Programs & Examples On #Scrollto

jQuery.scrollTo is a plugin for scrolling elements and the window with jQuery animation, by Ariel Flesler.

How can I update window.location.hash without jumping the document?

I used a combination of Attila Fulop (Lea Verou) solution for modern browsers and Gavin Brock solution for old browsers as follows:

if (history.pushState) {
    // IE10, Firefox, Chrome, etc.
    window.history.pushState(null, null, '#' + id);
} else {
    // IE9, IE8, etc
    window.location.hash = '#!' + id;

As observed by Gavin Brock, to capture the id back you will have to treat the string (which in this case can have or not the "!") as follows:

id = window.location.hash.replace(/^#!?/, '');

Before that, I tried a solution similar to the one proposed by user706270, but it did not work well with Internet Explorer: as its Javascript engine is not very fast, you can notice the scroll increase and decrease, which produces a nasty visual effect.

Trigger event when user scroll to specific element - with jQuery

Inview library triggered event and works well with jquery 1.8 and higher!

$('div').on('inview', function (event, visible) {
  if (visible == true) {
    // element is now visible in the viewport
  } else {
    // element has gone out of viewport

Read this

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

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

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

How can I scroll to a specific location on the page using jquery?

<script type="text/javascript">
                scrollTop: $('.our_companies').offset().top
            }, 1000);

            return false;

jQuery Scroll to bottom of page/iframe

scrollTop() returns the number of pixels that are hidden from view from the scrollable area, so giving it:


will actually overshoot the bottom of the page. For the scroll to actually 'stop' at the bottom of the page, the current height of the browser window needs subtracting. This will allow the use of easing if required, so it becomes:

$('html, body').animate({ 
   scrollTop: $(document).height()-$(window).height()}, 

How to use && in EL boolean expressions in Facelets?

In addition to the answer of BalusC, use the following Java RegExp to replace && with and:

Search:  (#\{[^\}]*)(&&)([^\}]*\})
Replace: $1and$3

You have run this regular expression replacement multiple times to find all occurences in case you are using >2 literals in your EL expressions. Mind to replace the leading # by $ if your EL expression syntax differs.

Unzipping files

I wrote a class for that too. You can load basic assets such as javascript/css/images directly from the zip using class methods. Hope it helps

Copy data into another table

CREATE TABLE `table2` LIKE `table1`;
INSERT INTO `table2` SELECT * FROM `table1`;

the first query will create the structure from table1 to table2 and second query will put the data from table1 to table2

Get an array of list element contents in jQuery

Without redundant intermediate arrays:

arr = $('li').map(function(i,el) {
    return $(el).text();

See jsfiddle demo

Drop rows with all zeros in pandas data frame

You can use a quick lambda function to check if all the values in a given row are 0. Then you can use the result of applying that lambda as a way to choose only the rows that match or don't match that condition:

import pandas as pd
import numpy as np


df = pd.DataFrame(np.random.randn(5,3), 
                  index=['one', 'two', 'three', 'four', 'five'],

df.loc[['one', 'three']] = 0

print df
print df.loc[~df.apply(lambda row: (row==0).all(), axis=1)]


              a         b         c
one    0.000000  0.000000  0.000000
two    2.240893  1.867558 -0.977278
three  0.000000  0.000000  0.000000
four   0.410599  0.144044  1.454274
five   0.761038  0.121675  0.443863

[5 rows x 3 columns]
             a         b         c
two   2.240893  1.867558 -0.977278
four  0.410599  0.144044  1.454274
five  0.761038  0.121675  0.443863

[3 rows x 3 columns]

afxwin.h file is missing in VC++ Express Edition

I see the question is about Express Edition, but this topic is easy to pop up in Google Search, and doesn't have a solution for other editions.

So. If you run into this problem with any VS Edition except Express, you can rerun installation and include MFC files.

jQuery function to get all unique elements from an array?

You can use a jQuery plugin called Array Utilities to get an array of unique items. It can be done like this:

var distinctArray = $.distinct([1, 2, 2, 3])

distinctArray = [1,2,3]

How to bind a List to a ComboBox?

Try something like this:

yourControl.DataSource = countryInstance.Cities;

And if you are using WebForms you will need to add this line:


What is the difference between & vs @ and = in angularJS

I would like to explain the concepts from the perspective of JavaScript prototype inheritance. Hopefully help to understand.

There are three options to define the scope of a directive:

  1. scope: false: Angular default. The directive's scope is exactly the one of its parent scope (parentScope).
  2. scope: true: Angular creates a scope for this directive. The scope prototypically inherits from parentScope.
  3. scope: {...}: isolated scope is explained below.

Specifying scope: {...} defines an isolatedScope. An isolatedScope does not inherit properties from parentScope, although isolatedScope.$parent === parentScope. It is defined through:

app.directive("myDirective", function() {
    return {
        scope: {
            ... // defining scope means that 'no inheritance from parent'.

isolatedScope does not have direct access to parentScope. But sometimes the directive needs to communicate with the parentScope. They communicate through @, = and &. The topic about using symbols @, = and & are talking about scenarios using isolatedScope.

It is usually used for some common components shared by different pages, like Modals. An isolated scope prevents polluting the global scope and is easy to share among pages.

Here is a basic directive: An image to illustrate is:

enter image description here

@: one-way binding

@ simply passes the property from parentScope to isolatedScope. It is called one-way binding, which means you cannot modify the value of parentScope properties. If you are familiar with JavaScript inheritance, you can understand these two scenarios easily:

  • If the binding property is a primitive type, like interpolatedProp in the example: you can modify interpolatedProp, but parentProp1 would not be changed. However, if you change the value of parentProp1, interpolatedProp will be overwritten with the new value (when angular $digest).

  • If the binding property is some object, like parentObj: since the one passed to isolatedScope is a reference, modifying the value will trigger this error:

    TypeError: Cannot assign to read only property 'x' of {"x":1,"y":2}

=: two-way binding

= is called two-way binding, which means any modification in childScope will also update the value in parentScope, and vice versa. This rule works for both primitives and objects. If you change the binding type of parentObj to be =, you will find that you can modify the value of parentObj.x. A typical example is ngModel.

&: function binding

& allows the directive to call some parentScope function and pass in some value from the directive. For example, check JSFiddle: & in directive scope.

Define a clickable template in the directive like:

<div ng-click="vm.onCheck({valueFromDirective: vm.value + ' is from the directive'})">

And use the directive like:

<div my-checkbox value="vm.myValue" on-check="vm.myFunction(valueFromDirective)"></div>

The variable valueFromDirective is passed from the directive to the parent controller through {valueFromDirective: ....

Reference: Understanding Scopes

How to display errors on laravel 4?

Further to @cw24's answer  •  as of Laravel 5.4 you would instead have the following amendment in public/index.php

try {
    $response = $kernel->handle(
        $request = Illuminate\Http\Request::capture()
} catch(\Exception $e) {
    echo "<pre>";
    echo $e;
    echo "</pre>";

And in my case, I had forgotten to fire up MySQL.
Which, by the way, is usually mysql.server start in Terminal

Change remote repository credentials (authentication) on Intellij IDEA 14

You can change your password from settings screen (Ctrl + Alt + S by default) as attached screenshot. After clearing, on the firts remote operation (like pull/push, etc.) it'll ask you your credentials)

IMPORTANT: Take a copy of the file before this operation.

Settings Screen

Install Application programmatically on Android

In Android Oreo and above version we have to approach different methods to install apk programatically.

 private void installApkProgramatically() {

    try {
        File path = activity.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS);

        File file = new File(path, filename);

        Uri uri;

        if (file.exists()) {

            Intent unKnownSourceIntent = new Intent(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES).setData(Uri.parse(String.format("package:%s", activity.getPackageName())));

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {

                if (!activity.getPackageManager().canRequestPackageInstalls()) {
                    startActivityForResult(unKnownSourceIntent, Constant.UNKNOWN_RESOURCE_INTENT_REQUEST_CODE);
                } else {
                    Uri fileUri = FileProvider.getUriForFile(activity.getBaseContext(), activity.getApplicationContext().getPackageName() + ".provider", file);
                    Intent intent = new Intent(Intent.ACTION_VIEW, fileUri);
                    intent.putExtra(Intent.EXTRA_NOT_UNKNOWN_SOURCE, true);
                    intent.setDataAndType(fileUri, "application/" + ".package-archive");
                    intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);

            } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {

                Intent intent1 = new Intent(Intent.ACTION_INSTALL_PACKAGE);
                uri = FileProvider.getUriForFile(activity.getApplicationContext(), BuildConfig.APPLICATION_ID + ".provider", file);
                activity.grantUriPermission("", uri, Intent.FLAG_GRANT_READ_URI_PERMISSION);
                activity.grantUriPermission("", uri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION);

            } else {
                Intent intent = new Intent(Intent.ACTION_VIEW);

                uri = Uri.fromFile(file);

        } else {

            Log.i(TAG, " file " + file.getPath() + " does not exist");
    } catch (Exception e) {

        Log.i(TAG, "" + e.getMessage());


In Oreo and above version we need unknown resource installation permission. so in activity result u have to check the result for the permission

public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    switch (requestCode) {

            switch (resultCode) {
                case Activity.RESULT_OK:

                case Activity.RESULT_CANCELED:
                    //unknown resouce installation cancelled


What processes are using which ports on unix?

netstat -ln | awk '/^(tcp|udp)/ { split($4, a, /:/); print $1, a[2]}' | sort -u

gives you the active tcp/udp ports. Then you can use the ports with fuser -n tcp or fuser -n udp, as root, and supposing that fuser is GNU fuser or has similar options.

If you need more help, let me know.

.map() a Javascript ES6 Map?

const mapMap = (callback, map) => new Map(Array.from(map).map(callback))_x000D_
var myMap = new Map([["thing1", 1], ["thing2", 2], ["thing3", 3]]);_x000D_
var newMap = mapMap((pair) => [pair[0], pair[1] + 1], myMap); // Map { 'thing1' => 2, 'thing2' => 3, 'thing3' => 4 }

Decode JSON with unknown structure

package main

import "encoding/json"

func main() {
    in := []byte(`{ "votes": { "option_A": "3" } }`)
    var raw map[string]interface{}
    if err := json.Unmarshal(in, &raw); err != nil {
    raw["count"] = 1
    out, err := json.Marshal(raw)
    if err != nil {

Create new project on Android, Error: Studio Unknown host ''

I was also having the same problem. I tried the following and it's working for me now:
Please try the following steps:

Go to..

File > Settings > Appearance & Behavior > System Settings > HTTP Proxy [Under IDE Settings] Enable following option Auto-detect proxy settings

On Mac it's under:

Android Studio > Preferences > Appearance & Behaviour... etc

you can also use the test connection button and check with to see if it works or not.

ojdbc14.jar vs. ojdbc6.jar

The "14" and "6" in those driver names refer to the JVM they were written for. If you're still using JDK 1.4 I'd say you have a serious problem and need to upgrade. JDK 1.4 is long past its useful support life. It didn't even have generics! JDK 6 u21 is the current production standard from Oracle/Sun. I'd recommend switching to it if you haven't already.

mssql convert varchar to float

You can convert varchars to floats, and you can do it in the manner you have expressed. Your varchar must not be a numeric value. There must be something else in it. You can use IsNumeric to test it. See this:

declare @thing varchar(100)

select @thing = '122.332'

--This returns 1 since it is numeric.
select isnumeric(@thing)

--This converts just fine.
select convert(float,@thing)

select @thing = '122.332.'

--This returns 0 since it is not numeric.
select isnumeric(@thing)

--This convert throws.
select convert(float,@thing)

Why am I getting "Cannot Connect to Server - A network-related or instance-specific error"?

I found the following techniques helpful:

  1. Make sure your database engine is configured to accept remote connections:

    • Start > All Programs > SQL Server 2005 > Configuration Tools > SQL Server Surface Area Configuration
    • Click on Surface Area Configuration for Services and Connections
    • Select the instance that is having a problem > Database Engine > Remote Connections
    • Enable local and remote connections
    • Restart instance
  2. You may need to create an exception on the firewall for the SQL Server instance and port you are using:

    • Start > Run > Firewall.cpl
    • Click on exceptions tab
    • Add sqlservr.exe (typically located in C:\Program Files (x86)\Microsoft SQL Server\MSSQL.x\MSSQL\Bin, check your installs for the actual folder path) and port (default is 1433)
    • Check your connection string as well
  3. Check if your SQL server services is up and running properly:

    • Go to All Programs > Microsoft SQL Server 2008 > Configuration Tools > SQL Server Configuration Manager > SQL Server Services
    • Check to make sure SQL Server service status is Running.

    In addition, ensure that your remote server is in the same network. Run sqlcmd -L to ascertain if your server is included in your network list.

  4. Enable TCP/IP in SQL Server Configuration

    When two or more SQL Servers are connected across network they do all communication using TCP/IP. The default port of SQL Server installation is 1433. This port can be changed through SQL Server Configuration Manager. TCP/IP should be enabled for SQL Server to be connected.

    • Go to All Programs >> Microsoft SQL Server 2008 >> Configuration Tools >> SQL Server Configuration Manager >> Select TCP/IP
    • Right Click on TCP/IP >> Click on Enable

    You must restart SQL Server Services for all the changes to take effect. Right click and go to menu properties to select location where default port of SQL Server can be changed.

What is mutex and semaphore in Java ? What is the main difference?

The object of synchronization Semaphore implements a classical traffic light. A traffic light controls access to a resource shared by a counter. If the counter is greater than zero, access is granted; If it is zero, access is denied. The counter counts the permissions that allow access to the shared resource. Then, to access the resource, a thread must receive permission from the traffic light. In general, to use a traffic light, the thread that wants to access the shared resource tries to acquire a permit. If the traffic light count is greater than zero, the thread acquires a permit, and the traffic light count is decremented. Otherwise the thread is locked until it can get a permission. When the thread no longer needs to access the shared resource, it releases the permission, so the traffic light count is increased. If there is another thread waiting for a permit, it acquires a permit at that time. The Semaphore class of Java implements this mechanism.

Semaphore has two builders:

Semaphore(int num)
Semaphore(int num, boolean come)

num specifies the initial count of the permit. Then num specifies the number of threads that can access a shared resource at a given time. If num is one, it can access the resource one thread at a time. By setting come as true, you can guarantee that the threads you are waiting for are granted permission in the order they requested.

How to loop through all elements of a form jQuery

   //your code here

Converting any object to a byte array in java

To convert the object to a byte array use the concept of Serialization and De-serialization.

The complete conversion from object to byte array explained in is tutorial.

Q. How can we convert object into byte array?

Q. How can we serialize a object?

Q. How can we De-serialize a object?

Q. What is the need of serialization and de-serialization?

MySQL error - #1932 - Table 'phpmyadmin.pma user config' doesn't exist in engine

If all the solutions above don't work, try to :

Add $i = 1; after /* Servers configuration */

in place of $i = 0 in your phpmyadmin file

Running XAMPP on local windows server, my mysql data files are not under the usual install path (C:\Xampp), but on another disk.

So now I have the phpmyadmin tables with the double __ like pma__table... and $i = 1;

How to solve "Plugin execution not covered by lifecycle configuration" for Spring Data Maven Builds





solved the problem for me.

Call Stored Procedure within Create Trigger in SQL Server

You pass an undefined rAgent_IP parameter in EXEC instead of the local variable @rAgent_IP.

Still, this trigger will fail if you perform a multi-record INSERT statement.

iReport not starting using JRE 8

iReport does not work with java 8.

  • if not yet installed, download and install java 7
  • find the install dir of your iReport and open the file: ireport.conf

(you will find it here: iReport-x.x.x\etc\ )

change this line:


to this (if not this is your java 7 install dir then replace the parameter value between ""s with your installed java 7's path):

jdkhome="C:\Program Files\Java\jdk1.7.0_67"

How to center div vertically inside of absolutely positioned parent div

For only vertical center

    <div style="text-align: left; position: relative;height: 56px;background-color: pink;">
        <div style="background-color: lightblue;position:absolute;top:50%;    transform: translateY(-50%);">test</div>

I always do like this, it's a very short and easy code to center both horizontally and vertically

    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
<div class="center">Hello Centered World!</div>

System.Collections.Generic.IEnumerable' does not contain any definition for 'ToList'

I was missing System.Data.Entity dll reference and problem was solved

Convert varchar dd/mm/yyyy to dd/mm/yyyy datetime

I think that more accurate is this syntax:


I add SELECT and GETDATE() for instant testing purposes :)

Converting unix timestamp string to readable date

i just successfully used:

>>> type(tstamp)
>>> newDt =
>>> type(newDt)

Username and password in command for git push

I used below format

git push https://username:[email protected]/file.git --all

and if your password or username contain @ replace it with %40

How to dump raw RTSP stream to file?

You can use mplayer.

mencoder -nocache -rtsp-stream-over-tcp rtsp://192.168.XXX.XXX/test.sdp -oac copy -ovc copy -o test.avi

The "copy" codec is just a dumb copy of the stream. Mencoder adds a header and stuff you probably want.

In the mplayer source file "stream/stream_rtsp.c" is a prebuffer_size setting of 640k and no option to change the size other then recompile. The result is that writing the stream is always delayed, which can be annoying for things like cameras, but besides this, you get an output file, and can play it back most places without a problem.

How can I pass a file argument to my bash script using a Terminal command in Linux?

It'll be easier (and more "proper", see below) if you just run your script as

myprogram /path/to/file

Then you can access the path within the script as $1 (for argument #1, similarly $2 is argument #2, etc.)

externalprogram "$file" [other parameters]

Or just

externalprogram "$1" [otherparameters]

If you want to extract the path from something like --file=/path/to/file, that's usually done with the getopts shell function. But that's more complicated than just referencing $1, and besides, switches like --file= are intended to be optional. I'm guessing your script requires a file name to be provided, so it doesn't make sense to pass it in an option.

Software Design vs. Software Architecture

I agree with many of the explanations; essentially we are recognizing the distinction between the architectural design and the detailed design of the software systems.

While the goal of the designer is to be as precise and concrete in the specifications as it will be necessary for the development; the architect essentially aims at specifying the structure and global behavior of the system just as much as required for the detailed design to begin with.

A good architect will prevent hyper-specifications - the architecture must not be overly specified but just enough, the (architectural) decisions established only for the aspects that present costliest risks to handle, and effectively provide a framework ("commonality") within which the detailed design can be worked upon i.e. variability for local functionality.

Indeed, the architecture process or life-cycle just follows this theme - adequate level of abstraction to outline the structure for the (architecturally) significant business requirements, and leave more details to the design phase for more concrete deliverables.

How to check if a user is logged in (how to properly use user.is_authenticated)?

For Django 2.0+ versions use:

    if request.auth:
       # Only for authenticated users.

For more info visit

request.user.is_authenticated() has been removed in Django 2.0+ versions.

How to diff a commit with its parent?

As @mipadi points out, you can use git show $COMMIT, but this also shows some headers and the commit message. If you want a straight diff, use git show --pretty=format:%b $COMMIT.

This is, obviously not a very short hand, so I'm keeping this alias in my .gitconfig

      sd = show --pretty=format:%b

This enables me to use git sd $COMMITto show diff.

How to create relationships in MySQL

Here are a couple of resources that will help get started: and

Also as others said, use a GUI - try downloading and installing Xampp (or Wamp) which run server-software (Apache and mySQL) on your computer. Then when you navigate to //localhost in a browser, select PHPMyAdmin to start working with a mySQL database visually. As mentioned above, used innoDB to allow you to make relationships as you requested. Makes it heaps easier to see what you're doing with the database tables. Just remember to STOP Apache and mySQL services when finished - these can open up ports which can expose you to hacking/malicious threats.

mongodb count num of distinct values per field/key

Here is example of using aggregation API. To complicate the case we're grouping by case-insensitive words from array property of the document.

        $match: {
            keywords: { $not: {$size: 0} }
    { $unwind: "$keywords" },
        $group: {
            _id: {$toLower: '$keywords'},
            count: { $sum: 1 }
        $match: {
            count: { $gte: 2 }
    { $sort : { count : -1} },
    { $limit : 100 }

that give result such as

{ "_id" : "inflammation", "count" : 765 }
{ "_id" : "obesity", "count" : 641 }
{ "_id" : "epidemiology", "count" : 617 }
{ "_id" : "cancer", "count" : 604 }
{ "_id" : "breast cancer", "count" : 596 }
{ "_id" : "apoptosis", "count" : 570 }
{ "_id" : "children", "count" : 487 }
{ "_id" : "depression", "count" : 474 }
{ "_id" : "hiv", "count" : 468 }
{ "_id" : "prognosis", "count" : 428 }

Symfony2 Setting a default choice field selection

The form should map the species->id value automatically to the selected entity select field. For example if your have a Breed entity that has a OnetoOne relationship with a Species entity in a join table called 'breed_species':

class Breed{

    private $species;

    * @ORM\OneToOne(targetEntity="BreedSpecies", mappedBy="breed")
    private $breedSpecies;

    public function getSpecies(){
       return $breedSpecies->getSpecies();

    private function getBreedSpecies(){
       return $this->$breedSpecies;

The field 'species' in the form class should pick up the species->id value from the 'species' attribute object in the Breed class passed to the form.

Alternatively, you can explicitly set the value by explicitly passing the species entity into the form using SetData():

    $breedForm = $this->createForm( new BreedForm(), $breed );
    $species   = $breed->getBreedSpecies()->getSpecies();

    $breedForm->get('species')->setData( $species );

    return $this->render( 'AcmeBundle:Computer:edit.html.twig'
                        , array( 'breed'     => $breed
                               , 'breedForm' => $breedForm->createView()

Passing route control with optional parameter after root in express?

That would work depending on what client.get does when passed undefined as its first parameter.

Something like this would be safer:

app.get('/:key?', function(req, res, next) {
    var key = req.params.key;
    if (!key) {
    client.get(key, function(err, reply) {
        if(client.get(reply)) {
        else {
            res.render('index', {
                link: null

There's no problem in calling next() inside the callback.

According to this, handlers are invoked in the order that they are added, so as long as your next route is app.get('/', ...) it will be called if there is no key.

Efficient way to remove ALL whitespace from String?

Try the replace method of the string in C#.

XML.Replace(" ", string.Empty);

Is there a <meta> tag to turn off caching in all browsers?

Try using

    <META HTTP-EQUIV="Pragma" CONTENT="no-cache">
    <META HTTP-EQUIV="Expires" CONTENT="-1">

Setting up a websocket on Apache?

I struggled to understand the proxy settings for websockets for https therefore let me put clarity here what i realized.

First you need to enable proxy and proxy_wstunnel apache modules and the apache configuration file will look like this.

<IfModule mod_ssl.c>
    <VirtualHost _default_:443>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/your_project_public_folder

      SSLEngine on
      SSLCertificateFile    /etc/ssl/certs/path_to_your_ssl_certificate
      SSLCertificateKeyFile /etc/ssl/private/path_to_your_ssl_key

      <Directory /var/www/your_project_public_folder>
              Options Indexes FollowSymLinks
              AllowOverride All
              Require all granted
              php_flag display_errors On
      ProxyRequests Off 
      ProxyPass /wss/  ws://

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined

in your frontend application use the url "wss://" this is very important mostly if you are stuck with websockets you might be making mistake in the front end url. You probably putting url wrongly like below.

wss:// -> port no should not be mentioned
ws:// -> url should start with wss only.
wss:// -> url should end with / -> most important

also interesting part is the last /wss/ is same as proxypass value if you writing proxypass /ws/ then in the front end you should write /ws/ in the end of url.

How to enable Logger.debug() in Log4j

This is probably happening because your log4j configuration is set to ERROR. Look for a file with contents like the following:

log4j.rootLogger=ERROR, CONSOLE

# console logging
log4j.appender.CONSOLE.layout.ConversionPattern=%d %-5p %-20.20t %-24c{1}: %m%n

The rootLogger is set to ERROR level here using a CONSOLE appender.

Note that some appenders like the console appender also have a Threshold property that can be used to overrule the rootLoggers level. You need to check both in this case.

Register DLL file on Windows Server 2008 R2

Find value in an array

I'm guessing that you're trying to find if a certain value exists inside the array, and if that's the case, you can use Array#include?(value):

a = [1,2,3,4,5]
a.include?(3)   # => true
a.include?(9)   # => false

If you mean something else, check the Ruby Array API

Changing the Git remote 'push to' default

To change which upstream remote is "wired" to your branch, use the git branch command with the upstream configuration flag.

Ensure the remote exists first:

git remote -vv

Set the preferred remote for the current (checked out) branch:

git branch --set-upstream-to <remote-name>

Validate the branch is setup with the correct upstream remote:

git branch -vv

How do I left align these Bootstrap form items?

If you are saying that your problem is how to left align the form labels, see if this helps:

Try changing the text-align left / right in the CSS

.form-horizontal .control-label{
    /* text-align:right; */

Good luck!

Including another class in SCSS

Another option could be using an Attribute Selector:

  //your style here

Whereas every class starting with "your-class-name" uses this style.

So in your case, you could do it like so:

  display: inline-block;
  //some other properties
   color: darken(#FFFFFF, 10%);

  //specifically for class b
  width: 100px;
     color: darken(#FFFFFF, 20%);

More about Attribute Selectors on w3Schools

What is the quickest way to HTTP GET in Python?

Python 3:

import urllib.request
contents = urllib.request.urlopen("").read()

Python 2:

import urllib2
contents = urllib2.urlopen("").read()

Documentation for urllib.request and read.

git index.lock File exists when I try to commit, but cannot delete the file

On Linux, Unix, Git Bash, or Cygwin, try:

rm -f .git/index.lock

On Windows Command Prompt, try:

del .git\index.lock

For Windows:

  • From a PowerShell console opened as administrator, try

    rm -Force ./.git/index.lock
  • If that does not work, you must kill all git.exe processes

    taskkill /F /IM git.exe

    SUCCESS: The process "git.exe" with PID 20448 has been terminated.
    SUCCESS: The process "git.exe" with PID 11312 has been terminated.
    SUCCESS: The process "git.exe" with PID 23868 has been terminated.
    SUCCESS: The process "git.exe" with PID 27496 has been terminated.
    SUCCESS: The process "git.exe" with PID 33480 has been terminated.
    SUCCESS: The process "git.exe" with PID 28036 has been terminated. \

    rm -Force ./.git/index.lock

How to load image files with webpack file-loader

Install file loader first:

$ npm install file-loader --save-dev

And add this rule in webpack.config.js

                test: /\.(png|jpg|gif)$/,
                use: [{
                    loader: 'file-loader',
                    options: {}

How to use refs in React with Typescript

For those looking on how to do it when you have an array of elements:

const textInputRefs = useRef<(HTMLDivElement | null)[]>([])


const onClickFocus = (event: React.BaseSyntheticEvent, index: number) => {


{, index) => (
        inputRef={(ref) => textInputs.current[index] = ref}
        onClick={event => onClickFocus(event, index)}

Run class in Jar file

Use java -cp myjar.jar com.mypackage.myClass.

  1. If the class is not in a package then simply java -cp myjar.jar myClass.

  2. If you are not within the directory where myJar.jar is located, then you can do:

    1. On Unix or Linux platforms:

      java -cp /location_of_jar/myjar.jar com.mypackage.myClass

    2. On Windows:

      java -cp c:\location_of_jar\myjar.jar com.mypackage.myClass

When do I use the PHP constant "PHP_EOL"?

I just experienced this issue when outputting to a Windows client. Sure, PHP_EOL is for server side, but most content output from php is for windows clients. So I have to place my findings here for the next person.

A) echo 'My Text' . PHP_EOL; // Bad because this just outputs \n and most versions of windows notepad display this on a single line, and most windows accounting software can't import this type of end of line character.

B) echo 'My Text \r\n'; //Bad because single quoted php strings do not interpret \r\n

C) echo "My Text \r\n"; // Yay it works! Looks correct in notepad, and works when importing the file to other windows software such as windows accounting and windows manufacturing software.

How to get the Touch position in android?

    public boolean onTouch(View v, MotionEvent event) {
       float x = event.getX();
       float y = event.getY();
       return true;

Using the "start" command with parameters passed to the started program

If you must use double quotation mark at any parameter, you can get error "'c:\somepath' is not recognized a an internal or external command, operable program or batch file". I suggest below solution when using double qoutation mark:

What's the difference between a POST and a PUT HTTP REQUEST?

As far as i know, PUT is mostly used for update the records.

  1. POST - To create document or any other resource

  2. PUT - To update the created document or any other resource.

But to be clear on that PUT usually 'Replaces' the existing record if it is there and creates if it not there..

Appending a line break to an output file in a shell script


echo "`date` User `whoami` started the script."$'\n' >> output.log

or just:

echo $'\n' >> output.log

LINQ: Select an object and change some properties without creating a new object

If you just want to update the property on all elements then

someList.All(x => { x.SomeProp = "foo"; return true; })

How do I spool to a CSV formatted file using SQLPLUS?

Use vi or vim to write the sql, use colsep with a control-A (in vi and vim precede the ctrl-A with a ctrl-v). Be sure to set the linesize and pagesize to something rational and turn on trimspool and trimout.

spool it off to a file. Then...

sed -e 's/,/;/g' -e 's/ *{ctrl-a} */,/g'  {spooled file}  > output.csv

That sed thing can be turned into a script. The " *" before and after the ctrl-A squeezes out all the useless spaces. Isn't it great that they bothered to enable html output from sqlplus but NOT native csv?????

I do it this way because it handles commas in the data. I turns them to semi-colons.

Move_uploaded_file() function is not working

If you are on a windows machine, there won't be any problems with uploading or writing to the specified folder path, except the syntactical errors.

But in case of Linux users, there is a workaround to this problem, even if there are no syntactical errors visible.

First of all, I am assuming that you are using this in a Linux environment and you need to upload something to your project folder in the public directory.

Even if you are having the write and read access to the project folder, PHP is not handled by the end user. It is and can be handled by a www-data user, or group.

So in order to make this www-data get access first type in;

sudo chgrp "www-data" your_project_folder

once its done, if there is no write access to the following as well;

sudo chown g+w your_project_folder

That will do the trick in Linux.

Please, not that this is done in a Linux environment, with phpmyadmin, and mysql running.

Starting with Zend Tutorial - Zend_DB_Adapter throws Exception: "SQLSTATE[HY000] [2002] No such file or directory"

Do not assume your unix_socket which would be different from one to another, try to find it.

First of all, get your unix_socket location.

$ mysql -u root -p

Enter your mysql password and login your mysql server from command line.

mysql> show variables like '%sock%';
| Variable_name | Value                                 |
| socket        | /opt/local/var/run/mysql5/mysqld.sock |

Your unix_soket could be diffrent.

Then change your php.ini, find your php.ini file from

<? phpinfo();

You maybe install many php with different version, so please don't assume your php.ini file location, get it from your 'phpinfo';

Change your php.ini:

mysql.default_socket = /opt/local/var/run/mysql5/mysqld.sock

mysqli.default_socket = /opt/local/var/run/mysql5/mysqld.sock

pdo_mysql.default_socket = /opt/local/var/run/mysql5/mysqld.sock

Then restart your apache or php-fpm.

onKeyPress Vs. onKeyUp and onKeyDown

Updated Answer:


  • Fires multiple times when you hold keys down.
  • Fires meta key.


  • Fires multiple times when you hold keys down.
  • Does not fire meta keys.


  • Fires once at the end when you release key.
  • Fires meta key.

This is the behavior in both addEventListener and jQuery.,console,output <-- try example

shows example with holding down for SSS

(answer has been edited with correct response, screenshot & example)

"The system cannot find the file specified" when running C++ program

Since this thread is one of the top results for that error and has no fix yet, I'll post what I found to fix it, originally found in this thread: Build Failure? "Unable to start program... The system cannot find the file specificed" which lead me to this thread: Error 'LINK : fatal error LNK1123: failure during conversion to COFF: file invalid or corrupt' after installing Visual Studio 2012 Release Preview

Basically all I did is this: Project Properties -> Configuration Properties -> Linker (General) -> Enable Incremental Linking -> "No (/INCREMENTAL:NO)"

How to remove default mouse-over effect on WPF buttons?

The Muffin Man had a very simple answer which worked for me.

To add a little more specific direction, at least for VS 2013:

  • Right-click the control
  • Select Edit Template => Edit a copy...
  • I selected 'Application' for where to save the style
    • From here you can directly edit App.xaml and see the intuitively named properties. For my purposes, I just set RenderMouseOver="False"
  • Then, in the MainWindow.xaml or wherever your GUI is, you can paste the new style at the end of the Button tag, e.g. ... Style="{DynamicResource MouseOverNonDefault}"/>

Best algorithm for detecting cycles in a directed graph

If you can't add a "visited" property to the nodes, use a set (or map) and just add all visited nodes to the set unless they are already in the set. Use a unique key or the address of the objects as the "key".

This also gives you the information about the "root" node of the cyclic dependency which will come in handy when a user has to fix the problem.

Another solution is to try to find the next dependency to execute. For this, you must have some stack where you can remember where you are now and what you need to do next. Check if a dependency is already on this stack before you execute it. If it is, you've found a cycle.

While this might seem to have a complexity of O(N*M) you must remember that the stack has a very limited depth (so N is small) and that M becomes smaller with each dependency that you can check off as "executed" plus you can stop the search when you found a leaf (so you never have to check every node -> M will be small, too).

In MetaMake, I created the graph as a list of lists and then deleted every node as I executed them which naturally cut down the search volume. I never actually had to run an independent check, it all happened automatically during normal execution.

If you need a "test only" mode, just add a "dry-run" flag which disables the execution of the actual jobs.

Subscript out of bounds - general definition and solution?

This came from standford's sna free tutorial and it states that ...

# Reachability can only be computed on one vertex at a time. To # get graph-wide statistics, change the value of "vertex" # manually or write a for loop. (Remember that, unlike R objects, # igraph objects are numbered from 0.)

ok, so when ever using igraph, the first roll/column is 0 other than 1, but matrix starts at 1, thus for any calculation under igraph, you would need x-1, shown at

this_node_reach <- subcomponent(g, (i - 1), mode = m)

but for the alter calculation, there is a typo here

alter = this_node_reach[j] + 1

delete +1 and it will work alright

How to list the certificates stored in a PKCS12 keystore with keytool?

You can list down the entries (certificates details) with the keytool and even you don't need to mention the store type.

keytool -list -v -keystore cert.p12 -storepass <password>

 Keystore type: PKCS12
 Keystore provider: SunJSSE

 Your keystore contains 1 entry
 Alias name: 1
 Creation date: Jul 11, 2020
 Entry type: PrivateKeyEntry
 Certificate chain length: 2

ImportError: No module named dateutil.parser

For Python 3:

pip3 install python-dateutil

Rotating x axis labels in R for barplot

You can use ggplot2 to rotate the x-axis label adding an additional layer

theme(axis.text.x = element_text(angle = 90, hjust = 1))

Change color inside strings.xml

Try this

For red color,

<string name="hello_worldRed"><![CDATA[<b><font color=#FF0000>Hello world!</font></b>]]></string>

For blue,

<string name="hello_worldBlue"><![CDATA[<b><font color=#0000FF>Hello world!</font></b>]]></string>

In java code,

//red color text
TextView redColorTextView = (TextView)findViewById(;
String redString = getResources().getString(R.string.hello_worldRed)

//Blue color text
TextView blueColorTextView = (TextView)findViewById(;
String blueString = getResources().getString(R.string.hello_worldBlue)

CSS for the "down arrow" on a <select> element?

I don't know if it is stylable with CSS (probably not in IE), but please: do not use a "fake" drop-down box using javascript, because the usability of these things usually is horrible. Among other things, keyboard navigation is usually absent.

JPA: How to get entity based on field value other than ID?

Using CrudRepository and JPA query works for me:


public interface TokenCrudRepository extends CrudRepository<Token, Integer> {

 * Finds a token by using the user as a search criteria.
 * @param user
 * @return  A token element matching with the given user.
    @Query("SELECT t FROM Token t WHERE LOWER(t.user) = LOWER(:user)")
    public Token find(@Param("user") String user);


and you invoke the find custom method like this:

public void destroyCurrentToken(String user){
    AbstractApplicationContext context = getContext();

    repository = context.getBean(TokenCrudRepository.class);

    Token token = ((TokenCrudRepository) repository).find(user);

    int idToken = token.getId();



How to extract a string using JavaScript Regex?

function extractSummary(iCalContent) {
  var rx = /\nSUMMARY:(.*)\n/g;
  var arr = rx.exec(iCalContent);
  return arr[1]; 

You need these changes:

  • Put the * inside the parenthesis as suggested above. Otherwise your matching group will contain only one character.

  • Get rid of the ^ and $. With the global option they match on start and end of the full string, rather than on start and end of lines. Match on explicit newlines instead.

  • I suppose you want the matching group (what's inside the parenthesis) rather than the full array? arr[0] is the full match ("\nSUMMARY:...") and the next indexes contain the group matches.

  • String.match(regexp) is supposed to return an array with the matches. In my browser it doesn't (Safari on Mac returns only the full match, not the groups), but Regexp.exec(string) works.

Check if string contains a value in array

You can concatenate the array values with implode and a separator of | and then use preg_match to search for the value.

Here is the solution I came up with ...

$emails = array('@gmail', '@hotmail', '@outlook', '@live', '@msn', '@yahoo', '@ymail', '@aol');
$emails = implode('|', $emails);

if(!preg_match("/$emails/i", $email)){
 // do something

FlutterError: Unable to load asset

I ran into this issue and very nearly gave up on Flutter until I stumbled upon the cause. In my case what I was doing was along the following lines

static Future<String> resourceText(String resName) async
  ZLibCodec zlc = new ZLibCodec(gzip:false,raw:true,level:9);
  var data= await rootBundle.load('assets/path/to/$resName');
  String result = new 
  return puzzle;
 } catch(e)
  debugPrint('Resource Error $resName $e');
  return ''; 

static Future<String> fallBackText(String textName) async
 if (testCondtion) return 'Some Required Text';
 else return resourceText('default');

where Some Required Text was a text string sent back if the testCondition was being met. Failing that I was trying to pick up default text from the app resources and send that back instead. My mistake was in the line return resourceText('default');. After changing it to read return await resourceText('default') things worked just as expected.

This issue arises from the fact that rootBundle.load operates asynchronously. In order to return its results correctly we need to await their availability which I had failed to do. It strikes me as slightly surprising that neither the Flutter VSCode plugin nor the Flutter build process flag up this as an error. While there may well be other reasons why rootBundle.load fails this answer will, hopefully, help others who are running into mysterious asset load failures in Flutter.

Oracle SELECT TOP 10 records

With regards to the poor performance there are any number of things it could be, and it really ought to be a separate question. However, there is one obvious thing that could be a problem:


If HISTORY_DATE really is a date column and if it has an index then this rewrite will perform better:


This is because a datatype conversion disables the use of a B-Tree index.

How to search by key=>value in a multidimensional array in PHP

$arr = array(0 => array("id"=>1,"name"=>"cat 1"),
             1 => array("id"=>2,"name"=>"cat 2"),
             2 => array("id"=>3,"name"=>"cat 1")
$arr = array_filter($arr, function($ar) {
   return ($ar['name'] == 'cat 1');
   //return ($ar['name'] == 'cat 1' AND $ar['id'] == '3');// you can add multiple conditions

echo "<pre>";



How do I create a timer in WPF?

Adding to the above. You use the Dispatch timer if you want the tick events marshalled back to the UI thread. Otherwise I would use System.Timers.Timer.

Get max and min value from array in JavaScript

Why not store it as an array of prices instead of object?

prices = []
$(allProducts).each(function () {
    var price = parseFloat($(this).data('price'));
prices.sort(function(a, b) { return a - b }); //this is the magic line which sort the array

That way you can just

prices[0]; // cheapest
prices[prices.length - 1]; // most expensive

Note that you can do shift() and pop() to get min and max price respectively, but it will take off the price from the array.

Even better alternative is to use Sergei solution below, by using Math.max and min respectively.


I realized that this would be wrong if you have something like [11.5, 3.1, 3.5, 3.7] as 11.5 is treated as a string, and would come before the 3.x in dictionary order, you need to pass in custom sort function to make sure they are indeed treated as float:

prices.sort(function(a, b) { return a - b });

Spring default behavior for lazy-init

For those coming here and are using Java config you can set the Bean to lazy-init using annotations like this:

In the configuration class:

// @Lazy - For all Beans to load lazily
public class AppConf {

    public Demo demo() {
        return new Demo();

For component scanning and auto-wiring:

public class Demo {

public class B {

    @Lazy // If this is not here, Demo will still get eagerly instantiated to satisfy this request.
    private Demo demo;


MS-access reports - The search key was not found in any record - on save

Following on from @Wilf's answer, I was trying to import a spreadsheet which had spaces in one of the headings, which I eliminated. I checked for leading and trailing spaces, but still had the same problem - until I used Ctrl-Right from the last real heading cell, and found another cell on the first row that looked blank but obviously contained some whitespace. After deleting this, my import works. Thanks for the pointers :)

How can I multiply and divide using only bit shifting and adding?

X * 2 = 1 bit shift left
X / 2 = 1 bit shift right
X * 3 = shift left 1 bit and then add X

How to find the operating system version using JavaScript?

@Ludwig 's solution was brilliant. A couple of fixes (which didn't have to do with operating system, and I couldn't place as a comment on his original posting because this is too long):

  1. IE 11 no longer identifies itself as MS IE.
  2. Chrome on IOS spoofs itself as Safari

Here they are:

(function (window) {
    /* test cases
            'browserInfo result: OS: ' + browserInfo.os +' '+ browserInfo.osVersion + '\n'+
                'Browser: ' + browserInfo.browser +' '+ browserInfo.browserVersion + '\n' +
                'Mobile: ' + + '\n' +
                'Cookies: ' + browserInfo.cookies + '\n' +
                'Screen Size: ' + browserInfo.screen
        var unknown = 'Unknown';

        // screen
        var screenSize = '';
        if (screen.width) {
            width = (screen.width) ? screen.width : '';
            height = (screen.height) ? screen.height : '';
            screenSize += '' + width + " x " + height;

        var nVer = navigator.appVersion;
        var nAgt = navigator.userAgent;
        var browser = navigator.appName;
        var version = '' + parseFloat(navigator.appVersion);
        var majorVersion = parseInt(navigator.appVersion, 10);
        var nameOffset, verOffset, ix;

        // Opera
        if ((verOffset = nAgt.indexOf('Opera')) != -1) {
            browser = 'Opera';
            version = nAgt.substring(verOffset + 6);
            if ((verOffset = nAgt.indexOf('Version')) != -1) {
                version = nAgt.substring(verOffset + 8);
        // MSIE
        else if ((verOffset = nAgt.indexOf('MSIE')) != -1) {
            browser = 'Microsoft Internet Explorer';
            version = nAgt.substring(verOffset + 5);

        //IE 11 no longer identifies itself as MS IE, so trap it
        else if ((browser == 'Netscape') && (nAgt.indexOf('Trident/') != -1)) {

            browser = 'Microsoft Internet Explorer';
            version = nAgt.substring(verOffset + 5);
            if ((verOffset = nAgt.indexOf('rv:')) != -1) {
                version = nAgt.substring(verOffset + 3);


        // Chrome
        else if ((verOffset = nAgt.indexOf('Chrome')) != -1) {
            browser = 'Chrome';
            version = nAgt.substring(verOffset + 7);
        // Safari
        else if ((verOffset = nAgt.indexOf('Safari')) != -1) {
            browser = 'Safari';
            version = nAgt.substring(verOffset + 7);
            if ((verOffset = nAgt.indexOf('Version')) != -1) {
                version = nAgt.substring(verOffset + 8);

            // Chrome on iPad identifies itself as Safari. Actual results do not match what Google claims
            //  at:
            //  No mention of chrome in the user agent string. However it does mention CriOS, which presumably
            //  can be keyed on to detect it.
            if (nAgt.indexOf('CriOS') != -1) {
                //Chrome on iPad spoofing Safari...correct it.
                browser = 'Chrome';
                //Don't believe there is a way to grab the accurate version number, so leaving that for now.
        // Firefox
        else if ((verOffset = nAgt.indexOf('Firefox')) != -1) {
            browser = 'Firefox';
            version = nAgt.substring(verOffset + 8);
        // Other browsers
        else if ((nameOffset = nAgt.lastIndexOf(' ') + 1) < (verOffset = nAgt.lastIndexOf('/'))) {
            browser = nAgt.substring(nameOffset, verOffset);
            version = nAgt.substring(verOffset + 1);
            if (browser.toLowerCase() == browser.toUpperCase()) {
                browser = navigator.appName;
        // trim the version string
        if ((ix = version.indexOf(';')) != -1) version = version.substring(0, ix);
        if ((ix = version.indexOf(' ')) != -1) version = version.substring(0, ix);
        if ((ix = version.indexOf(')')) != -1) version = version.substring(0, ix);

        majorVersion = parseInt('' + version, 10);
        if (isNaN(majorVersion)) {
            version = '' + parseFloat(navigator.appVersion);
            majorVersion = parseInt(navigator.appVersion, 10);

        // mobile version
        var mobile = /Mobile|mini|Fennec|Android|iP(ad|od|hone)/.test(nVer);

        // cookie
        var cookieEnabled = (navigator.cookieEnabled) ? true : false;

        if (typeof navigator.cookieEnabled == 'undefined' && !cookieEnabled) {
            document.cookie = 'testcookie';
            cookieEnabled = (document.cookie.indexOf('testcookie') != -1) ? true : false;

        // system
        var os = unknown;
        var clientStrings = [
            {s:'Windows 3.11', r:/Win16/},
            {s:'Windows 95', r:/(Windows 95|Win95|Windows_95)/},
            {s:'Windows ME', r:/(Win 9x 4.90|Windows ME)/},
            {s:'Windows 98', r:/(Windows 98|Win98)/},
            {s:'Windows CE', r:/Windows CE/},
            {s:'Windows 2000', r:/(Windows NT 5.0|Windows 2000)/},
            {s:'Windows XP', r:/(Windows NT 5.1|Windows XP)/},
            {s:'Windows Server 2003', r:/Windows NT 5.2/},
            {s:'Windows Vista', r:/Windows NT 6.0/},
            {s:'Windows 7', r:/(Windows 7|Windows NT 6.1)/},
            {s:'Windows 8.1', r:/(Windows 8.1|Windows NT 6.3)/},
            {s:'Windows 8', r:/(Windows 8|Windows NT 6.2)/},
            {s:'Windows NT 4.0', r:/(Windows NT 4.0|WinNT4.0|WinNT|Windows NT)/},
            {s:'Windows ME', r:/Windows ME/},
            {s:'Android', r:/Android/},
            {s:'Open BSD', r:/OpenBSD/},
            {s:'Sun OS', r:/SunOS/},
            {s:'Linux', r:/(Linux|X11)/},
            {s:'iOS', r:/(iPhone|iPad|iPod)/},
            {s:'Mac OS X', r:/Mac OS X/},
            {s:'Mac OS', r:/(MacPPC|MacIntel|Mac_PowerPC|Macintosh)/},
            {s:'QNX', r:/QNX/},
            {s:'UNIX', r:/UNIX/},
            {s:'BeOS', r:/BeOS/},
            {s:'OS/2', r:/OS\/2/},
            {s:'Search Bot', r:/(nuhk|Googlebot|Yammybot|Openbot|Slurp|MSNBot|Ask Jeeves\/Teoma|ia_archiver)/}
        for (var id in clientStrings) {
            var cs = clientStrings[id];
            if (cs.r.test(nAgt)) {
                os = cs.s;

        var osVersion = unknown;

        if (/Windows/.test(os)) {
            osVersion = /Windows (.*)/.exec(os)[1];
            os = 'Windows';

        switch (os) {
            case 'Mac OS X':
                osVersion = /Mac OS X (10[\.\_\d]+)/.exec(nAgt)[1];

            case 'Android':
                osVersion = /Android ([\.\_\d]+)/.exec(nAgt)[1];

            case 'iOS':
                osVersion = /OS (\d+)_(\d+)_?(\d+)?/.exec(nVer);
                osVersion = osVersion[1] + '.' + osVersion[2] + '.' + (osVersion[3] | 0);


    window.browserInfo = {
        screen: screenSize,
        browser: browser,
        browserVersion: version,
        mobile: mobile,
        os: os,
        osVersion: osVersion,
        cookies: cookieEnabled

php date validation

Though checkdate is good, this seems much concise function to validate and also you can give formats. [Source]

function validateDate($date, $format = 'Y-m-d H:i:s') {
    $d = DateTime::createFromFormat($format, $date);
    return $d && $d->format($format) == $date;

function was copied from this answer or

The extra ->format() is needed for cases where the date is invalid but createFromFormat still manages to create a DateTime object. For example:

// Gives "2016-11-10 ..." because Thursday falls on Nov 10
DateTime::createFromFormat('D M j Y', 'Thu Nov 9 2016');

// false, Nov 9 is a Wednesday
validateDate('Thu Nov 9 2016', 'D M j Y');

Transform DateTime into simple Date in Ruby on Rails

For old Ruby (1.8.x):

myDate = Date.parse(myDateTime.to_s)

Android studio doesn't list my phone under "Choose Device"

In my case, android studio selectively doesnt recognize my device for projects with COMPILE AND TARGET SDKVERSION 29 under the app level build.gradle.

I fixed this either by downloading 'sources for android 29' which comes up after clicking the 'show package details' under the sdk manager tab or by reducing the compile and targetsdkversions to 28

$_POST not working. "Notice: Undefined index: username..."

first of all,

be sure that there is a post

if(isset($_POST['username'])) { 
    // check if the username has been set

second, and most importantly, sanitize the data, meaning that

$query = "SELECT password FROM users WHERE username='".$_POST['username']."'";

is deadly dangerous, instead use

$query = "SELECT password FROM users WHERE username='".mysql_real_escape_string($_POST['username'])."'";

and please research the subject sql injection

C# Public Enums in Classes

You need to define the enum outside of the class.

public enum card_suits

public class Card
     // ...

That being said, you may also want to consider using the standard naming guidelines for Enums, which would be CardSuit instead of card_suits, since Pascal Casing is suggested, and the enum is not marked with the FlagsAttribute, suggesting multiple values are appropriate in a single variable.

Online SQL Query Syntax Checker

SQLFiddle will let you test out your queries, while it doesn't explicitly correct syntax etc. per se it does let you play around with the script and will definitely let you know if things are working or not.

Rails migration for change column

Just generate migration:

rails g migration change_column_to_new_from_table_name

Update migration like this:

class ClassName < ActiveRecord::Migration
  change_table :table_name do |table|
    table.change :column_name, :data_type

and finally

rake db:migrate

curl -GET and -X GET

By default you use curl without explicitly saying which request method to use. If you just pass in a HTTP URL like curl it will use GET. If you use -d or -F curl will use POST, -I will cause a HEAD and -T will make it a PUT.

If for whatever reason you're not happy with these default choices that curl does for you, you can override those request methods by specifying -X [WHATEVER]. This way you can for example send a DELETE by doing curl -X DELETE [URL].

It is thus pointless to do curl -X GET [URL] as GET would be used anyway. In the same vein it is pointless to do curl -X POST -d data [URL]... But you can make a fun and somewhat rare request that sends a request-body in a GET request with something like curl -X GET -d data [URL].

Digging deeper

curl -GET (using a single dash) is just wrong for this purpose. That's the equivalent of specifying the -G, -E and -T options and that will do something completely different.

There's also a curl option called --get to not confuse matters with either. It is the long form of -G, which is used to convert data specified with -d into a GET request instead of a POST.

(I subsequently used my own answer here to populate the curl FAQ to cover this.)


Modern versions of curl will inform users about this unnecessary and potentially harmful use of -X when verbose mode is enabled (-v) - to make users aware. Further explained and motivated in this blog post.

-G converts a POST + body to a GET + query

You can ask curl to convert a set of -d options and instead of sending them in the request body with POST, put them at the end of the URL's query string and issue a GET, with the use of `-G. Like this:

curl -d name=daniel -d grumpy=yes -G

How to import data from text file to mysql database

It should be as simple as...

LOAD DATA INFILE '/tmp/mydata.txt' INTO TABLE PerformanceReport;

By default LOAD DATA INFILE uses tab delimited, one row per line, so should take it in just fine.

TypeError: Object of type 'bytes' is not JSON serializable

I was dealing with this issue today, and I knew that I had something encoded as a bytes object that I was trying to serialize as json with json.dump(my_json_object, write_to_file.json). my_json_object in this case was a very large json object that I had created, so I had several dicts, lists, and strings to look at to find what was still in bytes format.

The way I ended up solving it: the write_to_file.json will have everything up to the bytes object that is causing the issue.

In my particular case this was a line obtained through

for line in text:
    json_object['line'] = line.strip()

I solved by first finding this error with the help of the write_to_file.json, then by correcting it to:

for line in text:
    json_object['line'] = line.strip().decode()

In MVC, how do I return a string result?

You can also just return string if you know that's the only thing the method will ever return. For example:

public string MyActionName() {
  return "Hi there!";

How to Scroll Down - JQuery

    jQuery(function ($) {
        $('li#linkss').find('a').on('click', function (e) {
                link_href = $(this).attr('href')
                , $linkElem = $(link_href)
                , $linkElem_scroll = $linkElem.get(0) && $linkElem.position().top - 115;
            $('html, body')
                    scrollTop: $linkElem_scroll
                }, 'slow');

using lodash .groupBy. how to add your own keys for grouped output?

Highest voted answer uses Lodash _.chain function which is considered a bad practice now "Why using _.chain is a mistake."

Here is a fewliner that approaches the problem from functional programming perspective:

import tap from "lodash/fp/tap";
import flow from "lodash/fp/flow";
import groupBy from "lodash/fp/groupBy";

const map = require('lodash/fp/map').convert({ 'cap': false });

const result = flow(
      map((users, color) => ({color, users})),

Where input is an array that you want to convert.

Big O, how do you calculate/approximate it?

Familiarity with the algorithms/data structures I use and/or quick glance analysis of iteration nesting. The difficulty is when you call a library function, possibly multiple times - you can often be unsure of whether you are calling the function unnecessarily at times or what implementation they are using. Maybe library functions should have a complexity/efficiency measure, whether that be Big O or some other metric, that is available in documentation or even IntelliSense.

Saving data to a file in C#

I think you might want something like this

// Compose a string that consists of three lines.
string lines = "First line.\r\nSecond line.\r\nThird line.";

// Write the string to a file.
System.IO.StreamWriter file = new System.IO.StreamWriter("c:\\test.txt");


Predicate Delegates in C#

Simply -> they provide True/False values based on condition mostly used for querying. mostly used with delegates

consider example of list

List<Program> blabla= new List<Program>();
        blabla.Add(new Program("shubham", 1));
        blabla.Add(new Program("google", 3));
        blabla.Add(new Program("world",5));
        blabla.Add(new Program("hello", 5));
        blabla.Add(new Program("bye", 2));

contains names and ages. Now say we want to find names on condition So I Will use,

    Predicate<Program> test = delegate (Program p) { return p.age > 3; };
        List<Program> matches = blabla.FindAll(test);
        Action<Program> print = Console.WriteLine;

tried to Keep it Simple!

Bootstrap - How to add a logo to navbar class?

I would suggest you to use either an image or text. So, Remove the text and add it in your image(using Photoshop, maybe). Then, Use a width and height 100% for the image. it will do the trick. because the image can be resized based on the container. But, you have to manually resize the text. If you can provide the fiddle, I can help you achieve this.

Simple If/Else Razor Syntax

A little bit off topic maybe, but for modern browsers (IE9 and newer) you can use the css odd/even selectors to achieve want you want.

tr:nth-child(even) { /* your alt-row stuff */}
tr:nth-child(odd) { /* the other rows */ }


tr { /* all table rows */ }
tr:nth-child(even) { /* your alt-row stuff */}

How to convert 2D float numpy array to 2D int numpy array?

Use the astype method.

>>> x = np.array([[1.0, 2.3], [1.3, 2.9]])
>>> x
array([[ 1. ,  2.3],
       [ 1.3,  2.9]])
>>> x.astype(int)
array([[1, 2],
       [1, 2]])

Handle spring security authentication exceptions with @ExceptionHandler

I was able to handle that by simply overriding the method 'unsuccessfulAuthentication' in my filter. There, I send an error response to the client with the desired HTTP status code.

protected void unsuccessfulAuthentication(HttpServletRequest request, HttpServletResponse response,
        AuthenticationException failed) throws IOException, ServletException {

    if (failed.getCause() instanceof RecordNotFoundException) {
        response.sendError((HttpServletResponse.SC_NOT_FOUND), failed.getMessage());

How do I center a Bootstrap div with a 'spanX' class?

Incidentally, if your span class is even-numbered (e.g. span8) you can add an offset class to center it – for span8 that would be offset2 (assuming the default 12-column grid), for span6 it would be offset3 and so on (basically, half the number of remaining columns if you subtract the span-number from the total number of columns in the grid).

UPDATE Bootstrap 3 renamed a lot of classes so all the span*classes should be col-md-* and the offset classes should be col-md-offset-*, assuming you're using the medium-sized responsive grid.

I created a quick demo here, hope it helps:

Reading CSV file and storing values into an array

Still wrong. You need to compensate for "" in quotes. Here is my solution Microsoft style csv.

               /// <summary>
    /// Microsoft style csv file.  " is the quote character, "" is an escaped quote.
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="sepChar"></param>
    /// <param name="quoteChar"></param>
    /// <param name="escChar"></param>
    /// <returns></returns>
    public static List<string[]> ReadCSVFileMSStyle(string fileName, char sepChar = ',', char quoteChar = '"')
        List<string[]> ret = new List<string[]>();

        string[] csvRows = System.IO.File.ReadAllLines(fileName);

        foreach (string csvRow in csvRows)
            bool inQuotes = false;
            List<string> fields = new List<string>();
            string field = "";
            for (int i = 0; i < csvRow.Length; i++)
                if (inQuotes)
                    // Is it a "" inside quoted area? (escaped litteral quote)
                    if(i < csvRow.Length - 1 && csvRow[i] == quoteChar && csvRow[i+1] == quoteChar)
                        field += quoteChar;
                    else if(csvRow[i] == quoteChar)
                        inQuotes = false;
                        field += csvRow[i];
                else // Not in quoted region
                     if (csvRow[i] == quoteChar)
                        inQuotes = true;
                    if (csvRow[i] == sepChar)
                        field = "";
                        field += csvRow[i];
            if (!string.IsNullOrEmpty(field))
                field = "";

        return ret;

Bootstrap date and time picker

If you are still interested in a javascript api to select both date and time data, have a look at these projects which are forks of bootstrap datepicker:

The first fork is a big refactor on the parsing/formatting codebase and besides providing all views to select date/time using mouse/touch, it also has a mask option (by default) which lets the user to quickly type the date/time based on a pre-specified format.

What does `dword ptr` mean?

It is a 32bit declaration. If you type at the top of an assembly file the statement [bits 32], then you don't need to type DWORD PTR. So for example:

[bits 32]
and  [ebp-4], 0

How to split a large text file into smaller files with equal number of lines?

split (from GNU coreutils, since version 8.8 from 2010-12-22) includes the following parameter:

-n, --number=CHUNKS     generate CHUNKS output files; see explanation below

CHUNKS may be:
  N       split into N files based on size of input
  K/N     output Kth of N to stdout
  l/N     split into N files without splitting lines/records
  l/K/N   output Kth of N to stdout without splitting lines/records
  r/N     like 'l' but use round robin distribution
  r/K/N   likewise but only output Kth of N to stdout

Thus, split -n 4 input output. will generate four files (output.a{a,b,c,d}) with the same amount of bytes, but lines might be broken in the middle.

If we want to preserve full lines (i.e. split by lines), then this should work:

split -n l/4 input output.

Related answer:

angularjs: allows only numbers to be typed into a text box


 <input type="text" name="number" only-digits>

// Just type 123

  .directive('onlyDigits', function () {
    return {
      require: 'ngModel',
      restrict: 'A',
      link: function (scope, element, attr, ctrl) {
        function inputValue(val) {
          if (val) {
            var digits = val.replace(/[^0-9]/g, '');

            if (digits !== val) {
            return parseInt(digits,10);
          return undefined;

// type: 123 or 123.45

 .directive('onlyDigits', function () {
    return {
      require: 'ngModel',
      restrict: 'A',
      link: function (scope, element, attr, ctrl) {
        function inputValue(val) {
          if (val) {
            var digits = val.replace(/[^0-9.]/g, '');

            if (digits.split('.').length > 2) {
              digits = digits.substring(0, digits.length - 1);

            if (digits !== val) {
            return parseFloat(digits);
          return undefined;

Java Compare Two Lists

I found a very basic example of List comparison at List Compare This example verifies the size first and then checks the availability of the particular element of one list in another.

Redirect in Spring MVC

It is possible to define a urlBasedViewResolver in your properties file:

index.viewClass =org.springframework.web.servlet.view.JstlView  
index.prefix = /WEB-INF/jsp/  
index.suffix =.jsp

String to byte array in php

print_r(unpack("H*","The quick fox jumped over the lazy brown dog"))

Array ( [1] => 54686520717569636b20666f78206a756d706564206f76657220746865206c617a792062726f776e20646f67 ) 

T = 0x54, h = 0x68, ...

You can split the result into two-hex-character chunks if necessary.

How do I get a YouTube video thumbnail from the YouTube API?

// Get image form video URL
$url = $video['video_url'];

$urls = parse_url($url);

//Expect the URL to be, where abcd is the video ID
if ($urls['host'] == '') :

    $imgPath = ltrim($urls['path'],'/');

//Expect the URL to be
elseif (strpos($urls['path'],'embed') == 1) :

    $imgPath = end(explode('/',$urls['path']));

//Expect the URL to be abcd only
elseif (strpos($url,'/') === false):

    $imgPath = $url;

//Expect the URL to be
else :


    $imgPath = $v;


Android Studio 3.0 Execution failed for task: unable to merge dex

For me, the problem was the use of Java 1.8 in a module, but not in the app module. I added this to the app build gradle and worked:

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8

a page can have only one server-side form tag

It sounds like you have a form tag in a Master Page and in the Page that is throwing the error.

You can have only one.

Search text in fields in every table of a MySQL database

You could use


Then get the columns in those tables (in a loop) with


and then with that info create many many queries which you can also UNION if you need.

But this is extremely heavy on the database. Specially if you are doing a LIKE search.

How to implement endless list with RecyclerView?

Although the accepted answer works perfectly, the solution below uses addOnScrollListener since setOnScrollListener is deprecated, and reduces number of variables, and if conditions.

final LinearLayoutManager layoutManager = new LinearLayoutManager(context);

feedsRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);

        if (dy > 0) {   
            if ((layoutManager.getChildCount() + layoutManager.findFirstVisibleItemPosition()) >= layoutManager.getItemCount()) {
                Log.d("TAG", "End of list");

Google Chrome Full Black Screen

You didn't mention anything about the environment you're running. This problem occurs on VirtualBox when running on Windows 10. One thing you can try is disabling 3D Acceleration on your VM, this is a known issue.

Subdomain on different host

UPDATE - I do not have Total DNS enabled at GoDaddy because the domain is hosted at DiscountASP. As such, I could not add an A Record and that is why GoDaddy was only offering to forward my subdomain to a different site. I finally realized that I had to go to DiscountASP to add the A Record to point to DreamHost. Now waiting to see if it all works!

Of course, use the stinkin' IP! I'm not sure why that wasn't registering for me. I guess their helper text example of pointing to another url was throwing me off.

Thanks for both of the replies. I 'got it' as soon as I read Bryant's response which was first but Saif kicked it up a notch and added a little more detail.


SSIS Connection Manager Not Storing SQL Password

Check the text contents of the connection manager file itself, the password field might be configured in the Project.params file, in which case entering the password into the connection manager window will cause it to not save.

Sum the digits of a number

You can try this

def sumDigits(number):
    sum = 0
        lastdigit = number%10
        sum += lastdigit
        number = number//10

    return sum

iptables v1.4.14: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)

The table names are case-sensitive so you should use lower-case nat instead of upper-case NAT. For example;

iptables -t nat -A POSTROUTING -s -o eth0 -j MASQUERADE

Bootstrap: adding gaps between divs

The easiest way to do it is to add mb-5 to your classes. That is <div class='row mb-5'>.


  • mb varies betweeen 1 to 5
  • The Div MUST have the row class

phpMyAdmin Error: The mbstring extension is missing. Please check your PHP configuration

This worked for me on Kali-linux 2018 :

apt-get install php7.0-mbstring

service apache2 restart

SVN Commit failed, access forbidden

I had a similar issue in Mac where svn was picking mac login as user name and I was getting error as

svn: E170013: Unable to connect to a repository at URL 'https://repo:8443/svn/proj/trunk'
svn: E175013: Access to '/svn/proj/trunk' forbidden

I used the --username along with svn command to pass the correct username which helped me. Alternatively, you can delete ~/.subversion/auth file, after which svn will prompt you for username.

/usr/lib/x86_64-linux-gnu/ version CXXABI_1.3.8' not found

I had the same problem on my Ubuntu 14.04 when tried to install TopTracker. I got such errors:

/usr/share/toptracker/bin/TopTracker: /usr/lib/x86_64-linux-gnu/ version 'CXXABI_1.3.8' not found (required by /usr/share/toptracker/bin/TopTracker) /usr/share/toptracker/bin/TopTracker: /usr/lib/x86_64-linux-gnu/ version 'GLIBCXX_3.4.21' not found (required by /usr/share/toptracker/bin/TopTracker) /usr/share/toptracker/bin/TopTracker: /usr/lib/x86_64-linux-gnu/ version 'CXXABI_1.3.9' not found (required by /usr/share/toptracker/bin/TopTracker)

But I then installed gcc 4.9 version and problem gone:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-4.9 g++-4.9

Seeding the random number generator in Javascript

Please see Pierre L'Ecuyer's work going back to the late 1980s and early 1990s. There are others as well. Creating a (pseudo) random number generator on your own, if you are not an expert, is pretty dangerous, because there is a high likelihood of either the results not being statistically random or in having a small period. Pierre (and others) have put together some good (pseudo) random number generators that are easy to implement. I use one of his LFSR generators.

Phil Troy

Slidedown and slideup layout with animation

I had a similar requirement in the app I am working on. And, I found a third-party library which does a slide-up, slide-down and slide-right in Android.

Refer to the link for more details:

To set up the library(copied from the ReadMe portion of its Github page on request):

Get SlideUp library

Add the JitPack repository to your build file. Add it in your root build.gradle at the end of repositories:

allprojects {
  repositories {
    maven { url '' }
    maven { url "" } // or google() in AS 3.0

Add the dependency (in the Module gradle)

dependencies {
    compile 'com.github.mancj:SlideUp-Android:2.2.1'
    compile 'ru.ztrap:RxSlideUp2:2.x.x' //optional, for reactive listeners based on RxJava-2
    compile 'ru.ztrap:RxSlideUp:1.x.x' //optional, for reactive listeners based on RxJava

To add the SlideUp into your project, follow these three simple steps:

Step 1:

create any type of layout


Step 2:

Find that view in your activity/fragment

View slideView = findViewById(;

Step 3:

Create a SlideUp object and pass in your view

slideUp = new SlideUpBuilder(slideView)


You may also refer to the sample project on the link. I found it quite useful.

What's the equivalent of Java's Thread.sleep() in JavaScript?

Assuming you're able to use ECMAScript 2017 you can emulate similar behaviour by using async/await and setTimeout. Here's an example sleep function:

async function sleep(msec) {
    return new Promise(resolve => setTimeout(resolve, msec));

You can then use the sleep function in any other async function like this:

async function testSleep() {
    console.log("Waiting for 1 second...");
    await sleep(1000);
    console.log("Waiting done."); // Called 1 second after the first console.log

This is nice because it avoids needing a callback. The down side is that it can only be used in async functions. Behind the scenes the testSleep function is paused, and after the sleep completes it is resumed.

From MDN:

The await expression causes async function execution to pause until a Promise is fulfilled or rejected, and to resume execution of the async function after fulfillment.

For a full explanation see:

Select rows with same id but different value in another column

Join the same table back to itself. Use an inner join so that rows that don't match are discarded. In the joined set, there will be rows that have a matching ARIDNR in another row in the table with a different LIEFNR. Allow those ARIDNR to appear in the final set.

    SELECT a.ARIDNR FROM YourTable a
    JOIN YourTable b on b.ARIDNR = a.ARIDNR AND b.LIEFNR <> a.LIEFNR

Handling JSON Post Request in Go

You need to read from req.Body. The ParseForm method is reading from the req.Body and then parsing it in standard HTTP encoded format. What you want is to read the body and parse it in JSON format.

Here's your code updated.

package main

import (

type test_struct struct {
    Test string

func test(rw http.ResponseWriter, req *http.Request) {
    body, err := ioutil.ReadAll(req.Body)
    if err != nil {
    var t test_struct
    err = json.Unmarshal(body, &t)
    if err != nil {

func main() {
    http.HandleFunc("/test", test)
    log.Fatal(http.ListenAndServe(":8082", nil))

Python Error: "ValueError: need more than 1 value to unpack"

Probably you didn't provide an argument on the command line. In that case, sys.argv only contains one value, but it would have to have two in order to provide values for both user_name and script.

How do you split and unsplit a window/view in Eclipse IDE?

This is possible with the menu items Window>Editor>Toggle Split Editor.

Current shortcut for splitting is:

Azerty keyboard:

  • Ctrl + _ for split horizontally, and
  • Ctrl + { for split vertically.

Qwerty US keyboard:

  • Ctrl + Shift + - (accessing _) for split horizontally, and
  • Ctrl + Shift + [ (accessing {) for split vertically.

MacOS - Qwerty US keyboard:

  • + Shift + - (accessing _) for split horizontally, and
  • + Shift + [ (accessing {) for split vertically.

On any other keyboard if a required key is unavailable (like { on a german Qwertz keyboard), the following generic approach may work:

  • Alt + ASCII code + Ctrl then release Alt

Example: ASCII for '{' = 123, so press 'Alt', '1', '2', '3', 'Ctrl' and release 'Alt', effectively typing '{' while 'Ctrl' is pressed, to split vertically.

Example of vertical split:


  • The menu items Window>Editor>Toggle Split Editor were added with Eclipse Luna 4.4 M4, as mentioned by Lars Vogel in "Split editor implemented in Eclipse M4 Luna"
  • The split editor is one of the oldest and most upvoted Eclipse bug! Bug 8009
  • The split editor functionality has been developed in Bug 378298, and will be available as of Eclipse Luna M4. The Note & Newsworthy of Eclipse Luna M4 will contain the announcement.

How can I find the number of days between two Date objects in Ruby?

all of these steered me to the correct result, but I wound up doing - DateTime.parse("01-01-1995").mjd

PostgreSQL error: Fatal: role "username" does not exist

sudo su - postgres

psql template1

creating role on pgsql with privilege as "superuser"

CREATE ROLE username superuser;
eg. CREATE ROLE demo superuser;

Then create user

CREATE USER username; 
eg. CREATE USER demo;

Assign privilege to user

GRANT ROOT TO username;

And then enable login that user, so you can run e.g.: psql template1, from normal $ terminal:


Chart creating dynamically. in .net, c#

Microsoft has a nice chart control. Download it here. Great video on this here. Example code is here. Happy coding!

How do you easily horizontally center a <div> using CSS?

The title of the question and the content is actually different, so I will post two solutions for that using Flexbox.

I guess Flexbox will replace/add to the current standard solution by the time IE8 and IE9 is completely destroyed ;)

Check the current Browser compatibility table for flexbox

Single element

.container {_x000D_
  display: flex;_x000D_
  justify-content: center;_x000D_
<div class="container">_x000D_
  <img src="">_x000D_

Multiple elements but center only one

Default behaviour is flex-direction: row which will align all the child items in a single line. Setting it to flex-direction: column will help the lines to be stacked.

.container {_x000D_
  display: flex;_x000D_
  flex-direction: column;_x000D_
.centered {_x000D_
  align-self: center;_x000D_
<div class="container">_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 survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged._x000D_
  <div class="centered"><img src=""></div>_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_x000D_
    has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. </p>_x000D_

CSS Background Opacity

I would do something like this

<div class="container">
  <div class="text">
    <p>text yay!</p>


.container {
    position: relative;

.container::before {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: url('/path/to/image.png');
    opacity: .4;
    content: "";
    z-index: -1;

It should work. This is assuming you are required to have a semi-transparent image BTW, and not a color (which you should just use rgba for). Also assumed is that you can't just alter the opacity of the image beforehand in Photoshop.

Are there any Java method ordering conventions?

My "convention": static before instance, public before private, constructor before methods, but main method at the bottom (if present).

Sending cookies with postman

You can enable Interceptor in browser and in Postman separately. For send/recieve cookies you should enable Interceptor in Postman. So if you enable interceptor only in browser - it will not work. Actually you don't need enable Interceptor in browser at all - if you don't want to flood your postman history with unnecessary requests.

How do I insert non breaking space character &nbsp; in a JSF page?

Not necessary to give 160 . 141 will also work. For the value field provide value="&#141" .

Angular 4.3 - HttpClient set params

Since HTTP Params class is immutable therefore you need to chain the set method:

const params = new HttpParams()
.set('aaa', '111')
.set('bbb', "222");

C string append

man page of strcat says that arg1 and arg2 are appended to arg1.. and returns the pointer of s1. If you dont want disturb str1,str2 then you have write your own function.

char * my_strcat(const char * str1, const char * str2)
   char * ret = malloc(strlen(str1)+strlen(str2));

     sprintf(ret, "%s%s", str1, str2);
     return ret;
   return NULL;    

Hope this solves your purpose

What does "static" mean in C?

It depends:

int foo()
   static int x;
   return ++x;

The function would return 1, 2, 3, etc. --- the variable is not on the stack.


static int foo()

It means that this function has scope only in this file. So a.c and b.c can have different foo()s, and foo is not exposed to shared objects. So if you defined foo in a.c you couldn't access it from b.c or from any other places.

In most C libraries all "private" functions are static and most "public" are not.

Where is localhost folder located in Mac or Mac OS X?

There are actually two place where where mac os x serves website by default:

/Library/WebServer/Documents --> http://localhost

~/Sites --> http://localhost/~user/

How to use localization in C#

A fix and elaboration of @Fredrik Mörk answer.

  • Add a strings.resx Resource file to your project (or a different filename)
  • Set Access Modifier to Public (in the opened strings.resx file tab)
  • Add a string resouce in the resx file: (example: name Hello, value Hello)
  • Save the resource file

Visual Studio auto-generates a respective strings class, which is actually placed in strings.Designer.cs. The class is in the same namespace that you would expect a newly created .cs file to be placed in.

This code always prints Hello, because this is the default resource and no language-specific resources are available:


Now add a new language-specific resource:

  • Add (for French)
  • Add a string with the same name as previously, but different value: (name Hello, value Salut)

The following code prints Salut:

Thread.CurrentThread.CurrentUICulture = CultureInfo.GetCultureInfo("fr-FR");

What resource is used depends on Thread.CurrentThread.CurrentUICulture. It is set depending on Windows UI language setting, or can be set manually like in this example. Learn more about this here.

You can add country-specific resources like or

The string to be used is determined in this priority order:

  • From country-specific resource like
  • From language-specific resource like
  • From default strings.resx

Note that language-specific resources generate satellite assemblies.

Also learn how CurrentCulture differs from CurrentUICulture here.

How to convert CSV file to multiline JSON?

Add the indent parameter to json.dumps

 data = {'this': ['has', 'some', 'things'],
         'in': {'it': 'with', 'some': 'more'}}
 print(json.dumps(data, indent=4))

Also note that, you can simply use json.dump with the open jsonfile:

json.dump(data, jsonfile)

INNER JOIN same table

I don't know how the table is created but try this...

SELECT users1.user_id, users2.user_parent_id
FROM users AS users1
INNER JOIN users AS users2
ON =
WHERE users1.user_id = users2.user_parent_id

Setting a minimum/maximum character count for any character using a regular expression

Like this: .

The . means any character except newline (which sometimes is but often isn't included, check your regex flavour).

You can rewrite your expression as ^.{1,35}$, which should match any line of length 1-35.

Make copy of an array

You can also use Arrays.copyOfRange.


public static void main(String[] args) {
    int[] a = {1,2,3};
    int[] b = Arrays.copyOfRange(a, 0, a.length);
    a[0] = 5;
    System.out.println(Arrays.toString(a)); // [5,2,3]
    System.out.println(Arrays.toString(b)); // [1,2,3]

This method is similar to Arrays.copyOf, but it's more flexible. Both of them use System.arraycopy under the hood.


Any way (or shortcut) to auto import the classes in IntelliJ IDEA like in Eclipse?

Seems like IntelliJ IDEA will import missed class automatically, and you can import them by hit Alt + Enter manually.

"SELECT ... IN (SELECT ...)" query in CodeIgniter

I think you can create a simple SQL query:

$sql="select username from user where id in (select id from idtables)";

and then you can use it normally.

How to set header and options in axios?

You can also selected headers to every axios request:

// Add a request interceptor
axios.interceptors.request.use(function (config) {
    config.headers.Authorization = 'AUTH_TOKEN';
    return config;

Second method

axios.defaults.headers.common['Authorization'] = 'AUTH_TOKEN';

Get the content of a sharepoint folder with Excel VBA

I messed around with this problem for a bit, and found a very simple, 2-line solution, simply replacing the 'http' and all the forward slashes like this:

myFilePath = replace(myFilePath, "/", "\")
myFilePath = replace(myFilePath, "http:", "")

It might not work for everybody, but it worked for me

If you are using a secure site (or wish to cater for both) you may wish to add the following line:

myFilePath = replace(myFilePath, "https:", "")

Quick unix command to display specific lines in the middle of a file?

I'd first split the file into few smaller ones like this

$ split --lines=50000 /path/to/large/file /path/to/output/file/prefix

and then grep on the resulting files.

JS - window.history - Delete a state

There is no way to delete or read the past history.

You could try going around it by emulating history in your own memory and calling history.pushState everytime window popstate event is emitted (which is proposed by the currently accepted Mike's answer), but it has a lot of disadvantages that will result in even worse UX than not supporting the browser history at all in your dynamic web app, because:

  • popstate event can happen when user goes back ~2-3 states to the past
  • popstate event can happen when user goes forward

So even if you try going around it by building virtual history, it's very likely that it can also lead into a situation where you have blank history states (to which going back/forward does nothing), or where that going back/forward skips some of your history states totally.

#define macro for debug printing in C?

I would do something like

#ifdef DEBUG
#define debug_print(fmt, ...) fprintf(stderr, fmt, __VA_ARGS__)
#define debug_print(fmt, ...) do {} while (0)

I think this is cleaner.

installation app blocked by play protect

I found the solution: Go to the link below and submit your application.

Play Protect Appeals Submission Form

After a few days, the problem will be fixed

How to sort with a lambda?

Got it.

sort(mMyClassVector.begin(), mMyClassVector.end(), 
    [](const MyClass & a, const MyClass & b) -> bool
    return a.mProperty > b.mProperty; 

I assumed it'd figure out that the > operator returned a bool (per documentation). But apparently it is not so.

Cannot find JavaScriptSerializer in .Net 4.0

Did you include a reference to System.Web.Extensions? If you click on your first link it says which assembly it's in.

How to check edittext's text is email address or not?

For Email Address validation try this simple and easy code.

    String email = inputEmail.getText().toString().trim();

    if (!Patterns.EMAIL_ADDRESS.matcher(email).matches())
        inputEmail.setError("Enter Valid Email Address");

Cross field validation with Hibernate Validator (JSR 303)

Why not try Oval:

I looks like it supports OGNL so maybe you could do it by a more natural

@Assert(expr = "_value ==_this.pass").

Get unique values from arraylist in java

You should use a Set. A Set is a Collection that contains no duplicates.

If you have a List that contains duplicates, you can get the unique entries like this:

List<String> gasList = // create list with duplicates...
Set<String> uniqueGas = new HashSet<String>(gasList);
System.out.println("Unique gas count: " + uniqueGas.size());

NOTE: This HashSet constructor identifies duplicates by invoking the elements' equals() methods.

How to Parse a JSON Object In Android

JSONArray jsonArray = new JSONArray(yourJsonString);

for (int i = 0; i < jsonArray.length(); i++) {
     JSONObject obj1 = jsonArray.getJSONObject(i);
     JSONArray results = patient.getJSONArray("results");
     String indexForPhone =  patientProfile.getJSONObject(0).getString("indexForPhone"));

Change to JSONArray, then convert to JSONObject.

html select option SELECTED

You're missing quotes for $_GET['sel'] - fixing this might help solving your issue sooner :)

connecting MySQL server to NetBeans

I just had the same issue with Netbeans 8.2 and trying to connect to mySQL server on a Mac OS machine. The only thing that worked for me was to add the following to the url of the connection string: &serverTimezone=UTC (or if you are connecting via Hibernate.cfg.xml then escape the & as &) Not surprisingly I found the solution on this stack overflow post also:

MySQL JDBC Driver 5.1.33 - Time Zone Issue

Best Regards, Claudio

Android Dialog: Removing title bar

You can try this simple android dialog popup library. It is very simple to use on your activity.

When submit button is clicked try following code after including above lib in your code

   .title(R.string.title) //ignore if not needed
   .icon(R.drawable.icon) //ignore if not needed
   .cancelable(false) //ignore if not needed
   .when(new Pop.Yah() {
       public void clicked(DialogInterface dialog, View view) {
           Toast.makeText(getBaseContext(), "Yah button clicked", Toast.LENGTH_LONG).show();

Add one line in your gradle and you good to go

dependencies {
    compile 'com.vistrav:pop:2.0'

SQL Current month/ year question

This should work for SQL Server:

year = DATEPART(yyyy, GETDATE())

List Directories and get the name of the Directory

You seem to be using Python as if it were the shell. Whenever I've needed to do something like what you're doing, I've used os.walk()

For example, as explained here: [x[0] for x in os.walk(directory)] should give you all of the subdirectories, recursively.

Maven: Non-resolvable parent POM

Just for reference.

The joys of Maven.

Putting the relative path of the modules to ../pom.xml solved it.

The parent element has a relativePath element that you need to point to the directory of the parent. It defaults to ..

When should I use File.separator and when File.pathSeparator?

You use separator when you are building a file path. So in unix the separator is /. So if you wanted to build the unix path /var/temp you would do it like this:

String path = File.separator + "var"+ File.separator + "temp"

You use the pathSeparator when you are dealing with a list of files like in a classpath. For example, if your app took a list of jars as argument the standard way to format that list on unix is: /path/to/jar1.jar:/path/to/jar2.jar:/path/to/jar3.jar

So given a list of files you would do something like this:

String listOfFiles = ...
String[] filePaths = listOfFiles.split(File.pathSeparator);

Installing Oracle Instant Client

The directions state:

  1. Download the appropriate Instant Client packages for your platform. All installations REQUIRE the Basic package.
  2. Unzip the packages into a single directory such as "instantclient".
  3. Set the library loading path in your environment to the directory in Step 2 ("instantclient"). On many UNIX platforms, LD_LIBRARY_PATH is the appropriate environment variable. On Windows, PATH should be used.
  4. Start your application and enjoy.

Suggest extracting/unzipping into a new directory. They've suggested instantclient, but you can name the directory anything you like. Name it C:\OracleInstantClient\ if you choose.

Then in Step 3, open a Windows Command Prompt. Type:

PATH C:\OracleInstantClient; %PATH%`

That's all there is to it!

append multiple values for one key in a dictionary

If you want a (almost) one-liner:

from collections import deque

d = {}
deque((d.setdefault(year, []).append(value) for year, value in source_of_data), maxlen=0)

Using dict.setdefault, you can encapsulate the idea of "check if the key already exists and make a new list if not" into a single call. This allows you to write a generator expression which is consumed by deque as efficiently as possible since the queue length is set to zero. The deque will be discarded immediately and the result will be in d.

This is something I just did for fun. I don't recommend using it. There is a time and a place to consume arbitrary iterables through a deque, and this is definitely not it.

google maps v3 marker info window on mouseover

Thanks to duncan answer, I end up with this:

marker.addListener('mouseover', () =>, marker))
marker.addListener('mouseout', () => infoWindow.close())

How to detect Safari, Chrome, IE, Firefox and Opera browser?

const isChrome = /Chrome/.test(navigator.userAgent)
const isFirefox = /Firefox/.test(navigator.userAgent)

commands not found on zsh

My solution:

Change back to bash:

source .bashrc


echo $PATH

copy this:


back to the zsh:

source .zsh

open .zshrc:

and paste:

 export PATH=/home/frank/.asdf/shims:/home/frank/....

restart terminal

angular js unknown provider

I faced similar issue today and issues was really very small

 app.directive('removeFriend', function($scope) {
return {
    restrict: 'E',
    templateUrl: 'removeFriend.html',
    controller: function($scope) {
        $scope.removing = false;
        $scope.startRemove = function() {
            $scope.removing = true;
        $scope.cancelRemove = function() {
            $scope.removing = false;
        $scope.removeFriend = function(friend) {
            var idx = $scope.user.friends.indexOf(friend)
            if (idx > -1) {
                $scope.user.friends.splice(idx, 1);

If you observe the above block, in the first line you will observe I injected $scope by mistake which is incorrect. I removed that unwanted dependency to solve the issue.

 app.directive('removeFriend', function() {
return {
    restrict: 'E',
    templateUrl: 'removeFriend.html',
    controller: function($scope) {
        $scope.removing = false;
        $scope.startRemove = function() {
            $scope.removing = true;
        $scope.cancelRemove = function() {
            $scope.removing = false;
        $scope.removeFriend = function(friend) {
            var idx = $scope.user.friends.indexOf(friend)
            if (idx > -1) {
                $scope.user.friends.splice(idx, 1);

Combining a class selector and an attribute selector with jQuery

I think you just need to remove the space. i.e.

$(".myclass[reference=12345]").css('border', '#000 solid 1px');

There is a fiddle here

Best way to check if a character array is empty

Depends on whether or not your array is holding a null-terminated string. If so, then

if(text[0] == '\0') {}

should be sufficient.

Edit: Another method would be...

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

which is potentially less efficient but clearly expresses your intent.

Writing a large resultset to an Excel file using POI

I updated BigGridDemo to support multiple sheets.

package com.gdais.common.apache.poi.bigexcelwriter;

import static*;

import java.util.Enumeration;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;


public class BigExcelWriterImpl implements BigExcelWriter {

private static final String XML_ENCODING = "UTF-8";

private final File outputFile;

private final File tempFileOutputDir;

private File templateFile = null;

private XSSFWorkbook workbook = null;

private LinkedHashMap<String, XSSFSheet> addedSheets = new LinkedHashMap<String, XSSFSheet>();

private Map<XSSFSheet, File> sheetTempFiles = new HashMap<XSSFSheet, File>();

BigExcelWriterImpl(@Nonnull File outputFile) {
    this.outputFile = outputFile;
    this.tempFileOutputDir = outputFile.getParentFile();

public BigExcelWriter createWorkbook() {
    workbook = new XSSFWorkbook();
    return this;

public BigExcelWriter addSheets(String... sheetNames) {
    checkState(workbook != null, "workbook must be created before adding sheets");

    for (String sheetName : sheetNames) {
        XSSFSheet sheet = workbook.createSheet(sheetName);
        addedSheets.put(sheetName, sheet);

    return this;

public BigExcelWriter writeWorkbookTemplate() throws IOException {
    checkState(workbook != null, "workbook must be created before writing template");
    checkState(templateFile == null, "template file already written");

    templateFile = File.createTempFile(FilenameUtils.removeExtension(outputFile.getName())
            + "-template", ".xlsx", tempFileOutputDir);
    FileOutputStream os = new FileOutputStream(templateFile);

    return this;

public SpreadsheetWriter createSpreadsheetWriter(String sheetName) throws IOException {
    if (!addedSheets.containsKey(sheetName)) {

    return createSpreadsheetWriter(addedSheets.get(sheetName));

public SpreadsheetWriter createSpreadsheetWriter(XSSFSheet sheet) throws IOException {
    checkState(!sheetTempFiles.containsKey(sheet), "writer already created for this sheet");

    File tempSheetFile = File.createTempFile(
                    + "-sheet" + sheet.getSheetName(), ".xml", tempFileOutputDir);

    Writer out = null;
    try {
        out = new OutputStreamWriter(new FileOutputStream(tempSheetFile), XML_ENCODING);
        SpreadsheetWriter sw = new SpreadsheetWriterImpl(out);

        sheetTempFiles.put(sheet, tempSheetFile);
        return sw;
    } catch (RuntimeException e) {
        if (out != null) {
        throw e;

private static Function<XSSFSheet, String> getSheetName = new Function<XSSFSheet, String>() {

    public String apply(XSSFSheet sheet) {
        return sheet.getPackagePart().getPartName().getName().substring(1);

public File completeWorkbook() throws IOException {
    FileOutputStream out = null;
    try {
        out = new FileOutputStream(outputFile);
        ZipOutputStream zos = new ZipOutputStream(out);

        Iterable<String> sheetEntries = Iterables.transform(sheetTempFiles.keySet(),
        System.out.println("Sheet Entries: " + sheetEntries);
        copyTemplateMinusEntries(templateFile, zos, sheetEntries);

        for (Map.Entry<XSSFSheet, File> entry : sheetTempFiles.entrySet()) {
            XSSFSheet sheet = entry.getKey();
            substituteSheet(entry.getValue(), getSheetName.apply(sheet), zos);

        return outputFile;
    } finally {
        if (out != null) {

private static void copyTemplateMinusEntries(File templateFile,
        ZipOutputStream zos, Iterable<String> entries) throws IOException {

    ZipFile templateZip = new ZipFile(templateFile);

    Enumeration<ZipEntry> en = (Enumeration<ZipEntry>) templateZip.entries();
    while (en.hasMoreElements()) {
        ZipEntry ze = en.nextElement();
        if (!Iterables.contains(entries, ze.getName())) {
            System.out.println("Adding template entry: " + ze.getName());
            zos.putNextEntry(new ZipEntry(ze.getName()));
            InputStream is = templateZip.getInputStream(ze);
            copyStream(is, zos);

private static void substituteSheet(File tmpfile, String entry,
        ZipOutputStream zos)
        throws IOException {
    System.out.println("Adding sheet entry: " + entry);
    zos.putNextEntry(new ZipEntry(entry));
    InputStream is = new FileInputStream(tmpfile);
    copyStream(is, zos);

private static void copyStream(InputStream in, OutputStream out) throws IOException {
    byte[] chunk = new byte[1024];
    int count;
    while ((count = >= 0) {
        out.write(chunk, 0, count);

public Workbook getWorkbook() {
    return workbook;

public ImmutableList<XSSFSheet> getSheets() {
    return ImmutableList.copyOf(addedSheets.values());


package com.gdais.common.apache.poi.bigexcelwriter;

import java.util.Calendar;


class SpreadsheetWriterImpl implements SpreadsheetWriter {

private static final String XML_ENCODING = "UTF-8";

private final Writer _out;
private int _rownum;

SpreadsheetWriterImpl(Writer out) {
    _out = out;

public SpreadsheetWriter closeFile() throws IOException {

    return this;

public SpreadsheetWriter beginSheet() throws IOException {
    _out.write("<?xml version=\"1.0\" encoding=\""
            + XML_ENCODING
            + "\"?>"
            "<worksheet xmlns=\"\">");

    return this;

public SpreadsheetWriter endSheet() throws IOException {

    return this;

 * Insert a new row
 * @param rownum
 *            0-based row number
public SpreadsheetWriter insertRow(int rownum) throws IOException {
    _out.write("<row r=\"" + (rownum + 1) + "\">\n");
    this._rownum = rownum;

    return this;

 * Insert row end marker
public SpreadsheetWriter endRow() throws IOException {

    return this;

public SpreadsheetWriter createCell(int columnIndex, String value, int styleIndex)
        throws IOException {
    String ref = new CellReference(_rownum, columnIndex).formatAsString();
    _out.write("<c r=\"" + ref + "\" t=\"inlineStr\"");
    if (styleIndex != -1) {
        _out.write(" s=\"" + styleIndex + "\"");
    _out.write("<is><t>" + value + "</t></is>");

    return this;

public SpreadsheetWriter createCell(int columnIndex, String value) throws IOException {
    createCell(columnIndex, value, -1);

    return this;

public SpreadsheetWriter createCell(int columnIndex, double value, int styleIndex)
        throws IOException {
    String ref = new CellReference(_rownum, columnIndex).formatAsString();
    _out.write("<c r=\"" + ref + "\" t=\"n\"");
    if (styleIndex != -1) {
        _out.write(" s=\"" + styleIndex + "\"");
    _out.write("<v>" + value + "</v>");

    return this;

public SpreadsheetWriter createCell(int columnIndex, double value) throws IOException {
    createCell(columnIndex, value, -1);

    return this;

public SpreadsheetWriter createCell(int columnIndex, Calendar value, int styleIndex)
        throws IOException {
    createCell(columnIndex, DateUtil.getExcelDate(value, false), styleIndex);

    return this;

public SpreadsheetWriter createCell(int columnIndex, Calendar value)
        throws IOException {
    createCell(columnIndex, value, -1);

    return this;

How to pass datetime from c# to sql correctly?

You've already done it correctly by using a DateTime parameter with the value from the DateTime, so it should already work. Forget about ToString() - since that isn't used here.

If there is a difference, it is most likely to do with different precision between the two environments; maybe choose a rounding (seconds, maybe?) and use that. Also keep in mind UTC/local/unknown (the DB has no concept of the "kind" of date; .NET does).

I have a table and the date-times in it are in the format: 2011-07-01 15:17:33.357

Note that datetimes in the database aren't in any such format; that is just your query-client showing you white lies. It is stored as a number (and even that is an implementation detail), because humans have this odd tendency not to realise that the date you've shown is the same as 40723.6371916281. Stupid humans. By treating it simply as a "datetime" throughout, you shouldn't get any problems.

Clear MySQL query cache without restarting server

I believe you can use...


...if the user you're running as has reload rights. Alternatively, you can defragment the query cache via...


See the Query Cache Status and Maintenance section of the MySQL manual for more information.

Windows batch files: .bat vs .cmd?

The extension makes no difference.

There are slight differences between COMMAND.COM handling the file vs CMD.EXE.

How do I run msbuild from the command line using Windows SDK 7.1?

The SetEnv.cmd script that the "SDK command prompt" shortcut runs checks for cl.exe in various places before setting up entries to add to PATH. So it fails to add anything if a native C compiler is not installed.

To fix that, apply the following patch to <SDK install dir>\Bin\SetEnv.cmd. This will also fix missing paths to other tools located in <SDK install dir>\Bin and subfolders. Of course, you can install the C compiler instead to work around this bug.

--- SetEnv.Cmd_ 2010-04-27 19:52:00.000000000 +0400
+++ SetEnv.Cmd  2013-12-02 15:05:30.834400000 +0400
@@ -228,10 +228,10 @@

 IF "%CURRENT_CPU%" =="x64" (
   IF "%TARGET_CPU%" == "x64" (
+    SET "FxTools=%FrameworkDir64%\%FrameworkVersion%;%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework64\v3.5;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools\x64;%WindowsSdkDir%Bin\x64;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\amd64\cl.exe" (
       SET "VCTools=%VCTools%\amd64;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools\x64;%WindowsSdkDir%Bin\x64;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir64%\%FrameworkVersion%;%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework64\v3.5;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The x64 compilers are not currently installed.
@@ -239,10 +239,10 @@
       ECHO .
   ) ELSE IF "%TARGET_CPU%" == "IA64" (
+    SET "FxTools=%FrameworkDir64%\%FrameworkVersion%;%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework64\v3.5;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools\x64;%WindowsSdkDir%Bin\x64;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\x86_ia64\cl.exe" (
       SET "VCTools=%VCTools%\x86_ia64;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools\x64;%WindowsSdkDir%Bin\x64;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir64%\%FrameworkVersion%;%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework64\v3.5;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The IA64 compilers are not currently installed.
@@ -250,10 +250,10 @@
       ECHO .
   ) ELSE IF "%TARGET_CPU%" == "x86" (
+    SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\cl.exe" (
       SET "VCTools=%VCTools%;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The x86 compilers are not currently installed.
@@ -263,10 +263,10 @@
 ) ELSE IF "%CURRENT_CPU%" =="IA64" (
   IF "%TARGET_CPU%" == "IA64" (
+    SET "FxTools=%FrameworkDir64%\%FrameworkVersion%;%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework64\v3.5;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools\IA64;%WindowsSdkDir%Bin\IA64;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\IA64\cl.exe" (
       SET "VCTools=%VCTools%\IA64;%VCTools%;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools\IA64;%WindowsSdkDir%Bin\IA64;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir64%\%FrameworkVersion%;%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework64\v3.5;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The IA64 compilers are not currently installed.
@@ -274,10 +274,10 @@
       ECHO .
   ) ELSE IF "%TARGET_CPU%" == "x64" (
+    SET "FxTools=%FrameworkDir64%\%FrameworkVersion%;%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework64\v3.5;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools\IA64;%WindowsSdkDir%Bin\IA64;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\x86_amd64\cl.exe" (
       SET "VCTools=%VCTools%\x86_amd64;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools\IA64;%WindowsSdkDir%Bin\IA64;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir64%\%FrameworkVersion%;%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework64\v3.5;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The VC compilers are not currently installed.
@@ -285,10 +285,10 @@
       ECHO .
   ) ELSE IF "%TARGET_CPU%" == "x86" (
+    SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\cl.exe" (
       SET "VCTools=%VCTools%;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The x86 compilers are not currently installed.
@@ -298,10 +298,10 @@
 ) ELSE IF "%CURRENT_CPU%"=="x86" (
   IF "%TARGET_CPU%" == "x64" (
+    SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\x86_amd64\cl.exe" (
       SET "VCTools=%VCTools%\x86_amd64;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The x64 cross compilers are not currently installed.
@@ -309,10 +309,10 @@
       ECHO .
   ) ELSE IF "%TARGET_CPU%" == "IA64" (
+    SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\x86_IA64\cl.exe" (
       SET "VCTools=%VCTools%\x86_IA64;%VCTools%;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The IA64 compilers are not currently installed.
@@ -320,10 +320,10 @@
       ECHO .
   ) ELSE IF "%TARGET_CPU%" == "x86" (
+    SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
+    SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
     IF EXIST "%VCTools%\cl.exe" (
       SET "VCTools=%VCTools%;%VCTools%\VCPackages;"
-      SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
-      SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
     ) ELSE (
       SET VCTools=
       ECHO The x86 compilers are not currently installed. x86-x86
@@ -331,15 +331,17 @@
       ECHO .
-) ELSE IF EXIST "%VCTools%\cl.exe" (
-  SET "VCTools=%VCTools%;%VCTools%\VCPackages;"
-  SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
-  SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
 ) ELSE (
-  SET VCTools=
-  ECHO The x86 compilers are not currently installed. default
-  ECHO Please go to Add/Remove Programs to update your installation.
-  ECHO .
+  SET "FxTools=%FrameworkDir32%%FrameworkVersion%;%windir%\Microsoft.NET\Framework\v3.5;"
+  SET "SdkTools=%WindowsSdkDir%Bin\NETFX 4.0 Tools;%WindowsSdkDir%Bin;"
+  IF EXIST "%VCTools%\cl.exe" (
+    SET "VCTools=%VCTools%;%VCTools%\VCPackages;"
+  ) ELSE (
+    SET VCTools=
+    ECHO The x86 compilers are not currently installed. default
+    ECHO Please go to Add/Remove Programs to update your installation.
+    ECHO .
+  )

 :: --------------------------------------------------------------------------------------------

PHP: Get the key from an array in a foreach loop

Use foreach with key and value.


foreach($samplearr as $key => $val) {
     print "<tr><td>" 
         . $key 
         . "</td><td>" 
         . $val['value1'] 
         . "</td><td>" 
         . $val['value2'] 
         . "</td></tr>";

Converting from IEnumerable to List

another way

List<int> list=new List<int>();

IEnumerable<int> enumerable =Enumerable.Range(1, 300);  

foreach (var item in enumerable )  

Complexities of binary tree traversals

T(n) = 2T(n/2)+ c

T(n/2) = 2T(n/4) + c => T(n) = 4T(n/4) + 2c + c

similarly T(n) = 8T(n/8) + 4c+ 2c + c



last step ... T(n) = nT(1) + c(sum of powers of 2 from 0 to h(height of tree))

so Complexity is O(2^(h+1) -1)

but h = log(n)

so, O(2n - 1) = O(n)

Convert .cer certificate to .jks

Export a certificate from a keystore:

keytool -export -alias mydomain -file mydomain.crt -keystore keystore.jks

Eclipse reported "Failed to load JNI shared library"

Installing a 64-bit version of Java will solve the issue. Go to page Java Downloads for All Operating Systems

This is a problem due to the incompatibility of the Java version and the Eclipse version both should be 64 bit if you are using a 64-bit system.

HTML/Javascript Button Click Counter

After looking at the code you're having typos, here is the updated code

var clicks = 0; // should be var not int
    function clickME() {
        clicks += 1;
        document.getElementById("clicks").innerHTML = clicks; //getElementById() not getElementByID() Which you corrected in edit


Note: Don't use in-built handlers, as .click() is javascript function try giving different name like clickME()

Reload browser window after POST without prompting user to resend POST data

This worked for me.

window.location = window.location.pathname;

Tested on

  • Chrome 44.0.2403
  • IE edge
  • Firefox 39.0

Error in data frame undefined columns selected

Are you meaning?

data2 <- data1[good,]



you're selecting columns in a wrong way (using a logical vector of complete rows).

Consider that parameter pollutant is not used; is it a column name that you want to extract? if so it should be something like

data2 <- data1[good, pollutant]

Furthermore consider that you have to rbind the data.frames inside the for loop, otherwise you get only the last data.frame (its completed.cases)

And last but not least, i'd prefer generating filenames eg with

id <- 1:322
paste0( directory, "/", gsub(" ", "0", sprintf("%3d",id)), ".csv")

A little modified chunk of ?sprintf

The string fmt (in our case "%3d") contains normal characters, which are passed through to the output string, and also conversion specifications which operate on the arguments provided through .... The allowed conversion specifications start with a % and end with one of the letters in the set aAdifeEgGosxX%. These letters denote the following types:

  • d: integer

Eg a more general example

    sprintf("I am %10d years old", 25)
[1] "I am         25 years old"
          |        |
          1       10

How to update the constant height constraint of a UIView programmatically?

First connect the Height constraint in to our viewcontroller for creating IBOutlet like the below code shown

@IBOutlet weak var select_dateHeight: NSLayoutConstraint!

then put the below code in view did load or inside any actions

self.select_dateHeight.constant = 0 // we can change the height value

if it is inside a button click

@IBAction func Feedback_button(_ sender: Any) {
 self.select_dateHeight.constant = 0


Getting an attribute value in xml element

How about:


import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;

public class Demo {

    public static void main(String[] args) throws Exception {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document document = db.parse(new File("input.xml"));
        NodeList nodeList = document.getElementsByTagName("Item");
        for(int x=0,size= nodeList.getLength(); x<size; x++) {

Color text in discord

Discord doesn't allow colored text. Though, currently, you have two options to "mimic" colored text.

Option #1 (Markdown code-blocks)

Discord supports Markdown and uses highlight.js to highlight code-blocks. Some programming languages have specific color outputs from highlight.js and can be used to mimic colored output.

To use code-blocks, send a normal message in this format (Which follows Markdown's standard format).


Languages that currently reproduce nice colors: prolog (red/orange), css (yellow).

Option #2 (Embeds)

Discord now supports Embeds and Webhooks, which can be used to display colored blocks, they also support markdown. For documentation on how to use Embeds, please read your lib's documentation.

(Embed Cheat-sheet)
Embed Cheat-sheet

Check whether a string matches a regex in JS

I would recommend using the execute method which returns null if no match exists otherwise it returns a helpful object.

let case1 = /^([a-z0-9]{5,})$/.exec("abc1");
console.log(case1); //null

let case2 = /^([a-z0-9]{5,})$/.exec("pass3434");
console.log(case2); // ['pass3434', 'pass3434', index:0, input:'pass3434', groups: undefined]

How can javascript upload a blob?

2019 Update

This updates the answers with the latest Fetch API and doesn't need jQuery.

Disclaimer: doesn't work on IE, Opera Mini and older browsers. See caniuse.

Basic Fetch

It could be as simple as:

  fetch(``, {method:"POST", body:blobData})
                .then(response => console.log(response.text()))

Fetch with Error Handling

After adding error handling, it could look like:

fetch(``, {method:"POST", body:blobData})
            .then(response => {
                if (response.ok) return response;
                else throw Error(`Server returned ${response.status}: ${response.statusText}`)
            .then(response => console.log(response.text()))
            .catch(err => {

PHP Code

This is the server-side code in upload.php.

    // gets entire POST body
    $data = file_get_contents('php://input');
    // write the data out to the file
    $fp = fopen("path/to/file", "wb");

    fwrite($fp, $data);

Prevent WebView from displaying "web page not available"

You could use a GET request to get the page content and then display that data using the Webview , this way you are not using multiple server calls. Alternative you can use Javascript to check the DOM object for validity.