Programs & Examples On #Headereditemscontrol

How to initialize a vector of vectors on a struct?

Like this:

#include <vector>

// ...

std::vector<std::vector<int>> A(dimension, std::vector<int>(dimension));

(Pre-C++11 you need to leave whitespace between the angled brackets.)

Replace a character at a specific index in a string?

Turn the String into a char[], replace the letter by index, then convert the array back into a String.

String myName = "domanokz";
char[] myNameChars = myName.toCharArray();
myNameChars[4] = 'x';
myName = String.valueOf(myNameChars);

Detect If Browser Tab Has Focus

Surprising to see nobody mentioned document.hasFocus

if (document.hasFocus()) console.log('Tab is active')

MDN has more information.

java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare();

From :

Additionally, the Android UI toolkit is not thread-safe. So, you must not manipulate your UI from a worker thread—you must do all manipulation to your user interface from the UI thread. Thus, there are simply two rules to Android's single thread model:

  1. Do not block the UI thread
  2. Do not access the Android UI toolkit from outside the UI thread

You have to detect idleness in a worker thread and show a toast in the main thread.

Please post some code, if you want a more detailed answer.

After code publication :

In strings.xml

<string name="idleness_toast">"You are getting late do it fast"</string>


Toast.makeText(getApplicationContext(), getString(R.string.idleness_toast), 

Don't use AlertDialog, make a choice. AlertDialog and Toast are two different things.

How can the default node version be set using NVM?

Alert: This answer is for MacOS only

Let suppose you have 2 versions of nodeJS inside your nvm, namely v13.10.1 & v15.4.0

And, v15.4.0 is default

> nvm list
->      v15.4.0
default -> 15.4.0 (-> v15.4.0)

And, you want to switch the default to v13.10.1

Follow these steps on your Mac terminal:

  1. Run the command:

    nvm alias default 13.10.1

This will make the default point to v13.10.1 as...

default -> 13.10.1 (-> v13.10.1)
  1. Open new instance of terminal. Now check the node version here as...

node -v

You will get...

  1. nvm list will also show the new default version.

    nvm list

Just an info: The NodeJS versions taken as example above will have their different npm versions. You can cross-verify it in terminal by running npm -v

Google Play Services Missing in Emulator (Android 4.4.2)

You will not able to test the app using the Google-Play-Service library in emulator. In order to test that app in emulator you need to install some system framework in your emulator to make it work.

Refer the above answer to install Google play service on your emulator.

Use find command but exclude files in two directories


find \( -path "./tmp" -o -path "./scripts" \) -prune -o  -name "*_peaks.bed" -print


find \( -path "./tmp" -o -path "./scripts" \) -prune -false -o  -name "*_peaks.bed"


find \( -path "./tmp" -path "./scripts" \) ! -prune -o  -name "*_peaks.bed"

The order is important. It evaluates from left to right. Always begin with the path exclusion.


Do not use -not (or !) to exclude whole directory. Use -prune. As explained in the manual:

-prune    The primary shall always evaluate as  true;  it
          shall  cause  find  not  to descend the current
          pathname if it is a directory.  If  the  -depth
          primary  is specified, the -prune primary shall
          have no effect.

and in the GNU find manual:

-path pattern
              To ignore  a  whole
              directory  tree,  use  -prune rather than checking
              every file in the tree.

Indeed, if you use -not -path "./pathname", find will evaluate the expression for each node under "./pathname".

find expressions are just condition evaluation.

  • \( \) - groups operation (you can use -path "./tmp" -prune -o -path "./scripts" -prune -o, but it is more verbose).
  • -path "./script" -prune - if -path returns true and is a directory, return true for that directory and do not descend into it.
  • -path "./script" ! -prune - it evaluates as (-path "./script") AND (! -prune). It revert the "always true" of prune to always false. It avoids printing "./script" as a match.
  • -path "./script" -prune -false - since -prune always returns true, you can follow it with -false to do the same than !.
  • -o - OR operator. If no operator is specified between two expressions, it defaults to AND operator.

Hence, \( -path "./tmp" -o -path "./scripts" \) -prune -o -name "*_peaks.bed" -print is expanded to:

[ (-path "./tmp" OR -path "./script") AND -prune ] OR ( -name "*_peaks.bed" AND print )

The print is important here because without it is expanded to:

{ [ (-path "./tmp" OR -path "./script" )  AND -prune ]  OR (-name "*_peaks.bed" ) } AND print

-print is added by find - that is why most of the time, you do not need to add it in you expression. And since -prune returns true, it will print "./script" and "./tmp".

It is not necessary in the others because we switched -prune to always return false.

Hint: You can use find -D opt expr 2>&1 1>/dev/null to see how it is optimized and expanded,
find -D search expr 2>&1 1>/dev/null to see which path is checked.

Javascript - removing undefined fields from an object

A one-liner using ES6 arrow function and ternary operator:

Object.keys(obj).forEach(key => obj[key] === undefined ? delete obj[key] : {});

Or use short-circuit evaluation instead of ternary: (@Matt Langlois, thanks for the info!)

Object.keys(obj).forEach(key => obj[key] === undefined && delete obj[key])

Same example using if statement:

Object.keys(obj).forEach(key => {
  if (obj[key] === undefined) {
    delete obj[key];

If you want to remove the items from nested objects as well, you can use a recursive function:

const removeEmpty = (obj) => {
  let newObj = {};
  Object.keys(obj).forEach((key) => {
    if (obj[key] === Object(obj[key])) newObj[key] = removeEmpty(obj[key]);
    else if (obj[key] !== undefined) newObj[key] = obj[key];
  return newObj;

Importing class/java files in Eclipse

You can import a bunch of .java files to your existing project without creating a new project. Here are the steps:

  1. Right-click on the Default Package in the Project Manager pane underneath your project and choose Import
  2. An Import Wizard window will display. Choose File system and select the Next button
  3. You are now prompted to choose a file
  4. Simply browse your folder with .java files in it
  5. Select desired .java files
  6. Click on Finish to finish the import wizard

Check the following webpage for more information:

UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 13: ordinal not in range(128)

To find ANY and ALL unicode error related... Using the following command:

grep -r -P '[^\x00-\x7f]' /etc/apache2 /etc/letsencrypt /etc/nginx

Found mine in

/etc/letsencrypt/options-ssl-nginx.conf:        # The following CSP directives don't use default-src as 

Using shed, I found the offending sequence. It turned out to be an editor mistake.

00008099:     C2  194 302 11000010
00008100:     A0  160 240 10100000
00008101:  d  64  100 144 01100100
00008102:  e  65  101 145 01100101
00008103:  f  66  102 146 01100110
00008104:  a  61  097 141 01100001
00008105:  u  75  117 165 01110101
00008106:  l  6C  108 154 01101100
00008107:  t  74  116 164 01110100
00008108:  -  2D  045 055 00101101
00008109:  s  73  115 163 01110011
00008110:  r  72  114 162 01110010
00008111:  c  63  099 143 01100011
00008112:     C2  194 302 11000010
00008113:     A0  160 240 10100000

How to use mongoose findOne

Use obj[0].nick and you will get desired result,

S3 Static Website Hosting Route All Paths to Index.html

I ran into the same problem today but the solution of @Mark-Nutter was incomplete to remove the hashbang from my angularjs application.

In fact you have to go to Edit Permissions, click on Add more permissions and then add the right List on your bucket to everyone. With this configuration, AWS S3 will now, be able to return 404 error and then the redirection rule will properly catch the case.

Just like this : enter image description here

And then you can go to Edit Redirection Rules and add this rule :


Here you can replace the HostName with your domain and the KeyPrefix #!/ if you don't use the hashbang method for SEO purpose.

Of course, all of this will only work if you have already have setup html5mode in your angular application.


Strangest language feature

In PHP function names are not case sensitive. This might lead you to think that all identifiers in php are not case sensitive. Guess again. Variables ARE case sensitive. WTF.

function add($a, $b)
    return $a + $b;

$foo = add(1, 2);
$Foo = Add(3, 4);

echo "foo is $foo"; // outputs foo is 3
echo "Foo is $Foo"; // outputs Foo is 7

Failed to find Build Tools revision 23.0.1

In the Gradle Console (link available in the window bottom right), you have two tabs: the error is shown in Gradle Build tab. Click on the Gradle Sync tab, then click on the Install Build Tools XX.X.X and sync project link. This will download the build version required by your project.

You may also change your project SDK version but you don't always have this option if it is imposed.

How can I remove an SSH key?

If you're trying to perform an SSH-related operation and get the following error:

$ git fetch
no such identity: <ssh key path>: No such file or directory

You can remove the missing SSH key from your SSH agent with the following:

$ eval `ssh-agent -s`  # start ssh agent
$ ssh-add -D <ssh key path>  # delete ssh key

PHP Fatal error: Cannot access empty property

First, don't declare variables using var, but

public $my_value;

Then you can access it using


and not


How to unstage large number of files without deleting the content

If you want to unstage all the changes use below command,

git reset --soft HEAD

In the case you want to unstage changes and revert them from the working directory,

git reset --hard HEAD

Get current index from foreach loop

IEnumerable list = DataGridDetail.ItemsSource as IEnumerable;
List<string> lstFile = new List<string>();

int i = 0;
foreach (var row in list)
bool IsChecked = (bool)((CheckBox)DataGridDetail.Columns[0].GetCellContent(row)).IsChecked;
if (IsChecked)
--Here i want to get the index or current row from the list                   


jquery select option click handler

The problem that I had with the change handler was that it triggered on every keypress that I scrolled up and down the <select>.

I wanted to get the event for whenever an option was clicked or when enter was pressed on the desired option. This is how I ended up doing it:

let blockChange = false;

$element.keydown(function (e) {

    const keycode = (e.keyCode ? e.keyCode : e.which);

    // prevents select opening when enter is pressed
    if (keycode === 13) {

    // lets the change event know that these keypresses are to be ignored
    if([38, 40].indexOf(keycode) > -1){
        blockChange = true;


$element.keyup(function(e) {

    const keycode = (e.keyCode ? e.keyCode : e.which);
    // handle enter press
    if(keycode === 13) {


$element.change(function(e) {

    // this effective handles the click only as preventDefault was used on enter
    if(!blockChange) {
    blockChange = false;


How can I get the Windows last reboot reason

Take a look at the Event Log API. Case a) (bluescreen, user cut the power cord or system hang) causes a note ('system did not shutdown correctly' or something like that) to be left in the 'System' event log the next time the system is rebooted properly. You should be able to access it programmatically using the above API (honestly, I've never used it but it should work).

How to get a variable value if variable name is stored as string?

eval "Z=\$$Y"

sets Z to "foo"

Take care using eval since this may allow accidential excution of code through values in ${Y}. This may cause harm through code injection.

For example

Y="\`touch /tmp/eval-is-evil\`"

would create /tmp/eval-is-evil. This could also be some rm -rf /, of course.

How to wrap text around an image using HTML/CSS

With CSS Shapes you can go one step further than just float text around a rectangular image.

You can actually wrap text such that it takes the shape of the edge of the image or polygon that you are wrapping it around.

DEMO FIDDLE (Currently working on webkit - caniuse)

.oval {_x000D_
  width: 400px;_x000D_
  height: 250px;_x000D_
  color: #111;_x000D_
  border-radius: 50%;_x000D_
  text-align: center;_x000D_
  font-size: 90px;_x000D_
  float: left;_x000D_
  shape-outside: ellipse();_x000D_
  padding: 10px;_x000D_
  background-color: MediumPurple;_x000D_
  background-clip: content-box;_x000D_
span {_x000D_
  padding-top: 70px;_x000D_
  display: inline-block;_x000D_
<div class="oval"><span>PHP</span>_x000D_
<p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has_x000D_
  survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing_x000D_
  software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley_x000D_
  of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing_x000D_
  Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy_x000D_
  text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised_x000D_
  in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>

Also, here is a good list apart article on CSS Shapes

Create tap-able "links" in the NSAttributedString of a UILabel?

Translating @samwize's Extension to Swift 4:

extension UITapGestureRecognizer {
    func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
        guard let attrString = label.attributedText else {
            return false

        let layoutManager = NSLayoutManager()
        let textContainer = NSTextContainer(size: .zero)
        let textStorage = NSTextStorage(attributedString: attrString)


        textContainer.lineFragmentPadding = 0
        textContainer.lineBreakMode = label.lineBreakMode
        textContainer.maximumNumberOfLines = label.numberOfLines
        let labelSize = label.bounds.size
        textContainer.size = labelSize

        let locationOfTouchInLabel = self.location(in: label)
        let textBoundingBox = layoutManager.usedRect(for: textContainer)
        let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x, y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y)
        let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x, y: locationOfTouchInLabel.y - textContainerOffset.y)
        let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        return NSLocationInRange(indexOfCharacter, targetRange)

To set up the recognizer (once you colored the text and stuff):

lblTermsOfUse.isUserInteractionEnabled = true
lblTermsOfUse.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleTapOnLabel(_:))))

...then the gesture recognizer:

@objc func handleTapOnLabel(_ recognizer: UITapGestureRecognizer) {
    guard let text = lblAgreeToTerms.attributedText?.string else {

    if let range = text.range(of: NSLocalizedString("_onboarding_terms", comment: "terms")),
        recognizer.didTapAttributedTextInLabel(label: lblAgreeToTerms, inRange: NSRange(range, in: text)) {
    } else if let range = text.range(of: NSLocalizedString("_onboarding_privacy", comment: "privacy")),
        recognizer.didTapAttributedTextInLabel(label: lblAgreeToTerms, inRange: NSRange(range, in: text)) {


Actually they are the same. LEFT OUTER JOIN is same as LEFT JOIN and RIGHT OUTER JOIN is same as RIGHT JOIN. It is more informative way to compare from INNER Join.

See this Wikipedia article for details.

rand() returns the same number each time the program is run

For what its worth you are also only generating numbers between 0 and 99 (inclusive). If you wanted to generate values between 0 and 100 you would need.

rand() % 101

in addition to calling srand() as mentioned by others.

Get text from pressed button

If you're sure that the OnClickListener instance is applied to a Button, then you could just cast the received view to a Button and get the text:

public void onClick(View view){
Button b = (Button)view;
String text = b.getText().toString();

Can't find SDK folder inside Android studio path, and SDK manager not opening

If your are using android studio go to file >> project structure on the left pane press on SDK location . you will find the path where your sdk is located

HTML input field hint

If you mean like a text in the background, I'd say you use a label with the input field and position it on the input using CSS, of course. With JS, you fade out the label when the input receives values and fade it in when the input is empty. In this way, it is not possible for the user to submit the description, whether by accident or intent.

getting only name of the class Class.getName()

Get simple name instead of path.

String onlyClassName =  this.getLocalClassName(); 

call above method in onCreate

Css height in percent not working

Add height:100% to body


How to check if a network port is open on linux?

In case when you probing TCP ports with intention to listen on it, it’s better to actually call listen. The approach with tring to connect don’t 'see' client ports of established connections, because nobody listen on its. But these ports cannot be used to listen on its.

import socket

def check_port(port, rais=True):
    """ True -- it's possible to listen on this port for TCP/IPv4 or TCP/IPv6
    connections. False -- otherwise.
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.bind(('', port))
        sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
        sock.bind(('::1', port))
    except socket.error as e:
        return False
        if rais:
            raise RuntimeError(
                "The server is already running on port {0}".format(port))
    return True

I want to multiply two columns in a pandas DataFrame and add the result into a new column

Good solution from bmu. I think it's more readable to put the values inside the parentheses vs outside.

    df['Values'] = np.where(df.Action == 'Sell', 

Using some pandas built in functions.

    df['Values'] = np.where(df.Action.eq('Sell'), 

Best way to store time (hh:mm) in a database

The saving of time in UTC format can help better as Kristen suggested.

Make sure that you are using 24 hr clock because there is no meridian AM or PM be used in UTC.


  • 4:12 AM - 0412
  • 10:12 AM - 1012
  • 2:28 PM - 1428
  • 11:56 PM - 2356

Its still preferrable to use standard four digit format.

How can I explicitly free memory in Python?

Others have posted some ways that you might be able to "coax" the Python interpreter into freeing the memory (or otherwise avoid having memory problems). Chances are you should try their ideas out first. However, I feel it important to give you a direct answer to your question.

There isn't really any way to directly tell Python to free memory. The fact of that matter is that if you want that low a level of control, you're going to have to write an extension in C or C++.

That said, there are some tools to help with this:

How do I remove trailing whitespace using a regular expression?

Try just removing trailing spaces and tabs:

[ \t]+$

Get the current first responder without using a private API

This is good candidate for recursion! No need to add a category to UIView.

Usage (from your view controller):

UIView *firstResponder = [self findFirstResponder:[self view]];


// This is a recursive function
- (UIView *)findFirstResponder:(UIView *)view {

    if ([view isFirstResponder]) return view; // Base case

    for (UIView *subView in [view subviews]) {
        if ([self findFirstResponder:subView]) return subView; // Recursion
    return nil;

UnicodeDecodeError: 'utf8' codec can't decode byte 0xa5 in position 0: invalid start byte

This solution worked for me:

import pandas as pd
data = pd.read_csv("training.csv", encoding = 'unicode_escape')

How to multi-line "Replace in files..." in Notepad++

Actually it's way easier to use ToolBucket plugin for Notepad++ to multiline replace.

To activate it just go to N++ menu:

Plugins > Plugin Manager > Show Plugin Manager > Check ToolBucket > Install.

Restart N++ and press ALT + SHIFT + F to multiline edit.

Failed to decode downloaded font

For me, the mistake was forgetting to put FTP into binary mode before uploading the font files.


You can test for this by uploading other types of binary data like images. If they also fail to display, then this may be your issue.

HTML <input type='file'> File Selection Event

jQuery way:

$('input[name=myInputName]').change(function(ev) {

    // your code

Node.js: get path from the request

Combining solutions above when using express request:

let url=url.parse(req.originalUrl);
let page = url.parse(uri).path?url.parse(uri).path.match('^[^?]*')[0].split('/').slice(1)[0] : '';

this will handle all cases like


etc. Some examples:

> urls
[ 'http://localhost/page',
  'http://localhost:3000' ]
> => url.parse(uri).path?url.parse(uri).path.match('^[^?]*')[0].split('/').slice(1)[0] : '' )
[ 'page', 'page', 'page', '', '', '', 'page', 'page', '', '' ]

AssertionError: View function mapping is overwriting an existing endpoint function: main

Adding @wraps(f) above the wrapper function solved my issue.

def list_ownership(f):
    def decorator(*args,**kwargs):
        return f(args,kwargs)
    return decorator

How to load CSS Asynchronously

The trick to triggering an asynchronous stylesheet download is to use a <link> element and set an invalid value for the media attribute (I'm using media="none", but any value will do). When a media query evaluates to false, the browser will still download the stylesheet, but it won't wait for the content to be available before rendering the page.

<link rel="stylesheet" href="css.css" media="none">

Once the stylesheet has finished downloading the media attribute must be set to a valid value so the style rules will be applied to the document. The onload event is used to switch the media property to all:

<link rel="stylesheet" href="css.css" media="none" onload="if(media!='all')media='all'">

This method of loading CSS will deliver useable content to visitors much quicker than the standard approach. Critical CSS can still be served with the usual blocking approach (or you can inline it for ultimate performance) and non-critical styles can be progressively downloaded and applied later in the parsing / rendering process.

This technique uses JavaScript, but you can cater for non-JavaScript browsers by wrapping the equivalent blocking <link> elements in a <noscript> element:

<link rel="stylesheet" href="css.css" media="none" onload="if(media!='all')media='all'"><noscript><link rel="stylesheet" href="css.css"></noscript>

You can see the operation in

enter image description here

Source in

Using an index to get an item, Python

You can use _ _getitem__(key) function.

>>> iterable = ('A', 'B', 'C', 'D', 'E')
>>> key = 4
>>> iterable.__getitem__(key)

Unable to copy file - access to the path is denied

Just make sure that the folder is NOT Read-Only and rebuild the solution

Adding items to end of linked list

public static Node insertNodeAtTail(Node head,Object data) {
               Node node = new Node(data);
        = null;
                if (head == null){
                    return node;
                    Node temp = head;
                    while( != null){
                        temp =;
           = node; 
                    return head;

Perform Segue programmatically and pass parameters to the destination view

Old question but here's the code on how to do what you are asking. In this case I am passing data from a selected cell in a table view to another view controller.

in the .h file of the trget view:

@property(weak, nonatomic)  NSObject* dataModel;

in the .m file:

@synthesize dataModel;

dataModel can be string, int, or like in this case it's a model that contains many items

- (void)someMethod {
     [self performSegueWithIdentifier:@"loginMainSegue" sender:self];


- (void)someMethod {
    UIViewController *myController = [self.storyboard instantiateViewControllerWithIdentifier:@"HomeController"];
    [self.navigationController pushViewController: myController animated:YES];

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if([segue.identifier isEqualToString:@"storyDetailsSegway"]) {
        UITableViewCell *cell = (UITableViewCell *) sender;
        NSIndexPath *indexPath = [self.tableView indexPathForCell:cell];
        NSDictionary *storiesDict =[topStories objectAtIndex:[indexPath row]];
        StoryModel *storyModel = [[StoryModel alloc] init];
        storyModel = storiesDict;
        StoryDetails *controller = (StoryDetails *)segue.destinationViewController;
        controller.dataModel= storyModel;

JavaScript: How do I print a message to the error console?

console.error(message); //gives you the red errormessage
console.log(message); //gives the default message
console.warn(message); //gives the warn message with the exclamation mark in front of it; //gives an info message with an 'i' in front of the message

You also can add CSS to your logging messages:

console.log('%c My message here', "background: blue; color: white; padding-left:10px;");

Html.RenderPartial() syntax with Razor

  • RenderPartial() is a void method that writes to the response stream. A void method, in C#, needs a ; and hence must be enclosed by { }.

  • Partial() is a method that returns an MvcHtmlString. In Razor, You can call a property or a method that returns such a string with just a @ prefix to distinguish it from plain HTML you have on the page.

How to save a base64 image to user's disk using JavaScript?

In JavaScript you cannot have the direct access to the filesystem. However, you can make browser to pop up a dialog window allowing the user to pick the save location. In order to do this, use the replace method with your Base64String and replace "image/png" with "image/octet-stream":

"data:image/png;base64,iVBORw0KG...".replace("image/png", "image/octet-stream");

Also, W3C-compliant browsers provide 2 methods to work with base64-encoded and binary data:

Probably, you will find them useful in a way...

Here is a refactored version of what I understand you need:

window.addEventListener('DOMContentLoaded', () => {_x000D_
  const img = document.getElementById('embedImage');_x000D_
  img.src = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUA' +_x000D_
  img.addEventListener('load', () => button.removeAttribute('disabled'));_x000D_
  const button = document.getElementById('saveImage');_x000D_
  button.addEventListener('click', () => {_x000D_
    window.location.href = img.src.replace('image/png', 'image/octet-stream');_x000D_
<!DOCTYPE html>_x000D_
  <img id="embedImage" alt="Red dot" />_x000D_
  <button id="saveImage" disabled="disabled">save image</button>_x000D_

Regular Expressions- Match Anything

  1. Regex:

    /I bought.*sheep./

    Matches - the whole string till the end of line

    I bought sheep. I bought a sheep. I bought five sheep.

  2. Regex:

    /I bought(.*)sheep./

    Matches - the whole string and also capture the sub string within () for further use

    I bought sheep. I bought a sheep. I bought five sheep.

    I boughtsheep. I bought a sheep. I bought fivesheep.

    Example using Javascript/Regex

    'I bought sheep. I bought a sheep. I bought five sheep.'.match(/I bought(.*)sheep./)[0];


    "I bought sheep. I bought a sheep. I bought five sheep."

    'I bought sheep. I bought a sheep. I bought five sheep.'.match(/I bought(.*)sheep./)[1];


    " sheep. I bought a sheep. I bought five "

javascript windows alert with redirect function

Use this if you also want to consider non-javascript users:

echo ("<SCRIPT LANGUAGE='JavaScript'>
           window.alert('Succesfully Updated')
           <a href=''>Successfully Updated. Click here if you are not redirected.</a>

Is there a max size for POST parameter content?

As per this the default is 2 MB for your <Connector>.

maxPostSize = The maximum size in bytes of the POST which will be handled by the container FORM URL parameter parsing. The limit can be disabled by setting this attribute to a value less than or equal to 0. If not specified, this attribute is set to 2097152 (2 megabytes).

Edit Tomcat's server.xml. In the <Connector> element, add an attribute maxPostSize and set a larger value (in bytes) to increase the limit.

Having said that, if this is the issue, you should have got an exception on the lines of Post data too big in tomcat

For Further Info

Test if object implements interface

Recently I tried using Andrew Kennan's answer and it didn't work for me for some reason. I used this instead and it worked (note: writing the namespace might be required).

if (typeof(someObject).GetInterface("MyNamespace.IMyInterface") != null)

Sending Arguments To Background Worker?

Check out the DoWorkEventArgs.Argument Property:


private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    // Do not access the form's BackgroundWorker reference directly.
    // Instead, use the reference provided by the sender parameter.
    BackgroundWorker bw = sender as BackgroundWorker;

    // Extract the argument.
    int arg = (int)e.Argument;

    // Start the time-consuming operation.
    e.Result = TimeConsumingOperation(bw, arg);

    // If the operation was canceled by the user, 
    // set the DoWorkEventArgs.Cancel property to true.
    if (bw.CancellationPending)
        e.Cancel = true;

background-size in shorthand background property (CSS3)

try out like this

body {
   background: #fff url("!--MIZO-PRO--!") no-repeat center 15px top 15px/100px;

/* 100px is the background size */

How to connect to a MS Access file (mdb) using C#?

Here's how to use a Jet OLEDB or Ace OLEDB Access DB:

using System.Data;
using System.Data.OleDb;

string myConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;" +
                           "Data Source=C:\myPath\myFile.mdb;" +                                    
                           "Persist Security Info=True;" +
                           "Jet OLEDB:Database Password=myPassword;";
    // Open OleDb Connection
    OleDbConnection myConnection = new OleDbConnection();
    myConnection.ConnectionString = myConnectionString;

    // Execute Queries
    OleDbCommand cmd = myConnection.CreateCommand();
    cmd.CommandText = "SELECT * FROM `myTable`";
    OleDbDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection); // close conn after complete

    // Load the result into a DataTable
    DataTable myDataTable = new DataTable();
catch (Exception ex)
    Console.WriteLine("OLEDB Connection FAILED: " + ex.Message);

Checking if type == list in python

Your issue is that you have re-defined list as a variable previously in your code. This means that when you do type(tmpDict[key])==list if will return False because they aren't equal.

That being said, you should instead use isinstance(tmpDict[key], list) when testing the type of something, this won't avoid the problem of overwriting list but is a more Pythonic way of checking the type.

Go to particular revision

Before executing this command keep in mind that it will leave you in detached head status

Use git checkout <sha1> to check out a particular commit.

Where <sha1> is the commit unique number that you can obtain with git log

Here are some options after you are in detached head status:

  • Copy the files or make the changes that you need to a folder outside your git folder, checkout the branch were you need them git checkout <existingBranch> and replace files
  • Create a new local branch git checkout -b <new_branch_name> <sha1>

Getting a link to go to a specific section on another page

You can simply use

 <a href="directry/filename.html#section5" >click me</a>

to link to a section/id of another page by

org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update

You can find your sample code completely here:

Have a look and check the differences. specially the even_id in :

<set name="attendees" cascade="all">
    <key column="event_id"/>
    <one-to-many class="Attendee"/>

Disabled href tag

The best answer is always the simplest. No need for any coding.

If the (a) anchor tag has no href attribute, it is only a placeholder for a hyperlink. Supported by all browsers!

<a href="/">free web counters</a><br  />_x000D_
<a "/">free web counters</a>

How to Get a Sublist in C#

Use the Where clause from LINQ:

List<object> x = new List<object>();

var z = x.Where(p => p == "A");
z = x.Where(p => p == "B");

In the statements above "p" is the object that is in the list. So if you used a data object, i.e.:

public class Client
    public string Name { get; set; }

then your linq would look like this:

List<Client> x = new List<Client>();
x.Add(new Client() { Name = "A" });
x.Add(new Client() { Name = "B" });
x.Add(new Client() { Name = "C" });
x.Add(new Client() { Name = "D" });
x.Add(new Client() { Name = "B" });

var z = x.Where(p => p.Name == "A");
z = x.Where(p => p.Name == "B");

Using sed, how do you print the first 'N' characters of a line?

colrm x

For example, if you need the first 100 characters:

cat file |colrm 101 

It's been around for years and is in most linux's and bsd's (freebsd for sure), usually by default. I can't remember ever having to type apt-get install colrm.

How to convert JSON string to array

    "action" : "create",
    "record" : {
                "type": "$product",
                "fields": {
                           "name": "Bread",
                           "price": "2.11"
                "namespaces": { "my.demo": "n" }
echo $str;
echo "<br>";
$jsonstr = json_decode($str, true);


i think this should Work, its just that the Keys should also be in double quotes if they are not numerals.

Sort columns of a dataframe by column name

Similar to other syntax above but for learning - can you sort by column names?

sort(colnames(test[1:ncol(test)] ))

Import-CSV and Foreach

You can create the headers on the fly (no need to specify delimiter when the delimiter is a comma):

Import-CSV $filepath -Header IP1,IP2,IP3,IP4 | Foreach-Object{
   Write-Host $_.IP1
   Write-Host $_.IP2

"undefined" function declared in another file?

I ran into the same issue with Go11, just wanted to share how I did solve it for helping others just in case they run into the same issue.

I had my Go project outside $GOPATH, so I had to turned on GO111MODULE=on without this option turned on, it will give you this issue; even if you you try to build or test the whole package or directory it won't be solved without GO111MODULE=on

Restoring MySQL database from physical files

I once copied these files to the database storage folder for a mysql database which was working, started the db and waited for it to "repair" the files, then extracted them with mysqldump.

Hiding table data using <div style="display:none">

Just set the display:none on the elements that you want to hide:

<tr><th>Test Table</th><tr>
<tr style="display:none"><td>1. 123456789</td><tr>
<tr><td>2. 123456789</td><tr>
<tr><td>3. 123456789</td><tr>

Selecting data from two different servers in SQL Server

Simplified solution for adding linked servers

First server

EXEC sp_addlinkedserver @server='ip,port\instancename'

Second Login

EXEC sp_addlinkedsrvlogin 'ip,port\instancename', 'false', NULL, 'remote_db_loginname', 'remote_db_pass'

Execute queries from linked to local db

INSERT INTO Tbl (Col1, Col2, Col3)
SELECT Col1, Col2, Col3
FROM [ip,port\instancename].[linkedDBName].[linkedTblSchema].[linkedTblName]

Difference between SRC and HREF

NOTE: @John-Yin's answer is more appropriate considering the changes in the specs.

Yes. There is a differentiation between src and href and they can't be used interchangeably. We use src for replaced elements while href for establishing a relationship between the referencing document and an external resource.

href (Hypertext Reference) attribute specifies the location of a Web resource thus defining a link or relationship between the current element (in case of anchor a) or current document (in case of link) and the destination anchor or resource defined by this attribute. When we write:

<link href="style.css" rel="stylesheet" />

The browser understands that this resource is a stylesheet and the processing parsing of the page is not paused (rendering might be paused since the browser needs the style rules to paint and render the page). It is not similar to dumping the contents of the css file inside the style tag. (Hence it is advisable to use link rather than @import for attaching stylesheets to your html document.)

src (Source) attribute just embeds the resource in the current document at the location of the element's definition. For eg. When the browser finds

<script src="script.js"></script>

The loading and processing of the page is paused until this the browser fetches, compiles and executes the file. It is similar to dumping the contents of the js file inside the script tag. Similar is the case with img tag. It is an empty tag and the content, that should come inside it, is defined by the src attribute. The browser pauses the loading until it fetches and loads the image. [so is the case with iframe]

This is the reason why it is advisable to load all JavaScript files at the bottom (before the </body> tag)

update : Refer @John-Yin's answer for more info on how it is implemented as per HTML 5 specs.

Create an ISO date object in javascript

In node, the Mongo driver will give you an ISO string, not the object. (ex: Mon Nov 24 2014 01:30:34 GMT-0800 (PST)) So, simply convert it to a js Date by: new Date(ISOString);

Transpose a range in VBA

Something like this should do it for you.

Sub CombineColumns1()
    Dim xRng As Range
    Dim i As Long, j As Integer
    Dim xNextRow As Long
    Dim xTxt As String
    On Error Resume Next
    With ActiveSheet
        xTxt = .RangeSelection.Address
        Set xRng = Application.InputBox("please select the data range", "Kutools for Excel", xTxt, , , , , 8)
        If xRng Is Nothing Then Exit Sub
        j = xRng.Columns(1).Column
        For i = 4 To xRng.Columns.Count Step 3
            'Need to recalculate the last row, as some of the final columns may not have data in all rows
            xNextRow = .Cells(.Rows.Count, j).End(xlUp).Row + 1

            .Range(xRng.Cells(1, i), xRng.Cells(xRng.Rows.Count, i + 2)).Copy .Cells(xNextRow, j)
            .Range(xRng.Cells(1, i), xRng.Cells(xRng.Rows.Count, i + 2)).Clear
    End With
End Sub

You could do this too.

Sub TransposeFormulas()
    Dim vFormulas As Variant
    Dim oSel As Range
    If TypeName(Selection) <> "Range" Then
        MsgBox "Please select a range of cells first.", _
                vbOKOnly + vbInformation, "Transpose formulas"
        Exit Sub
    End If
    Set oSel = Selection
    vFormulas = oSel.Formula
    vFormulas = Application.WorksheetFunction.Transpose(vFormulas)
    oSel.Offset(oSel.Rows.Count + 2).Resize(oSel.Columns.Count, oSel.Rows.Count).Formula = vFormulas
End Sub

See this for more info.

std::string to float or double

std::string num = "0.6";
double temp = ::atof(num.c_str());

Does it for me, it is a valid C++ syntax to convert a string to a double.

You can do it with the stringstream or boost::lexical_cast but those come with a performance penalty.

Ahaha you have a Qt project ...

QString winOpacity("0.6");
double temp = winOpacity.toDouble();

Extra note:
If the input data is a const char*, QByteArray::toDouble will be faster.

How to fix syntax error, unexpected T_IF error in php?

PHP parser errors take some getting used to; if it complains about an unexpected 'something' at line X, look at line X-1 first. In this case it will not tell you that you forgot a semi-colon at the end of the previous line , instead it will complain about the if that comes next.

You'll get used to it :)

E: Unable to locate package mongodb-org

The currently accepted answer works, but will install an outdated version of Mongo.

The Mongo documentation states that: MongoDB only provides packages for Ubuntu 12.04 LTS (Precise Pangolin) and 14.04 LTS (Trusty Tahr). However, These packages may work with other Ubuntu releases.

So, to get the lastest stable Mongo (3.0), use this (the different step is the second one):

    apt-key adv --keyserver hkp:// --recv 7F0CEB10
    echo "deb trusty/mongodb-org/3.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb.list
    apt-get update
    apt-get install mongodb-org

Hope this helps.

I would like to add that as a previous step, you must check your GNU/Linux Distro Release, which will construct the Repo list url. For me, as I am using this:

DISTRIB_DESCRIPTION="Linux Mint 17.2 Rafaela"
VERSION="14.04.2 LTS, Trusty Tahr"
PRETTY_NAME="Ubuntu 14.04.2 LTS"

The original 2nd step:

"Create a list file for MongoDB": "echo "deb "$(lsb_release -sc)"/mongodb-org/3.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.0.list"

Didn't work as intended because it generated an incorrect Repo url. Basically, it put the distribution codename "rafaela" within the url repo which doesn't exist. You can check the Repo url at your package manager under Software Sources, Additional Repositories.

What I did was to browse the site:

And I found out that for Ubuntu, "trusty" and "precise" are the only web folders available, not "rafaela".

Solution: Open as root the file 'mongodb-org-3.1.list' or 'mongodb.list' and replace "rafaela" or your release version for the corresponding version (for me it was: "trusty"), save the changes and continue with next steps. Also, your package manager can let you change easily the repo url as well.

Hope it works for you.! ---

How to find the port for MS SQL Server 2008?

Try this (requires access to sys.dm_exec_connections):

FROM sys.dm_exec_connections 
WHERE local_tcp_port IS NOT NULL

Only variables should be passed by reference

end(...[explode('.', $file_name)]) has worked since PHP 5.6. This is documented in the RFC although not in PHP docs themselves.

Importing .py files in Google Colab

Try this way:

I have a package named plant_seedlings. The package is stored in google drive. What I should do is to copy this package in /usr/local/lib/python3.6/dist-packages/.

!cp /content/drive/ai/plant_seedlings.tar.gz /usr/local/lib/python3.6/dist-packages/

!cd /usr/local/lib/python3.6/dist-packages/ && tar -xzf plant_seedlings.tar.gz

!cd /content

!python -m plant_seedlings

How can I use jQuery to make an input readonly?

Use this example to make text box ReadOnly or Not.

<input type="textbox" class="txt" id="txt"/>
<input type="button" class="Btn_readOnly" value="Readonly" />
<input type="button" class="Btn_notreadOnly" value="Not Readonly" />


           $("#txt").prop("readonly", true);

           $("#txt").prop("readonly", false);


LINQ equivalent of foreach for IEnumerable<T>

Fredrik has provided the fix, but it may be worth considering why this isn't in the framework to start with. I believe the idea is that the LINQ query operators should be side-effect-free, fitting in with a reasonably functional way of looking at the world. Clearly ForEach is exactly the opposite - a purely side-effect-based construct.

That's not to say this is a bad thing to do - just thinking about the philosophical reasons behind the decision.

How to ensure that there is a delay before a service is started in systemd?

You can run the sleep command before your ExecStart with ExecStartPre :

ExecStartPre=/bin/sleep 30

Move view with keyboard using Swift

Here is my solution (actually this code is for the case when you have few textfields in your view, this works also for the case when you have one textfield)

class MyViewController: UIViewController, UITextFieldDelegate {

@IBOutlet weak var firstTextField: UITextField!
@IBOutlet weak var secondTextField: UITextField!

var activeTextField: UITextField!
var viewWasMoved: Bool = false

override func viewDidLoad() {
    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(PrintViewController.keyboardWillShow(_:)), name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(PrintViewController.keyboardWillHide(_:)), name: UIKeyboardWillHideNotification, object: nil)

override func viewDidDisappear(animated: Bool) {

func textFieldDidBeginEditing(textField: UITextField) {
    self.activeTextField = textField

func textFieldDidEndEditing(textField: UITextField) {
    self.activeTextField = nil

func textFieldShouldReturn(textField: UITextField) -> Bool {
    return true

func keyboardWillShow(notification: NSNotification) {

    let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()

    var aRect: CGRect = self.view.frame
    aRect.size.height -= keyboardSize!.height

    let activeTextFieldRect: CGRect? = activeTextField?.frame
    let activeTextFieldOrigin: CGPoint? = activeTextFieldRect?.origin

    if (!CGRectContainsPoint(aRect, activeTextFieldOrigin!)) {
        self.viewWasMoved = true
        self.view.frame.origin.y -= keyboardSize!.height
    } else {
        self.viewWasMoved = false

func keyboardWillHide(notification: NSNotification) {
    if (self.viewWasMoved) {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
            self.view.frame.origin.y += keyboardSize.height

How to select an element with 2 classes

Just chain them together:

.a.b {
  color: #666;

get all the elements of a particular form

Use this

var theForm = document.forms['formname']
[] (el, i) {

The el stands for the particular form element. It is better to use this than the foreach loop, as the foreach loop also returns a function as one of the element. However this only returns the DOM elements of the form.

JSON string to JS object

You can use this library from to translate your string into a JSON object.

var var1_obj = JSON.parse(var1);

Or you can use the jquery-json library as well.

var var1_obj = $.toJSON(var1);

How to Get the Current URL Inside @if Statement (Blade) in Laravel 4?

You can also use Route::current()->getName() to check your route name.

Example: routes.php

Route::get('test', ['as'=>'testing', function() {
    return View::make('test');


@if(Route::current()->getName() == 'testing')
    Hello This is testing

How to capture multiple repeated groups?

You actually have one capture group that will match multiple times. Not multiple capture groups.

javascript (js) solution:

let string = "HI,THERE,TOM";
let myRegexp = /([A-Z]+),?/g;       //modify as you like
let match = myRegexp.exec(string);  //js function, output described below
while(match!=null){                 //loops through matches
    console.log(match[1]);          //do whatever you want with each match
    match = myRegexp.exec(bob);     //find next match




// matched text: match[0]
// match start: match.index
// capturing group n: match[n]

As you can see, this will work for any number of matches.

Apache POI Excel - how to configure columns to be expanded?

You can wrap the text as well. PFB sample code:

CellStyle wrapCellStyle = new_workbook.createCellStyle();

How can I use xargs to copy files that have spaces and quotes in their names?

You can combine all of that into a single find command:

find . -iname "*foobar*" -exec cp -- "{}" ~/foo/bar \;

This will handle filenames and directories with spaces in them. You can use -name to get case-sensitive results.

Note: The -- flag passed to cp prevents it from processing files starting with - as options.

CSS background image to fit width, height should auto-scale in proportion

Try this, {
    background: rgba(0, 0, 0, 0) url("img/shopping_bgImg.jpg") no-repeat scroll center center / cover;

How do I get the number of elements in a list?

And for completeness (primarily educational), it is possible without using the len() function. I would not condone this as a good option DO NOT PROGRAM LIKE THIS IN PYTHON, but it serves a purpose for learning algorithms.

def count(list):
    item_count = 0
    for item in list[:]:
        item_count += 1
    return item_count


(The colon in list[:] is implicit and is therefore also optional.)

The lesson here for new programmers is: You can’t get the number of items in a list without counting them at some point. The question becomes: when is a good time to count them? For example, high-performance code like the connect system call for sockets (written in C) connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen);, does not calculate the length of elements (giving that responsibility to the calling code). Notice that the length of the address is passed along to save the step of counting the length first? Another option: computationally, it might make sense to keep track of the number of items as you add them within the object that you pass. Mind that this takes up more space in memory. See Naftuli Kay‘s answer.

Example of keeping track of the length to improve performance while taking up more space in memory. Note that I never use the len() function because the length is tracked:

class MyList(object):
    def __init__(self):
        self._data = []
        self.length = 0 # length tracker that takes up memory but makes length op O(1) time

        # the implicit iterator in a list class
    def __iter__(self):
        for elem in self._data:
            yield elem

    def add(self, elem):
        self.length += 1

    def remove(self, elem):
        self.length -= 1

mylist = MyList()
print(mylist.length) # 3
print(mylist.length) # 2

The model backing the 'ApplicationDbContext' context has changed since the database was created

If you delete the "[__MigrationHistory]" table from your "database > System Tables" then it will work.

TypeError: sequence item 0: expected string, int found

String interpolation is a nice way to pass in a formatted string.

values = ', '.join('$%s' % v for v in value_list)

SQL Server : login success but "The database [dbName] is not accessible. (ObjectExplorer)"

In my case it worked when I had opened SQL Server Management Studio with Administrator credentials and I right-clicked on the database and select "Go online" or something like this.

How do I reset a sequence in Oracle?

I make an alternative that the user don’t need to know the values, the system get and use variables to update.

--Atualizando sequence da tabela SIGA_TRANSACAO, pois está desatualizada
 actual_sequence_number INTEGER;
 max_number_from_table INTEGER;
 difference INTEGER;
 SELECT [nome_da_sequence].nextval INTO actual_sequence_number FROM DUAL;
 SELECT MAX([nome_da_coluna]) INTO max_number_from_table FROM [nome_da_tabela];
 SELECT (max_number_from_table-actual_sequence_number) INTO difference FROM DUAL;
IF difference > 0 then
 EXECUTE IMMEDIATE CONCAT('alter sequence [nome_da_sequence] increment by ', difference);
 --aqui ele puxa o próximo valor usando o incremento necessário
 SELECT [nome_da_sequence].nextval INTO actual_sequence_number from dual;
--aqui volta o incremento para 1, para que futuras inserções funcionem normalmente
 DBMS_OUTPUT.put_line ('A sequence [nome_da_sequence] foi atualizada.');
 DBMS_OUTPUT.put_line ('A sequence [nome_da_sequence] NÃO foi atualizada, já estava OK!');

How to disable textbox from editing?

You can set the ReadOnly property to true.

Quoth the link:

When this property is set to true, the contents of the control cannot be changed by the user at runtime. With this property set to true, you can still set the value of the Text property in code. You can use this feature instead of disabling the control with the Enabled property to allow the contents to be copied and ToolTips to be shown.

Repeat-until or equivalent loop in Python

UNTIL cond

Is equivalent to

while True:
    if cond:

How to kill a child process by the parent process?

Send a SIGTERM or a SIGKILL to it:

SIGTERM is polite and lets the process clean up before it goes, whereas, SIGKILL is for when it won't listen >:)

Example from the shell (man page: )

kill -9 pid

In C, you can do the same thing using the kill syscall:

kill(pid, SIGKILL);

See the following man page:

Visually managing MongoDB documents and collections

The real answer is ... No.

So far as I have found there is no reasonable or publicly available Windows MonogoDB client which is really very sad since MongoDB is pretty sweet.

I've thought about throwing together a simple app with WPF on Codeplex ... but I haven't been super motivated.

What would features would you be interested in having? Maybe you can inspire me or others?

For example, do you just want to view DBs / collections & perhaps simple edits (so you don't have to use the shell) or do you require something more complex?

Get selected value/text from Select on change

function test(a) {_x000D_
    var x = (a.value || a.options[a.selectedIndex].value);  //crossbrowser solution =)_x000D_
<select onchange="test(this)" id="select_id">_x000D_
    <option value="0">-Select-</option>_x000D_
    <option value="1">Communication</option>_x000D_
    <option value="2">Communication</option>_x000D_
    <option value="3">Communication</option>_x000D_

Center align a column in twitter bootstrap

If you cannot put 1 column, you can simply put 2 column in the middle... (I am just combining answers) For Bootstrap 3

<div class="row">
   <div class="col-lg-5 ">5 columns left</div>
   <div class="col-lg-2 col-centered">2 column middle</div>
   <div class="col-lg-5">5 columns right</div>

Even, you can text centered column by adding this to style:

  display: block;
  margin-left: auto;
  margin-right: auto;
  text-align: center;

Additionally, there is another solution here

Change size of axes title and labels in ggplot2

If you are creating many graphs, you could be tired of typing for each graph the lines of code controlling for the size of the titles and texts. What I typically do is creating an object (of class "theme" "gg") that defines the desired theme characteristics. You can do that at the beginning of your code.

My_Theme = theme(
  axis.title.x = element_text(size = 16),
  axis.text.x = element_text(size = 14),
  axis.title.y = element_text(size = 16))

Next, all you will have to do is adding My_Theme to your graphs.

g + My_Theme
if you have another graph, g1, just write:
g1 + My_Theme 
and so on.

What is JNDI? What is its basic use? When is it used?

What is JNDI ?

JNDI stands for Java Naming and Directory Interface. It comes standard with J2EE.

What is its basic use?

With this API, you can access many types of data, like objects, devices, files of naming and directory services, eg. it is used by EJB to find remote objects. JNDI is designed to provide a common interface to access existing services like DNS, NDS, LDAP, CORBA and RMI.

When it is used?

You can use the JNDI to perform naming operations, including read operations and operations for updating the namespace. The following operations are described here.

How to vertically center <div> inside the parent element with CSS?

have you try this one?

.parentdiv {
 margin: auto;
 position: absolute;
 top: 0; left: 0; bottom: 0; right: 0;
 height: 300px; // at least you have to specify height

hope this helps

OrderBy descending in Lambda expression?

As Brannon says, it's OrderByDescending and ThenByDescending:

var query = from person in people
            orderby person.Name descending, person.Age descending
            select person.Name;

is equivalent to:

var query = people.OrderByDescending(person => person.Name)
                  .ThenByDescending(person => person.Age)
                  .Select(person => person.Name);

How to hide the border for specified rows of a table?

You can simply add these lines of codes here to hide a row,

Either you can write border:0 or border-style:hidden; border: none or it will happen the same thing

<style type="text/css">_x000D_
              table, th, td {_x000D_
               border: 1px solid;_x000D_
              tr.hide_all > td, td.hide_all{_x000D_
                 border: 0;_x000D_
      <tr class= hide_all>_x000D_

running these lines of codes can solve the problem easily

Ripple effect on Android Lollipop CardView

You should add following to CardView:


Can I use multiple versions of jQuery on the same page?

You can have as many different jQuery versions on your page as you want.

Use jQuery.noConflict():

<script src="" type="text/javascript"></script>
    var $i = jQuery.noConflict();

<script src=""></script>
    var $j = jQuery.noConflict();

<script type="text/javascript" src=""></script>
    var $k = jQuery.noConflict();

DEMO | Source

Handle Guzzle exception and get HTTP body

Guzzle 3.x

Per the docs, you can catch the appropriate exception type (ClientErrorResponseException for 4xx errors) and call its getResponse() method to get the response object, then call getBody() on that:

use Guzzle\Http\Exception\ClientErrorResponseException;


try {
    $response = $request->send();
} catch (ClientErrorResponseException $exception) {
    $responseBody = $exception->getResponse()->getBody(true);

Passing true to the getBody function indicates that you want to get the response body as a string. Otherwise you will get it as instance of class Guzzle\Http\EntityBody.

repository element was not specified in the POM inside distributionManagement element or in -DaltDep loymentRepository=id::layout::url parameter

The issue is fixed by adding repository url under distributionManagement tab in main pom.xml.

Jenkin maven goal : clean deploy -U -Dmaven.test.skip=true


Console errors. Failed to load resource: net::ERR_INSECURE_RESPONSE

I had this problem with chrome when I was working on a WordPress site. I added this code

$_SERVER['HTTPS'] = false;

into the theme's functions.php file - it asks you to log in again when you save the file but once it's logged in it works straight away.

How to run eclipse in clean mode? what happens if we do so?

For clean mode: start the platform like

eclipse -clean

That's all. The platform will clear some cached OSGi bundle information, it helps or is recommended if you install new plugins manually or remove unused plugins.

It will not affect any workspace related data.

How to find the Vagrant IP?

I did at VagrantFile:

REMOTE_IP = %x{/usr/local/bin/vagrant ssh-config | /bin/grep -i HostName | /usr/bin/cut -d\' \' -f4}
run "ping #{REMOTE_IP}"

As you can see, I used the "%x{}" ruby function.

Set value of textbox using JQuery

1) you are calling it wrong way try:


2) if it doesn't work call your .js file at the end of the page or trigger your function on document.ready event

$(document).ready(function() {

Find out which remote branch a local branch is tracking

I think git branch -av only tells you what branches you have and which commit they're at, leaving you to infer which remote branches the local branches are tracking.

git remote show origin explicitly tells you which branches are tracking which remote branches. Here's example output from a repository with a single commit and a remote branch called abranch:

$ git branch -av
* abranch                d875bf4 initial commit
  master                 d875bf4 initial commit
  remotes/origin/HEAD    -> origin/master
  remotes/origin/abranch d875bf4 initial commit
  remotes/origin/master  d875bf4 initial commit


$ git remote show origin
* remote origin
  Fetch URL: /home/ageorge/tmp/d/../exrepo/
  Push  URL: /home/ageorge/tmp/d/../exrepo/
  HEAD branch (remote HEAD is ambiguous, may be one of the following):
  Remote branches:
    abranch tracked
    master  tracked
  Local branches configured for 'git pull':
    abranch merges with remote abranch
    master  merges with remote master
  Local refs configured for 'git push':
    abranch pushes to abranch (up to date)
    master  pushes to master  (up to date)

What is the difference between square brackets and parentheses in a regex?

The first 2 examples act very differently if you are REPLACING them by something. If you match on this:

str = str.replace(/^(7|8|9)/ig,''); 

you would replace 7 or 8 or 9 by the empty string.

If you match on this

str = str.replace(/^[7|8|9]/ig,''); 

you will replace 7 or 8 or 9 OR THE VERTICAL BAR!!!! by the empty string.

I just found this out the hard way.

Ansible - read inventory hosts and variables to group_vars/all file

If you want to refer one host define under /etc/ansible/host in a task or role, the bellow link might help:

How to remove leading zeros from alphanumeric text?

I made some benchmark tests and found, that the fastest way (by far) is this solution:

    private static String removeLeadingZeros(String s) {
      try {
          Integer intVal = Integer.parseInt(s);
          s = intVal.toString();
      } catch (Exception ex) {
          // whatever
      return s;

Especially regular expressions are very slow in a long iteration. (I needed to find out the fastest way for a batchjob.)

Squash my last X commits together using Git

Tried all approaches mention here. But finally my issue resolved by following this link.

$ git fetch upstream
$ git checkout omgpull 
$ git rebase -i upstream/master

 < choose squash for all of your commits, except the first one >
 < Edit the commit message to make sense, and describe all your changes >

$ git push origin omgpull -f

How do I format date and time on ssrs report?

If the date and time is in its own cell (aka textbox), then you should look at applying the format to the entire textbox. This will create cleaner exports to other formats; in particular, the value will export as a datetime value to Excel instead of a string.

Use the properties pane or dialog to set the format for the textbox to "MM/dd/yyyy hh:mm tt"

I would only use Ian's answer if the datetime is being concatenated with another string.

Calling a java method from c++ in Android

Solution posted by Denys S. in the question post:

I quite messed it up with c to c++ conversion (basically env variable stuff), but I got it working with the following code for C++:

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

jstring Java_the_package_MainActivity_getJniString( JNIEnv* env, jobject obj){

    jstring jstr = (*env)->NewStringUTF(env, "This comes from jni.");
    jclass clazz = (*env)->FindClass(env, "com/inceptix/android/t3d/MainActivity");
    jmethodID messageMe = (*env)->GetMethodID(env, clazz, "messageMe", "(Ljava/lang/String;)Ljava/lang/String;");
    jobject result = (*env)->CallObjectMethod(env, obj, messageMe, jstr);

    const char* str = (*env)->GetStringUTFChars(env,(jstring) result, NULL); // should be released but what a heck, it's a tutorial :)
    printf("%s\n", str);

    return (*env)->NewStringUTF(env, str);

And next code for java methods:

    public class MainActivity extends Activity {
    private static String LIB_NAME = "thelib";

    static {

    /** Called when the activity is first created. */
    public void onCreate(Bundle savedInstanceState) {
        TextView tv = (TextView) findViewById(;

    // please, let me live even though I used this dark programming technique
    public String messageMe(String text) {
        return text;

    public native String getJniString();

How to bind inverse boolean properties in WPF?

With standart binding you need to use converters that looks little windy. So, I recommend you to look at my project CalcBinding, which was developed specially to resolve this problem and some others. With advanced binding you can write expressions with many source properties directly in xaml. Say, you can write something like:

<Button IsEnabled="{c:Binding Path=!IsReadOnly}" />


<Button Content="{c:Binding ElementName=grid, Path=ActualWidth+Height}"/>


<Label Content="{c:Binding A+B+C }" />


<Button Visibility="{c:Binding IsChecked, FalseToVisibility=Hidden}" />

where A, B, C, IsChecked - properties of viewModel and it will work properly

How can I make a TextArea 100% width without overflowing when padding is present in CSS?

No, you cannot do that with CSS. That is the reason Microsoft initially introduced another, and maybe more practical box model. The box model that eventually won, makes it inpractical to mix percentages and units.

I don't think it is OK with you to express padding and border widths in percentage of the parent too.

PostgreSQL delete with inner join

FROM m_productprice B  
     USING m_product C 
WHERE B.m_product_id = C.m_product_id AND
      C.upc = '7094' AND                 


FROM m_productprice
WHERE m_pricelist_version_id='1000020' AND 
      m_product_id IN (SELECT m_product_id 
                       FROM m_product 
                       WHERE upc = '7094'); 

What exactly is nullptr?

It is a keyword because the standard will specify it as such. ;-) According to the latest public draft (n2914)

2.14.7 Pointer literals [lex.nullptr]


The pointer literal is the keyword nullptr. It is an rvalue of type std::nullptr_t.

It's useful because it does not implicitly convert to an integral value.

Using LIKE operator with stored procedure parameters

I was working on same. Check below statement. Worked for me!!

SELECT * FROM [Schema].[Table] WHERE [Column] LIKE '%' + @Parameter + '%'

What is reflection and why is it useful?


Take for example a remote application which gives your application an object which you obtain using their API Methods . Now based on the object you might need to perform some sort of computation .

The provider guarantees that object can be of 3 types and we need to perform computation based on what type of object .

So we might implement in 3 classes each containing a different logic .Obviously the object information is available in runtime so you cannot statically code to perform computation hence reflection is used to instantiate the object of the class that you require to perform the computation based on the object received from the provider .

How do you delete an ActiveRecord object?

If you are using Rails 5 and above, the following solution will work.

#delete based on id
user_id = 50
User.find(id: user_id).delete_all

#delete based on condition
threshold_age = 20
User.where(age: threshold_age).delete_all

How would I get everything before a : in a string Python

I have benchmarked these various technics under Python 3.7.0 (IPython).


  • fastest (when the split symbol c is known): pre-compiled regex.
  • fastest (otherwise): s.partition(c)[0].
  • safe (i.e., when c may not be in s): partition, split.
  • unsafe: index, regex.


import string, random, re

SYMBOLS = string.ascii_uppercase + string.digits
SIZE = 100

def create_test_set(string_length):
    for _ in range(SIZE):
        random_string = ''.join(random.choices(SYMBOLS, k=string_length))
        yield (random.choice(random_string), random_string)

for string_length in (2**4, 2**8, 2**16, 2**32):
    print("\nString length:", string_length)
    print("  regex (compiled):", end=" ")
    test_set_for_regex = ((re.compile("(.*?)" + c).match, s) for (c, s) in test_set)
    %timeit [re_match(s).group() for (re_match, s) in test_set_for_regex]
    test_set = list(create_test_set(16))
    print("  partition:       ", end=" ")
    %timeit [s.partition(c)[0] for (c, s) in test_set]
    print("  index:           ", end=" ")
    %timeit [s[:s.index(c)] for (c, s) in test_set]
    print("  split (limited): ", end=" ")
    %timeit [s.split(c, 1)[0] for (c, s) in test_set]
    print("  split:           ", end=" ")
    %timeit [s.split(c)[0] for (c, s) in test_set]
    print("  regex:           ", end=" ")
    %timeit [re.match("(.*?)" + c, s).group() for (c, s) in test_set]


String length: 16
  regex (compiled): 156 ns ± 4.41 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
  partition:        19.3 µs ± 430 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)
  index:            26.1 µs ± 341 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  split (limited):  26.8 µs ± 1.26 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  split:            26.3 µs ± 835 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  regex:            128 µs ± 4.02 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)

String length: 256
  regex (compiled): 167 ns ± 2.7 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
  partition:        20.9 µs ± 694 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  index:            28.6 µs ± 2.73 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  split (limited):  27.4 µs ± 979 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  split:            31.5 µs ± 4.86 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  regex:            148 µs ± 7.05 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

String length: 65536
  regex (compiled): 173 ns ± 3.95 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
  partition:        20.9 µs ± 613 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)
  index:            27.7 µs ± 515 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  split (limited):  27.2 µs ± 796 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  split:            26.5 µs ± 377 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  regex:            128 µs ± 1.5 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)

String length: 4294967296
  regex (compiled): 165 ns ± 1.2 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
  partition:        19.9 µs ± 144 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)
  index:            27.7 µs ± 571 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  split (limited):  26.1 µs ± 472 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  split:            28.1 µs ± 1.69 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)
  regex:            137 µs ± 6.53 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)

How to apply two CSS classes to a single element

As others have pointed out, you simply delimit them with a space.

However, knowing how the selectors work is also useful.

Consider this piece of HTML...

<div class="a"></div>
<div class="b"></div>
<div class="a b"></div>

Using .a { ... } as a selector will select the first and third. However, if you want to select one which has both a and b, you can use the selector .a.b { ... }. Note that this won't work in IE6, it will simply select .b (the last one).

When should I use a List vs a LinkedList

So many average answers here...

Some linked list implementations use underlying blocks of pre allocated nodes. If they don't do this than constant time / linear time is less relevant as memory performance will be poor and cache performance even worse.

Use linked lists when

1) You want thread safety. You can build better thread safe algos. Locking costs will dominate a concurrent style list.

2) If you have a large queue like structures and want to remove or add anywhere but the end all the time . >100K lists exists but are not that common.

Make error: missing separator

My error was on a variable declaration line with a multi-line extension. I have a trailing space after the "\" which made that an invalid line continuation.

MY_VAR = \
   val1 \ <-- 0x20 there caused the error.

How do I set the size of an HTML text box?

Elements can be sized with the height and width attributes.

bool to int conversion

There seems to be no problem since the int to bool cast is done implicitly. This works in Microsoft Visual C++, GCC and Intel C++ compiler. No problem in either C or C++.

Excel - programm cells to change colour based on another cell

  1. Select cell B3 and click the Conditional Formatting button in the ribbon and choose "New Rule".
  2. Select "Use a formula to determine which cells to format"
  3. Enter the formula: =IF(B2="X",IF(B3="Y", TRUE, FALSE),FALSE), and choose to fill green when this is true
  4. Create another rule and enter the formula =IF(B2="X",IF(B3="W", TRUE, FALSE),FALSE) and choose to fill red when this is true.

More details - conditional formatting with a formula applies the format when the formula evaluates to TRUE. You can use a compound IF formula to return true or false based on the values of any cells.

Android - Get value from HashMap

HashMap<String, String> meMap = new HashMap<String, String>();
meMap.put("Color1", "Red");
meMap.put("Color2", "Blue");
meMap.put("Color3", "Green");
meMap.put("Color4", "White");

Iterator myVeryOwnIterator = meMap.values().iterator();
while(myVeryOwnIterator.hasNext()) {
    Toast.makeText(getBaseContext(),, Toast.LENGTH_SHORT).show();

When should I use Async Controllers in ASP.NET MVC?

async actions help best when the actions does some I\O operations to DB or some network bound calls where the thread that processes the request will be stalled before it gets answer from the DB or network bound call which you just invoked. It's best you use await with them and it will really improve the responsiveness of your application (because less ASP input\output threads will be stalled while waiting for the DB or any other operation like that). In all my applications whenever many calls to DB very necessary I've always wrapped them in awaiatable method and called that with await keyword.

Failed to load ApplicationContext from Unit Test: FileNotFound

I added the spring folder to the build path and, after clean&build, it worked.

Python: How to create a unique file name?

This can be done using the unique function in ufp.path module.

import ufp.path

if current path exists 'test.ext' file. ufp.path.unique function return './test (d1).ext'.

How to get row count in sqlite using Android?

c.getCount() returns 1 because the cursor contains a single row (the one with the real COUNT(*)). The count you need is the int value of first row in cursor.

public int getTaskCount(long tasklist_Id) {

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor= db.rawQuery(
         new String[] { String.valueOf(tasklist_Id) }
    int count = 0;
    if(null != cursor)
        if(cursor.getCount() > 0){
          count = cursor.getInt(0);

    return count;

MongoDB Show all contents from all collections

Once you are in terminal/command line, access the database/collection you want to use as follows:

show dbs
use <db name>
show collections

choose your collection and type the following to see all contents of that collection:


More info here on the MongoDB Quick Reference Guide.

How to check size of a file using Bash?

alternative solution with awk and double parenthesis:

SIZE=$(du -sb $FILENAME | awk '{ print $1 }')

if ((SIZE<90000)) ; then 
    echo "less"; 
    echo "not less"; 

Convert to/from DateTime and Time in Ruby

As an update to the state of the Ruby ecosystem, Date, DateTime and Time now have methods to convert between the various classes. Using Ruby 1.9.2+:

[1] pry(main)> ts = 'Jan 1, 2000 12:01:01'
=> "Jan 1, 2000 12:01:01"
[2] pry(main)> require 'time'
=> true
[3] pry(main)> require 'date'
=> true
[4] pry(main)> ds = Date.parse(ts)
=> #<Date: 2000-01-01 (4903089/2,0,2299161)>
[5] pry(main)> ds.to_date
=> #<Date: 2000-01-01 (4903089/2,0,2299161)>
[6] pry(main)> ds.to_datetime
=> #<DateTime: 2000-01-01T00:00:00+00:00 (4903089/2,0,2299161)>
[7] pry(main)> ds.to_time
=> 2000-01-01 00:00:00 -0700
[8] pry(main)> ds.to_time.class
=> Time
[9] pry(main)> ds.to_datetime.class
=> DateTime
[10] pry(main)> ts = Time.parse(ts)
=> 2000-01-01 12:01:01 -0700
[11] pry(main)> ts.class
=> Time
[12] pry(main)> ts.to_date
=> #<Date: 2000-01-01 (4903089/2,0,2299161)>
[13] pry(main)> ts.to_date.class
=> Date
[14] pry(main)> ts.to_datetime
=> #<DateTime: 2000-01-01T12:01:01-07:00 (211813513261/86400,-7/24,2299161)>
[15] pry(main)> ts.to_datetime.class
=> DateTime

How to get the IP address of the docker host from inside a docker container

This is a minimalistic implementation in Node.js for who is running the host on AWS EC2 instances, using the afore mentioned EC2 Metadata instance

const cp = require('child_process');
const ec2 = function (callback) {
    const URL = '';
    // we make it silent and timeout to 1 sec
    const args = [URL, '-s', '--max-time', '1'];
    const opts = {};
    cp.execFile('curl', args, opts, (error, stdout) => {
        if (error) return callback(new Error('ec2 ip error'));
        else return callback(null, stdout);
        .on('error', (error) => callback(new Error('ec2 ip error')));

and used as

ec2(function(err, ip) {
        if(err) console.log(err)
        else console.log(ip);

Trying to include a library, but keep getting 'undefined reference to' messages

The trick here is to put the library AFTER the module you are compiling. The problem is a reference thing. The linker resolves references in order, so when the library is BEFORE the module being compiled, the linker gets confused and does not think that any of the functions in the library are needed. By putting the library AFTER the module, the references to the library in the module are resolved by the linker.

using wildcards in LDAP search filters/queries

Your best bet would be to anticipate prefixes, so:

"(|(displayName=SEARCHKEY*)(displayName=ITSM - SEARCHKEY*)(displayName=alt prefix - SEARCHKEY*))"

Clunky, but I'm doing a similar thing within my organization.


Thanks HansUp for your answer, it is very helpful and it works!

I found three patterns working in Access, yours is the best, because it works in all cases.

  • INNER JOIN, your variant. I will call it "closed set pattern". It is possible to join more than two tables to the same table with good performance only with this pattern.

    SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
           INNER JOIN person AS cr 
           ON class.C_P_ClassRep=cr.P_Nr
         INNER JOIN person AS cr2
         ON class.C_P_ClassRep2nd=cr2.P_Nr


  • INNER JOIN "chained-set pattern"

    SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
    FROM person AS cr
    INNER JOIN ( class 
       INNER JOIN ( person AS cr2
       ) ON class.C_P_ClassRep2nd=cr2.P_Nr
    ) ON class.C_P_ClassRep=cr.P_Nr

    SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
    FROM class, person AS cr, person AS cr2
    WHERE class.C_P_ClassRep=cr.P_Nr AND class.C_P_ClassRep2nd=cr2.P_Nr

best practice to generate random token for forgot password

This answers the 'best random' request:

Adi's answer1 from Security.StackExchange has a solution for this:

Make sure you have OpenSSL support, and you'll never go wrong with this one-liner

$token = bin2hex(openssl_random_pseudo_bytes(16));

1. Adi, Mon Nov 12 2018, Celeritas, "Generating an unguessable token for confirmation e-mails", Sep 20 '13 at 7:06,

How do I break out of a loop in Scala?

Here is a tail recursive version. Compared to the for-comprehensions it is a bit cryptic, admittedly, but I'd say its functional :)

def run(start:Int) = {
  def tr(i:Int, largest:Int):Int = tr1(i, i, largest) match {
    case x if i > 1 => tr(i-1, x)
    case _ => largest

  def tr1(i:Int,j:Int, largest:Int):Int = i*j match {
    case x if x < largest || j < 2 => largest
    case x if x.toString.equals(x.toString.reverse) => tr1(i, j-1, x)
    case _ => tr1(i, j-1, largest)

  tr(start, 0)

As you can see, the tr function is the counterpart of the outer for-comprehensions, and tr1 of the inner one. You're welcome if you know a way to optimize my version.

Replacing characters in Ant property

Just an FYI for answer Replacing characters in Ant property - if you are trying to use this inside of a maven execution, you can't reference maven variables directly. You will need something like this:

<property name="propATemp" value="${propA}"/>
    <loadresource property="propB">
    <propertyresource name="propATemp" />

for-in statement

TypeScript isn't giving you a gun to shoot yourself in the foot with.

The iterator variable is a string because it is a string, full stop. Observe:

var obj = {};
obj['0'] = 'quote zero quote';
obj[0.0] = 'zero point zero';
obj['[object Object]'] = 'literal string "[object Object]"';
obj[<any>obj] = 'this obj'
obj[<any>undefined] = 'undefined';
obj[<any>"undefined"] = 'the literal string "undefined"';

for(var key in obj) {
    console.log('Type: ' + typeof key);
    console.log(key + ' => ' + obj[key]);

How many key/value pairs are in obj now? 6, more or less? No, 3, and all of the keys are strings:

Type: string
0 => zero point zero
Type: string
[object Object] => this obj; 
Type: string
undefined => the literal string "undefined" 

Play local (hard-drive) video file with HTML5 video tag?

That will be possible only if the HTML file is also loaded with the file protocol from the local user's harddisk.

If the HTML page is served by HTTP from a server, you can't access any local files by specifying them in a src attribute with the file:// protocol as that would mean you could access any file on the users computer without the user knowing which would be a huge security risk.

As Dimitar Bonev said, you can access a file if the user selects it using a file selector on their own. Without that step, it's forbidden by all browsers for good reasons. Thus, while his answer might prove useful for many people, it loosens the requirement from the code in the original question.

How to make a JTable non-editable

You can use a TableModel.

Define a class like this:

public class MyModel extends AbstractTableModel{
    //not necessary

actually isCellEditable() is false by default so you may omit it. (see:

Then use the setModel() method of your JTable.

JTable myTable = new JTable();
myTable.setModel(new MyModel());

How to condense if/else into one line in Python?

Python's if can be used as a ternary operator:

>>> 'true' if True else 'false'
>>> 'true' if False else 'false'

How to access POST form fields


As of Express version 4.16+, their own body-parser implementation is now included in the default Express package so there is no need for you to download another dependency.

You may have added a line to your code that looks like the following:

app.use(bodyparser.json()); //utilizes the body-parser package

If you are using Express 4.16+ you can now replace that line with:

app.use(express.json()); //Used to parse JSON bodies

This should not introduce any breaking changes into your applications since the code in express.json() is based on bodyparser.json().

If you also have the following code in your environment:

app.use(bodyParser.urlencoded({extended: true}));

You can replace that with:

app.use(express.urlencoded()); //Parse URL-encoded bodies

A final note of caution: There are still some very specific cases where body-parser might still be necessary but for the most part Express’ implementation of body-parser is all you will need for the majority of use cases.

(See the docs at expressjs/bodyparser for more details).

What is the OAuth 2.0 Bearer Token exactly?

Please read the example in rfc6749 sec 7.1 first.

The bearer token is a type of access token, which does NOT require PoP(proof-of-possession) mechanism.

PoP means kind of multi-factor authentication to make access token more secure. ref

Proof-of-Possession refers to Cryptographic methods that mitigate the risk of Security Tokens being stolen and used by an attacker. In contrast to 'Bearer Tokens', where mere possession of the Security Token allows the attacker to use it, a PoP Security Token cannot be so easily used - the attacker MUST have both the token itself and access to some key associated with the token (which is why they are sometimes referred to 'Holder-of-Key' (HoK) tokens).

Maybe it's not the case, but I would say,

  • access token = payment methods
  • bearer token = cash
  • access token with PoP mechanism = credit card (signature or password will be verified, sometimes need to show your ID to match the name on the card)

BTW, there's a draft of "OAuth 2.0 Proof-of-Possession (PoP) Security Architecture" now.

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver

I was getting same kinda error but after copying the ojdbc14.jar into lib folder, no more exception.(copy ojdbc14.jar from somewhere and paste it into lib folder inside WebContent.)

Getting value from a cell from a gridview on RowDataBound event

When you use a TemplateField and bind literal text to it like you are doing, will actually insert a control FOR YOU! It gets put into a DataBoundLiteralControl. You can see this if you look in the debugger near your line of code that is getting the empty text.

So, to access the information without changing your template to use a control, you would cast like this:

string percentage = ((DataBoundLiteralControl)e.Row.Cells[7].Controls[0]).Text;

That will get you your text!

Image change every 30 seconds - loop

You should take a look at various javascript libraries, they should be able to help you out:

All of them have tutorials, and fade in/fade out is a basic usage.

For e.g. in jQuery:

var $img = $("img"), i = 0, speed = 200;
window.setInterval(function() {
  $img.fadeOut(speed, function() {
    $img.attr("src", images[(++i % images.length)]);
}, 30000);

ASP.NET file download from server

Simple solution for downloading a file from the server:

protected void btnDownload_Click(object sender, EventArgs e)
            string FileName = "Durgesh.jpg"; // It's a file name displayed on downloaded file on client side.

            System.Web.HttpResponse response = System.Web.HttpContext.Current.Response;
            response.ContentType = "image/jpeg";
            response.AddHeader("Content-Disposition", "attachment; filename=" + FileName + ";");

SQL how to check that two tables has exactly the same data?

Source: Use NATURAL FULL JOIN to compare two tables in SQL by Lukas Eder

Clever approach of using NATURAL FULL JOIN to detect the same/different rows between two tables.

Example 1 - status flag:

SELECT t1.*, t2.*, CASE WHEN t1 IS NULL OR t2 IS NULL THEN 'Not equal' ELSE 'Equal' END

Example 2 - filtering rows

FROM (SELECT 't1' AS t1, t1.* FROM t1) t1 
NATURAL FULL JOIN (SELECT 't2' AS t2, t2.* FROM t2) t2 
WHERE t1 IS NULL OR t2 IS NULL -- show differences
--WHERE  t1 IS NOT NULL AND t2 IS NOT NULL    -- show the same

db<>fiddle demo

curl : (1) Protocol https not supported or disabled in libcurl

Solved this problem with flag --with-darwinssl

Go to folder with curl source code

Download it here

sudo ./configure --with-darwinssl
make install

restart your console and it is done!

jQuery - What are differences between $(document).ready and $(window).load?

$(document).ready(function(e) { 
    // executes when HTML-Document is loaded and DOM is ready  
    console.log("page is loading now"); 

$(document).load(function(e) { 
    //when html page complete loaded
    console.log("completely loaded"); 

Save Javascript objects in sessionStorage

Use case:

 sesssionStorage.setObj(1,{,action:'save firstObject'});
 sesssionStorage.setObj(2,{,action:'save 2nd object'}); 
 //Query first object
  //Retrieve date created of 2nd object
  new Date(sesssionStorage.getObj(1).date)


Storage.prototype.setObj = function(key, obj) {

        return this.setItem(key, JSON.stringify(obj))
    Storage.prototype.getObj = function(key) {
        return JSON.parse(this.getItem(key))

How to copy an object by value, not by reference

Can't you just make a copy constructor? By the way Java always passes references by value, so you keep pointing to the same object.

Quickly create large file on a Windows system

Check out RDFC

RDFC is probably not the fastest, but it does allocate data blocks. The absolutely fastest would have to use lower level API to just obtain cluster chains and put them into MFT without writing data.

Beware that there's no silver bullet here - if "creation" returns instantly that means you got a sparse file which just fakes a large file, but you won't get data blocks/chains till you write into it. If you just read is you'd get very fast zeros which could make you believe that your drive all of the sudden got blazingly fast :-)

SOAP vs REST (differences)

What is REST

REST stands for representational state transfer, it's actually an architectural style for creating Web API which treats everything(data or functionality) as recourse. It expects; exposing resources through URI and responding in multiple formats and representational transfer of state of the resources in stateless manner. Here I am talking about two things:

  1. Stateless manner: Provided by HTTP.
  2. Representational transfer of state: For example if we are adding an employee. . into our system, it's in POST state of HTTP, after this it would be in GET state of HTTP, PUT and DELETE likewise.

REST can use SOAP web services because it is a concept and can use any protocol like HTTP, SOAP.SOAP uses services interfaces to expose the business logic. REST uses URI to expose business logic.

REST is not REST without HATEOAS. This means that a client only knows the entry point URI and the resources are supposed to return links the client should follow. Those fancy documentation generators that give URI patterns for everything you can do in a REST API miss the point completely. They are not only documenting something that's supposed to be following the standard, but when you do that, you're coupling the client to one particular moment in the evolution of the API, and any changes on the API have to be documented and applied, or it will break.

HATEOAS, an abbreviation for Hypermedia As The Engine Of Application State, is a constraint of the REST application architecture that distinguishes it from most other network application architectures. The principle is that a client interacts with a network application entirely through hypermedia provided dynamically by application servers. A REST client needs no prior knowledge about how to interact with any particular application or server beyond a generic understanding of hypermedia. By contrast, in some service-oriented architectures (SOA), clients and servers interact through a fixed interface shared through documentation or an interface description language (IDL).

Reference 1 Reference 2

Merge two Excel tables Based on matching data in Columns

Put the table in the second image on Sheet2, columns D to F.

In Sheet1, cell D2 use the formula


copy across and down.

Edit: here is a picture. The data is in two sheets. On Sheet1, enter the formula into cell D2. Then copy the formula across to F2 and then down as many rows as you need.

enter image description here

How to apply font anti-alias effects in CSS?

Short answer: You can't.

CSS does not have techniques which affect the rendering of fonts in the browser; only the system can do that.

Obviously, text sharpness can easily be achieved with pixel-dense screens, but if you're using a normal PC that's gonna be hard to achieve.

There are some newer fonts that are smooth but at the sacrifice of it appearing somewhat blurry (look at most of Adobe's fonts, for example). You can also find some smooth-but-blurry-by-design fonts at Google Fonts, however.

There are some new CSS3 techniques for font rendering and text effects though the consistency, performance, and reliability of these techniques vary so largely to the point where you generally shouldn't rely on them too much.

How to select/get drop down option in Selenium 2

This is the code to select value from the drop down

The value for selectlocator will be the xpath or name of dropdown box, and for optionLocator will have the value to be selected from the dropdown box.

public static boolean select(final String selectLocator,
        final String optionLocator) {
    try {
        for (int k = 0; k <= new Select(element(selectLocator))
                .getOptions().size() - 1; k++) {
        if (combo1.contains(optionLocator)) {
            new Select(element(selectLocator)).selectByValue(optionLocator);
            combocheck = element(selectLocator).getValue();
            combo = "";

            return true;
        } else {
            combo = "The Value " + optionLocator
                    + " Does Not Exist In The Combobox";
            return false;
    } catch (Exception e) {
        return false;

private static RenderedWebElement element(final String locator) {
    try {

        return (RenderedWebElement) drivers.findElement(by(locator));
    } catch (Exception e) {
        return (RenderedWebElement) drivers.findElement(by(locator));



Getting IPV4 address from a sockaddr structure

Once sockaddr cast to sockaddr_in, it becomes this:

struct sockaddr_in {
    u_short     sin_family;
    u_short     sin_port;
    struct      in_addr sin_addr;
    char        sin_zero[8];

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

I convert String to Date in format ("yyyy-MM-dd") to save into Mysql data base .

 String date ="2016-05-01";
 SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
 Date parsed = format.parse(date);
 java.sql.Date sql = new java.sql.Date(parsed.getTime());

sql it's my output in date format

Lazy Method for Reading Big File in Python?

I think we can write like this:

def read_file(path, block_size=1024): 
    with open(path, 'rb') as f: 
        while True: 
            piece = 
            if piece: 
                yield piece 

for piece in read_file(path):

Can't find System.Windows.Media namespace?

Add PresentationCore.dll to your references. This dll url in my pc - C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\PresentationCore.dll

How do I read the file content from the Internal storage - Android App

Take a look this how to use storages in android

To read data from internal storage you need your app files folder and read content from here

String yourFilePath = context.getFilesDir() + "/" + "hello.txt";
File yourFile = new File( yourFilePath );

Also you can use this approach

FileInputStream fis = context.openFileInput("hello.txt");
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader bufferedReader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {

415 Unsupported Media Type - POST json to OData service in lightswitch 2012

It looks like this issue has to do with the difference between the Content-Type and Accept headers. In HTTP, Content-Type is used in request and response payloads to convey the media type of the current payload. Accept is used in request payloads to say what media types the server may use in the response payload.

So, having a Content-Type in a request without a body (like your GET request) has no meaning. When you do a POST request, you are sending a message body, so the Content-Type does matter.

If a server is not able to process the Content-Type of the request, it will return a 415 HTTP error. (If a server is not able to satisfy any of the media types in the request Accept header, it will return a 406 error.)

In OData v3, the media type "application/json" is interpreted to mean the new JSON format ("JSON light"). If the server does not support reading JSON light, it will throw a 415 error when it sees that the incoming request is JSON light. In your payload, your request body is verbose JSON, not JSON light, so the server should be able to process your request. It just doesn't because it sees the JSON light content type.

You could fix this in one of two ways:

  1. Make the Content-Type "application/json;odata=verbose" in your POST request, or
  2. Include the DataServiceVersion header in the request and set it be less than v3. For example:

    DataServiceVersion: 2.0;

(Option 2 assumes that you aren't using any v3 features in your request payload.)

Spring's overriding bean

Question was more about XML but as annotation are more popular nowadays and it works similarly I'll show by example. Let's create class Foo:

public class Foo {
    private String name;

    public String getName() {
        return name;

    public void setName(String name) { = name;

and two Configuration files (you can't create one):

public class Configuration1 {
    public Foo foo() {
        Foo foo = new Foo();
        return foo;


public class Configuration2 {
    public Foo foo() {
        Foo foo = new Foo();
        return foo;

and let's see what happens when calling foo.getName():

public class OverridingBeanDefinitionsApplication {

    public static void main(String[] args) {, args);

        AnnotationConfigApplicationContext applicationContext =
                new AnnotationConfigApplicationContext(
                        Configuration1.class, Configuration2.class);

        Foo foo = applicationContext.getBean(Foo.class);

in this example result is: configuration2. The Spring Container gets all configuration metadata sources and merges bean definitions in those sources. In this example there are two @Beans. Order in which they are fed into ApplicationContext decide. You can flip new AnnotationConfigApplicationContext(Configuration2.class, Configuration1.class); and result will be configuration1.

jQuery: How to get to a particular child of a parent?

This will find the first parent with class box then find the first child class with regex matching something and get the id.


WinSCP: Permission denied. Error code: 3 Error message from server: Permission denied

You possibly do not have create permissions to the folder. So WinSCP fails to create a temporary file for the transfer.

You have two options:

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

I would have to agree a foreach would be a lot easier something like

foreach(AllIntegerIDs allIntegerIDs in integerList)
Console.WriteLine("{0}\t{1}\t{2}\t{3}\t{4}\n", allIntegerIDs.m_MessageID,

Also I would suggest you add properties to access your information instead of public fields, depending on your .net version you can add it like public int MessageType {get; set;} and get rid of the m_ from your public fields, properties etc as it shouldnt be there.

How to call function of one php file from another php file and pass parameters to it?

files directory:





function sum(a,b){
 return a+b;
function product(a,b){
return a*b;


require_once "functions.php";
echo "sum of two numbers ". sum(4,2);
echo "<br>"; //  create break line
echo "product of two numbers ".product(2,3);

The Output Is :

sum of two numbers 6 product of two numbers 6

Note: don't write public before function. Public, private, these modifiers can only use when you create class.

How to resolve ORA 00936 Missing Expression Error?

This answer is not the answer for the above mentioned question but it is related to same topic and might be useful for people searching for same error.

I faced the same error when I executed below mentioned query.

select OR.* from ORDER_REL_STAT OR

problem with above query was OR is keyword so it was expecting other values when I replaced with some other alias it worked fine.

download a file from Spring boot rest service

If you need to download a huge file from the server's file system, then ByteArrayResource can take all Java heap space. In that case, you can use FileSystemResource


I had added an additional line to the application's manifest file, which is android:installLocation="preferExternal". by using this line it forces to install the app to the external storage. see the example below,

<manifest xmlns:android=""
    android:installLocation="preferExternal" >

Select from where field not equal to Mysql Php

The key is the sql query, which you will set up as a string:

$sqlquery = "SELECT field1, field2 FROM table WHERE NOT columnA = 'x' AND NOT columbB = 'y'";

Note that there are a lot of ways to specify NOT. Another one that works just as well is:

$sqlquery = "SELECT field1, field2 FROM table WHERE columnA != 'x' AND columbB != 'y'";

Here is a full example of how to use it:

$link = mysql_connect($dbHost,$dbUser,$dbPass) or die("Unable to connect to database");
mysql_select_db("$dbName") or die("Unable to select database $dbName");
$sqlquery = "SELECT field1, field2 FROM table WHERE NOT columnA = 'x' AND NOT columbB = 'y'";

while ($row = mysql_fetch_assoc($result) {
//do stuff

You can do whatever you would like within the above while loop. Access each field of the table as an element of the $row array which means that $row['field1'] will give you the value for field1 on the current row, and $row['field2'] will give you the value for field2.

Note that if the column(s) could have NULL values, those will not be found using either of the above syntaxes. You will need to add clauses to include NULL values:

$sqlquery = "SELECT field1, field2 FROM table WHERE (NOT columnA = 'x' OR columnA IS NULL) AND (NOT columbB = 'y' OR columnB IS NULL)";

best way to get the key of a key/value javascript object

I was having the same problem and this is what worked

//example of an Object
var person = {

//How to access a single key or value
var key = Object.keys(person)[0];
var value = person.firstName;

How do I convert a byte array to Base64 in Java?


byte[] data = Base64.encode(base64str);

Encoding converts to Base64

You would need to reference commons codec from your project in order for that code to work.

For java8:

import java.util.Base64

Cannot overwrite model once compiled Mongoose

This happened to me when I write like this:

import User from '../myuser/User.js';

However, the true path is '../myUser/User.js'

Display open transactions in MySQL

By using this query you can see all open transactions.

List All:


if you want to kill a hang transaction copy transaction id and kill transaction by using this command:

KILL <id>    // e.g KILL 16543

Vertical dividers on horizontal UL menu

A simpler solution would be to just add #navigation ul li~li { border-left: 1px solid #857D7A; }

How to compare numbers in bash?

The bracket stuff (e.g., [[ $a -gt $b ]] or (( $a > $b )) ) isn't enough if you want to use float numbers as well; it would report a syntax error. If you want to compare float numbers or float number to integer, you can use (( $(bc <<< "...") )).

For example,


if (( $(bc <<<"$a > $b") )); then 
    echo "a is greater than b"
    echo "a is not greater than b"

You can include more than one comparison in the if statement. For example,


if (( $(bc <<<"$b == $c && $b < $a") )); then 
    echo "b is equal to c but less than a"
    echo "b is either not equal to c and/or not less than a"

That's helpful if you want to check if a numeric variable (integer or not) is within a numeric range.

How can I run a html file from terminal?

python -mhtmllib test.html or curl|python -mhtmllib -

Set width of dropdown element in HTML select dropdown options

Small And Best One

width: 202px;
<select id="test" size="1" name="mrraja">

Git Diff with Beyond Compare

For whatever reason, for me, the tmp file created by git diff was being deleted before it opened in beyond compare. I had to copy it out to another location first.

cp -r $2 "/cygdrive/c/temp$2"
cygstart /cygdrive/c/Program\ Files\ \(x86\)/Beyond\ Compare\ 3/BCompare.exe "C:/temp$2" "$5"

How to get an enum value from a string value in Java?

Using Blah.valueOf(string) is best but you can use Enum.valueOf(Blah.class, string) as well.

How to embed a YouTube channel into a webpage

In order to embed your channel, all you need to do is copy then paste the following code in another web-page.

<script src=""></script>

Make sure to replace the YourChannelName with your actual channel name.

For example: if your channel name were CaliChick94066 your channel embed code would be:

<script src=""></script>

Please look at the following links:

YouTube on your site

Embed YouTube Channel

You just have to name the URL to your channel name. Also you can play with the height and the border color and size. Hope it helps

How to delete columns in pyspark dataframe

Maybe a little bit off topic, but here is the solution using Scala. Make an Array of column names from your oldDataFrame and delete the columns that you want to drop ("colExclude"). Then pass the Array[Column] to select and unpack it.

val columnsToKeep: Array[Column] = oldDataFrame.columns.diff(Array("colExclude"))
                                               .map(x => oldDataFrame.col(x))
val newDataFrame: DataFrame = _*)

How to select an item in a ListView programmatically?

I know this is an old question, but I think this is the definitive answer.

listViewRamos.Items[i].Focused = true;
listViewRamos.Items[i].Selected = true;

If there is a chance the control does not have the focus but you want to force the focus to the control, then you can add the following line.


Why Microsoft didn't just add a SelectItem() method that does all this for you is beyond me.