation
    func updateConstraint(heightShift: CGFloat) {
        topConstraint.constant = heightShift

        UIView.animate(withDuration: 0.3) {

            // request layout on the *superview*

Simplest way to serve static data from outside the application server in a Java web application

Read the InputStream of a file and write it to ServletOutputStream for sending binary data to the client.

  • Local file You can read a file directly using FileInputStream('path/image.png').
  • Mongo DataBase file's you can get InputStream using GridFS.
public class URLStream extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public URLStream() {

    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        File source = new File("D:\\SVN_Commit.PNG");
        long start = System.nanoTime();

        InputStream image = new FileInputStream(source);

        /*String fileID = request.getParameter("id");
        System.out.println("Requested File ID : "+fileID);
        // Mongo DB GridFS -
        image = outputImageFile.getInputStream();*/

        if( image != null ) {
            BufferedInputStream bin = null;
            BufferedOutputStream bout = null;
            ServletOutputStream sos = response.getOutputStream();
            try {
                bin = new BufferedInputStream( image );
                bout = new BufferedOutputStream( sos );
                int ch =0; ;
                while((!=-1) {
            } finally {

        } else {
            PrintWriter writer = response.getWriter();
            writer.append("Something went wrong with your request.");
            System.out.println("Image not available.");
        System.out.println("Time taken by Stream Copy = "+(System.nanoTime()-start));

Result the URL directly to the src attibute.

<img src='' alt="mongodb File"/>
<img src='' alt="local file"/>

<video controls="controls" src=""></video>

UnicodeEncodeError: 'ascii' codec can't encode character u'\xa0' in position 20: ordinal not in range(128)

Update for python 3.0 and later. Try the following in the python editor:

locale-gen en_US.UTF-8
export LANG=en_US.UTF-8 LANGUAGE=en_US.en

This sets the system`s default locale encoding to the UTF-8 format.

More can be read here at PEP 538 -- Coercing the legacy C locale to a UTF-8 based locale.

database vs. flat files

Difference between database and flat files are given below:

  • Database provide more flexibility whereas flat file provide less flexibility.

  • Database system provide data consistency whereas flat file can not provide data consistency.

  • Database is more secure over flat files.
  • Database support DML and DDL whereas flat files can not support these.

  • Less data redundancy in database whereas more data redundancy in flat files.

Javascript Drag and drop for touch devices

I had the same solution as gregpress answer, but my draggable items used a class instead of an id. It seems to work.

var $target = $(;  
if( $target.hasClass('draggable') ) {  

How to keep :active css style after click a button


:active denotes the interaction state (so for a button will be applied during press), :focus may be a better choice here. However, the styling will be lost once another element gains focus.

The final potential alternative using CSS would be to use :target, assuming the items being clicked are setting routes (e.g. anchors) within the page- however this can be interrupted if you are using routing (e.g. Angular), however this doesnt seem the case here.

.active:active {_x000D_
  color: red;_x000D_
.focus:focus {_x000D_
  color: red;_x000D_
:target {_x000D_
  color: red;_x000D_
<button class='active'>Active</button>_x000D_
<button class='focus'>Focus</button>_x000D_
<a href='#target1' id='target1' class='target'>Target 1</a>_x000D_
<a href='#target2' id='target2' class='target'>Target 2</a>_x000D_
<a href='#target3' id='target3' class='target'>Target 3</a>

Javascript / jQuery

As such, there is no way in CSS to absolutely toggle a styled state- if none of the above work for you, you will either need to combine with a change in your HTML (e.g. based on a checkbox) or programatically apply/remove a class using e.g. jQuery

$('button').on('click', function(){_x000D_
<script src=""></script>_x000D_

How to print full stack trace in exception?

Recommend to use LINQPad related nuget package, then you can use exceptionInstance.Dump().

enter image description here

For .NET core:

  • Install LINQPad.Runtime

For .NET framework 4 etc.

  • Install LINQPad

Sample code:

using System;
using LINQPad;

namespace csharp_Dump_test
    public class Program
        public static void Main()
            catch (Exception ex)

        private static void dosome()
            throw new Exception("Unable.");

Running result: enter image description here

LinqPad nuget package is the most awesome tool for printing exception stack information. May it be helpful for you.

How do I position one image on top of another in HTML?

Here's code that may give you ideas:

.containerdiv { float: left; position: relative; } 
.cornerimage { position: absolute; top: 0; right: 0; } 

<div class="containerdiv">
    <img border="0" src="" alt=""">
    <img class="cornerimage" border="0" src="" alt="">


I suspect that Espo's solution may be inconvenient because it requires you to position both images absolutely. You may want the first one to position itself in the flow.

Usually, there is a natural way to do that is CSS. You put position: relative on the container element, and then absolutely position children inside it. Unfortunately, you cannot put one image inside another. That's why I needed container div. Notice that I made it a float to make it autofit to its contents. Making it display: inline-block should theoretically work as well, but browser support is poor there.

EDIT: I deleted size attributes from the images to illustrate my point better. If you want the container image to have its default sizes and you don't know the size beforehand, you cannot use the background trick. If you do, it is a better way to go.

What is &amp used for

HTML doesn't recognize the & but it will recognize &amp; because it is equal to & in HTML

I looked over this post someone had made:

What does if __name__ == "__main__": do?

if __name__ = "__main__" means that if you are running the python file normally like python it will assign the special variable __name__ to "__main__" but if you are importing the file like "import foo" it will assign __name__ to "foo" and will not run the function.

shell script to remove a file if it already exist

if [ $( ls <file> ) ]; then rm <file>; fi

Also, if you redirect your output with > instead of >> it will overwrite the previous file

Get key and value of object in JavaScript?

Object.keys(top_brands).forEach(function(key) {
  var value = top_brands[key];
  // use "key" and "value" here...

Btw, note that Object.keys and forEach are not available in ancient browsers, but you should use some polyfill anyway.

angular 2 sort and filter

A pipe takes in data as input and transforms it to a desired output. Add this pipe file:orderby.ts inside your /app folder .


//The pipe class implements the PipeTransform interface's transform method that accepts an input value and an optional array of parameters and returns the transformed value.

import { Pipe,PipeTransform } from "angular2/core";

//We tell Angular that this is a pipe by applying the @Pipe decorator which we import from the core Angular library.


  //The @Pipe decorator takes an object with a name property whose value is the pipe name that we'll use within a template expression. It must be a valid JavaScript identifier. Our pipe's name is orderby.

  name: "orderby"

export class OrderByPipe implements PipeTransform {
  transform(array:Array<any>, args?) {

    // Check if array exists, in this case array contains articles and args is an array that has 1 element : !id

    if(array) {

      // get the first element

      let orderByValue = args[0]
      let byVal = 1

      // check if exclamation point 

      if(orderByValue.charAt(0) == "!") {

        // reverse the array

        byVal = -1
        orderByValue = orderByValue.substring(1)

      array.sort((a: any, b: any) => {
        if(a[orderByValue] < b[orderByValue]) {
          return -1*byVal;
        } else if (a[orderByValue] > b[orderByValue]) {
          return 1*byVal;
        } else {
          return 0;
      return array;

In your component file (app.component.ts) import the pipe that you just added using: import {OrderByPipe} from './orderby';

Then, add *ngFor="#article of articles | orderby:'id'" inside your template if you want to sort your articles by id in ascending order or orderby:'!id'" in descending order.

We add parameters to a pipe by following the pipe name with a colon ( : ) and then the parameter value

We must list our pipe in the pipes array of the @Component decorator. pipes: [ OrderByPipe ] .


import {Component, OnInit} from 'angular2/core';
import {OrderByPipe} from './orderby';

    selector: 'my-app',
    template: `
      <h2>orderby-pipe by N2B</h2>
      <p *ngFor="#article of articles | orderby:'id'">
        Article title : {{article.title}}
    pipes: [ OrderByPipe ]

export class AppComponent{
        this.articles = [
            id: 1,
            title: "title1"
            id: 2,
            title: "title2",


More info here on my github and this post on my website

Select distinct values from a table field

In addition to the still very relevant answer of jujule, I find it quite important to also be aware of the implications of order_by() on distinct("field_name") queries. This is, however, a Postgres only feature!

If you are using Postgres and if you define a field name that the query should be distinct for, then order_by() needs to begin with the same field name (or field names) in the same sequence (there may be more fields afterward).


When you specify field names, you must provide an order_by() in the QuerySet, and the fields in order_by() must start with the fields in distinct(), in the same order.

For example, SELECT DISTINCT ON (a) gives you the first row for each value in column a. If you don’t specify an order, you’ll get some arbitrary row.

If you want to e-g- extract a list of cities that you know shops in , the example of jujule would have to be adapted to this:

# returns an iterable Queryset of cities.
models.Shop.objects.order_by('city').values_list('city', flat=True).distinct('city')  

Format the date using Ruby on Rails

Once you have parsed the timestamp string and have a time object (see other answers for details), you can use Time.to_formatted_s from Rails. It has several formats built in that you can specify with symbols.


time =                     # => Thu Jan 18 06:10:17 CST 2007

time.to_formatted_s(:time)          # => "06:10"
time.to_s(:time)                    # => "06:10"

time.to_formatted_s(:db)            # => "2007-01-18 06:10:17"
time.to_formatted_s(:number)        # => "20070118061017"
time.to_formatted_s(:short)         # => "18 Jan 06:10"
time.to_formatted_s(:long)          # => "January 18, 2007 06:10"
time.to_formatted_s(:long_ordinal)  # => "January 18th, 2007 06:10"
time.to_formatted_s(:rfc822)        # => "Thu, 18 Jan 2007 06:10:17 -0600"

(Time.to_s is an alias)

You can also define your own formats - usually in an initializer (Thanks to Dave Newton for pointing this out). This is how it's done:

# config/initializers/time_formats.rb
Time::DATE_FORMATS[:month_and_year] = "%B %Y"
Time::DATE_FORMATS[:short_ordinal] = lambda { |time| time.strftime("%B #{}") }

Mac OS X - EnvironmentError: mysql_config not found

This answer is for MacOS users who did not install from brew but rather from the official .dmg/.pkg. That installer fails to edit your PATH, causing things to break out of the box:

  1. All MySQL commands like mysql, mysqladmin, mysql_config, etc cannot be found, and as a result:
  2. the "MySQL Preference Pane" fails to appear in System Preferences, and
  3. you cannot install any API that communicates with MySQL, including mysqlclient

What you have to do is appending the MySQL bin folder (typically /usr/local/mysql/bin in your PATH by adding this line in your ~/.bash_profile file:

export PATH="/usr/local/mysql/bin/:$PATH"

You should then reload your ~/.bash_profile for the change to take effect in your current Terminal session:

source ~/.bash_profile

Before installing mysqlclient, however, you need to accept the XcodeBuild license:

sudo xcodebuild -license

Follow their directions to sign away your family, after which you should be able to install mysqlclient without issue:

pip install mysqlclient

After installing that, you must do one more thing to fix a runtime bug that ships with MySQL (Dynamic Library libmysqlclient.dylib not found), by adding this line to your system dynamic libraries path:

export DYLD_LIBRARY_PATH=/usr/local/mysql/lib/:$DYLD_LIBRARY_PATH

Create a Path from String in Java7

From the javadocs..

Path p1 = Paths.get("/tmp/foo"); 

is the same as

Path p4 = FileSystems.getDefault().getPath("/tmp/foo");

Path p3 = Paths.get(URI.create("file:///Users/joe/"));

Path p5 = Paths.get(System.getProperty("user.home"),"logs", "foo.log"); 

In Windows, creates file C:\joe\logs\foo.log (assuming user home as C:\joe)
In Unix, creates file /u/joe/logs/foo.log (assuming user home as /u/joe)

Error: Argument is not a function, got undefined

Because this pops-up in Google when trying to find an answer to: "Error: Argument '' is not a function, got undefined".

It's possible that you are trying to create the same module twice.

The angular.module is a global place for creating, registering and retrieving AngularJS modules.

Passing one argument retrieves an existing angular.Module, whereas passing more than one argument creates a new angular.Module



angular.module('myApp', []) Is used to create a module without injecting any dependencies.

angular.module('myApp') (Without argument) is used to get an existing module.

ImportError: DLL load failed: The specified module could not be found

To make it short, it means that you lacked some "dependencies" for the libraries you wanted to use. Before trying to use any kind of library, first it is suggested to look up whether it needs another library in python "family". What do I mean?

Downloading "dlls" is something that I avoid. I had the same problem with another library "kivy". The problem occurred when I wanted to use Python 3.4v instead of 3.5 Everything was working correctly in 3.5 but I just wanted to use the stable version for kivy which is 3.4 as they officially "advise". So, I switched to 3.4 but then I had the very same "dll" error saying lots of things are missing. So I checked the website and learned that I needed to install extra "dependencies" from the official website of kivy, then the problem got solved.

Iterating through all the cells in Excel VBA or VSTO 2005

If you only need to look at the cells that are in use you can use:

sub IterateCells()

   For Each Cell in ActiveSheet.UsedRange.Cells
      'do some stuff

End Sub

that will hit everything in the range from A1 to the last cell with data (the bottom right-most cell)

What is a software framework?

Beyond definitions, which are sometimes understandable only if you already understand, an example helped me.

I think I got a glimmer of understanding when loooking at sorting a list in .Net; an example of a framework providing a functionality that's tailored by user code providing specific functionality. Take List.Sort(IComparer). The sort algorithm, which resides in the .Net framework in the Sort method, needs to do a series of compares; does object A come before or after object B? But Sort itself has no clue how to do the compare; only the type being sorted knows that. You couldn't write a comparison sort algorithm that can be reused by many users and anticipate all the various types you'd be called upon to sort. You've got to leave that bit of work up to the user itself. So here, sort, aka the framework, calls back to a method in the user code, the type being sorted so it can do the compare. (Or a delegate can be used; same point.)

Did I get this right?

How do I center content in a div using CSS?

Update 2020:

There are several options available*:

*Disclaimer: This list may not be complete.

Using Flexbox
Nowadays, we can use flexbox. It is quite a handy alternative to the css-transform option. I would use this solution almost always. If it is just one element maybe not, but for example if I had to support an array of data e.g. rows and columns and I want them to be relatively centered in the very middle.

.flexbox {
  display: flex;
  height: 100px;
  flex-flow: row wrap;
  align-items: center;
  justify-content: center;
  background-color: #eaeaea;
  border: 1px dotted #333;

.item {
  /* default => flex: 0 1 auto */
  background-color: #fff;
  border: 1px dotted #333;
  box-sizing: border-box;
<div class="flexbox">
  <div class="item">I am centered in the middle.</div>
  <div class="item">I am centered in the middle, too.</div>

Using CSS 2D-Transform
This is still a good option, was also the accepted solution back in 2015. It is very slim and simple to apply and does not mess with the layouting of other elements.

.boxes {
  position: relative;

.box {
  position: relative;
  display: inline-block;
  float: left;
  width: 200px;
  height: 200px;
  font-weight: bold;
  color: #333;
  margin-right: 10px;
  margin-bottom: 10px;
  background-color: #eaeaea;

.h-center {
  text-align: center;

.v-center span {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  transform: translate(0, -50%);
<div class="boxes">
  <div class="box h-center">horizontally centered lorem ipsun dolor sit amet</div>
  <div class="box v-center"><span>vertically centered lorem ipsun dolor sit amet lorem ipsun dolor sit amet</span></div>
  <div class="box h-center v-center"><span>horizontally and vertically centered lorem ipsun dolor sit amet</span></div>

Note: This does also work with :after and :before pseudo-elements.

Using Grid
This might just be an overkill, but it depends on your DOM. If you want to use grid anyway, then why not. It is very powerful alternative and you are really maximum flexible with the design.

Note: To align the items vertically we use flexbox in combination with grid. But we could also use display: grid on the items.

.grid {
  display: grid;
  width: 400px;
  grid-template-rows: 100px;
  grid-template-columns: 100px 100px 100px;
  grid-gap: 3px;
  align-items: center;
  justify-content: center;
  background-color: #eaeaea;
  border: 1px dotted #333;

.item {
  display: flex;
  justify-content: center;
  align-items: center;
  border: 1px dotted #333;
  box-sizing: border-box;

.item-large {
  height: 80px;
<div class="grid">
  <div class="item">Item 1</div>
  <div class="item item-large">Item 2</div>
  <div class="item">Item 3</div>

Further reading:

CSS article about grid
CSS article about flexbox
CSS article about centering without flexbox or grid

UITableViewCell Selected Background Color on Multiple Selection

For Swift 3,4 and 5 you can do this in two ways.

1) class: UITableViewCell

override func awakeFromNib() {
    //Costumize cell

    selectionStyle = .none


2) tableView cellForRowAt

    cell.selectionStyle = .none

If you want to set selection color for specific cell, check this answer: as modal popup?

A pop-up is a child of the parent window, but it is not a child of the parent DOCUMENT. It is its own independent browser window and is not contained by the parent.

Use an absolutely-positioned DIV and a translucent overlay instead.

EDIT - example

You need jQuery for this:

html, body {

#overlay { 


.dialog {
    border:2px solid #3366CC;

<script type="text/javascript">
$(document).ready(function() { init() })

function init() {
    $('#overlay').click(function() { closeDialog(); })

function openDialog(element) {
    //this is the general dialog handler.
    //pass the element name and this will copy
    //the contents of the element to the dialog box

    $('#overlay').css('height', $(document.body).height() + 'px')

function closeDialog() {

function centerMe(element) {
    //pass element name to be centered on screen
    var pWidth = $(window).width();
    var pTop = $(window).scrollTop()
    var eWidth = $(element).width()
    var height = $(element).height()
    $(element).css('top', '130px')
    $(element).css('left', parseInt((pWidth / 2) - (eWidth / 2)) + 'px')


<a href="javascript:;//close me" onclick="openDialog($('#content'))">show dialog A</a>

<a href="javascript:;//close me" onclick="openDialog($('#contentB'))">show dialog B</a>

<div id="dialog" class="dialog" style="display:none"></div>
<div id="overlay" style="display:none"></div>
<div id="content" style="display:none">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin nisl felis, placerat in sollicitudin quis, hendrerit vitae diam. Nunc ornare iaculis urna. 

<div id="contentB" style="display:none">
    Moooo mooo moo moo moo!!! 

How do I make a "div" button submit the form its sitting in?

To keep the scripting in one place rather than using onClick in the HTML tag, add the following code to your script block:

$('#id-of-the-button').click(function() {document.forms[0].submit()});

Which assumes you just have the one form on the page.

insert vertical divider line between two nested divs, not full height

Try this. I set the blue box to float right, gave left and right a fixed height, and added a white border on the right of the left div. Also added rounded corners to more match your example (These won't work in ie 8 or less). I also took out the position: relative. You don't need it. Block level elements are set to position relative by default.

See it here:

#left {
  float: left;
  width: 44%;
  margin: 0;
  padding: 0;
  border-right: 1px solid white;

#right {
  position: relative;
  float: right;
  width: 49%;
  margin: 0;
  padding: 0;

#blue_box {
  border-radius: 10px;
  -webkit-border-radius: 10px;
  width: 45%;
  min-width: 400px;
  max-width: 600px;
  padding: 2%;
  float: right;

Move_uploaded_file() function is not working

$move = "/Users/George/Desktop/uploads/".$_FILES['file']['name'];

That's one.

move_uploaded_file($_FILES['file']['tmp_name'], $move);

That's two.

Check if the uploads dir is writeable

That's three.

Return Values

Returns TRUE on success.

If filename is not a valid upload file, then no action will occur, and move_uploaded_file() will return FALSE.

If filename is a valid upload file, but cannot be moved for some reason, no action will occur, and move_uploaded_file() will return FALSE. Additionally, a warning will be issued.

Look at return value of the function.

That's it.

Delegates in swift?


I am explaining with example of Delegate with two viewControllers.In this case, SecondVC Object is sending data back to first View Controller.

Class with Protocol Declaration

protocol  getDataDelegate  {
    func getDataFromAnotherVC(temp: String)

import UIKit
class SecondVC: UIViewController {

    var delegateCustom : getDataDelegate?
    override func viewDidLoad() {

    override func didReceiveMemoryWarning() {
        // Dispose of any resources that can be recreated.
    @IBAction func backToMainVC(sender: AnyObject) {
      //calling method defined in first View Controller with Object  
      self.delegateCustom?.getDataFromAnotherVC(temp: "I am sending data from second controller to first view controller.Its my first delegate example. I am done with custom delegates.")

In First ViewController Protocol conforming is done here:

class ViewController: UIViewController, getDataDelegate

Protocol method definition in First View Controller(ViewController)

func getDataFromAnotherVC(temp : String)
  // dataString from SecondVC
   lblForData.text = dataString

During push the SecondVC from First View Controller (ViewController)

let objectPush = SecondVC()
objectPush.delegateCustom = self
self.navigationController.pushViewController(objectPush, animated: true)

.mp4 file not playing in chrome

This started out as an attempt to cast video from my pc to a tv (with subtitles) eventually using Chromecast. And I ended up in this "does not play mp4" situation. However I seemed to have proved that Chrome will play (exactly the same) mp4 as long as it isn't wrapped in html(5) So here is what I have constructed. I have made a webpage under localhost and in there is a default.htm which contains:-

<!DOCTYPE html>
<video  controls >
 <source src="sample.mp4" type="video/mp4">
 <track kind="subtitles" src="sample.vtt" label="gcsubs" srclang="eng">

the video and subtitle files are stored in the same folder as default.htm

I have the very latest version of Chrome (just updated this morning)

When I type the appropriate localhost... into my Chrome browser a black square appears with a "GO" arrow and an elapsed time bar, a mute button and an icon which says "CC". If I hit the go arrow, nothing happens (it doesn't change to "pause", the elapsed time doesn't move, and the timer sticks at 0:00. There are no error messages - nothing!

(note that if I input localhost.. to IE11 the video plays!!!!

In Chrome if I enter the disc address of sample.mp4 (i.e. C:\webstore\sample.mp4 then Chrome will play the video fine?.

This last bit is probably a working solution for Chromecast except that I cannot see any subtitles. I really want a solution with working subtitles. I just don't understand what is different in Chrome between the two methods of playing mp4

CSS-moving text from left to right

I like using the following to prevent things being outside my div elements. It helps with CSS rollovers too.


this will hide anything that moves/is outside of the div which will prevent the browser expanding and causing a scroll bar to appear.

Sorting Directory.GetFiles()

A more succinct VB.Net version, if anyone is interested

Dim filePaths As Linq.IOrderedEnumerable(Of IO.FileInfo) = _
  New DirectoryInfo("c:\temp").GetFiles() _
   .OrderBy(Function(f As FileInfo) f.CreationTime)
For Each fi As IO.FileInfo In filePaths
  ' Do whatever you wish here

How to select the first, second, or third element with a given class name?

Use CSS nth-child with the prefix class name

div.myclass:nth-child(1) {
  color: #000;

div.myclass:nth-child(2) {
  color: #FFF;

div.myclass:nth-child(3) {
  color: #006;

returning a Void object

If you just don't need anything as your type, you can use void. This can be used for implementing functions, or actions. You could then do something like this:

interface Action<T> {
    public T execute();

abstract class VoidAction implements Action<Void> {
    public Void execute() {
        return null;

    abstract void executeInternal();

Or you could omit the abstract class, and do the return null in every action that doesn't require a return value yourself.

You could then use those actions like this:

Given a method

private static <T> T executeAction(Action<T> action) {
    return action.execute();

you can call it like

String result = executeAction(new Action<String>() {
    public String execute() {
        //code here
        return "Return me!";

or, for the void action (note that you're not assigning the result to anything)

executeAction(new VoidAction() {
    public void executeInternal() {
        //code here

How to avoid HTTP error 429 (Too Many Requests) python

Writing this piece of code fixed my problem:

requests.get(link, headers = {'User-agent': 'your bot 0.1'})

Gaussian filter in MATLAB

In MATLAB R2015a or newer, it is no longer necessary (or advisable from a performance standpoint) to use fspecial followed by imfilter since there is a new function called imgaussfilt that performs this operation in one step and more efficiently.

The basic syntax:

B = imgaussfilt(A,sigma) filters image A with a 2-D Gaussian smoothing kernel with standard deviation specified by sigma.

The size of the filter for a given Gaussian standard deviation (sigam) is chosen automatically, but can also be specified manually:

B = imgaussfilt(A,sigma,'FilterSize',[3 3]);

The default is 2*ceil(2*sigma)+1.

Additional features of imgaussfilter are ability to operate on gpuArrays, filtering in frequency or spacial domain, and advanced image padding options. It looks a lot like IPP... hmmm. Plus, there's a 3D version called imgaussfilt3.

How to properly assert that an exception gets raised in pytest?

Have you tried to remove "pytrace=True" ?, pytrace=True) # before # after

Have you tried to run with '--fulltrace' ?

How to properly add include directories with CMake

First, you use include_directories() to tell CMake to add the directory as -I to the compilation command line. Second, you list the headers in your add_executable() or add_library() call.

As an example, if your project's sources are in src, and you need headers from include, you could do it like this:



Java Could not reserve enough space for object heap error

If you go thru this IBM link on java, it says that on 32 bit windows the recommended heap size is 1.5 GB and the Maximum heap size is 1.8 GB. So your jvm does not gets initialized for -Xmx2G and above.

Also if you go thru this SO answer, clearly the DLL bindings are an issue for memory reservation changing which is no trivial task. Hence what may be recommended is that you go for 64-bit Windows and a 64-bit JVM. while it will chew up more RAM, you will have much more contiguous virtual address space.

How to access SVG elements with Javascript

Is it possible to do it this way, as opposed to using something like Raphael or jQuery SVG?


If it is possible, what's the technique?

This annotated code snippet works:

<!DOCTYPE html>
        <title>SVG Illustrator Test</title> 

        <object data="alpha.svg" type="image/svg+xml"
         id="alphasvg" width="100%" height="100%"></object>

            var a = document.getElementById("alphasvg");

            // It's important to add an load event listener to the object,
            // as it will load the svg doc asynchronously

                // get the inner DOM of alpha.svg
                var svgDoc = a.contentDocument;
                // get the inner element by id
                var delta = svgDoc.getElementById("delta");
                // add behaviour
                        alert('hello world!')
                }, false);
            }, false);

Note that a limitation of this technique is that it is restricted by the same-origin policy, so alpha.svg must be hosted on the same domain as the .html file, otherwise the inner DOM of the object will be inaccessible.

Important thing to run this HTML, you need host HTML file to web server like IIS, Tomcat

The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'NTLM'

I had the same problem, to solve it set specific user from domain in iis -> action sidebar->Basic Settings -> Connect as... -> specific user

enter image description here

How do you create nested dict in Python?

If you want to create a nested dictionary given a list (arbitrary length) for a path and perform a function on an item that may exist at the end of the path, this handy little recursive function is quite helpful:

def ensure_path(data, path, default=None, default_func=lambda x: x):

    - Ensures a path exists within a nested dictionary


    - `data`:
        - Type: dict
        - What: A dictionary to check if the path exists
    - `path`:
        - Type: list of strs
        - What: The path to check


    - `default`:
        - Type: any
        - What: The default item to add to a path that does not yet exist
        - Default: None

    - `default_func`:
        - Type: function
        - What: A single input function that takes in the current path item (or default) and adjusts it
        - Default: `lambda x: x` # Returns the value in the dict or the default value if none was present
    if len(path)>1:
        if path[0] not in data:
        data[path[0]]=ensure_path(data=data[path[0]], path=path[1:], default=default, default_func=default_func)
        if path[0] not in data:
    return data


ensure_path(data=data, path=['a','c'], default=[1])
print(data) #=> {'a':{'b':1, 'c':[1]}}
ensure_path(data=data, path=['a','c'], default=[1], default_func=lambda x:x+[2])
print(data) #=> {'a': {'b': 1, 'c': [1, 2]}}

Read a zipped file as a pandas DataFrame

It seems you don't even have to specify the compression any more. The following snippet loads the data from into df.

import pandas as pd
df = pd.read_csv('')

(Of course you will need to specify separator, header, etc. if they are different from the defaults.)

Finding non-numeric rows in dataframe in pandas?

Sorry about the confusion, this should be the correct approach. Do you want only to capture 'bad' only, not things like 'good'; Or just any non-numerical values?

np.where(np.any(np.isnan(df.convert_objects(convert_numeric=True)), axis=1))

MYSQL order by both Ascending and Descending sorting

I don't understand what the meaning of ordering with the same column ASC and DESC in the same ORDER BY, but this how you can do it: naam DESC, naam ASC like so:

ORDER BY `product_category_id` DESC,`naam` DESC, `naam` ASC

htaccess redirect all pages to single page

If your aim is to redirect all pages to a single maintenance page (as the title could suggest also this), then use:

RewriteEngine on
RewriteCond %{REQUEST_URI} !/maintenance.php$ 
RewriteCond %{REMOTE_HOST} !^000\.000\.000\.000
RewriteRule $ /maintenance.php [R=302,L] 

Where 000 000 000 000 should be replaced by your ip adress.


Detect if checkbox is checked or unchecked in Angular.js ng-change event

You could just use the bound ng-model (answers[item.questID]) value itself in your ng-change method to detect if it has been checked or not.


<input type="checkbox" ng-model="answers[item.questID]" 
     ng-change="stateChanged(item.questID)" /> <!-- Pass the specific id -->


$scope.stateChanged = function (qId) {
   if($scope.answers[qId]){ //If it is checked

Check if number is decimal

$lat = '-25.3654';

if(preg_match('/./',$lat)) {
    echo "\nYes its a decimal value\n";
    echo 'No its not a decimal value';

How to move a git repository into another directory and make that directory a git repository?

It's even simpler than that. Just did this (on Windows, but it should work on other OS):

  1. Create newrepo.
  2. Move gitrepo1 into newrepo.
  3. Move .git from gitrepo1 to newrepo (up one level).
  4. Commit changes (fix tracking as required).

Git just sees you added a directory and renamed a bunch of files. No biggie.

Can constructors throw exceptions in Java?


If the constructor doesn't receive valid input, or can't construct the object in a valid manner, it has no other option but to throw an exception and alert its caller.

How to deal with page breaks when printing a large HTML table

I ended up following @vicenteherrera's approach, with some tweaks (that are possibly bootstrap 3 specific).

Basically; we can't break trs, or tds because they're not block-level elements. So we embed divs into each, and apply our page-break-* rules against the div. Secondly; we add some padding to the top of each of these divs, to compensate for any styling artifacts.

    @media print {
        /* avoid cutting tr's in half */
        th div, td div {
        // Wrap each tr and td's content within a div
        // (todo: add logic so we only do this when printing)
        $("table tbody th, table tbody td").wrapInner("<div></div>");

The margin and padding adjustments were necessary to offset some kind of jitter that was being introduced (by my guess - from bootstrap). I'm not sure that I'm presenting any new solution from the other answers to this question, but I figure maybe this will help someone.

How would I get a cron job to run every 30 minutes?

crontab does not understand "intervals", it only understands "schedule"

valid hours: 0-23 -- valid minutes: 0-59

example #1

30 * * * * your_command

this means "run when the minute of each hour is 30" (would run at: 1:30, 2:30, 3:30, etc)

example #2

*/30 * * * * your_command

this means "run when the minute of each hour is evenly divisible by 30" (would run at: 1:30, 2:00, 2:30, 3:00, etc)

example #3

0,30 * * * * your_command

this means "run when the minute of each hour is 0 or 30" (would run at: 1:30, 2:00, 2:30, 3:00, etc)

it's another way to accomplish the same results as example #2

example #4

19 * * * * your_command

this means "run when the minute of each hour is 19" (would run at: 1:19, 2:19, 3:19, etc)

example #5

*/19 * * * * your_command

this means "run when the minute of each hour is evenly divisible by 19" (would run at: 1:19, 1:38, 1:57, 2:19, 2:38, 2:57 etc)

note: several refinements have been made to this post by various users including the author

Flutter - Wrap text on overflow, like insert ellipsis or fade

I think the parent Container needs to be given a maxWidth of the proper size. It looks like the Text box will fill whatever space it is given above.

How to read numbers from file in Python?

To me this kind of seemingly simple problem is what Python is all about. Especially if you're coming from a language like C++, where simple text parsing can be a pain in the butt, you'll really appreciate the functionally unit-wise solution that python can give you. I'd keep it really simple with a couple of built-in functions and some generator expressions.

You'll need open(name, mode), myfile.readlines(), mystring.split(), int(myval), and then you'll probably want to use a couple of generators to put them all together in a pythonic way.

# This opens a handle to your file, in 'r' read mode
file_handle = open('mynumbers.txt', 'r')
# Read in all the lines of your file into a list of lines
lines_list = file_handle.readlines()
# Extract dimensions from first line. Cast values to integers from strings.
cols, rows = (int(val) for val in lines_list[0].split())
# Do a double-nested list comprehension to get the rest of the data into your matrix
my_data = [[int(val) for val in line.split()] for line in lines_list[1:]]

Look up generator expressions here. They can really simplify your code into discrete functional units! Imagine doing the same thing in 4 lines in C++... It would be a monster. Especially the list generators, when I was I C++ guy I always wished I had something like that, and I'd often end up building custom functions to construct each kind of array I wanted.

Why doesn't Java allow overriding of static methods?

What good will it do to override static methods. You cannot call static methods through an instance.

MySubClass.static1()   // If you overrode, you have to call it through MySubClass anyway.

EDIT : It appears that through an unfortunate oversight in language design, you can call static methods through an instance. Generally nobody does that. My bad.

Insert a line at specific line number with sed or awk

POSIX sed (and for example OS X's sed, the sed below) require i to be followed by a backslash and a newline. Also at least OS X's sed does not include a newline after the inserted text:

$ seq 3|gsed '2i1.5'
$ seq 3|sed '2i1.5'
sed: 1: "2i1.5": command i expects \ followed by text
$ seq 3|sed $'2i\\\n1.5'
$ seq 3|sed $'2i\\\n1.5\n'

To replace a line, you can use the c (change) or s (substitute) commands with a numeric address:

$ seq 3|sed $'2c\\\n1.5\n'
$ seq 3|gsed '2c1.5'
$ seq 3|sed '2s/.*/1.5/'

Alternatives using awk:

$ seq 3|awk 'NR==2{print 1.5}1'
$ seq 3|awk '{print NR==2?1.5:$0}'

awk interprets backslashes in variables passed with -v but not in variables passed using ENVIRON:

$ seq 3|awk -v v='a\ba' '{print NR==2?v:$0}'
$ seq 3|v='a\ba' awk '{print NR==2?ENVIRON["v"]:$0}'

Both ENVIRON and -v are defined by POSIX.

How to calculate distance from Wifi router using Signal Strength?

In general, this is a really bad way of doing things due to multipath interference. This is definitely more of an RF engineering question than a coding one.

Tl;dr, the wifi RF energy gets scattered in different directions after bouncing off walls, people, the floor etc. There's no way of telling where you are by trianglation alone, unless you're in an empty room with the wifi beacons placed in exactly the right place.

Google is able to get away with this because they essentially can map where every wifi SSID is to a GPS location when any android user (who opts in to their service) walks into range. That way, the next time a user walks by there, even without a perfect GPS signal, the google mothership can tell where you are. Typically, they'll use that in conjunction with a crappy GPS signal.

What I have seen done is a grid of Zigbee or BTLE devices. If you know where these are laid out, you can used the combined RSS to figure out relatively which ones you're closest to, and go from there.

How to determine total number of open/active connections in ms sql server 2005

I know this is old, but thought it would be a good idea to update. If an accurate count is needed, then column ECID should probably be filtered as well. A SPID with parallel threads can show up multiple times in sysprocesses and filtering ECID=0 will return the primary thread for each SPID.

    DB_NAME(dbid) as DBName, 
    COUNT(dbid) as NumberOfConnections,
    loginame as LoginName
    sys.sysprocesses with (nolock)
    dbid > 0
    and ecid=0
    dbid, loginame

jQuery - multiple $(document).ready ...?

All will get executed and On first Called first run basis!!

<div id="target"></div>

    jQuery('#target').append('target edit 1<br>');
    jQuery('#target').append('target edit 2<br>');
    jQuery('#target').append('target edit 3<br>');

Demo As you can see they do not replace each other

Also one thing i would like to mention

in place of this


you can use this shortcut

   //dom ready codes

See full command of running/stopped container in Docker

Moving Dylan's comment into a full-blown answer because TOO USEFUL:

docker run --rm -v /var/run/docker.sock:/var/run/docker.sock assaflavie/runlike YOUR-CONTAINER

What does it do? Runs inside a container, gets you the complete docker run command, then removes the container for you.

Python error message io.UnsupportedOperation: not readable

This will let you read, write and create the file if it don't exist:

f = open('filename.txt','a+')
f = open('filename.txt','r+')

Often used commands:

f.readline() #Read next line #Jump to beginning #Read all file
f.write('test text') #Write 'test text' to file
f.close() #Close file

How to sum the values of a JavaScript object?

Sum the object key value by parse Integer. Converting string format to integer and summing the values

var obj = {
  pay: 22
var x = parseInt(;
console.log(x + 20);

How do I make a redirect in PHP?

1. Using header, a built-in PHP function

a) Simple redirect without parameters

   header('Location: index.php');

b) Redirect with GET parameters

      $id = 2;
      header("Location: index.php?id=$id&msg=succesfully redirect");

2. Redirect with JavaScript in PHP

a) Simple redirect without parameters

     echo "<script>location.href='index.php';</script>";

b) Redirect with GET parameters

     $id = 2;
     echo "<script>location.href='index.php?id=$id&msg=succesfully redirect';</script>";

Catching errors in Angular HttpClient

For Angular 6+ , .catch doesn't work directly with Observable. You have to use


Below code:

import { IEmployee } from './interfaces/employee';
import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';

  providedIn: 'root'
export class EmployeeService {

  private url = '/assets/data/employee.json';

  constructor(private http: HttpClient) { }

  getEmployees(): Observable<IEmployee[]> {
    return this.http.get<IEmployee[]>(this.url)
                    .pipe(catchError(this.errorHandler));  // catch error

  /** Error Handling method */

  errorHandler(error: HttpErrorResponse) {
    if (error.error instanceof ErrorEvent) {
      // A client-side or network error occurred. Handle it accordingly.
      console.error('An error occurred:', error.error.message);
    } else {
      // The backend returned an unsuccessful response code.
      // The response body may contain clues as to what went wrong,
        `Backend returned code ${error.status}, ` +
        `body was: ${error.error}`);
    // return an observable with a user-facing error message
    return throwError(
      'Something bad happened; please try again later.');

For more details, refer to the Angular Guide for Http

Need to find element in selenium by css

Only using class names is not sufficient in your case.

  • By.cssSelector(".ban") has 15 matching nodes
  • By.cssSelector(".hot") has 11 matching nodes
  • By.cssSelector("") has 5 matching nodes

Therefore you need more restrictions to narrow it down. Option 1 and 2 below are available for css selector, 1 might be the one that suits your needs best.

Option 1: Using list items' index (CssSelector or XPath)


  • Not stable enough if site's structure changes


driver.FindElement(By.CssSelector("#rightbar > .menu > li:nth-of-type(3) > h5"));

Option 2: Using Selenium's FindElements, then index them. (CssSelector or XPath)


  • Not stable enough if site's structure changes
  • Not the native selector's way


// note that By.CssSelector("") and //*[contains(@class, 'ban hot')] are different, but doesn't matter in your case
IList<IWebElement> hotBanners = driver.FindElements(By.CssSelector(""));
IWebElement banUsStates = hotBanners[3];

Option 3: Using text (XPath only)


  • Not for multilanguage sites
  • Only for XPath, not for Selenium's CssSelector


driver.FindElement(By.XPath("//h5[contains(@class, 'ban hot') and text() = 'us states']"));

Option 4: Index the grouped selector (XPath only)


  • Not stable enough if site's structure changes
  • Only for XPath, not CssSelector


driver.FindElement(By.XPath("(//h5[contains(@class, 'ban hot')])[3]"));

Option 5: Find the hidden list items link by href, then traverse back to h5 (XPath only)


  • Only for XPath, not CssSelector
  • Low performance
  • Tricky XPath


driver.FindElement(By.XPath(".//li[.//ul/li/a[contains(@href, '')]]/h5"));

Accessing a local website from another computer inside the local network in IIS 7

do not turn off firewall, Go Control Panel\System and Security\Windows Firewall then Advanced settings then Inbound Rules->From right pan choose New Rule-> Port-> TCP and type in port number 80 then give a name in next window, that's it.

Jquery mouseenter() vs mouseover()

You see the behavior when your target element contains child elements:

Each time your mouse enters or leaves a child element, mouseover is triggered, but not mouseenter.

$('#my_div').bind("mouseover mouseenter", function(e) {_x000D_
  var el = $("#" + e.type);_x000D_
  var n = +el.text();_x000D_
#my_div {_x000D_
  padding: 0 20px 20px 0;_x000D_
  background-color: #eee;_x000D_
  margin-bottom: 10px;_x000D_
  width: 90px;_x000D_
  overflow: hidden;_x000D_
#my_div>div {_x000D_
  float: left;_x000D_
  margin: 20px 0 0 20px;_x000D_
  height: 25px;_x000D_
  width: 25px;_x000D_
  background-color: #aaa;_x000D_
<script src=""></script>_x000D_
<div>MouseEnter: <span id="mouseenter">0</span></div>_x000D_
<div>MouseOver: <span id="mouseover">0</span></div>_x000D_
<div id="my_div">_x000D_

MVC web api: No 'Access-Control-Allow-Origin' header is present on the requested resource

I know that people will probably find this very obvious at first, but really think about this. This can often happen if you've done something wrong.

For instance, I've had this problem because I didn't add a host entry to my hosts file. The real problem was DNS resolution. Or I just got the base URL wrong.

Sometimes I get this error if the identity token came from one server, but I'm trying to use it on another.

Sometimes you'll get this error if you've got the resource wrong.

You might get this if you put the CORS middleware too late in the chain.

Can't install APK from browser downloads

It shouldn't be HTTP headers if the file has been downloaded successfully and it's the same file that you can open from OI.

A shot in the dark, but could it be that you are not allowing installation from unknown sources, and that OI is somehow bypassing that?

Settings > Applications > Unknown sources...


Answer extracted from comments which worked. Ensure the Content-Type is set to application/

[Vue warn]: Cannot find element

I get the same error. the solution is to put your script code before the end of body, not in the head section.

Vim: How to insert in visual block mode?

You might also have a use case where you want to delete a block of text and replace it .

Like this

Hello World
Hello World

You can visual block select before "W" and hit Shift+i - Type "Cool" - Hit ESC and then delete "World" by visual block selection .

Alternatively, the cooler way to do it is to just visual block select "World" in both lines. Type c for change. Now you are in the insert mode. Insert the stuff you want and hit ESC. Both gets reflected with lesser keystrokes.

Hello Cool 
Hello Cool

Visual Studio Code: How to show line endings

If you want to set it to LF as default, you can go to File->Preferences->Settings and under user settings you can paste this line in below your other user settings.

"files.eol": "\n"

For example.

"git.confirmSync": false,
"window.zoomLevel": -1,
"workbench.activityBar.visible": true,
"editor.wordWrap": true,
"workbench.iconTheme": "vscode-icons",
"window.menuBarVisibility": "default",
"vsicons.projectDetection.autoReload": true,
"files.eol": "\n"

Visual Studio breakpoints not being hit

Right click on your project, then left click Properties, and select the Web tab. Debuggers > ASP.NET

ERROR 2003 (HY000): Can't connect to MySQL server on '' (111)

If you are using ubuntu, you have to use the following steps to avoid this error(if there is no replication enabled):

  1. run the command vim /etc/mysql/my.cnf
  2. comment bind-address = using the # symbol
  3. restart your mysql server once.


In Step 1, if you cannot find bind-address in the my.cnf file, look for it in /etc/mysql/mysql.conf.d/mysqld.cnf file.

Update in case of MySQL replication enabled

Try to connect MySQL server on IP for which MySQL server is bind in 'my.cnfinstead oflocalhost or`.

Change language of Visual Studio 2017 RC

Polish-> English (VS on MAC) answer: When I started a project and was forced to download Visual Studio, went to their page and saw that Microsoft logo I knew there would be problems... And here it is. It occurred difficult to change the language of VS on Mac. My OS is purely English and only because of the fact I downloaded it using a browser with Polish set as a default language I got the wrong version. I had to reinstall the version to the newest and then Visual Studio Community -> Preferences(in the environment section) -> Visual Style-> User Interface Language.

It translates to polish: Visual Studio Community -> Preferencje -> Styl Wizualny w sekcji Srodowisko -> Jezyk interfejsu uzytkownika -> English.

If you don't see such an option then, as I was, you are forced to upgrade this crappy VS to the newest version.

How to create Toast in Flutter?

In case the Fluttertoast package given so far doesnt work... Then I will suggest you try toast.
It has no frills and no ceremony.

enter image description here

It just works.

I noticed a bug within the example given within its Readme though:"Toast plugin app", duration: Toast.LENGTH_SHORT, gravity: Toast.BOTTOM);

While the method requires a context. So do well to add 'context' like this:"Toast plugin app", context, duration: Toast.LENGTH_SHORT, gravity: Toast.BOTTOM);

There is a chance that this would have been fixed by the time you checked though, I already submitted a PR.

QLabel: set color of text and background

I add this answer because I think it could be useful to anybody.

I step into the problem of setting RGBA colors (that is, RGB color with an Alpha value for transparency) for color display labels in my painting application.

As I came across the first answer, I was unable to set an RGBA color. I have also tried things like:

myLabel.setStyleSheet("QLabel { background-color : %s"

where color is an RGBA color.

So, my dirty solution was to extend QLabel and override paintEvent() method filling its bounding rect.

Today, I've open up the qt-assistant and read the style reference properties list. Affortunately, it has an example that states the following:

QLineEdit { background-color: rgb(255, 0, 0) }

Thats open up my mind in doing something like the code below, as an example:

myLabel= QLabel()
myLabel.setAutoFillBackground(True) # This is important!!
color  = QtGui.QColor(233, 10, 150)
alpha  = 140
values = "{r}, {g}, {b}, {a}".format(r =,
                                     g =,
                                     b =,
                                     a = alpha
myLabel.setStyleSheet("QLabel { background-color: rgba("+values+"); }")

Note that setAutoFillBackground() set in False will not make it work.


File to import not found or unreadable: compass

In short, if you've installed the gem the run:

compass compile

in your rails root dir

Microsoft.WebApplication.targets was not found, on the build server. What's your solution?

Add dependency through NuGet & set a Build Parameter

Goal: no changes / installs necessary to the build agents

I have taken a hybrid approach to the NuGet approach by Lloyd here, which was based off of the committing binary dependencies solution by Andrik.

The reason why is I want to be able to add new build agents without having to pre-configure them with items such as this.

  1. On a machine with Visual Studio, Open the solution; ignore that the web project fails.
  2. In the NuGet package manager, add MSBuild.Microsoft.VisualStudio.Web.targets, as Lloyd mentioned.
  3. This will resolve the binaries to [solution]\packages\MSBuild.Microsoft.VisualStudio.Web.targets.nn.n.n.n\tools\VSToolsPath\
    1. You can copy these to a references folder & commit,
    2. Or just use them where they are at. I chose this, but I'm going to have to deal with the version number in the path later.

In Version 7, I did the following. This may not have been necessary, and based on the comments is definitely not needed now. Please see the comments below.

  1. Next, in your TeamCity build configuration, add a build Paramenter for env.VSToolsPath and set it to the VSToolsPath folder; I used ..\packages\MSBuild.Microsoft.VisualStudio.Web.targets.\tools\VSToolsPath

How do I enable --enable-soap in php on linux?

Getting SOAP working usually does not require compiling PHP from source. I would recommend trying that only as a last option.

For good measure, check to see what your phpinfo says, if anything, about SOAP extensions:

$ php -i | grep -i soap

to ensure that it is the PHP extension that is missing.

Assuming you do not see anything about SOAP in the phpinfo, see what PHP SOAP packages might be available to you.

In Ubuntu/Debian you can search with:

$ apt-cache search php | grep -i soap

or in RHEL/Fedora you can search with:

$ yum search php | grep -i soap

There are usually two PHP SOAP packages available to you, usually php-soap and php-nusoap. php-soap is typically what you get with configuring PHP with --enable-soap.

In Ubuntu/Debian you can install with:

$ sudo apt-get install php-soap

Or in RHEL/Fedora you can install with:

$ sudo yum install php-soap

After the installation, you might need to place an ini file and restart Apache.

Convert integer to binary in C#

BCL provided Convert.ToString(n, 2) is good, but in case you need an alternate implementation which is few ticks faster than BCL provided one.

Following custom implementation works for all integers(-ve and +ve). Original source taken from

static string ToBinary(int n)
    int j = 0;
    char[] output = new char[32];

    if (n == 0)
        output[j++] = '0';
        int checkBit = 1 << 30;
        bool skipInitialZeros = true;
        // Check the sign bit separately, as 1<<31 will cause
        // +ve integer overflow
        if ((n & int.MinValue) == int.MinValue)
            output[j++] = '1';
            skipInitialZeros = false;

        for (int i = 0; i < 31; i++, checkBit >>= 1)
            if ((n & checkBit) == 0)
                if (skipInitialZeros)
                    output[j++] = '0';
                skipInitialZeros = false;
                output[j++] = '1';

    return new string(output, 0, j);

Above code is my implementation. So, I'm eager to hear any feedback :)

fatal error C1010 - "stdafx.h" in Visual Studio how can this be corrected?

The first line of every source file of your project must be the following:

#include <stdafx.h>

Visit here to understand Precompiled Headers

How to add a new schema to sql server 2008?

You can try this:

use database

declare @temp as int
select @temp = count(1) from sys.schemas where name = 'newSchema'

if @temp = 0 
    exec ('create SCHEMA temporal')
    print 'The schema newSchema was created in database'
print 'The schema newSchema already exists in database'

Undefined function mysql_connect()

Well, this is your chance! It looks like PDO is ready; use that instead.

Try checking to see if the PHP MySQL extension module is being loaded:


If it's not there, add the following to the php.ini file:


How to parse a JSON file in swift?

SwiftJSONParse: Parse JSON like a badass

Dead-simple and easy to read!

Example: get the value "mrap" from nicknames as a String from this JSON response

    "other": {
        "nicknames": ["mrap", "Mikee"]

It takes your json data NSData as it is, no need to preprocess.

let parser = JSONParser(jsonData)

if let handle = parser.getString("other.nicknames[0]") {
    // that's it!

Disclaimer: I made this and I hope it helps everyone. Feel free to improve on it!

Getting String Value from Json Object Android

Here is the solution I used for me Is works for fetching JSON from string

protected String getJSONFromString(String stringJSONArray) throws JSONException {
        return new StringBuffer(
               new JSONArray(stringJSONArray).getJSONObject(0).getString("cartype"))
                   .append(" ")
               new JSONArray(employeeID).getJSONObject(0).getString("model"))

Jinja2 shorthand conditional

Yes, it's possible to use inline if-expressions:

{{ 'Update' if files else 'Continue' }}

Java: Retrieving an element from a HashSet

The idea that you need to get the reference to the object that is contained inside a Set object is common. It can be archived by 2 ways:

  1. Use HashSet as you wanted, then:

    public Object getObjectReference(HashSet<Xobject> set, Xobject obj) {
        if (set.contains(obj)) {
            for (Xobject o : set) {
                if (obj.equals(o))
                    return o;
        return null;

For this approach to work, you need to override both hashCode() and equals(Object o) methods In the worst scenario we have O(n)

  1. Second approach is to use TreeSet

    public Object getObjectReference(TreeSet<Xobject> set, Xobject obj) {
        if (set.contains(obj)) {
            return set.floor(obj);
        return null;

This approach gives O(log(n)), more efficient. You don't need to override hashCode for this approach but you have to implement Comparable interface. ( define function compareTo(Object o)).

How to remove leading zeros using C#

It really depends on how long the NVARCHAR is, as a few of the above (especially the ones that convert through IntXX) methods will not work for:

String s = "005780327584329067506780657065786378061754654532164953264952469215462934562914562194562149516249516294563219437859043758430587066748932647329814687194673219673294677438907385032758065763278963247982360675680570678407806473296472036454612945621946";

Something like this would

String s ="0000058757843950000120465875468465874567456745674000004000".TrimStart(new Char[] { '0' } );
// s = "58757843950000120465875468465874567456745674000004000"

How to add data validation to a cell using VBA

Use this one:

Dim ws As Worksheet
Dim range1 As Range, rng As Range
'change Sheet1 to suit
Set ws = ThisWorkbook.Worksheets("Sheet1")

Set range1 = ws.Range("A1:A5")
Set rng = ws.Range("B1")

With rng.Validation
    .Delete 'delete previous validation
    .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, _
        Formula1:="='" & ws.Name & "'!" & range1.Address
End With

Note that when you're using Dim range1, rng As range, only rng has type of Range, but range1 is Variant. That's why I'm using Dim range1 As Range, rng As Range.
About meaning of parameters you can read is MSDN, but in short:

  • Type:=xlValidateList means validation type, in that case you should select value from list
  • AlertStyle:=xlValidAlertStop specifies the icon used in message boxes displayed during validation. If user enters any value out of list, he/she would get error message.
  • in your original code, Operator:= xlBetween is odd. It can be used only if two formulas are provided for validation.
  • Formula1:="='" & ws.Name & "'!" & range1.Address for list data validation provides address of list with values (in format =Sheet!A1:A5)

Sending email with attachments from C#, attachments arrive as Part 1.2 in Thunderbird

Simple code to send email with attachement.


using System.Net;
using System.Net.Mail;

public void email_send()
    MailMessage mail = new MailMessage();
    SmtpClient SmtpServer = new SmtpClient("");
    mail.From = new MailAddress("your [email protected]");
    mail.To.Add("[email protected]");
    mail.Subject = "Test Mail - 1";
    mail.Body = "mail with attachment";

    System.Net.Mail.Attachment attachment;
    attachment = new System.Net.Mail.Attachment("c:/textfile.txt");

    SmtpServer.Port = 587;
    SmtpServer.Credentials = new System.Net.NetworkCredential("your [email protected]", "your password");
    SmtpServer.EnableSsl = true;



C error: Expected expression before int

By C89, variable can only be defined at the top of a block.

if (a == 1)
    int b = 10;   // it's just a statement, syntacitially error 

if (a == 1)
{                  // refer to the beginning of a local block 
    int b = 10;    // at the top of the local block, syntacitially correct
}                  // refer to the end of a local block

if (a == 1)
    int b = 10;    // not at the top of the local block, syntacitially error, I guess

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

That error message is coming from docker and it not necessarily related to AWS as I have gotten same error when not using AWS ... its just saying docker is not getting authorization to proceed from whatever source of auth it happens to be using

In my case, in test I removed directory ~/.docker and got that error ... after I bounced my local docker registry then docker push was fine

Remove empty strings from array while keeping record Without Loop?

arr = arr.filter(v => v);

as returned v is implicity converted to truthy

What are .NumberFormat Options In Excel VBA?

Thanks to this question (and answers), I discovered an easy way to get at the exact NumberFormat string for virtually any format that Excel has to offer.

How to Obtain the NumberFormat String for Any Excel Number Format

Step 1: In the user interface, set a cell to the NumberFormat you want to use.

I manually formatted a cell to Chinese (PRC) currency

In my example, I selected the Chinese (PRC) Currency from the options contained in the "Account Numbers Format" combo box.

Step 2: Expand the Number Format dropdown and select "More Number Formats...".

Open the Number Format dropdown

Step 3: In the Number tab, in Category, click "Custom".

Click Custom

The "Sample" section shows the Chinese (PRC) currency formatting that I applied.

The "Type" input box contains the NumberFormat string that you can use programmatically.

So, in this example, the NumberFormat of my Chinese (PRC) Currency cell is as follows:

_ [$¥-804]* #,##0.00_ ;_ [$¥-804]* -#,##0.00_ ;_ [$¥-804]* "-"??_ ;_ @_ 

If you do these steps for each NumberFormat that you desire, then the world is yours.

I hope this helps.

What are the differences between Visual Studio Code and Visual Studio?

Out of the box, Visual Studio can compile, run and debug programs.

Out of the box, Visual Studio Code can do practically nothing but open and edit text files. It can be extended to compile, run, and debug, but you will need to install other software. It's a PITA.

If you're looking for a Notepad replacement, Visual Studio Code is your man.

If you want to develop and debug code without fiddling for days with settings and installing stuff, then Visual Studio is your man.

How to insert &nbsp; in XSLT

Use the entity code &#160; instead.

&nbsp; is a HTML "character entity reference". There is no named entity for non-breaking space in XML, so you use the code &#160;.

Wikipedia includes a list of XML and HTML entities, and you can see that there are only 5 "predefined entities" in XML, but HTML has over 200. I'll also point over to Creating a space (&nbsp;) in XSL which has excellent answers.

add new element in laravel collection object

As mentioned above if you wish to as a new element your queried collection you can use:

    $items = DB::select(DB::raw('SELECT * FROM items WHERE = '.$id.'  ;'));
    foreach($items as $item){
        $product = DB::select(DB::raw(' select * from product
               where product_id = '. $id.';' ));

        // or 
        // $items->put('products', $product);

but if you wish to add new element to each queried element you need to do like:

    $items = DB::select(DB::raw('SELECT * FROM items WHERE = '.$id.'  ;'));
    foreach($items as $item){
           $product = DB::select(DB::raw(' select * from product
                 where product_id = '. $id.';' ));

          $item->add_whatever_element_you_want = $product;

add_whatever_element_you_want can be whatever you wish that your element is named (like product for example).

Why do Twitter Bootstrap tables always have 100% width?

I've tried to add style="width: auto !important" and works great for me!

How to check if a string contains text from an array of substrings in JavaScript?

Not that I'm suggesting that you go and extend/modify String's prototype, but this is what I've done:


String.prototype.includes = function (includes) {_x000D_
    console.warn("String.prototype.includes() has been modified.");_x000D_
    return function (searchString, position) {_x000D_
        if (searchString instanceof Array) {_x000D_
            for (var i = 0; i < searchString.length; i++) {_x000D_
                if (, searchString[i], position)) {_x000D_
                    return true;_x000D_
            return false;_x000D_
        } else {_x000D_
            return, searchString, position);_x000D_
console.log('"Hello, World!".includes("foo");',          "Hello, World!".includes("foo")           ); // false_x000D_
console.log('"Hello, World!".includes(",");',            "Hello, World!".includes(",")             ); // true_x000D_
console.log('"Hello, World!".includes(["foo", ","])',    "Hello, World!".includes(["foo", ","])    ); // true_x000D_
console.log('"Hello, World!".includes(["foo", ","], 6)', "Hello, World!".includes(["foo", ","], 6) ); // false

HttpContext.Current.Session is null when routing requests

Just add attribute runAllManagedModulesForAllRequests="true" to system.webServer\modules in web.config.

This attribute is enabled by default in MVC and Dynamic Data projects.

In Oracle, is it possible to INSERT or UPDATE a record through a view?

Views in Oracle may be updateable under specific conditions. It can be tricky, and usually is not advisable.

From the Oracle 10g SQL Reference:

Notes on Updatable Views

An updatable view is one you can use to insert, update, or delete base table rows. You can create a view to be inherently updatable, or you can create an INSTEAD OF trigger on any view to make it updatable.

To learn whether and in what ways the columns of an inherently updatable view can be modified, query the USER_UPDATABLE_COLUMNS data dictionary view. The information displayed by this view is meaningful only for inherently updatable views. For a view to be inherently updatable, the following conditions must be met:

  • Each column in the view must map to a column of a single table. For example, if a view column maps to the output of a TABLE clause (an unnested collection), then the view is not inherently updatable.
  • The view must not contain any of the following constructs:
    • A set operator
    • a DISTINCT operator
    • An aggregate or analytic function
    • A collection expression in a SELECT list
    • A subquery in a SELECT list
    • A subquery designated WITH READ ONLY
    • Joins, with some exceptions, as documented in Oracle Database Administrator's Guide

In addition, if an inherently updatable view contains pseudocolumns or expressions, then you cannot update base table rows with an UPDATE statement that refers to any of these pseudocolumns or expressions.

If you want a join view to be updatable, then all of the following conditions must be true:

  • The DML statement must affect only one table underlying the join.
  • For an INSERT statement, the view must not be created WITH CHECK OPTION, and all columns into which values are inserted must come from a key-preserved table. A key-preserved table is one for which every primary key or unique key value in the base table is also unique in the join view.
  • For an UPDATE statement, all columns updated must be extracted from a key-preserved table. If the view was created WITH CHECK OPTION, then join columns and columns taken from tables that are referenced more than once in the view must be shielded from UPDATE.
  • For a DELETE statement, if the join results in more than one key-preserved table, then Oracle Database deletes from the first table named in the FROM clause, whether or not the view was created WITH CHECK OPTION.

How to add anchor tags dynamically to a div in Javascript?

<script type="text/javascript" language="javascript">
function createDiv()
  var divTag = document.createElement("div");            
  divTag.innerHTML = "Div tag created using Javascript DOM dynamically";        

How do you specify a different port number in SQL Management Studio?

Using the client manager affects all connections or sets a client machine specific alias.

Use the comma as above: this can be used in an app.config too

It's probably needed if you have firewalls between you and the server too...

Gradle version 2.2 is required. Current version is 2.10

The android studio and Gradle version looks like very bad managed. And there's tons of version in-capability issues. And the error message is mostly clueless. For this particular issue. The closest answer is from "Jitendra Singh". Change the version to:

 classpath ''

But in my case: Android studio 2.2 RC, I still get another error:

Could not find matching constructor for:,, android.databinding.tool.DataBindingBuilder,,,, org.gradle.tooling.provider.model.internal.DefaultToolingModelBuilderRegistry)

So I went to the maven central to find the latest version which is 2.1.3 for now. So after change to

buildscript {
    repositories {
    dependencies {
        classpath ''

Solved my problem eventually.

Make file echo displaying "$PATH" string

The make uses the $ for its own variable expansions. E.g. single character variable $A or variable with a long name - ${VAR} and $(VAR).

To put the $ into a command, use the $$, for example:

  @echo "Please execute next commands:"
  @echo 'setenv PATH /usr/local/greenhills/mips5/linux86:$$PATH'

Also note that to make the "" and '' (double and single quoting) do not play any role and they are passed verbatim to the shell. (Remove the @ sign to see what make sends to shell.) To prevent the shell from expanding $PATH, second line uses the ''.

Count number of matches of a regex in Javascript

('my string'.match(/\s/g) || []).length;

How to remove new line characters from data rows in mysql?

Playing with above answers, this one works for me

REPLACE(REPLACE(column_name , '\n', ''), '\r', '')

Parse Error: Adjacent JSX elements must be wrapped in an enclosing tag

There is a rule in react that a JSX expression must have exactly one outermost element.


const para = (


const para = (

libxml install error using pip

In case, you are using Ubuntu/Lubuntu 13.04 or Ubuntu 13.10 and having problem with "/usr/bin/ld: cannot find -lz", you may need also install zlib1g-dev package:

sudo apt-get install -y zlib1g-dev

Put it all together:

sudo apt-get install -y libxml2-dev libxslt1-dev zlib1g-dev python3-pip
sudo pip3 install lxml

SyntaxError: Unexpected token o in JSON at position 1

Don't ever use JSON.parse without wrapping it in try-catch block:

// payload 
let userData = null;

try {
    // Parse a JSON
    userData = JSON.parse(payload); 
} catch (e) {
    // You can read e for more info
    // Let's assume the error is that we already have parsed the payload
    // So just return that
    userData = payload;

// Now userData is the parsed result

Set value to an entire column of a pandas dataframe

Python can do unexpected things when new objects are defined from existing ones. You stated in a comment above that your dataframe is defined along the lines of df = df_all.loc[df_all['issueid']==specific_id,:]. In this case, df is really just a stand-in for the rows stored in the df_all object: a new object is NOT created in memory.

To avoid these issues altogether, I often have to remind myself to use the copy module, which explicitly forces objects to be copied in memory so that methods called on the new objects are not applied to the source object. I had the same problem as you, and avoided it using the deepcopy function.

In your case, this should get rid of the warning message:

from copy import deepcopy
df = deepcopy(df_all.loc[df_all['issueid']==specific_id,:])
df['industry'] = 'yyy'

EDIT: Also see David M.'s excellent comment below!

df = df_all.loc[df_all['issueid']==specific_id,:].copy()
df['industry'] = 'yyy'

MAX() and MAX() OVER PARTITION BY produces error 3504 in Teradata Query

Logically OLAP functions are calculated after GROUP BY/HAVING, so you can only access columns in GROUP BY or columns with an aggregate function. Following looks strange, but is Standard SQL:

SELECT employee_number,
           OVER (PARTITION BY course_code) AS max_course_date,
       MAX(course_completion_date) AS max_date
FROM employee_course_completion
WHERE course_code IN ('M910303', 'M91301R', 'M91301P')
GROUP BY employee_number, course_code

And as Teradata allows re-using an alias this also works:

SELECT employee_number,
           OVER (PARTITION BY course_code) AS max_course_date,
       MAX(course_completion_date) AS max_date
FROM employee_course_completion
WHERE course_code IN ('M910303', 'M91301R', 'M91301P')
GROUP BY employee_number, course_code

How can I get a precise time, for example in milliseconds in Objective-C?

mach_absolute_time() can be used to get precise measurements.


Also available is CACurrentMediaTime(), which is essentially the same thing but with an easier-to-use interface.

(Note: This answer was written in 2009. See Pavel Alexeev's answer for the simpler POSIX clock_gettime() interfaces available in newer versions of macOS and iOS.)

How to set zoom level in google map

Your code below is zooming the map to fit the specified bounds:

addMarker(27.703402,85.311668,'New Road');
center = bounds.getCenter();

If you only have 1 marker and add it to the bounds, that results in the closest zoom possible:

function addMarker(lat, lng, info) {
  var pt = new google.maps.LatLng(lat, lng);

If you keep track of the number of markers you have "added" to the map (or extended the bounds with), you can only call fitBounds if that number is greater than one. I usually push the markers into an array (for later use) and test the length of that array.

If you will only ever have one marker, don't use fitBounds. Call setCenter, setZoom with the marker position and your desired zoom level.

function addMarker(lat, lng, info) {
  var pt = new google.maps.LatLng(lat, lng);
  map.setZoom(your desired zoom);

#map {
  height: 100%;
  width: 100%;
  padding: 0;
  margin: 0;

  <script src="" type="text/javascript"></script>
  <script type="text/javascript">
    var icon = new google.maps.MarkerImage("", new google.maps.Size(32, 32), new google.maps.Point(0, 0), new google.maps.Point(16, 32));
    var center = null;
    var map = null;
    var currentPopup;
    var bounds = new google.maps.LatLngBounds();

    function addMarker(lat, lng, info) {
      var pt = new google.maps.LatLng(lat, lng);
      var marker = new google.maps.Marker({
        position: pt,
        icon: icon,
        map: map
      var popup = new google.maps.InfoWindow({
        content: info,
        maxWidth: 300
      google.maps.event.addListener(marker, "click", function() {
        if (currentPopup != null) {
          currentPopup = null;
        }, marker);
        currentPopup = popup;
      google.maps.event.addListener(popup, "closeclick", function() {
        currentPopup = null;

    function initMap() {
      map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(0, 0),
        zoom: 1,
        mapTypeId: google.maps.MapTypeId.ROADMAP,
        mapTypeControl: false,
        mapTypeControlOptions: {
          style: google.maps.MapTypeControlStyle.HORIZONTAL_BAR
        navigationControl: true,
        navigationControlOptions: {
          style: google.maps.NavigationControlStyle.SMALL
      addMarker(27.703402, 85.311668, 'New Road');
      // center = bounds.getCenter();
      // map.fitBounds(bounds);


<body onload="initMap()" style="margin:0px; border:0px; padding:0px;">
  <div id="map"></div>


Uncaught SyntaxError: Invalid or unexpected token

You should pass in quotes then it will be treated as string argument

<td><a href ="#"  onclick="Getinfo('');" >6/16/2016 2:02:29 AM</a>  </td>

Otherwise, it is treated as variable thus error is generated.

How do I write a correct micro-benchmark in Java?

I know this question has been marked as answered but I wanted to mention two libraries that help us to write micro benchmarks

Caliper from Google

Getting started tutorials


JMH from OpenJDK

Getting started tutorials

  1. Avoiding Benchmarking Pitfalls on the JVM
  2. Using JMH for Java Microbenchmarking
  3. Introduction to JMH

Android: failed to convert @drawable/picture into a drawable

Also check if the resource-name contains any illegal characters (for me it was a "-" in my-image)

What's the difference between getRequestURI and getPathInfo methods in HttpServletRequest?

I will put a small comparison table here (just to have it somewhere):

Servlet is mapped as /test%3F/* and the application is deployed under /app.


Method              URL-Decoded Result           
getContextPath()        no      /app
getLocalName()                  30thh.loc
getLocalPort()                  8480
getMethod()                     GET
getPathInfo()           yes     /a?+b
getProtocol()                   HTTP/1.1
getQueryString()        no      p+1=c+d&p+2=e+f
getRequestedSessionId() no      S%3F+ID
getRequestURI()         no      /app/test%3F/a%3F+b;jsessionid=S+ID
getRequestURL()         no      http://30thh.loc:8480/app/test%3F/a%3F+b;jsessionid=S+ID
getScheme()                     http
getServerName()                 30thh.loc
getServerPort()                 8480
getServletPath()        yes     /test?
getParameterNames()     yes     [p 2, p 1]
getParameter("p 1")     yes     c d

In the example above the server is running on the localhost:8480 and the name 30thh.loc was put into OS hosts file.


  • "+" is handled as space only in the query string

  • Anchor "#a" is not transferred to the server. Only the browser can work with it.

  • If the url-pattern in the servlet mapping does not end with * (for example /test or *.jsp), getPathInfo() returns null.

If Spring MVC is used

  • Method getPathInfo() returns null.

  • Method getServletPath() returns the part between the context path and the session ID. In the example above the value would be /test?/a?+b

  • Be careful with URL encoded parts of @RequestMapping and @RequestParam in Spring. It is buggy (current version 3.2.4) and is usually not working as expected.

How to add elements of a string array to a string array list?

Arrays.asList is the handy function available in Java to convert an array variable to List or Collection. For better under standing consider the below example:


import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Wetland {
    private String name;
    private List<String> species = new ArrayList<String>();

    public Wetland(String name, String[] speciesArr) { = name;
        this.species = Arrays.asList(speciesArr);

    public void display() {
        System.out.println("Name: " + name);
        System.out.println("Elements in the List");
        for (String string : species) {

     * @Description: Method to test your code
    public static void main(String[] args) {
        String name = "Colors";
        String speciesArr[] = new String [] {"red", "blue", "green"};
        Wetland wetland = new Wetland(name, speciesArr);



enter image description here

Proper way to concatenate variable strings

As simple as joining lists in python itself.

ansible -m debug -a msg="{{ '-'.join(('list', 'joined', 'together')) }}" localhost

localhost | SUCCESS => {
  "msg": "list-joined-together" }

Works the same way using variables:

ansible -m debug -a msg="{{ '-'.join((var1, var2, var3)) }}" localhost

Is it possible to get only the first character of a String?

String has a charAt method that returns the character at the specified position. Like arrays and Lists, String is 0-indexed, i.e. the first character is at index 0 and the last character is at index length() - 1.

So, assuming getSymbol() returns a String, to print the first character, you could do:

System.out.println(ld.getSymbol().charAt(0)); // char at index 0

Export HTML table to pdf using jspdf

Use get(0) instead of html(). In other words, replace

doc.fromHTML($('#htmlTableId').html(), 15, 15, {
    'width': 170,'elementHandlers': specialElementHandlers


doc.fromHTML($('#htmlTableId').get(0), 15, 15, {
    'width': 170,'elementHandlers': specialElementHandlers

Uploading into folder in FTP?

The folder is part of the URL you set when you create request: "". If you use "" then the file will be uploaded to a folder named wibble.

You may need to first use a request with Method = WebRequestMethods.Ftp.MakeDirectory to make the wibble folder if it doesn't already exist.

Android - Adding at least one Activity with an ACTION-VIEW intent-filter after Updating SDK version 23

this solution work only .if your want to ignore this Warning

<manifest xmlns:android=""

Define a global variable in a JavaScript function

To use the window object is not a good idea. As I see in comments,

'use strict';

function showMessage() {
    window.say_hello = 'hello!';


This will throw an error to use the say_hello variable we need to first call the showMessage function.

The server is not responding (or the local MySQL server's socket is not correctly configured) in wamp server

I face the same problem and changing

 $cfg['Servers'][$i]['host'] = 'localhost';


 $cfg['Servers'][$i]['host'] = '';

Solved this issue.

Run javascript script (.js file) in mongodb including another file inside js

Use Load function


You can directly call any .js file from the mongo shell, and mongo will execute the JavaScript.

Example : mongo localhost:27017/mydb myfile.js

This executes the myfile.js script in mongo shell connecting to mydb database with port 27017 in localhost.

For loading external js you can write


Suppose we have two js file myFileOne.js and myFileTwo.js


print('From file 1');
load('myFileTwo.js');     // Load other js file .


print('From file 2');


>mongo myFileOne.js


From file 1
From file 2

What is the meaning of "operator bool() const"

It's an implicit conversion to bool. I.e. wherever implicit conversions are allowed, your class can be converted to bool by calling that method.

sass :first-child not working

While @Andre is correct that there are issues with pseudo elements and their support, especially in older (IE) browsers, that support is improving all the time.

As for your question of, are there any issues, I'd say I've not really seen any, although the syntax for the pseudo-element can be a bit tricky, especially when first sussing it out. So:

  declarations: ...
    declarations: ...
      declarations: ...

which compiles as one would expect:

  declarations... }
div#top-level div.inside {
  declarations... }
div#top-level div.inside:first-child {
  declarations... }

I haven't seen any documentation on any of this, save for the statement that "sass can do everything that css can do." As always, with Haml and SASS the indentation is everything.

Printing Exception Message in java

try {
} catch (javax.script.ScriptException ex) {
// System.out.println(ex.getMessage());

Colspan all columns

try using "colSpan" instead of "colspan". IE likes the camelBack version...

nodejs mysql Error: Connection lost The server closed the connection

I do not recall my original use case for this mechanism. Nowadays, I cannot think of any valid use case.

Your client should be able to detect when the connection is lost and allow you to re-create the connection. If it important that part of program logic is executed using the same connection, then use transactions.

tl;dr; Do not use this method.

A pragmatic solution is to force MySQL to keep the connection alive:

setInterval(function () {
    db.query('SELECT 1');
}, 5000);

I prefer this solution to connection pool and handling disconnect because it does not require to structure your code in a way thats aware of connection presence. Making a query every 5 seconds ensures that the connection will remain alive and PROTOCOL_CONNECTION_LOST does not occur.

Furthermore, this method ensures that you are keeping the same connection alive, as opposed to re-connecting. This is important. Consider what would happen if your script relied on LAST_INSERT_ID() and mysql connection have been reset without you being aware about it?

However, this only ensures that connection time out (wait_timeout and interactive_timeout) does not occur. It will fail, as expected, in all others scenarios. Therefore, make sure to handle other errors.

What are the differences between json and simplejson Python modules?

In python3, if you a string of b'bytes', with json you have to .decode() the content before you can load it. simplejson takes care of this so you can just do simplejson.loads(byte_string).

Dictionary with list of strings as value

I'd wrap the dictionary in another class:

public class MyListDictionary

    private Dictionary<string, List<string>> internalDictionary = new Dictionary<string,List<string>>();

    public void Add(string key, string value)
        if (this.internalDictionary.ContainsKey(key))
            List<string> list = this.internalDictionary[key];
            if (list.Contains(value) == false)
            List<string> list = new List<string>();
            this.internalDictionary.Add(key, list);


Python error: AttributeError: 'module' object has no attribute

The way I would do it is to leave the __ files empty, and do:

import lib.mod1.mod11


from lib.mod1.mod11 import mod12

You may find that the mod1 dir is unnecessary, just have in lib.

How to locate the git config file in Mac

The solution to the problem is:

  1. Find the .gitconfig file

  2. [user] name = 1wQasdTeedFrsweXcs234saS56Scxs5423 email = [email protected] [credential] helper = osxkeychain [url ""] insteadOf = git:// [url "https://"] [url "https://"] insteadOf = git://

there would be a blank url="" replace it with url="https://"

    name = 1wQasdTeedFrsweXcs234saS56Scxs5423
    email = [email protected]
    helper = osxkeychain
[url "https://"]
    insteadOf = git://
[url "https://"]
[url "https://"]
    insteadOf = git://

This will work :)

Happy Bower-ing

IIS - 401.3 - Unauthorized

Just in case anyone else runs into this. I troubleshooted all of these steps and it turns out because I unzipped some files from a MAC, Microsoft automatically without any notification Encrypted the files. After hours of trying to set folder permissions I went in and saw the file names were green which means the files were encrypted and IIS will throw the same error even if folder permissions are correct.

Best way to remove an event handler in jQuery?

Thanks for the information. very helpful i used it for locking page interaction while in edit mode by another user. I used it in conjunction with ajaxComplete. Not necesarily the same behavior but somewhat similar.

function userPageLock(){
    $("body").bind("ajaxComplete.lockpage", function(){

function executePageLock(){
    //do something

How to add option to select list in jQuery


How to concatenate two IEnumerable<T> into a new IEnumerable<T>?

Yes, LINQ to Objects supports this with Enumerable.Concat:

var together = first.Concat(second);

NB: Should first or second be null you would receive a ArgumentNullException. To avoid this & treat nulls as you would an empty set, use the null coalescing operator like so:

var together = (first ?? Enumerable.Empty<string>()).Concat(second ?? Enumerable.Empty<string>()); //amending `<string>` to the appropriate type

Invoke a second script with arguments from a script

Much simpler actually:

Method 1:

Invoke-Expression $scriptPath $argumentList

Method 2:

& $scriptPath $argumentList

Method 3:

$scriptPath $argumentList

If you have spaces in your scriptPath, don't forget to escape them `"$scriptPath`"

lvalue required as left operand of assignment

You are trying to assign a value to a function, which is not possible in C. Try the comparison operator instead:

if (strcmp("hello", "hello") == 0)

How to create an integer array in Python?

two ways:

x = [0] * 10
x = [0 for i in xrange(10)]

Edit: replaced range by xrange to avoid creating another list.

Also: as many others have noted including Pi and Ben James, this creates a list, not a Python array. While a list is in many cases sufficient and easy enough, for performance critical uses (e.g. when duplicated in thousands of objects) you could look into python arrays. Look up the array module, as explained in the other answers in this thread.

How to get all Windows service names starting with a common word?

sc queryex type= service state= all | find /i "NATION"
  • use /i for case insensitive search
  • the white space after type=is deliberate and required

Do I use <img>, <object>, or <embed> for SVG files?

From IE9 and above you can use SVG in a ordinary IMG tag..

<img src="/static/image.svg">

Changing Jenkins build number

If you have access to the script console (Manage Jenkins -> Script Console), then you can do this following:


Getting the "real" Facebook profile picture URL from graph API

function getFacebookImageFromURL($url)
  $headers = get_headers($url, 1);
  if (isset($headers['Location']))
    return $headers['Location'];

$url = '';
$imageURL = getFacebookImageFromURL($url);

LINQ - Left Join, Group By, and Count

from p in context.ParentTable
join c in context.ChildTable on p.ParentId equals c.ChildParentId into j1
from j2 in j1.DefaultIfEmpty()
group j2 by p.ParentId into grouped
select new { ParentId = grouped.Key, Count = grouped.Count(t=>t.ChildId != null) }

How can I avoid ResultSet is closed exception in Java?

The exception states that your result is closed. You should examine your code and look for all location where you issue a ResultSet.close() call. Also look for Statement.close() and Connection.close(). For sure, one of them gets called before is called.

How to create a new component in Angular 4 using CLI

ng generate component componentName.

It will automatically import the component in module.ts

How to create major and minor gridlines with different linestyles in Python

Actually, it is as simple as setting major and minor separately:

In [9]: plot([23, 456, 676, 89, 906, 34, 2345])
Out[9]: [<matplotlib.lines.Line2D at 0x6112f90>]

In [10]: yscale('log')

In [11]: grid(b=True, which='major', color='b', linestyle='-')

In [12]: grid(b=True, which='minor', color='r', linestyle='--')

The gotcha with minor grids is that you have to have minor tick marks turned on too. In the above code this is done by yscale('log'), but it can also be done with plt.minorticks_on().

enter image description here

Sequence contains no matching element

For those of you who faced this issue while creating a controller through the context menu, reopening Visual Studio as an administrator fixed it.

Can dplyr join on multiple columns or composite key?

Updating to use tibble()

You can pass a named vector of length greater than 1 to the by argument of left_join():


d1 <- tibble(
  x = letters[1:3],
  y = LETTERS[1:3],
  a = rnorm(3)

d2 <- tibble(
  x2 = letters[3:1],
  y2 = LETTERS[3:1],
  b = rnorm(3)

left_join(d1, d2, by = c("x" = "x2", "y" = "y2"))

Remove multiple whitespaces

preg_replace('/(\s\s+|\t|\n)/', ' ', $row['message']);

This replaces all tabs, all newlines and all combinations of multiple spaces, tabs and newlines with a single space.

Upload failed You need to use a different version code for your APK because you already have one with version code 2

I kept getting same error again and again,

Finally I uploaded the apk file manually using Google Play Console as shown in screen shot.

Under App Release, You select the button "CREATE RELEASE" shown in the screen shot and upload your apk file from /android/app/bin/build/outputs/apk/release/app-release.apk

enter image description here

Doing a join across two databases with different collations on SQL Server and getting an error

A general purpose way is to coerce the collation to DATABASE_DEFAULT. This removes hardcoding the collation name which could change.

It's also useful for temp table and table variables, and where you may not know the server collation (eg you are a vendor placing your system on the customer's server)

    sone_field collate DATABASE_DEFAULT
    inner join
    table_2 on table_1.field collate DATABASE_DEFAULT = table_2.field
where whatever

In Unix, how do you remove everything in the current directory and below it?

Practice safe computing. Simply go up one level in the hierarchy and don't use a wildcard expression:

cd ..; rm -rf -- <dir-to-remove>

The two dashes -- tell rm that <dir-to-remove> is not a command-line option, even when it begins with a dash.

How to center the text in a JLabel?

The following constructor, JLabel(String, int), allow you to specify the horizontal alignment of the label.

JLabel label = new JLabel("The Label", SwingConstants.CENTER);

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

With Apache 2.4, the syntax for access control has changed. If using directives like:

Order deny,allow
Deny from all

does not work, you're likely using Apache 2.4.

The Apache 2.4 docs are here.

You need to use Require all denied in one of these ways:

# you can do it this way (with "not match")

<FilesMatch ^((?!index\.php).)*$>
  Require all denied

# or 

Require all denied

<Files index.php>
  Require all granted

Evenly space multiple views within a container view

Yes, you can do this solely in interface builder and without writing code - the one caveat is that you are resizing the label instead of distributing whitespace. In this case, align Label 2's X and Y to the superview so it is fixed in the center. Then set label 1's vertical space to the superview and to label 2 to the standard, repeat for label 3. After setting label 2 the easiest way to set label 1 and 3 is to resize them until they snap.

Here is the horizontal display, note that the vertical space between label 1 and 2 is set to standard:horizontal display

And here is the portrait version:enter image description here

I realize they are not absolutely 100% equally spaced between the baselines due to the difference between the standard space between labels and the standard space to the superview. If that bothers you, set the size to 0 instead of standard

Zero-pad digits in string

First of all, your description is misleading. Double is a floating point data type. You presumably want to pad your digits with leading zeros in a string. The following code does that:

$s = sprintf('%02d', $digit);

For more information, refer to the documentation of sprintf.

Compiler error: memset was not declared in this scope

You should include <string.h> (or its C++ equivalent, <cstring>).

getting "No column was specified for column 2 of 'd'" in sql server cte?

Just add an alias name as follows
sum(totalitems) as totalitems.

How to create a HTTP server in Android?

Consider this one: Very small, written in Java. I used it without any problem.

how to create a Java Date object of midnight today and midnight tomorrow?

Pretty much as the answers before, but nobody mentioned AM_PM parameter:

    Calendar cal = Calendar.getInstance();
    cal.set(Calendar.HOUR, 0);
    cal.set(Calendar.MINUTE, 0);
    cal.set(Calendar.SECOND, 0);
    cal.set(Calendar.MILLISECOND, 0);
    cal.set(Calendar.AM_PM, Calendar.AM);

Mark error in form using Bootstrap

Can use CSS to show error message only on error.

.form-group.has-error .help-block {
    display: block;

.form-group .help-block {
    display: none;

<div class="form-group has-error">
  <label class="control-label" for="inputError">Input with error</label>
  <input type="text" class="form-control" id="inputError">
  <span class="help-block">Please correct the error</span>

What is the cleanest way to ssh and run multiple commands in Bash?

Edit your script locally, then pipe it into ssh, e.g.

cat | ssh blah_server

where looks like your list above:

ls some_folder
pwd; mvc3 return raw html to view

Give a try to return bootstrap alert message, this worked for me

return Content("<div class='alert alert-success'><a class='close' data-dismiss='alert'>
&times;</a><strong style='width:12px'>Thanks!</strong> updated successfully</div>");

Note: Don't forget to add bootstrap css and js in your view page

hope helps someone.

Salt and hash a password in Python

The smart thing is not to write the crypto yourself but to use something like passlib:

It is easy to mess up writing your crypto code in a secure way. The nasty thing is that with non crypto code you often immediately notice it when it is not working since your program crashes. While with crypto code you often only find out after it is to late and your data has been compromised. Therefor I think it is better to use a package written by someone else who is knowledgable about the subject and which is based on battle tested protocols.

Also passlib has some nice features which make it easy to use and also easy to upgrade to a newer password hashing protocol if an old protocol turns out to be broken.

Also just a single round of sha512 is more vulnerable to dictionary attacks. sha512 is designed to be fast and this is actually a bad thing when trying to store passwords securely. Other people have thought long and hard about all this sort issues so you better take advantage of this.

How to convert the system date format to dd/mm/yy in SQL Server 2008 R2?

select convert(varchar(8), getdate(), 3)

simply use this for dd/mm/yy and this

select convert(varchar(8), getdate(), 1) 

for mm/dd/yy

Better way to find last used row

This gives you last used row in a specified column.

Optionally you can specify worksheet, else it will takes active sheet.

Function shtRowCount(colm As Integer, Optional ws As Worksheet) As Long

    If ws Is Nothing Then Set ws = ActiveSheet

    If ws.Cells(Rows.Count, colm) <> "" Then
        shtRowCount = ws.Cells(Rows.Count, colm).Row
        Exit Function
    End If

    shtRowCount = ws.Cells(Rows.Count, colm).Row

    If shtRowCount = 1 Then
        If ws.Cells(1, colm) = "" Then
            shtRowCount = 0
            shtRowCount = 1
        End If
    End If

End Function

Sub test()

    Dim lgLastRow As Long
    lgLastRow = shtRowCount(2) 'Column B

End Sub

How do you add an array to another array in Ruby and not end up with a multi-dimensional result?

You can just use the + operator!

irb(main):001:0> a = [1,2]
=> [1, 2]
irb(main):002:0> b = [3,4]
=> [3, 4]
irb(main):003:0> a + b
=> [1, 2, 3, 4]

You can read all about the array class here:

ERROR 403 in loading resources like CSS and JS in my index.php

You need to change permissions on the folder bootstrap/css. Your super user may be able to access it but it doesn't mean apache or nginx have access to it, that's why you still need to change the permissions.

Tip: I usually make the apache/nginx's user group owner of that kind of folders and give 775 permission to it.

Change project name on Android Studio

Just go to res>values>strings.xml. One line says Somethig-your name

<string name="app_name">Somethig-your name</string>

Just replace your original name to

 <string name="app_name">Your Name</string>

What's the difference between primitive and reference types?

From book OCA JAVA SE 7

Just as men and women are fundamentally different (according to John Gray, author of Men Are from Mars, Women Are from Venus), primitive variables and object reference variables differ from each other in multiple ways. The basic difference is that primitive variables store the actual values, whereas reference variables store the addresses of the objects they refer to. Let’s assume that a class Person is already defined. If you create an int variable a, and an object reference variable person, they will store their values in memory as shown in figure 2.13.

int a = 77;
Person person = new Person();

enter image description here

How to use ADB to send touch events to device using sendevent command?

Android comes with an input command-line tool that can simulate miscellaneous input events. To simulate tapping, it's:

input tap x y

You can use the adb shell ( > 2.3.5) to run the command remotely:

adb shell input tap x y

How do you use bcrypt for hashing passwords in PHP?

You can create a one-way hash with bcrypt using PHP's crypt() function and passing in an appropriate Blowfish salt. The most important of the whole equation is that A) the algorithm hasn't been compromised and B) you properly salt each password. Don't use an application-wide salt; that opens up your entire application to attack from a single set of Rainbow tables.

PHP - Crypt Function

What is the difference between char s[] and char *s?

C99 N1256 draft

There are two different uses of character string literals:

  1. Initialize char[]:

    char c[] = "abc";      

    This is "more magic", and described at 6.7.8/14 "Initialization":

    An array of character type may be initialized by a character string literal, optionally enclosed in braces. Successive characters of the character string literal (including the terminating null character if there is room or if the array is of unknown size) initialize the elements of the array.

    So this is just a shortcut for:

    char c[] = {'a', 'b', 'c', '\0'};

    Like any other regular array, c can be modified.

  2. Everywhere else: it generates an:

    So when you write:

    char *c = "abc";

    This is similar to:

    /* __unnamed is magic because modifying it gives UB. */
    static char __unnamed[] = "abc";
    char *c = __unnamed;

    Note the implicit cast from char[] to char *, which is always legal.

    Then if you modify c[0], you also modify __unnamed, which is UB.

    This is documented at 6.4.5 "String literals":

    5 In translation phase 7, a byte or code of value zero is appended to each multibyte character sequence that results from a string literal or literals. The multibyte character sequence is then used to initialize an array of static storage duration and length just sufficient to contain the sequence. For character string literals, the array elements have type char, and are initialized with the individual bytes of the multibyte character sequence [...]

    6 It is unspecified whether these arrays are distinct provided their elements have the appropriate values. If the program attempts to modify such an array, the behavior is undefined.

6.7.8/32 "Initialization" gives a direct example:

EXAMPLE 8: The declaration

char s[] = "abc", t[3] = "abc";

defines "plain" char array objects s and t whose elements are initialized with character string literals.

This declaration is identical to

char s[] = { 'a', 'b', 'c', '\0' },
t[] = { 'a', 'b', 'c' };

The contents of the arrays are modifiable. On the other hand, the declaration

char *p = "abc";

defines p with type "pointer to char" and initializes it to point to an object with type "array of char" with length 4 whose elements are initialized with a character string literal. If an attempt is made to use p to modify the contents of the array, the behavior is undefined.

GCC 4.8 x86-64 ELF implementation


#include <stdio.h>

int main(void) {
    char *s = "abc";
    printf("%s\n", s);
    return 0;

Compile and decompile:

gcc -ggdb -std=c99 -c main.c
objdump -Sr main.o

Output contains:

 char *s = "abc";
8:  48 c7 45 f8 00 00 00    movq   $0x0,-0x8(%rbp)
f:  00 
        c: R_X86_64_32S .rodata

Conclusion: GCC stores char* it in .rodata section, not in .text.

Note however that the default linker script puts .rodata and .text in the same segment, which has execute but no write permission. This can be observed with:

readelf -l a.out

which contains:

 Section to Segment mapping:
  Segment Sections...
   02     .text .rodata

If we do the same for char[]:

 char s[] = "abc";

we obtain:

17:   c7 45 f0 61 62 63 00    movl   $0x636261,-0x10(%rbp)

so it gets stored in the stack (relative to %rbp).

Download a single folder or directory from a GitHub repo

Open repo to codesandbox by replacing github to githubbox in url and on codesandbox go to file menu and Export it as a zip.

For following repo:

Enter following url:

In codesandbox go to file menu and Export it as a Zip.

Curl command line for consuming webServices?

Posting a string:

curl -d "String to post" ""

Posting the contents of a file:

curl -d @soap.xml ""

Ping with timestamp on Windows CLI

I also need this to monitor the network issue for my database mirroring time out issue. I use the command code as below:

ping -t|cmd /q /v /c "(pause&pause)>nul & for /l %a in () do (set /p "data=" && echo(!date! !time! !data!)&ping -n 2>nul" >C:\pingtest.txt

You just need to modify to your server name. It works perfectly for me. and remember to stop this when you finished. The pingtest.txt file will increase by 4.5 KB per min (around).

Thank for

UnmodifiableMap (Java Collections) vs ImmutableMap (Google)

Have a look at ImmutableMap JavaDoc: doc

There is information about that there:

Unlike Collections.unmodifiableMap(java.util.Map), which is a view of a separate map which can still change, an instance of ImmutableMap contains its own data and will never change. ImmutableMap is convenient for public static final maps ("constant maps") and also lets you easily make a "defensive copy" of a map provided to your class by a caller.

How to create large PDF files (10MB, 50MB, 100MB, 200MB, 500MB, 1GB, etc.) for testing purposes?

One possibility is, if you are familiar with PDF format:

  1. Create some simply PDF with one page (Page should be contained within one object)
  2. Copy object multiply times
  3. Add references to the copied objects to the page catalog
  4. Fix xref table

You get an valid document of any size, entire file will be processed by a reader.

How do you manually execute SQL commands in Ruby On Rails using NuoDB

For me, I couldn't get this to return a hash.

results = ActiveRecord::Base.connection.execute(sql)

But using the exec_query method worked.

results = ActiveRecord::Base.connection.exec_query(sql)

JavaScript pattern for multiple constructors

Didn't feel like doing it by hand as in bobince's answer, so I just completely ripped off jQuery's plugin options pattern.

Here's the constructor:

//default constructor for Preset 'class'
function Preset(params) {
    var properties = $.extend({
        //these are the defaults
        id: null,
        name: null,
        inItems: [],
        outItems: [],
    }, params);

    console.log('Preset instantiated'); =; =;
    this.inItems = properties.inItems;
    this.outItems = properties.outItems;

Here's different ways of instantiation:

presetNoParams = new Preset(); 
presetEmptyParams = new Preset({});
presetSomeParams = new Preset({id: 666, inItems:['item_1', 'item_2']});
presetAllParams = new Preset({id: 666, name: 'SOpreset', inItems: ['item_1', 'item_2'], outItems: ['item_3', 'item_4']});

And here's what that made:

Preset {id: null, name: null, inItems: Array[0], outItems: Array[0]}

Preset {id: null, name: null, inItems: Array[0], outItems: Array[0]}

Preset {id: 666, name: null, inItems: Array[2], outItems: Array[0]}

Preset {id: 666, name: "SOpreset", inItems: Array[2], outItems: Array[2]}

How do I initialize the base (super) class?

As of python 3.5.2, you can use:

class C(B):
def method(self, arg):
    super().method(arg)    # This does the same thing as:
                           # super(C, self).method(arg)

Convert A String (like testing123) To Binary In Java

public class HexadecimalToBinaryAndLong{
  public static void main(String[] args) throws IOException{
    BufferedReader bf = new BufferedReader(new InputStreamReader(;
    System.out.println("Enter the hexa value!");
    String hex = bf.readLine();
    int i = Integer.parseInt(hex);               //hex to decimal
    String by = Integer.toBinaryString(i);       //decimal to binary
    System.out.println("This is Binary: " + by);