Programs & Examples On #Hci

Host/controller interface in Bluetooth

http post - how to send Authorization header?

If you are like me, and starring at your angular/ionic typescript, which looks like..

  getPdf(endpoint: string): Observable<Blob> {
    let url = this.url + '/' + endpoint;
    let token = this.msal.accessToken;
    return<Blob>(url, {
      headers: new HttpHeaders(
          'Access-Control-Allow-Origin': 'https://localhost:5100',
          'Access-Control-Allow-Methods': 'POST',
          'Content-Type': 'application/pdf',
          'Authorization': 'Bearer ' + token,
          'Accept': '*/*',
        //responseType: ResponseContentType.Blob,

And while you are setting options but can't seem to figure why they aren't anywhere..

Well.. if you were like me and started this post from a copy/paste of a get, then...

Change to:

  getPdf(endpoint: string): Observable<Blob> {
    let url = this.url + '/' + endpoint;
    let token = this.msal.accessToken;
    return<Blob>(url, null, { //  <-----  notice the null  *****
      headers: new HttpHeaders(
          'Authorization': 'Bearer ' + token,
          'Accept': '*/*',
        //responseType: ResponseContentType.Blob,

Error: org.springframework.web.HttpMediaTypeNotSupportedException: Content type 'text/plain;charset=UTF-8' not supported

Building on what is mentioned in the comments, the simplest solution would be:

@RequestMapping(method = RequestMethod.PUT, consumes = MediaType.APPLICATION_JSON_VALUE)
public Collection<BudgetDTO> updateConsumerBudget(@RequestBody SomeDto someDto) throws GeneralException, ParseException {



class SomeDto {

   private List<WhateverBudgerPerDateDTO> budgetPerDate;

  //getters setters

The solution assumes that the HTTP request you are creating actually has

Content-Type:application/json instead of text/plain

Saving binary data as file using JavaScript from a browser


let bytes = [65,108,105,99,101,39,115,32,65,100,118,101,110,116,117,114,101];_x000D_
let base64data = btoa(String.fromCharCode.apply(null, bytes));_x000D_
let a = document.createElement('a');_x000D_
a.href = 'data:;base64,' + base64data;_x000D_ = 'binFile.txt'; _x000D_;

I convert here binary data to base64 (for bigger data conversion use this) - during downloading browser decode it automatically and save raw data in file. 2020.06.14 I upgrade Chrome to 83.0 and above SO snippet stop working (probably due to sandbox security restrictions) - but JSFiddle version works - here

How do I get the height and width of the Android Navigation Bar programmatically?

Tested code for getting height of navigation bar (in pixels):

public static int getNavBarHeight(Context c) {
    int resourceId = c.getResources()
                      .getIdentifier("navigation_bar_height", "dimen", "android");
    if (resourceId > 0) {
        return c.getResources().getDimensionPixelSize(resourceId);
    return 0;

Tested code for getting height of status bar (in pixels):

public static int getStatusBarHeight(Context c) {
    int resourceId = c.getResources()
                      .getIdentifier("status_bar_height", "dimen", "android");
    if (resourceId > 0) {
        return c.getResources().getDimensionPixelSize(resourceId);
    return 0;

Converting pixels to dp:

public static int pxToDp(int px) {
    return (int) (px / Resources.getSystem().getDisplayMetrics().density);

How to correctly iterate through getElementsByClassName

I followed Alohci's recommendation of looping in reverse because it's a live nodeList. Here's what I did for those who are curious...

  var activeObjects = documents.getElementsByClassName('active'); // a live nodeList

  //Use a reverse-loop because the array is an active NodeList
  while(activeObjects.length > 0) {
    var lastElem = activePaths[activePaths.length-1]; //select the last element

    //Remove the 'active' class from the element.  
    //This will automatically update the nodeList's length too.
    var className = lastElem.getAttribute('class').replace('active','');
    lastElem.setAttribute('class', className);

I want to calculate the distance between two points in Java

You need to explicitly tell Java that you wish to multiply.

(x1-x2) * (x1-x2) + (y1-y2) * (y1-y2)

Unlike written equations the compiler does not know this is what you wish to do.

Insert variable into Header Location PHP

header('Location:' . $your_variable);

Getting RSA private key from PEM BASE64 Encoded private key file

The problem you'll face is that there's two types of PEM formatted keys: PKCS8 and SSLeay. It doesn't help that OpenSSL seems to use both depending on the command:

The usual openssl genrsa command will generate a SSLeay format PEM. An export from an PKCS12 file with openssl pkcs12 -in file.p12 will create a PKCS8 file.

The latter PKCS8 format can be opened natively in Java using PKCS8EncodedKeySpec. SSLeay formatted keys, on the other hand, can not be opened natively.

To open SSLeay private keys, you can either use BouncyCastle provider as many have done before or Not-Yet-Commons-SSL have borrowed a minimal amount of necessary code from BouncyCastle to support parsing PKCS8 and SSLeay keys in PEM and DER format: (I'm not sure if Not-Yet-Commons-SSL will be FIPS compliant)

Key Format Identification

By inference from the OpenSSL man pages, key headers for two formats are as follows:

PKCS8 Format

Non-encrypted: -----BEGIN PRIVATE KEY-----

SSLeay Format


(These seem to be in contradiction to other answers but I've tested OpenSSL's output using PKCS8EncodedKeySpec. Only PKCS8 keys, showing ----BEGIN PRIVATE KEY----- work natively)

How do I connect to a terminal to a serial-to-USB device on Ubuntu 10.10 (Maverick Meerkat)?

I suggest that newbies connect a PL2303 to Ubuntu, chmod 777 /dev/ttyUSB0 (file-permissions) and connect to a CuteCom serial terminal. The CuteCom UI is simple \ intuitive. If the PL2303 is continuously broadcasting data, then Cutecom will display data in hex format

Mobile Redirect using htaccess

For Mobiles like

RewriteCond %{HTTP_REFERER} !^http://(.*)*$ [NC]
RewriteCond %{REQUEST_URI} !^/m/.*$
RewriteCond %{HTTP_USER_AGENT} "android|blackberry|iphone|ipod|iemobile|opera mobile|palmos|webos|googlebot-mobile" [NC]
RewriteRule ^(.*)$ /m/ [L,R=302]

Simple regular expression for a decimal with a precision of 2

Valid regex tokens vary by implementation. A generic form is:


More compact:


Both assume that both have at least one digit before and one after the decimal place.

To require that the whole string is a number of this form, wrap the expression in start and end tags such as (in Perl's form):


To match numbers without a leading digit before the decimal (.12) and whole numbers having a trailing period (12.) while excluding input of a single period (.), try the following:



Wrapped the fractional portion in ()? to make it optional. Be aware that this excludes forms such as 12. Including that would be more like ^\d+\\.?\d{0,2}$.


Use ^\d{1,6}(\.\d{1,2})?$ to stop repetition and give a restriction to whole part of the decimal value.

Why does .NET foreach loop throw NullRefException when collection is null?

Because behind the scenes the foreach acquires an enumerator, equivalent to this:

using (IEnumerator<int> enumerator = returnArray.getEnumerator()) {
    while (enumerator.MoveNext()) {
        int i = enumerator.Current;
        // do some more stuff

Why does git say "Pull is not possible because you have unmerged files"?

You are attempting to add one more new commits into your local branch while your working directory is not clean. As a result, Git is refusing to do the pull. Consider the following diagrams to better visualize the scenario:

remote: A <- B <- C <- D
local: A <- B*
(*indicates that you have several files which have been modified but not committed.)

There are two options for dealing with this situation. You can either discard the changes in your files, or retain them.

Option one: Throw away the changes
You can either use git checkout for each unmerged file, or you can use git reset --hard HEAD to reset all files in your branch to HEAD. By the way, HEAD in your local branch is B, without an asterisk. If you choose this option, the diagram becomes:

remote: A <- B <- C <- D
local: A <- B

Now when you pull, you can fast-forward your branch with the changes from master. After pulling, you branch would look like master:

local: A <- B <- C <- D

Option two: Retain the changes
If you want to keep the changes, you will first want to resolve any merge conflicts in each of the files. You can open each file in your IDE and look for the following symbols:

<<<<<<< HEAD
// your version of the code
// the remote's version of the code

Git is presenting you with two versions of code. The code contained within the HEAD markers is the version from your current local branch. The other version is what is coming from the remote. Once you have chosen a version of the code (and removed the other code along with the markers), you can add each file to your staging area by typing git add. The final step is to commit your result by typing git commit -m with an appropriate message. At this point, our diagram looks like this:

remote: A <- B <- C <- D
local: A <- B <- C'

Here I have labelled the commit we just made as C' because it is different from the commit C on the remote. Now, if you try to pull you will get a non-fast forward error. Git cannot play the changes in remote on your branch, because both your branch and the remote have diverged from the common ancestor commit B. At this point, if you want to pull you can either do another git merge, or git rebase your branch on the remote.

Getting a mastery of Git requires being able to understand and manipulate uni-directional linked lists. I hope this explanation will get you thinking in the right direction about using Git.

Simplest way to form a union of two lists

If it is a list, you can also use AddRange method.

var listB = new List<int>{3, 4, 5};  
var listA = new List<int>{1, 2, 3, 4, 5};

listA.AddRange(listB); // listA now has elements of listB also.

If you need new list (and exclude the duplicate), you can use Union

  var listB = new List<int>{3, 4, 5};  
  var listA = new List<int>{1, 2, 3, 4, 5};
  var listFinal = listA.Union(listB);

If you need new list (and include the duplicate), you can use Concat

  var listB = new List<int>{3, 4, 5};  
  var listA = new List<int>{1, 2, 3, 4, 5};
  var listFinal = listA.Concat(listB);

If you need common items, you can use Intersect.

var listB = new List<int>{3, 4, 5};  
var listA = new List<int>{1, 2, 3, 4};  
var listFinal = listA.Intersect(listB); //3,4

How to empty the message in a text area with jquery?


You can use this method too. Because everything between the open and close tag of textarea is html code.

How to fix .pch file missing on build?

If everything is right, but this mistake is present, it need check next section in ****.vcxproj file:

<ClCompile Include="stdafx.cpp">
  <PrecompiledHeader Condition=

In my case it there was an incorrect name of a configuration: only first word.

Array Size (Length) in C#

You can look at the documentation for Array to find out the answer to this question.

In this particular case you probably need Length:

int sizeOfArray = array.Length;

But since this is such a basic question and you no doubt have many more like this, rather than just telling you the answer I'd rather tell you how to find the answer yourself.

Visual Studio Intellisense

When you type the name of a variable and press the . key it shows you a list of all the methods, properties, events, etc. available on that object. When you highlight a member it gives you a brief description of what it does.

Press F1

If you find a method or property that might do what you want but you're not sure, you can move the cursor over it and press F1 to get help. Here you get a much more detailed description plus links to related information.


The search terms size of array in C# gives many links that tells you the answer to your question and much more. One of the most important skills a programmer must learn is how to find information. It is often faster to find the answer yourself, especially if the same question has been asked before.

Use a tutorial

If you are just beginning to learn C# you will find it easier to follow a tutorial. I can recommend the C# tutorials on MSDN. If you want a book, I'd recommend Essential C#.

Stack Overflow

If you're not able to find the answer on your own, please feel free to post the question on Stack Overflow. But we appreciate it if you show that you have taken the effort to find the answer yourself first.

Does Python have a toString() equivalent, and can I convert a db.Model element to String?

In python, the str() method is similar to the toString() method in other languages. It is called passing the object to convert to a string as a parameter. Internally it calls the __str__() method of the parameter object to get its string representation.

In this case, however, you are comparing a UserProperty author from the database, which is of type users.User with the nickname string. You will want to compare the nickname property of the author instead with in your template.

Printing 2D array in matrix format

Your can do it like this in short hands.

        int[,] values=new int[2,3]{{2,4,5},{4,5,2}};

        for (int i = 0; i < values.GetLength(0); i++)
            for (int k = 0; k < values.GetLength(1); k++) {


Iterate through DataSet

Just loop...

foreach(var table in DataSet1.Tables) {
    foreach(var col in table.Columns) {
    foreach(var row in table.Rows) {
        object[] values = row.ItemArray;

Is it possible to run one logrotate check manually?

Issue the following command,the way to run specified logrotate:

logrotate -vf /etc/logrotate.d/custom


-v :show the process

-f :forcing run

custom :user-defined log setting

eg: mongodb-log

# mongodb-log rotate

/data/var/log/mongodb/mongod.log {
    rotate 30

How to find the mime type of a file in python?

you can use imghdr Python module.

maven... Failed to clean project: Failed to delete ..\org.ow2.util.asm-asm-tree-3.1.jar

Close the target folder and its file you have opened before mvn clean

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

I looked around the internet for correct dimensions for these densities for square images, but couldn't find anything reliable.

If it's any consolation, referring to Veerababu Medisetti's answer I used these dimensions for SQUARES :)

xxxhdpi: 1280x1280 px
xxhdpi: 960x960 px
xhdpi: 640x640 px
hdpi: 480x480 px
mdpi: 320x320 px
ldpi: 240x240 px

Check if object is a jQuery object

return el instanceof jQuery ? el.size() > 0 : (el && el.tagName);

MVC Return Partial View as JSON

Instead of RenderViewToString I prefer a approach like

return Json(new { Url = Url.Action("Evil", model) });

then you can catch the result in your javascript and do something like

success: function(data) {
    $.post(data.Url, function(partial) { 

ASP.NET Bundles how to disable minification

Here's how to disable minification on a per-bundle basis:

bundles.Add(new StyleBundleRaw("~/Content/foobarcss").Include("/some/path/foobar.css"));
bundles.Add(new ScriptBundleRaw("~/Bundles/foobarjs").Include("/some/path/foobar.js"));

Sidenote: The paths used for your bundles must not coincide with any actual path in your published builds otherwise nothing will work. Also make sure to avoid using .js, .css and/or '.' and '_' anywhere in the name of the bundle. Keep the name as simple and as straightforward as possible, like in the example above.

The helper classes are shown below. Notice that in order to make these classes future-proof we surgically remove the js/css minifying instances instead of using .clear() and we also insert a mime-type-setter transformation without which production builds are bound to run into trouble especially when it comes to properly handing over css-bundles (firefox and chrome reject css bundles with mime-type set to "text/html" which is the default):

internal sealed class StyleBundleRaw : StyleBundle
        private static readonly BundleMimeType CssContentMimeType = new BundleMimeType("text/css");

        public StyleBundleRaw(string virtualPath) : this(virtualPath, cdnPath: null)

        public StyleBundleRaw(string virtualPath, string cdnPath) : base(virtualPath, cdnPath)
                 Transforms.Add(CssContentMimeType); //0 vital
                 Transforms.Remove(Transforms.FirstOrDefault(x => x is CssMinify)); //0
        //0 the guys at redmond in their infinite wisdom plugged the mimetype "text/css" right into cssminify    upon unwiring the minifier we
        //  need to somehow reenable the cssbundle to specify its mimetype otherwise it will advertise itself as html and wont load

internal sealed class ScriptBundleRaw : ScriptBundle
        private static readonly BundleMimeType JsContentMimeType = new BundleMimeType("text/javascript");

        public ScriptBundleRaw(string virtualPath) : this(virtualPath, cdnPath: null)

        public ScriptBundleRaw(string virtualPath, string cdnPath) : base(virtualPath, cdnPath)
                 Transforms.Add(JsContentMimeType); //0 vital
                 Transforms.Remove(Transforms.FirstOrDefault(x => x is JsMinify)); //0
        //0 the guys at redmond in their infinite wisdom plugged the mimetype "text/javascript" right into jsminify   upon unwiring the minifier we need
        //  to somehow reenable the jsbundle to specify its mimetype otherwise it will advertise itself as html causing it to be become unloadable by the browsers in published production builds

internal sealed class BundleMimeType : IBundleTransform
        private readonly string _mimeType;

        public BundleMimeType(string mimeType) { _mimeType = mimeType; }

        public void Process(BundleContext context, BundleResponse response)
                 if (context == null)
                          throw new ArgumentNullException(nameof(context));
                 if (response == null)
                          throw new ArgumentNullException(nameof(response));

         response.ContentType = _mimeType;

To make this whole thing work you need to install (via nuget):

WebGrease 1.6.0+ Microsoft.AspNet.Web.Optimization 1.1.3+

And your web.config should be enriched like so:

        <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="" newVersion="x.y.z.t" />
              <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="" newVersion="x.y.z.t" />

<!-- setting mimetypes like we do right below is absolutely vital for published builds because for some reason the -->
<!-- iis servers in production environments somehow dont know how to handle otf eot and other font related files   -->
      <!-- in case iis already has these mime types -->
      <remove fileExtension=".otf" />
      <remove fileExtension=".eot" />
      <remove fileExtension=".ttf" />
      <remove fileExtension=".woff" />
      <remove fileExtension=".woff2" />

      <mimeMap fileExtension=".otf" mimeType="font/otf" />
      <mimeMap fileExtension=".eot" mimeType="application/" />
      <mimeMap fileExtension=".ttf" mimeType="application/octet-stream" />
      <mimeMap fileExtension=".woff" mimeType="application/font-woff" />
      <mimeMap fileExtension=".woff2" mimeType="application/font-woff2" />

      <!-- also vital otherwise published builds wont work  -->
      <modules runAllManagedModulesForAllRequests="true">
         <remove name="BundleModule" />
         <add name="BundleModule" type="System.Web.Optimization.BundleModule" />

Note that you might have to take extra steps to make your css-bundles work in terms of fonts etc. But that's a different story.

How can I get the "network" time, (from the "Automatic" setting called "Use network-provided values"), NOT the time on the phone?

I didn't know, but found the question interesting. So I dug in the android code... Thanks open-source :)

The screen you show is DateTimeSettings. The checkbox "Use network-provided values" is associated to the shared preference String KEY_AUTO_TIME = "auto_time"; and also to Settings.System.AUTO_TIME

This settings is observed by an observed called mAutoTimeObserver in the 2 network ServiceStateTrackers: GsmServiceStateTracker and CdmaServiceStateTracker.

Both implementations call a method called revertToNitz() when the settings becomes true. Apparently NITZ is the equivalent of NTP in the carrier world.

Bottom line: You can set the time to the value provided by the carrier thanks to revertToNitz(). Unfortunately, I haven't found a mechanism to get the network time. If you really need to do this, I'm afraid, you'll have to copy these ServiceStateTrackers implementations, catch the intent raised by the framework (I suppose), and add a getter to mSavedTime.

Image re-size to 50% of original size in HTML

The percentage setting does not take into account the original image size. From w3schools :

In HTML 4.01, the width could be defined in pixels or in % of the containing element. In HTML5, the value must be in pixels.

Also, good practice advice from the same source :

Tip: Downsizing a large image with the height and width attributes forces a user to download the large image (even if it looks small on the page). To avoid this, rescale the image with a program before using it on a page.

SQL Server IIF vs CASE

IIF is a non-standard T-SQL function. It was added to SQL SERVER 2012, so that Access could migrate to SQL Server without refactoring the IIF's to CASE before hand. Once the Access db is fully migrated into SQL Server, you can refactor.

Fire event on enter key press for a textbox

Try this option.

update that coding part in Page_Load event before catching IsPostback

 TextBox1.Attributes.Add("onkeydown", "if(event.which || event.keyCode){if ((event.which == 13) || (event.keyCode == 13)) {document.getElementById('ctl00_ContentPlaceHolder1_Button1').click();return false;}} else {return true}; ");

Make a number a percentage

Numeral.js is a library I created that can can format numbers, currency, percentages and has support for localization.

numeral(0.7523).format('0%') // returns string "75%"

json_encode function: special characters

Use the below function.

function utf8_converter($array)
    array_walk_recursive($array, function (&$item, $key) {
        if (!mb_detect_encoding($item, 'utf-8', true)) {
                $item = utf8_encode($item);

    return $array;

Is there a conditional ternary operator in VB.NET?

If() is the closest equivalent but beware of implicit conversions going on if you have set "Option Strict off"

For example, if your not careful you may be tempted to try something like:

Dim foo As Integer? = If(someTrueExpression, Nothing, 2)

Will give "foo" a value of 0!

I think the '?' operator equivalent in C# would instead fail compilation

Failed to execute 'atob' on 'Window'

BlobBuilder is obsolete, use Blob constructor instead:

URL.createObjectURL(new Blob([/*whatever content*/] , {type:'text/plain'}));

This returns a blob URL which you can then use in an anchor's href. You can also modify an anchor's download attribute to manipulate the file name:

<a href="/*assign url here*/" id="link" download="whatever.txt">download me</a>

Fiddled. If I recall correctly, there are arbitrary restrictions on trusted non-user initiated downloads; thus we'll stick with a link clicking which is seen as sufficiently user-initiated :)

Update: it's actually pretty trivial to save current document's html! Whenever our interactive link is clicked, we'll update its href with a relevant blob. After executing the click-bound event, that's the download URL that will be navigated to!

$('#link').on('click', function(e){
  this.href = URL.createObjectURL(
    new Blob([document.documentElement.outerHTML] , {type:'text/html'})

Fiddled again.

Using C# to check if string contains a string in string array

here is how you can do it:

string stringToCheck = "text1";
string[] stringArray = { "text1", "testtest", "test1test2", "test2text1" };
foreach (string x in stringArray)
    if (stringToCheck.Contains(x))
        // Process...

UPDATE: May be you are looking for a better solution.. refer to @Anton Gogolev's answer below which makes use of LINQ.

Android ADB device offline, can't issue commands

As nobody gave an answer for my situation: you may not have access to the ~/.android/adbkey file. If you initially start adb with sudo, it will generate a public key pair, writing this to ~/.android/ and ~/android/adbkey. Of course, the private key is chmod 600 - only readable for root in your home directory. Subsequently starting adb as normal user will give no access to the private key file, which in turn will fail silently with "device offline".

Could not reserve enough space for object heap to start JVM

According to this post this error message means:

Heap size is larger than your computer's physical memory.

Edit: Heap is not the only memory that is reserved, I suppose. At least there are other JVM settings like PermGenSpace that ask for the memory. With heap size 128M and a PermGenSpace of 64M you already fill the space available.

Why not downsize other memory settings to free up space for the heap?

How does the "this" keyword work?

To understand "this" properly one must understand the context and scope and difference between them.

Scope: In javascript scope is related to the visibility of the variables, scope achieves through the use of the function. (Read more about scope)

Context: Context is related to objects. It refers to the object to which a function belongs. When you use the JavaScript “this” keyword, it refers to the object to which function belongs. For example, inside of a function, when you say: “this.accoutNumber”, you are referring to the property “accoutNumber”, that belongs to the object to which that function belongs.

If the object “myObj” has a method called “getMyName”, when the JavaScript keyword “this” is used inside of “getMyName”, it refers to “myObj”. If the function “getMyName” were executed in the global scope, then “this” refers to the window object (except in strict mode).

Now let's see some example:

        console.log('What is this: '+this);

Runnig abobve code in browser output will: enter image description here

According to the output you are inside of the context of the window object, it is also visible that window prototype refers to the Object.

Now let's try inside of a function:

        function myFunc(){
            console.log('What is this: '+this);


enter image description here The output is the same because we logged 'this' variable in the global scope and we logged it in functional scope, we didn't change the context. In both case context was same, related to widow object.

Now let's create our own object. In javascript, you can create an object in many ways.

        var firstName = "Nora";
        var lastName = "Zaman";
        var myObj = {
                console.log(firstName + " "+lastName);
                console.log(this.firstName +" "+this.lastName);
                return this;

      var context = myObj.printNameGetContext();

Output: enter image description here

So from the above example, we found that 'this' keyword is referring to a new context that is related to myObj, and myObject also has prototype chain to Object.

Let's go throw another example:

    <button class="btn">Click Me</button>
        function printMe(){
            //Terminal2: this function declared inside window context so this function belongs to the window object.
        document.querySelector('.btn').addEventListener('click', function(){
            //Terminal1: button context, this callback function belongs to DOM element 

output: Make sense right? (read comments) enter image description here

If you having trouble to understand the above example let's try with our own callback;

        var myObj = {
            printName:function(callback1, callback2){
                //Attaching callback1 with this myObj context
                this.callback1 = callback1;
                this.callback1(this.firstName +" "+this.lastName)
                //We did not attached callback2 with myObj so, it's reamin with window context by default
                 //test bellow codes
                 this.callback2 = callback2;
        var callback2 = function (){
        }, callback2);

output: enter image description here

Now let's Understand Scope, Self, IIFE and THIS how behaves

       var color = 'red'; // property of window
       var obj = {
           color:'blue', // property of window
           printColor: function(){ // property of obj, attached with obj
               var self = this;
               console.log('In printColor -- this.color: '+this.color);
               console.log('In printColor -- self.color: '+self.color);
               (function(){ // decleard inside of printColor but not property of object, it will executed on window context.
                    console.log('In IIFE -- this.color: '+this.color);
                    console.log('In IIFE -- self.color: '+self.color); 

               function nestedFunc(){// decleard inside of printColor but not property of object, it will executed on window context.
                    console.log('nested fun -- this.color: '+this.color);
                    console.log('nested fun -- self.color: '+self.color);

               nestedFunc(); // executed on window context
               return nestedFunc;

       obj.printColor()(); // returned function executed on window context

Output is pretty awesome right? enter image description here

here-document gives 'unexpected end of file' error

Please try to remove the preceeding spaces before EOF:-

/var/mail -s "$SUBJECT" "$EMAIL" <<-EOF

Using <tab> instead of <spaces> for ident AND using <<-EOF works fine.

The "-" removes the <tabs>, not <spaces>, but at least this works.

What are enums and why are they useful?

Instead of making a bunch of const int declarations

You can group them all in 1 enum

So its all organized by the common group they belong to

Convert Enum to String

All of these internally end up calling a method called InternalGetValueAsString. The difference between ToString and GetName would be that GetName has to verify a few things first:

  1. The type you entered isn't null.
  2. The type you entered is, in fact an enumeration.
  3. The value you passed in isn't null.
  4. The value you passed in is of a type that an enumeration can actually use as it's underlying type, or of the type of the enumeration itself. It uses GetType on the value to check this.

.ToString doesn't have to worry about any of these above issues, because it is called on an instance of the class itself, and not on a passed in version, therefore, due to the fact that the .ToString method doesn't have the same verification issues as the static methods, I would conclude that .ToString is the fastest way to get the value as a string.

add a string prefix to each value in a string column using Pandas

df['col'] = 'str' + df['col'].astype(str)


>>> df = pd.DataFrame({'col':['a',0]})
>>> df
0   a
1   0
>>> df['col'] = 'str' + df['col'].astype(str)
>>> df
0  stra
1  str0

Mergesort with Python

#here is my answer using two function one for merge and another for divide and 
l=int(input('enter range len'))      
print('list before sorting is',c)
def mergesort1(c,l,r):    
    while (i<len(l))&(j<len(r)):
        if l[i]<r[j]:
            i +=1            
            j +=1
        k +=1
    while i<len(l):
    while j<len(r):
    return c   
def mergesort(c):
    if len(c)<2:
        return c
    return    mergesort1(c,l,r)   

Case-insensitive string comparison in C++

Take advantage of the standard char_traits. Recall that a std::string is in fact a typedef for std::basic_string<char>, or more explicitly, std::basic_string<char, std::char_traits<char> >. The char_traits type describes how characters compare, how they copy, how they cast etc. All you need to do is typedef a new string over basic_string, and provide it with your own custom char_traits that compare case insensitively.

struct ci_char_traits : public char_traits<char> {
    static bool eq(char c1, char c2) { return toupper(c1) == toupper(c2); }
    static bool ne(char c1, char c2) { return toupper(c1) != toupper(c2); }
    static bool lt(char c1, char c2) { return toupper(c1) <  toupper(c2); }
    static int compare(const char* s1, const char* s2, size_t n) {
        while( n-- != 0 ) {
            if( toupper(*s1) < toupper(*s2) ) return -1;
            if( toupper(*s1) > toupper(*s2) ) return 1;
            ++s1; ++s2;
        return 0;
    static const char* find(const char* s, int n, char a) {
        while( n-- > 0 && toupper(*s) != toupper(a) ) {
        return s;

typedef std::basic_string<char, ci_char_traits> ci_string;

The details are on Guru of The Week number 29.

Jquery Smooth Scroll To DIV - Using ID value from Link

You can do this:

$('.searchbychar').click(function () {
    var divID = '#' +;
    $('html, body').animate({
        scrollTop: $(divID).offset().top
    }, 2000);


  • You need to prefix a class name with a . (dot) like in your first line of code.
  • $( 'searchbychar' ).click(function() {
  • Also, your code $('.searchbychar').attr('id') will return a string ID not a jQuery object. Hence, you can not apply .offset() method to it.

W3WP.EXE using 100% CPU - where to start?

This is a very old post, I know, but this is also a common problem. All of the suggested methods are very nice but they will always point to a process, and there are many chances that we already know that our site is making problems, but we just want to know what specific page is spending too much time in processing. The most precise and simple tool in my opinion is IIS itself.

  1. Just click on your server in the left pane of IIS.
  2. Click on 'Worker Processes' in the main pane. you already see what application pool is taking too much CPU.
  3. Double click on this line (eventually refresh by clicking 'Show All') to see what pages consume too much CPU time ('Time elapsed' column) in this pool

How to convert UTC timestamp to device local time in android

The answer from @prgDevelop returns 0 on my Android Marsmallow. Must return 7200000. These changes make it work fine:

int offset = TimeZone.getTimeZone(Time.getCurrentTimezone()).getRawOffset() + TimeZone.getTimeZone(Time.getCurrentTimezone()).getDSTSavings();

MSSQL Regular expression

As above the question was originally about MySQL


SELECT * FROM `table` WHERE ([url] NOT REGEXP '^[-A-Za-z0-9/.]+$')

Parsing date string in Go

I will suggest using time.RFC3339 constant from time package. You can check other constants from time package.

package main

import (

func main() {
    fmt.Println("Time parsing");
    dateString := "2014-11-12T11:45:26.371Z"
    time1, err := time.Parse(time.RFC3339,dateString);
    if err!=nil {
    fmt.Println("Error while parsing date :", err);

String to LocalDate


Since Java 1.8, you can achieve this without an extra library by using the java.time classes. See Tutorial.

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MMM-dd");
formatter = formatter.withLocale( putAppropriateLocaleHere );  // Locale specifies human language for translating, and cultural norms for lowercase/uppercase and abbreviations and such. Example: Locale.US or Locale.CANADA_FRENCH
LocalDate date = LocalDate.parse("2005-nov-12", formatter);

The syntax is nearly the same though.

How to view changes made to files on a certain revision in Subversion

The equivalent command in svn is:

svn log --diff -r revision

Position an element relative to its container

You have to explicitly set the position of the parent container along with the position of the child container. The typical way to do that is something like this:

    position: relative;
    left: 0px;  /* stick it wherever it was positioned by default */
    top: 0px;

    position: absolute;
    left: 10px;
    top: 10px;

Content Type application/soap+xml; charset=utf-8 was not supported by service

I also came across the same problem. In my case, I was using transfermode = streaming with Mtom. As it turns out, I had named one of my variables (for a structure), "HEADER". This conflicted with the message element [] as part of the http service download. Clearly, one must avoid using "reserved" words as parameter name.

Check status of one port on remote host

Press Windows + R type cmd and Enter

In command prompt type

telnet "machine name/ip" "port number"

If port is not open, this message will display:

"Connecting To "machine name"...Could not open connection to the host, on port "port number":

Otherwise you will be take in to opened port (empty screen will display)

How to reverse MD5 to get the original string?

Its not possible thats the whole point of hashing. You can however bruteforce by going through all possibilities (using all possible digits characters in every possible order) and hashing them and checking for a collision.

for more information on hashing and MD5 etc see: , , and

I myself created my own app to do this, its open source you can check the link: and of course the source. Here is the source for easy access it has a basic implementation in the comments:

import java.util.ArrayList;

public class Bruter {

    public ArrayList<String> characters = new ArrayList<>();
    public boolean found = false;
    public int maxLength;
    public int minLength;
    public int count;
    long starttime, endtime;
    public int minutes, seconds, hours, days;
    public char[] specialCharacters = {'~', '`', '!', '@', '#', '$', '%', '^',
        '&', '*', '(', ')', '_', '-', '+', '=', '{', '}', '[', ']', '|', '\\',
        ';', ':', '\'', '"', '<', '.', ',', '>', '/', '?', ' '};
    public boolean done = false;
    public boolean paused = false;

    public boolean isFound() {
        return found;

    public void setPaused(boolean paused) {
        this.paused = paused;

    public boolean isPaused() {
        return paused;

    public void setFound(boolean found) {
        this.found = found;

    public synchronized void setEndtime(long endtime) {
        this.endtime = endtime;

    public int getCounter() {
        return count;

    public long getRemainder() {
        return getNumberOfPossibilities() - count;

    public long getNumberOfPossibilities() {
        long possibilities = 0;
        for (int i = minLength; i <= maxLength; i++) {
            possibilities += (long) Math.pow(characters.size(), i);
        return possibilities;

    public void addExtendedSet() {
        for (char c = (char) 0; c <= (char) 31; c++) {

    public void addStandardCharacterSet() {
        for (char c = (char) 32; c <= (char) 127; c++) {

    public void addLowerCaseLetters() {
        for (char c = 'a'; c <= 'z'; c++) {

    public void addDigits() {
        for (int c = 0; c <= 9; c++) {

    public void addUpperCaseLetters() {
        for (char c = 'A'; c <= 'Z'; c++) {

    public void addSpecialCharacters() {
        for (char c : specialCharacters) {

    public void setMaxLength(int i) {
        maxLength = i;

    public void setMinLength(int i) {
        minLength = i;

    public int getPerSecond() {
        int i;
        try {
            i = (int) (getCounter() / calculateTimeDifference());
        } catch (Exception ex) {
            return 0;
        return i;


    public String calculateTimeElapsed() {
        long timeTaken = calculateTimeDifference();
        seconds = (int) timeTaken;
        if (seconds > 60) {
            minutes = (int) (seconds / 60);
            if (minutes * 60 > seconds) {
                minutes = minutes - 1;

            if (minutes > 60) {
                hours = (int) minutes / 60;
                if (hours * 60 > minutes) {
                    hours = hours - 1;

            if (hours > 24) {
                days = (int) hours / 24;
                if (days * 24 > hours) {
                    days = days - 1;
            seconds -= (minutes * 60);
            minutes -= (hours * 60);
            hours -= (days * 24);
            days -= (hours * 24);
        return "Time elapsed: " + days + "days " + hours + "h " + minutes + "min " + seconds + "s";

    private long calculateTimeDifference() {
        long timeTaken = (long) ((endtime - starttime) * (1 * Math.pow(10, -9)));
        return timeTaken;

    public boolean excludeChars(String s) {
        char[] arrayChars = s.toCharArray();
        for (int i = 0; i < arrayChars.length; i++) {
            characters.remove(arrayChars[i] + "");
        if (characters.size() < maxLength) {
            return false;
        } else {
            return true;


    public int getMaxLength() {
        return maxLength;

    public int getMinLength() {
        return minLength;

    public void setIsDone(Boolean b) {
        done = b;

    public boolean isDone() {
        return done;

import javax.swing.JOptionPane;

public class HashBruter extends Bruter {
     * public static void main(String[] args) {
     * final HashBruter hb = new HashBruter();
     * hb.setMaxLength(5); hb.setMinLength(1);
     * hb.addSpecialCharacters(); hb.addUpperCaseLetters();
     * hb.addLowerCaseLetters(); hb.addDigits();
     * hb.setType("sha-512");
     * hb.setHash("282154720ABD4FA76AD7CD5F8806AA8A19AEFB6D10042B0D57A311B86087DE4DE3186A92019D6EE51035106EE088DC6007BEB7BE46994D1463999968FBE9760E");
     * Thread thread = new Thread(new Runnable() {
     * @Override public void run() { hb.tryBruteForce(); } });
     * thread.start();
     * while (!hb.isFound()) { System.out.println("Hash: " +
     * hb.getGeneratedHash()); System.out.println("Number of Possibilities: " +
     * hb.getNumberOfPossibilities()); System.out.println("Checked hashes: " +
     * hb.getCounter()); System.out.println("Estimated hashes left: " +
     * hb.getRemainder()); }
     * System.out.println("Found " + hb.getType() + " hash collision: " +
     * hb.getGeneratedHash() + " password is: " + hb.getPassword());
     * }

    public String hash, generatedHash, password;
    public String type;

    public String getType() {
        return type;

    public String getPassword() {
        return password;

    public void setHash(String p) {
        hash = p;

    public void setType(String digestType) {
        type = digestType;

    public String getGeneratedHash() {
        return generatedHash;

    public void tryBruteForce() {
        starttime = System.nanoTime();
        for (int size = minLength; size <= maxLength; size++) {
            if (found == true || done == true) {
            } else {
                while (paused) {
                    try {
                    } catch (InterruptedException ex) {
                generateAllPossibleCombinations("", size);
        done = true;

    private void generateAllPossibleCombinations(String baseString, int length) {
        while (paused) {
            try {
            } catch (InterruptedException ex) {
        if (found == false || done == false) {
            if (baseString.length() == length) {
                if(type.equalsIgnoreCase("crc32")) {
                generatedHash = generateCRC32(baseString);
                } else if(type.equalsIgnoreCase("adler32")) {
                generatedHash = generateAdler32(baseString);
                } else if(type.equalsIgnoreCase("crc16")) {
                } else if(type.equalsIgnoreCase("crc64")) {
                else {
                generatedHash = generateHash(baseString.toCharArray());
                    password = baseString;
                if (hash.equals(generatedHash)) {
                    password = baseString;
                    found = true;
                    done = true;
            } else if (baseString.length() < length) {
                for (int n = 0; n < characters.size(); n++) {
                    generateAllPossibleCombinations(baseString + characters.get(n), length);

    private String generateHash(char[] passwordChar) {
        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance(type);
        } catch (NoSuchAlgorithmException e1) {
            JOptionPane.showMessageDialog(null, "No such algorithm for hashes exists", "Error", JOptionPane.ERROR_MESSAGE);
        String passwordString = new String(passwordChar);
        byte[] passwordByte = passwordString.getBytes();
        md.update(passwordByte, 0, passwordByte.length);
        byte[] encodedPassword = md.digest();
        String encodedPasswordInString = toHexString(encodedPassword);
        return encodedPasswordInString;

    private void byte2hex(byte b, StringBuffer buf) {
        char[] hexChars = {'0', '1', '2', '3', '4', '5', '6', '7', '8',
            '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        int high = ((b & 0xf0) >> 4);
        int low = (b & 0x0f);

    private String toHexString(byte[] block) {
        StringBuffer buf = new StringBuffer();
        int len = block.length;
        for (int i = 0; i < len; i++) {
            byte2hex(block[i], buf);
        return buf.toString();

    private String generateCRC32(String baseString) {

                //Convert string to bytes
                byte bytes[] = baseString.getBytes();

                Checksum checksum = new CRC32();

                 * To compute the CRC32 checksum for byte array, use
                 * void update(bytes[] b, int start, int length)
                 * method of CRC32 class.


                 * Get the generated checksum using
                 * getValue method of CRC32 class.
                return String.valueOf(checksum.getValue());
    private String generateAdler32(String baseString) {

                //Convert string to bytes
                byte bytes[] = baseString.getBytes();

                Checksum checksum = new Adler32();

                 * To compute the CRC32 checksum for byte array, use
                 * void update(bytes[] b, int start, int length)
                 * method of CRC32 class.


                 * Get the generated checksum using
                 * getValue method of CRC32 class.
                return String.valueOf(checksum.getValue());
 *  Compilation:  javac
 *  Execution:    java CRC16 s
 *  Reads in a string s as a command-line argument, and prints out
 *  its 16-bit Cyclic Redundancy Check (CRC16). Uses a lookup table.
 *  Reference:
 *  % java CRC16 123456789
 *  CRC16 = bb3d
 * Uses irreducible polynomial:  1 + x^2 + x^15 + x^16
    private String generateCRC16(String baseString) {
                int[] table = {
            0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
            0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
            0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
            0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
            0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
            0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
            0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
            0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
            0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
            0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
            0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
            0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
            0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
            0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
            0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
            0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
            0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
            0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
            0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
            0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
            0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
            0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
            0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
            0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
            0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
            0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
            0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
            0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
            0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
            0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
            0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
            0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040,

        byte[] bytes = baseString.getBytes();
        int crc = 0x0000;
        for (byte b : bytes) {
            crc = (crc >>> 8) ^ table[(crc ^ b) & 0xff];

        return Integer.toHexString(crc);
 * Copyright (c) 2009, 2012 Mountainminds GmbH & Co. KG and Contributors
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * Contributors:
 *    Marc R. Hoffmann - initial API and implementation

 * CRC64 checksum calculator based on the polynom specified in ISO 3309. The
 * implementation is based on the following publications:
 * <ul>
 * <li></li>
 * <li></li>
 * </ul>
    private static final long POLY64REV = 0xd800000000000000L;

    private static final long[] LOOKUPTABLE;

    static {
        LOOKUPTABLE = new long[0x100];
        for (int i = 0; i < 0x100; i++) {
            long v = i;
            for (int j = 0; j < 8; j++) {
                if ((v & 1) == 1) {
                    v = (v >>> 1) ^ POLY64REV;
                } else {
                    v = (v >>> 1);
            LOOKUPTABLE[i] = v;

     * Calculates the CRC64 checksum for the given data array.
     * @param data
     *            data to calculate checksum for
     * @return checksum value
    public static String generateCRC64(final byte[] data) {
        long sum = 0;
        for (int i = 0; i < data.length; i++) {
            final int lookupidx = ((int) sum ^ data[i]) & 0xff;
            sum = (sum >>> 8) ^ LOOKUPTABLE[lookupidx];
        return String.valueOf(sum);

you would use it like:

      final HashBruter hb = new HashBruter();

      hb.setMaxLength(5); hb.setMinLength(1);

     hb.addSpecialCharacters(); hb.addUpperCaseLetters();
     hb.addLowerCaseLetters(); hb.addDigits();



      Thread thread = new Thread(new Runnable() {

      @Override public void run() { hb.tryBruteForce(); } });


      while (!hb.isFound()) { System.out.println("Hash: " +
      hb.getGeneratedHash()); System.out.println("Number of Possibilities: " +
      hb.getNumberOfPossibilities()); System.out.println("Checked hashes: " +
     hb.getCounter()); System.out.println("Estimated hashes left: " +
     hb.getRemainder()); }

     System.out.println("Found " + hb.getType() + " hash collision: " +
     hb.getGeneratedHash() + " password is: " + hb.getPassword());

Display current path in terminal only

If you just want to get the information of current directory, you can type:


and you don't need to use the Nautilus, or you can use a teamviewer software to remote connect to the computer, you can get everything you want.

Python base64 data decode

i used chardet to detect possible encoding of this data ( if its text ), but get {'confidence': 0.0, 'encoding': None}. Then i tried to use pickle.load and get nothing again. I tried to save this as file , test many different formats and failed here too. Maybe you tell us what type have this 16512 bytes of mysterious data?

How can I include a YAML file inside another?

For Python users, you can try pyyaml-include.


pip install pyyaml-include


import yaml
from yamlinclude import YamlIncludeConstructor

YamlIncludeConstructor.add_to_loader_class(loader_class=yaml.FullLoader, base_dir='/your/conf/dir')

with open('0.yaml') as f:
    data = yaml.load(f, Loader=yaml.FullLoader)


Consider we have such YAML files:

+-- 0.yaml
+-- include.d
    +-- 1.yaml
    +-- 2.yaml
  • 1.yaml 's content:
name: "1"
  • 2.yaml 's content:
name: "2"

Include files by name

  • On top level:

    If 0.yaml was:

!include include.d/1.yaml

We'll get:

{"name": "1"}
  • In mapping:

    If 0.yaml was:

file1: !include include.d/1.yaml
file2: !include include.d/2.yaml

We'll get:

    name: "1"
    name: "2"
  • In sequence:

    If 0.yaml was:

  - !include include.d/1.yaml
  - !include include.d/2.yaml

We'll get:

  - name: "1"
  - name: "2"

? Note:

File name can be either absolute (like /usr/conf/1.5/Make.yml) or relative (like ../../cfg/img.yml).

Include files by wildcards

File name can contain shell-style wildcards. Data loaded from the file(s) found by wildcards will be set in a sequence.

If 0.yaml was:

files: !include include.d/*.yaml

We'll get:

  - name: "1"
  - name: "2"

? Note:

  • For Python>=3.5, if recursive argument of !include YAML tag is true, the pattern “**” will match any files and zero or more directories and subdirectories.
  • Using the “**” pattern in large directory trees may consume an inordinate amount of time because of recursive search.

In order to enable recursive argument, we shall write the !include tag in Mapping or Sequence mode:

  • Arguments in Sequence mode:
!include [tests/data/include.d/**/*.yaml, true]
  • Arguments in Mapping mode:
!include {pathname: tests/data/include.d/**/*.yaml, recursive: true}

What is the max size of localStorage values?

Quoting from the Wikipedia article on Web Storage:

Web storage can be viewed simplistically as an improvement on cookies, providing much greater storage capacity (10 MB per origin in Google Chrome(, Mozilla Firefox, and Opera; 10 MB per storage area in Internet Explorer) and better programmatic interfaces.

And also quoting from a John Resig article [posted January 2007]:

Storage Space

It is implied that, with DOM Storage, you have considerably more storage space than the typical user agent limitations imposed upon Cookies. However, the amount that is provided is not defined in the specification, nor is it meaningfully broadcast by the user agent.

If you look at the Mozilla source code we can see that 5120KB is the default storage size for an entire domain. This gives you considerably more space to work with than a typical 2KB cookie.

However, the size of this storage area can be customized by the user (so a 5MB storage area is not guaranteed, nor is it implied) and the user agent (Opera, for example, may only provide 3MB - but only time will tell.)

Spark Kill Running Application

  • copy past the application Id from the spark scheduler, for instance application_1428487296152_25597
  • connect to the server that have launch the job
  • yarn application -kill application_1428487296152_25597

Can (domain name) subdomains have an underscore "_" in it?

A note on terminology, in furtherance to Bortzmeyer's answer

One should be clear about definitions. As used here:

  • domain name is the identifier of a resource in a DNS database
  • label is the part of a domain name in between dots
  • hostname is a special type of domain name which identifies Internet hosts

The hostname is subject to the restrictions of RFC 952 and the slight relaxation of RFC 1123

RFC 2181 makes clear that there is a difference between a domain name and a hostname:

...[the fact that] any binary label can have an MX record does not imply that any binary name can be used as the host part of an e-mail address...

So underscores in hostnames are a no-no, underscores in domain names are a-ok.

In practice, one may well see hostnames with underscores. As the Robustness Principle says: "Be conservative in what you send, liberal in what you accept".

A note on encoding

In the 21st century, it turns out that hostnames as well as domain names may be internationalized! This means resorting to encodings in case of labels that contain characters that are outside the allowed set.

In particular, it allows one to encode the _ in hostnames (Update 2017-07: This is doubtful, see comments. The _ still cannot be used in hostnames. Indeed, it cannot even be used in internationalized labels.)

The first RFC for internationalization was RFC 3490 of March 2003, "Internationalizing Domain Names in Applications (IDNA)". Today, we have:

  • RFC 5890 "IDNA: Definitions and Document Framework"
  • RFC 5891 "IDNA: Protocol"
  • RFC 5892 "The Unicode Code Points and IDNA"
  • RFC 5893 "Right-to-Left Scripts for IDNA"
  • RFC 5894 "IDNA: Background, Explanation, and Rationale"
  • RFC 5895 "Mapping Characters for IDNA 2008"

You may also want to check the Wikipedia Entry

RFC 5890 introduces the term LDH (Letter-Digit-Hypen) label for labels used in hostnames and says:

This is the classical label form used, albeit with some additional restrictions, in hostnames (RFC 952). Its syntax is identical to that described as the "preferred name syntax" in Section 3.5 of RFC 1034 as modified by RFC 1123. Briefly, it is a string consisting of ASCII letters, digits, and the hyphen with the further restriction that the hyphen cannot appear at the beginning or end of the string. Like all DNS labels, its total length must not exceed 63 octets.

Going back to simpler times, this Internet draft is an early proposal for hostname internationalization. Hostnames with international characters may be encoded using, for example, 'RACE' encoding.

The author of the 'RACE encoding' proposal notes:

According to RFC 1035, host parts must be case-insensitive, start and end with a letter or digit, and contain only letters, digits, and the hyphen character ("-"). This, of course, excludes any internationalized characters, as well as many other characters in the ASCII character repertoire. Further, domain name parts must be 63 octets or shorter in length.... All post-converted name parts that contain internationalized characters begin with the string "bq--". (...) The string "bq--" was chosen because it is extremely unlikely to exist in host parts before this specification was produced.

Matrix Transpose in Python

The "best" answer has already been submitted, but I thought I would add that you can use nested list comprehensions, as seen in the Python Tutorial.

Here is how you could get a transposed array:

def matrixTranspose( matrix ):
    if not matrix: return []
    return [ [ row[ i ] for row in matrix ] for i in range( len( matrix[ 0 ] ) ) ]

SQL Bulk Insert with FIRSTROW parameter skips the following line

To let SQL handle quote escape and everything else do this

FROM  'C:\MyCSV.csv' 
 --FIRSTROW = 2,  --uncomment this if your CSV contains header, so start parsing at line 2

In regards to other answers, here is valuable info as well:

I keep seeing this in all answers: ROWTERMINATOR = '\n'
The \n means LF and it is Linux style EOL

In Windows the EOL is made of 2 chars CRLF so you need ROWTERMINATOR = '\r\n'

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How do I do a HTTP GET in Java?

The simplest way that doesn't require third party libraries it to create a URL object and then call either openConnection or openStream on it. Note that this is a pretty basic API, so you won't have a lot of control over the headers.

Efficiently sorting a numpy array in descending order?

temp[::-1].sort() sorts the array in place, whereas np.sort(temp)[::-1] creates a new array.

In [25]: temp = np.random.randint(1,10, 10)

In [26]: temp
Out[26]: array([5, 2, 7, 4, 4, 2, 8, 6, 4, 4])

In [27]: id(temp)
Out[27]: 139962713524944

In [28]: temp[::-1].sort()

In [29]: temp
Out[29]: array([8, 7, 6, 5, 4, 4, 4, 4, 2, 2])

In [30]: id(temp)
Out[30]: 139962713524944

is inaccessible due to its protection level

The reason being you can not access protected member data through the instance of the class.

Reason why it is not allowed is explained in this blog

How to use DbContext.Database.SqlQuery<TElement>(sql, params) with stored procedure? EF Code First CTP5

@Tom Halladay's answer is correct with the mention that you shopuld also check for null values and send DbNullable if params are null as you would get an exception like

The parameterized query '...' expects the parameter '@parameterName', which was not supplied.

Something like this helped me

public static object GetDBNullOrValue<T>(this T val)
    bool isDbNull = true;
    Type t = typeof(T);

    if (Nullable.GetUnderlyingType(t) != null)
        isDbNull = EqualityComparer<T>.Default.Equals(default(T), val);
    else if (t.IsValueType)
        isDbNull = false;
        isDbNull = val == null;

    return isDbNull ? DBNull.Value : (object) val;

(credit for the method goes to

Then use it like:

new SqlParameter("@parameterName", parameter.GetValueOrDbNull())

or another solution, more simple, but not generic would be:

new SqlParameter("@parameterName", parameter??(object)DBNull.Value)

Python sum() function with list parameter

Have you used the variable sum anywhere else? That would explain it.

>>> sum = 1
>>> numbers = [1, 2, 3]
>>> numsum = (sum(numbers))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'int' object is not callable

The name sum doesn't point to the function anymore now, it points to an integer.

Solution: Don't call your variable sum, call it total or something similar.

Remove whitespaces inside a string in javascript

Probably because you forgot to implement the solution in the accepted answer. That's the code that makes trim() work.


This answer only applies to older browsers. Newer browsers apparently support trim() natively.

How do I get the IP address into a batch-file variable?

For my system, I had numerous IPv4 Addresses, only one of which was correct. A simple way to sort out and check it is as follows:

for /f "tokens=1,2* delims=:" %%A in ('ipconfig ^| find "IPv4 Address"') do (
    set "tempip=%%~B"
    set "tempip=!tempip: =!"
    ping !tempip! -n 1 -w 50
    if !errorlevel!==0 (
        set localip=!tempip!
        goto foundlocal

SQL Server - NOT IN

One issue could be that if either make, model, or [serial number] were null, values would never get returned. Because string concatenations with null values always result in null, and not in () with null will always return nothing. The remedy for this is to use an operator such as IsNull(make, '') + IsNull(Model, ''), etc.

Make an image width 100% of parent div, but not bigger than its own width

Found this post on a Google search, and it solved my issue thanks to @jwal reply, but I made one addition to his solution.

img.content.x700 {
  width: auto !important; /*override the width below*/
  width: 100%;
  max-width: 678px;
  float: left;
  clear: both;

With the above I changed the max-width to the dimensions of the content container that my image is in. In this case it is: container width - padding - boarder = max width

This way my image won't break out of the containing div, and I can still float the image within the content div.

I've tested in IE 9, FireFox 18.0.2 and Chrome 25.0.1364.97, Safari iOS and seems to work.

Additional: I tested this on an image 1024px wide displayed at 678px (the max width), and an image 500px wide displayed at 500px (width of the image).

Openssl : error "self signed certificate in certificate chain"

The solution for the error is to add this line at the top of the code:


How to print number with commas as thousands separators?

You can also use '{:n}'.format( value ) for a locale representation. I think this is the simpliest way for a locale solution.

For more information, search for thousands in Python DOC.

For currency, you can use locale.currency, setting the flag grouping:


import locale

locale.setlocale( locale.LC_ALL, '' )
locale.currency( 1234567.89, grouping = True )


'R$ 1.234.567,89'

How to host material icons offline?

My recipe has three steps:

  1. to install material-design-icons package

    npm install material-design-icons
  2. to import material-icons.css file into .less or .scss file/ project

    @import "~/node_modules/material-design-icons/iconfont/material-icons.css";
  3. to include recommended code into the reactjs .js file/ project

    <i className='material-icons' style={{fontSize: '36px'}}>close</i>

The imported project "C:\Microsoft.CSharp.targets" was not found

ok so what if it say this: between the gt/lt signs

Import Project="$(MSBuildExtensionsPath)\Microsoft\Silverlight\v3.0\Microsoft.Silverlight.CSharp.targets" /

how do i fix the targets error?

I also found that import string in a demo project (specifically "Build your own MVVM Framework" by Rob Eisenburg).

If you replace that import with the one suggested by lomaxx VS2010 RTM reports that you need to install this.

Why should we include ttf, eot, woff, svg,... in a font-face

WOFF 2.0, based on the Brotli compression algorithm and other improvements over WOFF 1.0 giving more than 30 % reduction in file size, is supported in Chrome, Opera, and Firefox. has an example on how to use it.

Basically you add a src url to the woff2 file and specify the woff2 format. It is important to have this before the woff-format: the browser will use the first format that it supports.

alternatives to REPLACE on a text or ntext datatype

Assuming SQL Server 2000, the following StackOverflow question should address your problem.

If using SQL Server 2005/2008, you can use the following code (taken from here):

select cast(replace(cast(myntext as nvarchar(max)),'find','replace') as ntext)
from myntexttable

mysqli or PDO - what are the pros and cons?

PDO will make it a lot easier to scale if your site/web app gets really being as you can daily set up Master and slave connections to distribute the load across the database, plus PHP is heading towards moving to PDO as a standard.

PDO Info

Scaling a Web Application

Adding content to a linear layout dynamically?

LinearLayout layout = (LinearLayout)findViewById(;
View child = getLayoutInflater().inflate(R.layout.child, null);

lambda expression for exists within list

You can use the Contains() extension method:

list.Where(r => listofIds.Contains(r.Id))

Hex to ascii string conversion

strtol() is your friend here. The third parameter is the numerical base that you are converting.


#include <stdio.h>      /* printf */
#include <stdlib.h>     /* strtol */

int main(int argc, char **argv)
    long int num  = 0;
    long int num2 =0;
    char * str. = "f00d";
    char * str2 = "0xf00d";

    num = strtol( str, 0, 16);  //converts hexadecimal string to long.
    num2 = strtol( str2, 0, 0); //conversion depends on the string passed in, 0x... Is hex, 0... Is octal and everything else is decimal.

    printf( "%ld\n", num);
    printf( "%ld\n", num);

Insert all values of a table into another table in SQL

The insert statement actually has a syntax for doing just that. It's a lot easier if you specify the column names rather than selecting "*" though:

INSERT INTO new_table (Foo, Bar, Fizz, Buzz)
SELECT Foo, Bar, Fizz, Buzz
FROM initial_table
-- optionally WHERE ...

I'd better clarify this because for some reason this post is getting a few down-votes.

The INSERT INTO ... SELECT FROM syntax is for when the table you're inserting into ("new_table" in my example above) already exists. As others have said, the SELECT ... INTO syntax is for when you want to create the new table as part of the command.

You didn't specify whether the new table needs to be created as part of the command, so INSERT INTO ... SELECT FROM should be fine if your destination table already exists.

Correct way to use Modernizr to detect IE?

Modernizr doesn't detect browsers as such, it detects which feature and capability are present and this is the whole jist of what it's trying to do.

You could try hooking in a simple detection script like this and then using it to make your choice. I've included Version Detection as well just in case that's needed. If you only want to check of any version of IE you could just look for the navigator.userAgent having a value of "MSIE".

var BrowserDetect = {_x000D_
        init: function () {_x000D_
            this.browser = this.searchString(this.dataBrowser) || "Other";_x000D_
            this.version = this.searchVersion(navigator.userAgent) || this.searchVersion(navigator.appVersion) || "Unknown";_x000D_
        searchString: function (data) {_x000D_
            for (var i = 0; i < data.length; i++) {_x000D_
                var dataString = data[i].string;_x000D_
                this.versionSearchString = data[i].subString;_x000D_
                if (dataString.indexOf(data[i].subString) !== -1) {_x000D_
                    return data[i].identity;_x000D_
        searchVersion: function (dataString) {_x000D_
            var index = dataString.indexOf(this.versionSearchString);_x000D_
            if (index === -1) {_x000D_
            var rv = dataString.indexOf("rv:");_x000D_
            if (this.versionSearchString === "Trident" && rv !== -1) {_x000D_
                return parseFloat(dataString.substring(rv + 3));_x000D_
            } else {_x000D_
                return parseFloat(dataString.substring(index + this.versionSearchString.length + 1));_x000D_
        dataBrowser: [_x000D_
            {string: navigator.userAgent, subString: "Edge", identity: "MS Edge"},_x000D_
            {string: navigator.userAgent, subString: "MSIE", identity: "Explorer"},_x000D_
            {string: navigator.userAgent, subString: "Trident", identity: "Explorer"},_x000D_
            {string: navigator.userAgent, subString: "Firefox", identity: "Firefox"},_x000D_
            {string: navigator.userAgent, subString: "Opera", identity: "Opera"},  _x000D_
            {string: navigator.userAgent, subString: "OPR", identity: "Opera"},  _x000D_
            {string: navigator.userAgent, subString: "Chrome", identity: "Chrome"}, _x000D_
            {string: navigator.userAgent, subString: "Safari", identity: "Safari"}       _x000D_
    document.write("You are using <b>" + BrowserDetect.browser + "</b> with version <b>" + BrowserDetect.version + "</b>");

You can then simply check for:

BrowserDetect.browser == 'Explorer';
BrowserDetect.version <= 9;

Node update a specific package

Most of the time you can just npm update (or yarn upgrade) a module to get the latest non breaking changes (respecting the semver specified in your package.json) (<-- read that last part again).

npm update browser-sync
yarn upgrade browser-sync
  • Use npm|yarn outdated to see which modules have newer versions
  • Use npm update|yarn upgrade (without a package name) to update all modules
  • Include --save-dev|--dev if you want to save the newer version numbers to your package.json. (NOTE: as of npm v5.0 this is only necessary for devDependencies).

Major version upgrades:

In your case, it looks like you want the next major version (v2.x.x), which is likely to have breaking changes and you will need to update your app to accommodate those changes. You can install/save the latest 2.x.x by doing:

npm install browser-sync@2 --save-dev
yarn add browser-sync@2 --dev

...or the latest 2.1.x by doing:

npm install [email protected] --save-dev
yarn add [email protected] --dev

...or the latest and greatest by doing:

npm install browser-sync@latest --save-dev
yarn add browser-sync@latest --dev

Note: the last one is no different than doing this:

npm uninstall browser-sync --save-dev
npm install browser-sync --save-dev
yarn remove browser-sync --dev
yarn add browser-sync --dev

The --save-dev part is important. This will uninstall it, remove the value from your package.json, and then reinstall the latest version and save the new value to your package.json.

Disabling right click on images using jquery

what is your purpose of disabling the right click. problem with any technique is that there is always a way to go around them. the console for firefox (firebug) and chrome allow for unbinding of that event. or if you want the image to be protected one could always just take a look at their temporary cache for the images.

If you want to create your own contextual menu the preventDefault is fine. Just pick your battles here. not even a big JavaScript library like tnyMCE works on all browsers... and that is not because it's not possible ;-).


Personally I'm more in for an open internet. Native browser behavior should not be hindered by the pages interactions. I am sure that other ways can be found to interact that are not the right click.

How to install .MSI using PowerShell

You can use:

msiexec /i "c:\package.msi"

You can also add some more optional parameters. There are common msi parameters and parameters which are specific for your installer. For common parameters just call msiexec

Connecting to SQL Server Express - What is my server name?

If sql server is installed on your machine, you should check

Programs -> Microsoft SQL Server 20XX -> Configuration Tools -> SQL Server Configuration Manager -> SQL Server Services You'll see "SQL Server (MSSQLSERVER)"

Programs -> Microsoft SQL Server 20XX -> Configuration Tools -> SQL Server Configuration Manager -> SQL Server Network Configuration -> Protocols for MSSQLSERVER -> TCP/IP Make sure it's using port number 1433

If you want to see if the port is open and listening try this from your command prompt... telnet 1433

And yes, SQL Express installs use localhost\SQLEXPRESS as the instance name by default.

How to preSelect an html dropdown list with php?

I have 2 php files and i made this, and it works. (this is an example) the first code is from the one file and the second code from two file.

<form action="two.php" method="post">
<input type="submit" class="button" value="submit" name="one"/>
<select name="numbers">
<option value="1"> 1 </option>
<option value="2"> 2 </option>
<option value="3"> 3 </option>

if(isset ($_POST['one']))

$a='1' ;
else if($_POST['numbers']=='2')
$a='2' ;
else if ($_POST['numbers']=='3')
$a='3' ;


How to keep :active css style after clicking an element

Combine JS & CSS :

  /* 1st state */

  /* hover state */

  /* click state */
  /* after click state */


How do I put double quotes in a string in vba?

I prefer the answer of tabSF . implementing the same to your answer. here below is my approach

Worksheets("Sheet1").Range("A1").Value = "=IF(Sheet1!A1=0," & CHR(34) & CHR(34) & ",Sheet1!A1)"

Git: How to find a deleted file in the project commit history?

Here is my solution:

git log --all --full-history --oneline -- <RELATIVE_FILE_PATH>
git checkout <COMMIT_SHA>^ -- <RELATIVE_FILE_PATH>

How to compress image size?

Try this Method,this will convert your Image file to compressed format,and you can customized the compress level by varrying the value of x & y in the code(Indicated in comment line)

      File mImageFile = saveBitmapToFile(ImageFile);

      public File saveBitmapToFile(File file){

      try {

        // BitmapFactory options to downsize the image
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        o.inSampleSize = 6;
        // factor of downsizing the image

        FileInputStream inputStream = new FileInputStream(file);
        //Bitmap selectedBitmap = null;
        BitmapFactory.decodeStream(inputStream, null, o);

        // The new size we want to scale to
        final int REQUIRED_SIZE=200;        // x............

        // Find the correct scale value. It should be the power of 2.
        int scale = 1;
        while(o.outWidth / scale / 2 >= REQUIRED_SIZE &&
                o.outHeight / scale / 2 >= REQUIRED_SIZE) {
            scale *= 2;

        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        inputStream = new FileInputStream(file);

        Bitmap selectedBitmap = BitmapFactory.decodeStream(inputStream, null, o2);

        // here i override the original image file
        File outPutFile = File.createTempFile("abc","image");
        FileOutputStream outputStream = new FileOutputStream(outPutFile);
                                                  // y.......
        selectedBitmap.compress(Bitmap.CompressFormat.JPEG, 95 , outputStream);

        return outPutFile;
    } catch (Exception e) {
        return null;


SQL: IF clause within WHERE clause

The following example executes a query as part of the Boolean expression and then executes slightly different statement blocks based on the result of the Boolean expression. Each statement block starts with BEGIN and completes with END.

USE AdventureWorks2012;
DECLARE @AvgWeight decimal(8,2), @BikeCount int
(SELECT COUNT(*) FROM Production.Product WHERE Name LIKE 'Touring-3000%' ) > 5
   SET @BikeCount = 
        (SELECT COUNT(*) 
         FROM Production.Product 
         WHERE Name LIKE 'Touring-3000%');
   SET @AvgWeight = 
        (SELECT AVG(Weight) 
         FROM Production.Product 
         WHERE Name LIKE 'Touring-3000%');
   PRINT 'There are ' + CAST(@BikeCount AS varchar(3)) + ' Touring-3000 bikes.'
   PRINT 'The average weight of the top 5 Touring-3000 bikes is ' + CAST(@AvgWeight AS varchar(8)) + '.';
SET @AvgWeight = 
        (SELECT AVG(Weight)
         FROM Production.Product 
         WHERE Name LIKE 'Touring-3000%' );
   PRINT 'Average weight of the Touring-3000 bikes is ' + CAST(@AvgWeight AS varchar(8)) + '.' ;

Using nested IF...ELSE statements The following example shows how an IF … ELSE statement can be nested inside another. Set the @Number variable to 5, 50, and 500 to test each statement.

DECLARE @Number int
SET @Number = 50
IF @Number > 100
   PRINT 'The number is large.'
      IF @Number < 10
      PRINT 'The number is small'
      PRINT 'The number is medium'
   END ;

C#: Dynamic runtime cast

I think you're confusing the issues of casting and converting here.

  • Casting: The act of changing the type of a reference which points to an object. Either moving up or down the object hierarchy or to an implemented interface
  • Converting: Creating a new object from the original source object of a different type and accessing it through a reference to that type.

It's often hard to know the difference between the 2 in C# because both of them use the same C# operator: the cast.

In this situation you are almost certainly not looking for a cast operation. Casting a dynamic to another dynamic is essentially an identity conversion. It provides no value because you're just getting a dynamic reference back to the same underlying object. The resulting lookup would be no different.

Instead what you appear to want in this scenario is a conversion. That is morphing the underlying object to a different type and accessing the resulting object in a dynamic fashion. The best API for this is Convert.ChangeType.

public static dynamic Convert(dynamic source, Type dest) {
  return Convert.ChangeType(source, dest);


The updated question has the following line:

obj definitely implements castTo

If this is the case then the Cast method doesn't need to exist. The source object can simply be assigned to a dynamic reference.

dynamic d = source;

It sounds like what you're trying to accomplish is to see a particular interface or type in the hierarchy of source through a dynamic reference. That is simply not possible. The resulting dynamic reference will see the implementation object directly. It doesn't look through any particular type in the hierarchy of source. So the idea of casting to a different type in the hierarchy and then back to dynamic is exactly identical to just assigning to dynamic in the first place. It will still point to the same underlying object.

How to set dropdown arrow in spinner?

If you have a vector icon and not bitmap, you can set it this way.

            <shape android:shape="rectangle">
                <gradient android:angle="270" android:centerColor="#65FFFFFF" android:centerY="0.2" android:endColor="#00FFFFFF" android:startColor="@color/light_gray" />
                <stroke android:width="1dp" android:color="@color/darkGray" />
                <corners android:radius="@dimen/edit_text_corner_radius" />



Proper use of mutexes in Python

I would like to improve answer from chris-b a little bit more.

See below for my code:

from threading import Thread, Lock
import threading
mutex = Lock()

def processData(data, thread_safe):
    if thread_safe:
        thread_id = threading.get_ident()
        print('\nProcessing data:', data, "ThreadId:", thread_id)
        if thread_safe:

counter = 0
max_run = 100
thread_safe = False
while True:
    some_data = counter        
    t = Thread(target=processData, args=(some_data, thread_safe))
    counter = counter + 1
    if counter >= max_run:

In your first run if you set thread_safe = False in while loop, mutex will not be used, and threads will step over each others in print method as below;

Not Thread safe

but, if you set thread_safe = True and run it, you will see all the output comes perfectly fine;

Thread safe

hope this helps.

What is the difference between 'my' and 'our' in Perl?

This is only somewhat related to the question, but I've just discovered a (to me) obscure bit of perl syntax that you can use with "our" (package) variables that you can't use with "my" (local) variables.


our $foo = "BAR";

print $foo . "\n";
${"foo"} = "BAZ";
print $foo . "\n";



This won't work if you change 'our' to 'my'.

SASS :not selector

I tried re-creating this, and .someclass.notip was being generated for me but .someclass:not(.notip) was not, for as long as I did not have the @mixin tip() defined. Once I had that, it all worked.

$dropdown-width: 100px;
$comp-tip: true;

@mixin tip($pos:right) {


@mixin dropdown-pos($pos:right) {
  &:not(.notip) {
    @if $comp-tip == true{
      @if $pos == right {
        top:$dropdown-width * -0.6;
        background-color: #f00;
        @include tip($pos:$pos);
  &.notip {
    @if $pos == right {
      top: 0;
      left:$dropdown-width * 0.8;
      background-color: #00f;

.someclass { @include dropdown-pos(); }

EDIT: is a good place to debug your SASS because it gives you error messages. Undefined mixin 'tip'. it what I get when I remove @mixin tip($pos:right) { }

how do I initialize a float to its max/min value?

You can use std::numeric_limits which is defined in <limits> to find the minimum or maximum value of types (As long as a specialization exists for the type). You can also use it to retrieve infinity (and put a - in front for negative infinity).

#include <limits>



As noted in the comments, min() returns the lowest possible positive value. In other words the positive value closest to 0 that can be represented. The lowest possible value is the negative of the maximum possible value.

There is of course the std::max_element and min_element functions (defined in <algorithm>) which may be a better choice for finding the largest or smallest value in an array.

Gradients in Internet Explorer 9

The best cross-browser solution is

background: #fff;
background: -moz-linear-gradient(#fff, #000);
background: -webkit-linear-gradient(#fff, #000);
background: -o-linear-gradient(#fff, #000);
background: -ms-linear-gradient(#fff, #000);/*For IE10*/
background: linear-gradient(#fff, #000);
filter: progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr='#ffffff', endColorstr='#000000');/*For IE7-8-9*/ 
height: 1%;/*For IE7*/ 

Simple function to sort an array of objects

Array.prototype.sort_by = function(key_func, reverse=false){
    return this.sort( (a, b) => ( key_func(b) - key_func(a) ) * (reverse ? 1 : -1) ) 

Then for example if we have

var arr = [ {id: 0, balls: {red: 8,  blue: 10}},
            {id: 2, balls: {red: 6 , blue: 11}},
            {id: 1, balls: {red: 4 , blue: 15}} ]

arr.sort_by(el =>, reverse=true)
/* would result in
[ { id: 2, balls: {red: 6 , blue: 11 }},
  { id: 1, balls: {red: 4 , blue: 15 }},
  { id: 0, balls: {red: 8 , blue: 10 }} ]


arr.sort_by(el => +
/* would result in
[ { id: 2, balls: {red: 6 , blue: 11 }},    // red + blue= 17
  { id: 0, balls: {red: 8 , blue: 10 }},    // red + blue= 18
  { id: 1, balls: {red: 4 , blue: 15 }} ]   // red + blue= 19

Python multiprocessing PicklingError: Can't pickle <type 'function'>

When this problem comes up with multiprocessing a simple solution is to switch from Pool to ThreadPool. This can be done with no change of code other than the import-

from multiprocessing.pool import ThreadPool as Pool

This works because ThreadPool shares memory with the main thread, rather than creating a new process- this means that pickling is not required.

The downside to this method is that python isn't the greatest language with handling threads- it uses something called the Global Interpreter Lock to stay thread safe, which can slow down some use cases here. However, if you're primarily interacting with other systems (running HTTP commands, talking with a database, writing to filesystems) then your code is likely not bound by CPU and won't take much of a hit. In fact I've found when writing HTTP/HTTPS benchmarks that the threaded model used here has less overhead and delays, as the overhead from creating new processes is much higher than the overhead for creating new threads.

So if you're processing a ton of stuff in python userspace this might not be the best method.

Remove blank lines with grep

Here is another way of removing the white lines and lines starting with the # sign. I think this is quite useful to read configuration files.

[root@localhost ~]# cat /etc/sudoers | egrep -v '^(#|$)'
Defaults    requiretty
Defaults   !visiblepw
Defaults    always_set_home
Defaults    env_reset
root    ALL=(ALL)       ALL
%wheel  ALL=(ALL)       ALL

Getting String Value from Json Object Android

Please see my answer below, inspired by answers above but a bit more detailed...

// Get The Json Response (With Try Catch)
try {

    String s = null;

    if (response.body() != null) {

        s = response.body().string();

        // Convert Response Into Json Object (With Try Catch)
        JSONObject json = null;

        try {
            json = new JSONObject(s);

            // Extract The User Id From Json Object (With Try Catch)
            String stringToExtract = null;

            try {
                stringToExtract = json.getString("NeededString");

            } catch (JSONException e) {

        } catch (JSONException e) {


} catch (IOException e) {

Playing .mp3 and .wav in Java?

Nothing worked. but this one perfectly

google and download Jlayer library first.

import javazoom.jl.player.Player;

public class MusicPlay {

  public static void main(String[] args)  {


      FileInputStream fs = new FileInputStream("audio_file_path.mp3");
      Player player = new Player(fs);;

    } catch (Exception e){
      // catch exceptions.


How do I make a comment in a Dockerfile?

Docker treats lines that begin with # as a comment, unless the line is a valid parser directive. A # marker anywhere else in a line is treated as an argument.

example code:

# this line is a comment

RUN echo 'we are running some # of cool things'


we are running some # of cool things

How to convert JSON string to array

Use json_decode($json_string, TRUE) function to convert the JSON object to an array.


$json_string   = '{"a":1,"b":2,"c":3,"d":4,"e":5}';

$my_array_data = json_decode($json_string, TRUE);

NOTE: The second parameter will convert decoded JSON string into an associative array.




array(5) {

    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)

How to fix getImageData() error The canvas has been tainted by cross-origin data?

You are "tainting" the canvas by loading from a cross origins domain. Check out this MDN article:

Quick way to clear all selections on a multiselect enabled <select> with jQuery?

$('.clearAll').on('click', function() {_x000D_
<script src=""></script>_x000D_
<select class="dropdown" multiple>_x000D_
  <option value="volvo">Volvo</option>_x000D_
  <option value="saab">Saab</option>_x000D_
  <option value="opel">Opel</option>_x000D_
  <option value="audi">Audi</option>_x000D_
<button class='clearAll'>Clear All Selection</button>

Get local href value from anchor (a) tag

document.getElementById("link").getAttribute("href"); If you have more than one <a> tag, for example:

    <a href="1"></a>_x000D_
    <a href="2"></a>_x000D_
    <a href="3"></a>_x000D_

You can do it like this: document.getElementById("link")[0].getAttribute("href"); to access the first array of <a> tags, or depends on the condition you make.

HTML/CSS font color vs span style

You should use <span>, because as specified by the spec, <font> has been deprecated and probably won't display as you intend.

Refresh Page and Keep Scroll Position

I modified Sanoj Dushmantha's answer to use sessionStorage instead of localStorage. However, despite the documentation, browsers will still store this data even after the browser is closed. To fix this issue, I am removing the scroll position after it is reset.

    document.addEventListener("DOMContentLoaded", function (event) {
        var scrollpos = sessionStorage.getItem('scrollpos');
        if (scrollpos) {
            window.scrollTo(0, scrollpos);

    window.addEventListener("beforeunload", function (e) {
        sessionStorage.setItem('scrollpos', window.scrollY);

Changing the resolution of a VNC session in linux

As far as I know there's no way to change the client's resolution just using VNC, as it is just a "monitor mirroring" application.

TightVNC however (which is a VNC client and server application) can resize the screen on the client side, i.e. making everything a little smaller (similar to image resizing techniques in graphics programs). That should work if you don't use too small font sizes. VNC should theoretically be compatible between different VNC applications.

numpy: most efficient frequency counts for unique values in an array

Update: The method mentioned in the original answer is deprecated, we should use the new way instead:

>>> import numpy as np
>>> x = [1,1,1,2,2,2,5,25,1,1]
>>> np.array(np.unique(x, return_counts=True)).T
    array([[ 1,  5],
           [ 2,  3],
           [ 5,  1],
           [25,  1]])

Original answer:

you can use scipy.stats.itemfreq

>>> from scipy.stats import itemfreq
>>> x = [1,1,1,2,2,2,5,25,1,1]
>>> itemfreq(x)
/usr/local/bin/python:1: DeprecationWarning: `itemfreq` is deprecated! `itemfreq` is deprecated and will be removed in a future version. Use instead `np.unique(..., return_counts=True)`
array([[  1.,   5.],
       [  2.,   3.],
       [  5.,   1.],
       [ 25.,   1.]])

Chrome desktop notification example

Notify.js is a wrapper around the new webkit notifications. It works pretty well.

Numpy ValueError: setting an array element with a sequence. This message may appear without the existing of a sequence?

It's a pity that both of the answers analyze the problem but didn't give a direct answer. Let's see the code.

Z = np.array([1.0, 1.0, 1.0, 1.0])  

def func(TempLake, Z):
    A = TempLake
    B = Z
    return A * B
Nlayers = Z.size
N = 3
TempLake = np.zeros((N+1, Nlayers))
kOUT = np.zeros(N + 1)

for i in xrange(N):
    # store the i-th result of
    # function "func" in i-th item in kOUT
    kOUT[i] = func(TempLake[i], Z)

The error shows that you set the ith item of kOUT(dtype:int) into an array. Here every item in kOUT is an int, can't directly assign to another datatype. Hence you should declare the data type of kOUT when you create it. For example, like:

Change the statement below:

kOUT = np.zeros(N + 1)


kOUT = np.zeros(N + 1, dtype=object)


kOUT = np.zeros((N + 1, N + 1))

All code:

import numpy as np
Z = np.array([1.0, 1.0, 1.0, 1.0])

def func(TempLake, Z):
    A = TempLake
    B = Z
    return A * B

Nlayers = Z.size
N = 3
TempLake = np.zeros((N + 1, Nlayers))

kOUT = np.zeros(N + 1, dtype=object)
for i in xrange(N):
    kOUT[i] = func(TempLake[i], Z)

Hope it can help you.

byte[] to hex string

Hex, Linq-fu:

string.Concat(ba.Select(b => b.ToString("X2")).ToArray())

UPDATE with the times

As noted by @RubenBartelink, the code that don't have a conversion of IEnumerable<string> to an array: ba.Select(b => b.ToString("X2")) does not work prior to 4.0, the same code is now working on 4.0.

This code...

byte[] ba = { 1, 2, 4, 8, 16, 32 };

string s = string.Concat(ba.Select(b => b.ToString("X2")));
string t = string.Concat(ba.Select(b => b.ToString("X2")).ToArray());

Console.WriteLine (s);
Console.WriteLine (t);

...prior to .NET 4.0, the output is:


On .NET 4.0 onwards, string.Concat has an overload that accepts IEnumerable. Hence on 4.0, the above code will have same output for both variables s and t


Prior to 4.0, ba.Select(b => b.ToString("X2")) goes to overload (object arg0), the way for the IEnumerable<string> to go to a proper overload, i.e. (params string[] values), is we need to convert the IEnumerable<string> to string array. Prior to 4.0, string.Concat has 10 overload functions, on 4.0 it is now 12

Get most recent file in a directory on Linux

A note about reliability:

Since the newline character is as valid as any in a file name, any solution that relies on lines like the head/tail based ones are flawed.

With GNU ls, another option is to use the --quoting-style=shell-always option and a bash array:

eval "files=($(ls -t --quoting-style=shell-always))"
((${#files[@]} > 0)) && printf '%s\n' "${files[0]}"

(add the -A option to ls if you also want to consider hidden files).

If you want to limit to regular files (disregard directories, fifos, devices, symlinks, sockets...), you'd need to resort to GNU find.

With bash 4.4 or newer (for readarray -d) and GNU coreutils 8.25 or newer (for cut -z):

readarray -t -d '' files < <(
  LC_ALL=C find . -maxdepth 1 -type f ! -name '.*' -printf '%T@/%f\0' |
  sort -rzn | cut -zd/ -f2)

((${#files[@]} > 0)) && printf '%s\n' "${files[0]}"

Or recursively:

readarray -t -d '' files < <(
  LC_ALL=C find . -name . -o -name '.*' -prune -o -type f -printf '%T@%p\0' |
  sort -rzn | cut -zd/ -f2-)

Best here would be to use zsh and its glob qualifiers instead of bash to avoid all this hassle:

Newest regular file in the current directory:

printf '%s\n' *(.om[1])

Including hidden ones:

printf '%s\n' *([1])

Second newest:

printf '%s\n' *(.om[2])

Check file age after symlink resolution:

printf '%s\n' *([1])


printf '%s\n' **/*(.om[1])

Also, with the completion system (compinit and co) enabled, Ctrl+Xm becomes a completer that expands to the newest file.


vi Ctrl+Xm

Would make you edit the newest file (you also get a chance to see which it before you press Return).

vi Alt+2Ctrl+Xm

For the second-newest file.

vi *.cCtrl+Xm

for the newest c file.

vi *(.)Ctrl+Xm

for the newest regular file (not directory, nor fifo/device...), and so on.

Programmatically get height of navigation bar

I have used:

let originY: CGFloat = self.navigationController!.navigationBar.frame.maxY

Working great if you want to get the navigation bar height AND its Y origin.

Python: How to remove empty lists from a list?

You can use filter() instead of a list comprehension:

list2 = filter(None, list1)

If None is used as first argument to filter(), it filters out every value in the given list, which is False in a boolean context. This includes empty lists.

It might be slightly faster than the list comprehension, because it only executes a single function in Python, the rest is done in C.

Displaying the Error Messages in Laravel after being Redirected from controller

@if ($errors->has('category'))
    <span class="error">{{ $errors->first('category') }}</span>

How to Return partial view of another controller by controller?

The control searches for a view in the following order:

  • First in shared folder
  • Then in the folder matching the current controller (in your case it's Views/DEF)

As you do not have xxx.cshtml in those locations, it returns a "view not found" error.

Solution: You can use the complete path of your view:


 PartialView("~/views/ABC/XXX.cshtml", zyxmodel);

Editing an item in a list<T>

After adding an item to a list, you can replace it by writing

list[someIndex] = new MyClass();

You can modify an existing item in the list by writing

list[someIndex].SomeProperty = someValue;

EDIT: You can write

var index = list.FindIndex(c => c.Number == someTextBox.Text);
list[index] = new SomeClass(...);

Responsive timeline UI with Bootstrap3

.timeline {_x000D_
  list-style: none;_x000D_
  padding: 20px 0 20px;_x000D_
  position: relative;_x000D_
.timeline:before {_x000D_
  top: 0;_x000D_
  bottom: 0;_x000D_
  position: absolute;_x000D_
  content: " ";_x000D_
  width: 3px;_x000D_
  background-color: #eeeeee;_x000D_
  left: 50%;_x000D_
  margin-left: -1.5px;_x000D_
.timeline > li {_x000D_
  margin-bottom: 20px;_x000D_
  position: relative;_x000D_
.timeline > li:before,_x000D_
.timeline > li:after {_x000D_
  content: " ";_x000D_
  display: table;_x000D_
.timeline > li:after {_x000D_
  clear: both;_x000D_
.timeline > li:before,_x000D_
.timeline > li:after {_x000D_
  content: " ";_x000D_
  display: table;_x000D_
.timeline > li:after {_x000D_
  clear: both;_x000D_
.timeline > li > .timeline-panel {_x000D_
  width: 46%;_x000D_
  float: left;_x000D_
  border: 1px solid #d4d4d4;_x000D_
  border-radius: 2px;_x000D_
  padding: 20px;_x000D_
  position: relative;_x000D_
  -webkit-box-shadow: 0 1px 6px rgba(0, 0, 0, 0.175);_x000D_
  box-shadow: 0 1px 6px rgba(0, 0, 0, 0.175);_x000D_
.timeline > li > .timeline-panel:before {_x000D_
  position: absolute;_x000D_
  top: 26px;_x000D_
  right: -15px;_x000D_
  display: inline-block;_x000D_
  border-top: 15px solid transparent;_x000D_
  border-left: 15px solid #ccc;_x000D_
  border-right: 0 solid #ccc;_x000D_
  border-bottom: 15px solid transparent;_x000D_
  content: " ";_x000D_
.timeline > li > .timeline-panel:after {_x000D_
  position: absolute;_x000D_
  top: 27px;_x000D_
  right: -14px;_x000D_
  display: inline-block;_x000D_
  border-top: 14px solid transparent;_x000D_
  border-left: 14px solid #fff;_x000D_
  border-right: 0 solid #fff;_x000D_
  border-bottom: 14px solid transparent;_x000D_
  content: " ";_x000D_
.timeline > li > .timeline-badge {_x000D_
  color: #fff;_x000D_
  width: 50px;_x000D_
  height: 50px;_x000D_
  line-height: 50px;_x000D_
  font-size: 1.4em;_x000D_
  text-align: center;_x000D_
  position: absolute;_x000D_
  top: 16px;_x000D_
  left: 50%;_x000D_
  margin-left: -25px;_x000D_
  background-color: #999999;_x000D_
  z-index: 100;_x000D_
  border-top-right-radius: 50%;_x000D_
  border-top-left-radius: 50%;_x000D_
  border-bottom-right-radius: 50%;_x000D_
  border-bottom-left-radius: 50%;_x000D_
.timeline > li.timeline-inverted > .timeline-panel {_x000D_
  float: right;_x000D_
.timeline > li.timeline-inverted > .timeline-panel:before {_x000D_
  border-left-width: 0;_x000D_
  border-right-width: 15px;_x000D_
  left: -15px;_x000D_
  right: auto;_x000D_
.timeline > li.timeline-inverted > .timeline-panel:after {_x000D_
  border-left-width: 0;_x000D_
  border-right-width: 14px;_x000D_
  left: -14px;_x000D_
  right: auto;_x000D_
.timeline-badge.primary {_x000D_
  background-color: #2e6da4 !important;_x000D_
.timeline-badge.success {_x000D_
  background-color: #3f903f !important;_x000D_
.timeline-badge.warning {_x000D_
  background-color: #f0ad4e !important;_x000D_
.timeline-badge.danger {_x000D_
  background-color: #d9534f !important;_x000D_
_x000D_ {_x000D_
  background-color: #5bc0de !important;_x000D_
.timeline-title {_x000D_
  margin-top: 0;_x000D_
  color: inherit;_x000D_
.timeline-body > p,_x000D_
.timeline-body > ul {_x000D_
  margin-bottom: 0;_x000D_
.timeline-body > p + p {_x000D_
  margin-top: 5px;_x000D_
<div class="container">_x000D_
  <div class="page-header">_x000D_
    <h1 id="timeline">Timeline</h1>_x000D_
  <ul class="timeline">_x000D_
      <div class="timeline-badge"><i class="glyphicon glyphicon-check"></i></div>_x000D_
      <div class="timeline-panel">_x000D_
         <p><small class="text-muted"><i class="glyphicon glyphicon-time"></i> 11 hours ago via Twitter</small></p>_x000D_
        <div class="timeline-heading">_x000D_
          <h4 class="timeline-title">Mussum ipsum cacilds</h4>_x000D_
          <p><small class="text-muted"><i class="glyphicon glyphicon-time"></i> 11 hours ago via Twitter</small></p>_x000D_
        <div class="timeline-body">_x000D_
          <p>Mussum ipsum cacilds, vidis litro abertis. Consetis adipiscings elitis. Pra lá , depois divoltis porris, paradis. Paisis, filhis, espiritis santis. Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo._x000D_
            Manduma pindureta quium dia nois paga. Sapien in monti palavris qui num significa nadis i pareci latim. Interessantiss quisso pudia ce receita de bolis, mais bolis eu num gostis.</p>_x000D_
    <li class="timeline-inverted">_x000D_
      <div class="timeline-badge warning"><i class="glyphicon glyphicon-credit-card"></i></div>_x000D_
      <div class="timeline-panel">_x000D_
        <div class="timeline-heading">_x000D_
          <h4 class="timeline-title">Mussum ipsum cacilds</h4>_x000D_
        <div class="timeline-body">_x000D_
          <p>Mussum ipsum cacilds, vidis litro abertis. Consetis adipiscings elitis. Pra lá , depois divoltis porris, paradis. Paisis, filhis, espiritis santis. Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo._x000D_
            Manduma pindureta quium dia nois paga. Sapien in monti palavris qui num significa nadis i pareci latim. Interessantiss quisso pudia ce receita de bolis, mais bolis eu num gostis.</p>_x000D_
          <p>Suco de cevadiss, é um leite divinis, qui tem lupuliz, matis, aguis e fermentis. Interagi no mé, cursus quis, vehicula ac nisi. Aenean vel dui dui. Nullam leo erat, aliquet quis tempus a, posuere ut mi. Ut scelerisque neque et turpis posuere_x000D_
            pulvinar pellentesque nibh ullamcorper. Pharetra in mattis molestie, volutpat elementum justo. Aenean ut ante turpis. Pellentesque laoreet mé vel lectus scelerisque interdum cursus velit auctor. Lorem ipsum dolor sit amet, consectetur adipiscing_x000D_
            elit. Etiam ac mauris lectus, non scelerisque augue. Aenean justo massa.</p>_x000D_
      <div class="timeline-badge danger"><i class="glyphicon glyphicon-credit-card"></i></div>_x000D_
      <div class="timeline-panel">_x000D_
        <div class="timeline-heading">_x000D_
          <h4 class="timeline-title">Mussum ipsum cacilds</h4>_x000D_
        <div class="timeline-body">_x000D_
          <p>Mussum ipsum cacilds, vidis litro abertis. Consetis adipiscings elitis. Pra lá , depois divoltis porris, paradis. Paisis, filhis, espiritis santis. Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo._x000D_
            Manduma pindureta quium dia nois paga. Sapien in monti palavris qui num significa nadis i pareci latim. Interessantiss quisso pudia ce receita de bolis, mais bolis eu num gostis.</p>_x000D_
    <li class="timeline-inverted">_x000D_
      <div class="timeline-panel">_x000D_
        <div class="timeline-heading">_x000D_
          <h4 class="timeline-title">Mussum ipsum cacilds</h4>_x000D_
        <div class="timeline-body">_x000D_
          <p>Mussum ipsum cacilds, vidis litro abertis. Consetis adipiscings elitis. Pra lá , depois divoltis porris, paradis. Paisis, filhis, espiritis santis. Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo._x000D_
            Manduma pindureta quium dia nois paga. Sapien in monti palavris qui num significa nadis i pareci latim. Interessantiss quisso pudia ce receita de bolis, mais bolis eu num gostis.</p>_x000D_
      <div class="timeline-badge info"><i class="glyphicon glyphicon-floppy-disk"></i></div>_x000D_
      <div class="timeline-panel">_x000D_
        <div class="timeline-heading">_x000D_
          <h4 class="timeline-title">Mussum ipsum cacilds</h4>_x000D_
        <div class="timeline-body">_x000D_
          <p>Mussum ipsum cacilds, vidis litro abertis. Consetis adipiscings elitis. Pra lá , depois divoltis porris, paradis. Paisis, filhis, espiritis santis. Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo._x000D_
            Manduma pindureta quium dia nois paga. Sapien in monti palavris qui num significa nadis i pareci latim. Interessantiss quisso pudia ce receita de bolis, mais bolis eu num gostis.</p>_x000D_
          <div class="btn-group">_x000D_
            <button type="button" class="btn btn-primary btn-sm dropdown-toggle" data-toggle="dropdown">_x000D_
              <i class="glyphicon glyphicon-cog"></i> <span class="caret"></span>_x000D_
            <ul class="dropdown-menu" role="menu">_x000D_
              <li><a href="#">Action</a></li>_x000D_
              <li><a href="#">Another action</a></li>_x000D_
              <li><a href="#">Something else here</a></li>_x000D_
              <li class="divider"></li>_x000D_
              <li><a href="#">Separated link</a></li>_x000D_
      <div class="timeline-panel">_x000D_
        <div class="timeline-heading">_x000D_
          <h4 class="timeline-title">Mussum ipsum cacilds</h4>_x000D_
        <div class="timeline-body">_x000D_
          <p>Mussum ipsum cacilds, vidis litro abertis. Consetis adipiscings elitis. Pra lá , depois divoltis porris, paradis. Paisis, filhis, espiritis santis. Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo._x000D_
            Manduma pindureta quium dia nois paga. Sapien in monti palavris qui num significa nadis i pareci latim. Interessantiss quisso pudia ce receita de bolis, mais bolis eu num gostis.</p>_x000D_
    <li class="timeline-inverted">_x000D_
      <div class="timeline-badge success"><i class="glyphicon glyphicon-thumbs-up"></i></div>_x000D_
      <div class="timeline-panel">_x000D_
        <div class="timeline-heading">_x000D_
          <h4 class="timeline-title">Mussum ipsum cacilds</h4>_x000D_
        <div class="timeline-body">_x000D_
          <p>Mussum ipsum cacilds, vidis litro abertis. Consetis adipiscings elitis. Pra lá , depois divoltis porris, paradis. Paisis, filhis, espiritis santis. Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo._x000D_
            Manduma pindureta quium dia nois paga. Sapien in monti palavris qui num significa nadis i pareci latim. Interessantiss quisso pudia ce receita de bolis, mais bolis eu num gostis.</p>_x000D_

How to set locale in DatePipe in Angular 2?

I was struggling with the same issue and didn't work for me using this

{{dateObj | date:'ydM'}}

So, I've tried a workaround, not the best solution but it worked:

{{dateObj | date:'d'}}/{{dateObj | date:'M'}}/{{dateObj | date:'y'}}

I can always create a custom pipe.

Best Regular Expression for Email Validation in C#

This C# function uses a regular expression to evaluate whether the passed email address is syntactically valid or not.

public static bool isValidEmail(string inputEmail)
   string strRegex = @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
         @"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" + 
   Regex re = new Regex(strRegex);
   if (re.IsMatch(inputEmail))
    return (true);
    return (false);

What is "X-Content-Type-Options=nosniff"?

# prevent mime based attacks
Header set X-Content-Type-Options "nosniff"

This header prevents "mime" based attacks. This header prevents Internet Explorer from MIME-sniffing a response away from the declared content-type as the header instructs the browser not to override the response content type. With the nosniff option, if the server says the content is text/html, the browser will render it as text/html.

Defining arrays in Google Scripts

I think that maybe it is because you are declaring a variable that you already declared:

var Name = new Array(6);
var Name[0] = Name_cell.getValue();  //  <-- Here's the issue: 'var'

I think this should be like this:

var Name = new Array(6);
Name[0] = Name_cell.getValue();

Tell me if it works! ;)

Usage of __slots__?

Each python object has a __dict__ atttribute which is a dictionary containing all other attributes. e.g. when you type self.attr python is actually doing self.__dict__['attr']. As you can imagine using a dictionary to store attribute takes some extra space & time for accessing it.

However, when you use __slots__, any object created for that class won't have a __dict__ attribute. Instead, all attribute access is done directly via pointers.

So if want a C style structure rather than a full fledged class you can use __slots__ for compacting size of the objects & reducing attribute access time. A good example is a Point class containing attributes x & y. If you are going to have a lot of points, you can try using __slots__ in order to conserve some memory.

ORA-01861: literal does not match format string

If you are using JPA to hibernate make sure the Entity has the correct data type for a field defined against a date column like use java.util.Date instead of String.

How do I pick 2 random items from a Python set?

Use the random module:

import random
random.sample(set([1, 2, 3, 4, 5, 6]), 2)

This samples the two values without replacement (so the two values are different).

Is it valid to replace http:// with // in a <script src="http://...">?

1. Summary

Answer for 2019: you can still use protocol-relative URLs, but this technique an anti-pattern.


  1. You may have problems in developing.
  2. Some third-party tools may not support them.

Migrating from protocol-relative URLs to https:// it would be nice.

2. Relevance

This answer is relevant for January 2019. In the future, the data of this answer may be obsolete.

3. Anti-pattern

3.1. Argumentation

Paul Irish — front-end engineer and a developer advocate for the Google Chromewrite in 2014, December:

Now that SSL is encouraged for everyone and doesn’t have performance concerns, this technique is now an anti-pattern. If the asset you need is available on SSL, then always use the https:// asset.

Allowing the snippet to request over HTTP opens the door for attacks like the recent GitHub Man-on-the-side attack. It’s always safe to request HTTPS assets even if your site is on HTTP, however the reverse is not true.

3.2. Another links

3.3. Examples

4. Developing process

For example, I try to use clean-console.

  • Example file KiraCleanConsole__cdn_links_demo.html:
<!DOCTYPE html>
<html lang="en">
    <meta charset="UTF-8">
    <title>clean-console without protocol demonstration</title>
    <!-- Really dead link -->
    <script src=""></script>
    <!-- Package exists; link without “https:” -->
    <script src="//[email protected]/dist/jquery.min.js"></script>
    <!-- Package exists: link with “https:” -->
    <script src=""></script>
    Kira Goddess!
  • output:
D:\SashaDebugging>clean-console -i KiraCleanConsole__cdn_links_demo.html
checking KiraCleanConsole__cdn_links_demo.html
phantomjs: opening page KiraCleanConsole__cdn_links_demo.html

phantomjs: Unable to load resource (#3URL:file://[email protected]/dist/jquery.min.js)

phantomjs:   phantomjs://code/runner.js:30 in onResourceError
Error code: 203. Description: Error opening //[email protected]/dist/jquery.min.js: The network path was not found.

  phantomjs://code/runner.js:31 in onResourceError

phantomjs: Unable to load resource (#5URL:[email protected]/bowser.min.js)

phantomjs:   phantomjs://code/runner.js:30 in onResourceError
Error code: 203. Description: Error downloading[email protected]/bowser.min.js - server replied: Not Found

  phantomjs://code/runner.js:31 in onResourceError

phantomjs: Checking errors after sleeping for 1000ms
2 error(s) on KiraCleanConsole__cdn_links_demo.html

phantomjs process exited with code 2

Link //[email protected]/dist/jquery.min.js is valid, but I getting an error.

Pay attention to file://[email protected]/dist/jquery.min.js and read Thilo and bg17aw answers about file://.

I didn't know about this behavior and couldn't understand why I have problems like this for pageres.

5. Third-party tools

I use Clickable URLs Sublime Text package. Use it, I can simply open links from my text editor in browser.

CSS links examples

Both links in example are valid. But first link I can successfully open in browser use Clickable URLs, second link — no. This may not be very convenient.

6. Conclusion


  1. If you have problems as in Developing process item, you can set your development workflow.
  2. Else you have problems as in Third-party tools item, you can contribute tools.

But you don't need this additional problems. Read information by links in Anti-pattern item: protocol-relative URLs is obsolete.

Concatenate in jQuery Selector

Your concatenation syntax is correct.

Most likely the callback function isn't even being called. You can test that by putting an alert(), console.log() or debugger line in that function.

If it isn't being called, most likely there's an AJAX error. Look at chaining a .fail() handler after $.post() to find out what the error is, e.g.:

$.post('ajaxskeleton.php', {
    red: text       
}, function(){
    $('#part' + number).html(text);
}).fail(function(jqXHR, textStatus, errorThrown) {

Wait for a process to finish

From the bash manpage

   wait [n ...]
          Wait for each specified process and return its termination  status
          Each  n  may be a process ID or a job specification; if a
          job spec is given, all processes  in  that  job's  pipeline  are
          waited  for.  If n is not given, all currently active child processes
          are waited for, and the return  status  is  zero.   If  n
          specifies  a  non-existent  process or job, the return status is
          127.  Otherwise, the return status is the  exit  status  of  the
          last process or job waited for.

Bad Request - Invalid Hostname IIS7

Double check the exact URL you're providing. I saw this error when I missed off the route prefix defined in ASP.NET so it didn't know where to route the request.

How to use WebRequest to POST some data and read response?

Below is the code that read the data from the text file and sends it to the handler for processing and receive the response data from the handler and read it and store the data in the string builder class

 //Get the data from text file that needs to be sent.
                FileStream fileStream = new FileStream(@"G:\Papertest.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite);
                byte[] buffer = new byte[fileStream.Length];
                int count = fileStream.Read(buffer, 0, buffer.Length);

                //This is a handler would recieve the data and process it and sends back response.
                WebRequest myWebRequest = WebRequest.Create(@"http://localhost/Provider/ProcessorHandler.ashx");

                myWebRequest.ContentLength = buffer.Length;
                myWebRequest.ContentType = "application/octet-stream";
                myWebRequest.Method = "POST";
                // get the stream object that holds request stream.
                Stream stream = myWebRequest.GetRequestStream();
                       stream.Write(buffer, 0, buffer.Length);

                //Sends a web request and wait for response.
                    WebResponse webResponse = myWebRequest.GetResponse();
                    //get Stream Data from the response
                    Stream respData = webResponse.GetResponseStream();
                    //read the response from stream.
                    StreamReader streamReader = new StreamReader(respData);
                    string name;
                    StringBuilder str = new StringBuilder();
                    while ((name = streamReader.ReadLine()) != null)
                        str.Append(name); // Add to stringbuider when response contains multple lines data
                catch (Exception ex)
                    throw ex;

Replace one character with another in Bash

In bash, you can do pattern replacement in a string with the ${VARIABLE//PATTERN/REPLACEMENT} construct. Use just / and not // to replace only the first occurrence. The pattern is a wildcard pattern, like file globs.

string='foo bar qux'
one="${string/ /.}"     # sets one to ' qux'
all="${string// /.}"    # sets all to ''

Soft keyboard open and close listener in an activity in Android

 <LinearLayout xmlns:android=""

<---In the xml root use the id--->

final LinearLayout activityRootView = view.findViewById(; activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() { @Override public void onGlobalLayout() { Rect r = new Rect(); //r will be populated with the coordinates of your view that area still visible. activityRootView.getWindowVisibleDisplayFrame(r);

            int heightDiff = activityRootView.getRootView().getHeight() - r.height();
            if (heightDiff > 0.25 * activityRootView.getRootView().getHeight()) {
                // if more than 25% of the screen, its probably a keyboard...

            } else {
                //Keyboard not visible

How to split a string in shell and get the last field

There are many good answers here, but still I want to share this one using basename :

 basename $(echo "a:b:c:d:e" | tr ':' '/')

However it will fail if there are already some '/' in your string. If slash / is your delimiter then you just have to (and should) use basename.

It's not the best answer but it just shows how you can be creative using bash commands.

How to detect the swipe left or Right in Android?

Left to Right and Right to Left Swipe Detector

Firstly, declare two variable of float datatype.

private float x1, x2;

Secondly, wireup your xml view in java. Like I have ImageView

ImageView img = (ImageView) findViewById(;

Thirdly, setOnTouchListener on your ImageView.

                    new View.OnTouchListener() {
                    public boolean onTouch(View v, MotionEvent event) {
                        // TODO Auto-generated method stub
                        switch (event.getAction()) {
                        case MotionEvent.ACTION_DOWN:
                            x1 = event.getX();
                        case MotionEvent.ACTION_UP:
                            x2 = event.getX();
                            float deltaX = x2 - x1;
                            if (deltaX < 0) {
                                        "Right to Left swipe",
                            }else if(deltaX >0){
                                        "Left to Right swipe",

                        return false;

Initial bytes incorrect after Java AES/CBC decryption

Another solution using java.util.Base64 with Spring Boot

Encryptor Class

package com.jmendoza.springboot.crypto.cipher;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.util.Base64;

public class Encryptor {

    private byte[] key;
    private String algorithm;

    public String encrypt(String plainText) throws Exception {
        SecretKeySpec secretKey = new SecretKeySpec(key, algorithm);
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        return new String(Base64.getEncoder().encode(cipher.doFinal(plainText.getBytes(StandardCharsets.UTF_8))));

    public String decrypt(String cipherText) throws Exception {
        SecretKeySpec secretKey = new SecretKeySpec(key, algorithm);
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        return new String(cipher.doFinal(Base64.getDecoder().decode(cipherText)));

EncryptorController Class

package com.jmendoza.springboot.crypto.controller;

import com.jmendoza.springboot.crypto.cipher.Encryptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

public class EncryptorController {

    Encryptor encryptor;

    @GetMapping(value = "encrypt/{value}")
    public String encrypt(@PathVariable("value") final String value) throws Exception {
        return encryptor.encrypt(value);

    @GetMapping(value = "decrypt/{value}")
    public String decrypt(@PathVariable("value") final String value) throws Exception {
        return encryptor.decrypt(value);







Hibernate HQL Query : How to set a Collection as a named parameter of a Query?

In TorpedoQuery it look like this

Entity from = from(Entity.class);
where(from.getCode()).in("Joe", "Bob");
Query<Entity> select = select(from);

Add/delete row from a table

jQuery has a nice function for removing elements from the DOM.

The closest() function is cool because it will "get the first element that matches the selector by testing the element itself and traversing up through its ancestors."


Each delete button could run that very succinct code with a function call.

Clear the cache in JavaScript

I found a solution to this problem recently. In my case, I was trying to update an html element using javascript; I had been using XHR to update text based on data retrieved from a GET request. Although the XHR request happened frequently, the cached HTML data remained frustratingly the same.

Recently, I discovered a cache busting method in the fetch api. The fetch api replaces XHR, and it is super simple to use. Here's an example:

        async function updateHTMLElement(t) {
            let res = await fetch(url, {cache: "no-store"});
                let myTxt = await res.text();
                document.getElementById('myElement').innerHTML = myTxt;

Notice that {cache: "no-store"} argument? This causes the browser to bust the cache for that element, so that new data gets loaded properly. My goodness, this was a godsend for me. I hope this is helpful for you, too.

Tangentially, to bust the cache for an image that gets updated on the server side, but keeps the same src attribute, the simplest and oldest method is to simply use, and append that number as a url variable to the src attribute for that image. This works reliably for images, but not for HTML elements. But between these two techniques, you can update any info you need to now :-)

Which ChromeDriver version is compatible with which Chrome Browser version?

Compatibility matrix

Here is a chart of the compatibility between chromedriver and chrome. This information can be found at the Chromedriver downloads page.

chromedriver    chrome
2.46            71-73
2.45            70-72
2.44            69-71
2.43            69-71
2.42            68-70
2.41            67-69
2.40            66-68
2.39            66-68
2.38            65-67
2.37            64-66
2.36            63-65
2.35            62-64
2.34            61-63
2.33            60-62
2.28            57+
2.25            54+
2.24            53+
2.22            51+
2.19            44+
2.15            42+

After 2.46, the ChromeDriver major version matches Chrome

chromedriver    chrome
76.0.3809.68    76
75.0.3770.140   75
74.0.3729.6     74
73.0.3683.68    73

It seems compatibility is only guaranteed within that revision.

If you need to run chromedriver across multiple versions of chrome for some reason, well, plug the latest version number of chrome you're using into the Chromedriver version selection guide, then hope for the best. Actual compatibility will depend on the exact versions involved and what features you're using.

All versions are not cross-compatible.

For example, we had a bug today where chromedriver 2.33 was trying to run this on Chrome 65:

((ChromeDriver) driver).findElement("firstName")).sendKeys("hello")

Due to the navigation changes in Chrome 63, updated in Chromedriver 2.34, we got back

unknown error: call function result missing 'value'

Updating to Chromedriver 2.37 fixed the issue.

PostgreSQL Autoincrement

Whilst it looks like sequences are the equivalent to MySQL auto_increment, there are some subtle but important differences:

1. Failed Queries Increment The Sequence/Serial

The serial column gets incremented on failed queries. This leads to fragmentation from failed queries, not just row deletions. For example, run the following queries on your PostgreSQL database:

  uid serial NOT NULL PRIMARY KEY,
  col_b integer NOT NULL,
  CHECK (col_b>=0)

INSERT INTO table1 (col_b) VALUES(1);
INSERT INTO table1 (col_b) VALUES(-1);
INSERT INTO table1 (col_b) VALUES(2);

SELECT * FROM table1;

You should get the following output:

 uid | col_b 
   1 |     1
   3 |     2
(2 rows)

Notice how uid goes from 1 to 3 instead of 1 to 2.

This still occurs if you were to manually create your own sequence with:

    col_a smallint NOT NULL DEFAULT nextval('table1_seq'),
    col_b integer NOT NULL,
    CHECK (col_b>=0)
ALTER SEQUENCE table1_seq OWNED BY table1.col_a;

If you wish to test how MySQL is different, run the following on a MySQL database:

  col_b int unsigned NOT NULL

INSERT INTO table1 (col_b) VALUES(1);
INSERT INTO table1 (col_b) VALUES(-1);
INSERT INTO table1 (col_b) VALUES(2);

You should get the following with no fragementation:

| uid | col_b |
|   1 |     1 |
|   2 |     2 |
2 rows in set (0.00 sec)

2. Manually Setting the Serial Column Value Can Cause Future Queries to Fail.

This was pointed out by @trev in a previous answer.

To simulate this manually set the uid to 4 which will "clash" later.

INSERT INTO table1 (uid, col_b) VALUES(5, 5);

Table data:

 uid | col_b 
   1 |     1
   3 |     2
   5 |     5
(3 rows)

Run another insert:

INSERT INTO table1 (col_b) VALUES(6);

Table data:

 uid | col_b 
   1 |     1
   3 |     2
   5 |     5
   4 |     6

Now if you run another insert:

INSERT INTO table1 (col_b) VALUES(7);

It will fail with the following error message:

ERROR: duplicate key value violates unique constraint "table1_pkey" DETAIL: Key (uid)=(5) already exists.

In contrast, MySQL will handle this gracefully as shown below:

INSERT INTO table1 (uid, col_b) VALUES(4, 4);

Now insert another row without setting uid

INSERT INTO table1 (col_b) VALUES(3);

The query doesn't fail, uid just jumps to 5:

| uid | col_b |
|   1 |     1 |
|   2 |     2 |
|   4 |     4 |
|   5 |     3 |

Testing was performed on MySQL 5.6.33, for Linux (x86_64) and PostgreSQL 9.4.9


use desc with orderby at the end of the query to get the last values.

How can I output the value of an enum class in C++11

To write simpler,

enum class Color
    Red = 1,
    Green = 11,
    Blue = 111

int value = static_cast<int>(Color::Blue); // 111

How to determine SSL cert expiration date from a PEM encoded certificate?

Here's my bash command line to list multiple certificates in order of their expiration, most recently expiring first.

for pem in /etc/ssl/certs/*.pem; do 
   printf '%s: %s\n' \
      "$(date --date="$(openssl x509 -enddate -noout -in "$pem"|cut -d= -f 2)" --iso-8601)" \
done | sort

Sample output:

2015-12-16: /etc/ssl/certs/Staat_der_Nederlanden_Root_CA.pem
2016-03-22: /etc/ssl/certs/CA_Disig.pem
2016-08-14: /etc/ssl/certs/EBG_Elektronik_Sertifika_Hizmet_S.pem

How to bind to a PasswordBox in MVVM

While I agree it's important to avoid storing the password anywhere, I still need the ability to instantiate the view model without a view and execute my tests against it.

The solution that worked for me was to register the PasswordBox.Password function with the view model, and have the view model invoke it when executing the login code.

This does mean a line of code in the view's codebehind.

So, in my Login.xaml I have

<PasswordBox x:Name="PasswordBox"/>

and in Login.xaml.cs I have

LoginViewModel.PasswordHandler = () => PasswordBox.Password;

then in LoginViewModel.cs I have the PasswordHandler defined

public Func<string> PasswordHandler { get; set; }

and when login needs to happen the code invokes the handler to get the password from the view...

bool loginResult = Login(Username, PasswordHandler());

This way, when I want to test the viewmodel I can simply set PasswordHandler to an anonymous method that lets me deliver whatever password I want to use in the test.

jquery find closest previous sibling with class

I think all the answers are lacking something. I prefer using something like this


Saves you not adding :first inside the selector and is easier to read and understand. prevUntil() method has a better performance as well rather than using prevAll()

Loop through a comma-separated shell variable

Not messing with IFS
Not calling external command

for i in ${variable//,/ }
    # call your procedure/other scripts here below
    echo "$i"

Using bash string manipulation

Git fails when pushing commit to github

I tried to push to my own hosted bonobo-git server, and did not realise, that the http.postbuffer meant the project directory ...

so just for other confused ones:

why? In my case, I had large zip files with assets and some PSDs pushed as well - to big for the buffer I guess.

How to do this http.postbuffer: execute that command within your project src directory, next to the .git folder, not on the server.

be aware, large temp (chunk) files will be created of that buffer size.

Note: Just check your largest files, then set the buffer.

How to append to New Line in Node.js

Use the os.EOL constant instead.

var os = require("os");

function processInput ( text ) 
{'H://log.txt', 'a', 666, function( e, id ) {
   fs.write( id, text + os.EOL, null, 'utf8', function(){
    fs.close(id, function(){
     console.log('file is updated');

Is it possible to find out the users who have checked out my project on GitHub?

If by "checked out" you mean people who have cloned your project, then no it is not possible. You don't even need to be a GitHub user to clone a repository, so it would be infeasible to track this.

Converting a date string to a DateTime object using Joda Time library


    "04/02/2011 20:27:05" , 
    DateTimeFormatter.ofPattern( "dd/MM/uuuu HH:mm:ss" )


The modern approach uses the java.time classes that supplant the venerable Joda-Time project.

Parse as a LocalDateTime as your input lacks any indicator of time zone or offset-from-UTC.

String input = "04/02/2011 20:27:05" ;
DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd/MM/uuuu HH:mm:ss" ) ;
LocalDateTime ldt = LocalDateTime.parse( input , f ) ;

ldt.toString(): 2011-02-04T20:27:05

Tip: Where possible, use the standard ISO 8601 formats when exchanging date-time values as text rather than format seen here. Conveniently, the java.time classes use the standard formats when parsing/generating strings.

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Excluding files/directories from Gulp task

Gulp uses micromatch under the hood for matching globs, so if you want to exclude any of the .min.js files, you can achieve the same by using an extended globbing feature like this:


Basically what it says is: grab everything at any level inside of js that doesn't end with *.min.js

Why is nginx responding to any domain name?

You should have a default server for catch-all, you can return 404 or better to not respond at all (will save some bandwidth) by returning 444 which is nginx specific HTTP response that simply close the connection and return nothing

server {
    listen       80  default_server;
    server_name  _; # some invalid name that won't match anything
    return       444;

PostgreSQL visual interface similar to phpMyAdmin?

I would also highly recommend Adminer -

It is much faster than phpMyAdmin, does less funky iframe stuff, and supports both MySQL and PostgreSQL.

How to fix corrupt HDFS FIles

You can use

  hdfs fsck /

to determine which files are having problems. Look through the output for missing or corrupt blocks (ignore under-replicated blocks for now). This command is really verbose especially on a large HDFS filesystem so I normally get down to the meaningful output with

  hdfs fsck / | egrep -v '^\.+$' | grep -v eplica

which ignores lines with nothing but dots and lines talking about replication.

Once you find a file that is corrupt

  hdfs fsck /path/to/corrupt/file -locations -blocks -files

Use that output to determine where blocks might live. If the file is larger than your block size it might have multiple blocks.

You can use the reported block numbers to go around to the datanodes and the namenode logs searching for the machine or machines on which the blocks lived. Try looking for filesystem errors on those machines. Missing mount points, datanode not running, file system reformatted/reprovisioned. If you can find a problem in that way and bring the block back online that file will be healthy again.

Lather rinse and repeat until all files are healthy or you exhaust all alternatives looking for the blocks.

Once you determine what happened and you cannot recover any more blocks, just use the

  hdfs fs -rm /path/to/file/with/permanently/missing/blocks

command to get your HDFS filesystem back to healthy so you can start tracking new errors as they occur.

How to check if click event is already bound - JQuery

Here's my version:

Utils.eventBoundToFunction = function (element, eventType, fCallback) {
    if (!element || !'events') || !'events')[eventType] || !fCallback) {
        return false;

    for (runner in'events')[eventType]) {
        if ('events')[eventType][runner].handler == fCallback) {
            return true;


    return false;


Utils.eventBoundToFunction(okButton, 'click', handleOkButtonFunction)

How to get unique values in an array

These days, you can use ES6's Set data type to convert your array to a unique Set. Then, if you need to use array methods, you can turn it back into an Array:

var arr = ["a", "a", "b"];
var uniqueSet = new Set(arr); // {"a", "b"}
var uniqueArr = Array.from(uniqueSet); // ["a", "b"]
//Then continue to use array methods:
uniqueArr.join(", "); // "a, b"

How can I stop python.exe from closing immediately after I get an output?

Python files are executables, which means that you can run them directly from command prompt(assuming you have windows). You should be able to just enter in the directory, and then run the program. Also, (assuming you have python 3), you can write:

input("Press enter to close program")

and you can just press enter when you've read your results.

What is the difference between a hash join and a merge join (Oracle RDBMS )?

I just want to edit this for posterity that the tags for oracle weren't added when I answered this question. My response was more applicable to MS SQL.

Merge join is the best possible as it exploits the ordering, resulting in a single pass down the tables to do the join. IF you have two tables (or covering indexes) that have their ordering the same such as a primary key and an index of a table on that key then a merge join would result if you performed that action.

Hash join is the next best, as it's usually done when one table has a small number (relatively) of items, its effectively creating a temp table with hashes for each row which is then searched continuously to create the join.

Worst case is nested loop which is order (n * m) which means there is no ordering or size to exploit and the join is simply, for each row in table x, search table y for joins to do.

Extract a substring according to a pattern

For example using gsub or sub

    [1] "E001" "E002" "E003"

SQL Server: Cannot insert an explicit value into a timestamp column

How to insert current time into a timestamp with SQL Server:

In newer versions of SQL Server, timestamp is renamed to RowVersion. Rightly so, because timestamp name is misleading.

SQL Server's timestamp IS NOT set by the user and does not represent a date or a time. Timestamp is only good for making sure a row hasn't changed since it's been read.

If you want to store a date or a time, do not use timestamp, you must use one of the other datatypes, like for example datetime, smalldatetime, date, time or DATETIME2

For example:

create table wtf (
    id INT,
    leet timestamp

insert into wtf (id) values (15)

select * from wtf

15    0x00000000000007D3 

'timestamp' in mssql is some kind of internal datatype. Casting that number to datetime produces a nonsense number.

how to remove json object key and value.?

There are several ways to do this, lets see them one by one:

  1. delete method: The most common way

const myObject = {_x000D_
    "employeeid": "160915848",_x000D_
    "firstName": "tet",_x000D_
    "lastName": "test",_x000D_
    "email": "[email protected]",_x000D_
    "country": "Brasil",_x000D_
    "currentIndustry": "aaaaaaaaaaaaa",_x000D_
    "otherIndustry": "aaaaaaaaaaaaa",_x000D_
    "currentOrganization": "test",_x000D_
    "salary": "1234567"_x000D_
delete myObject['currentIndustry'];_x000D_
// OR delete myObject.currentIndustry;_x000D_

  1. By making key value undefined: Alternate & a faster way:

let myObject = {_x000D_
    "employeeid": "160915848",_x000D_
    "firstName": "tet",_x000D_
    "lastName": "test",_x000D_
    "email": "[email protected]",_x000D_
    "country": "Brasil",_x000D_
    "currentIndustry": "aaaaaaaaaaaaa",_x000D_
    "otherIndustry": "aaaaaaaaaaaaa",_x000D_
    "currentOrganization": "test",_x000D_
    "salary": "1234567"_x000D_
myObject.currentIndustry = undefined;_x000D_
myObject = JSON.parse(JSON.stringify(myObject));_x000D_

  1. With es6 spread Operator:

const myObject = {_x000D_
    "employeeid": "160915848",_x000D_
    "firstName": "tet",_x000D_
    "lastName": "test",_x000D_
    "email": "[email protected]",_x000D_
    "country": "Brasil",_x000D_
    "currentIndustry": "aaaaaaaaaaaaa",_x000D_
    "otherIndustry": "aaaaaaaaaaaaa",_x000D_
    "currentOrganization": "test",_x000D_
    "salary": "1234567"_x000D_
const {currentIndustry, ...filteredObject} = myObject;_x000D_

Or if you can use omit() of underscore js library:

const filteredObject = _.omit(currentIndustry, 'myObject');

When to use what??

If you don't wanna create a new filtered object, simply go for either option 1 or 2. Make sure you define your object with let while going with the second option as we are overriding the values. Or else you can use any of them.

hope this helps :)

How to pass payload via JSON file for curl?

curl sends POST requests with the default content type of application/x-www-form-urlencoded. If you want to send a JSON request, you will have to specify the correct content type header:

$ curl -vX POST http://server/api/v1/places.json -d @testplace.json \
--header "Content-Type: application/json"

But that will only work if the server accepts json input. The .json at the end of the url may only indicate that the output is json, it doesn't necessarily mean that it also will handle json input. The API documentation should give you a hint on whether it does or not.

The reason you get a 401 and not some other error is probably because the server can't extract the auth_token from your request.

How to format date with hours, minutes and seconds when using jQuery UI Datepicker?

Getting Started Install from npm:

npm install imask And import or require:

import IMask from 'imask';

or use CDN:

var dateMask = IMask(element, {
  mask: Date,  // enable date mask

  // other options are optional
  pattern: 'Y-`m-`d',  // Pattern mask with defined blocks, default is 'd{.}`m{.}`Y'
  // you can provide your own blocks definitions, default blocks for date mask are:
  blocks: {
    d: {
      mask: IMask.MaskedRange,
      from: 1,
      to: 31,
      maxLength: 2,
    m: {
      mask: IMask.MaskedRange,
      from: 1,
      to: 12,
      maxLength: 2,
    Y: {
      mask: IMask.MaskedRange,
      from: 1900,
      to: 9999,
  // define date -> str convertion
  format: function (date) {
    var day = date.getDate();
    var month = date.getMonth() + 1;
    var year = date.getFullYear();

    if (day < 10) day = "0" + day;
    if (month < 10) month = "0" + month;

    return [year, month, day].join('-');
  // define str -> date convertion
  parse: function (str) {
    var yearMonthDay = str.split('-');
    return new Date(yearMonthDay[0], yearMonthDay[1] - 1, yearMonthDay[2]);

  // optional interval options
  min: new Date(2000, 0, 1),  // defaults to `1900-01-01`
  max: new Date(2020, 0, 1),  // defaults to `9999-01-01`

  autofix: true,  // defaults to `false`

  // also Pattern options can be set
  lazy: false,

  // and other common options
  overwrite: true  // defaults to `false`

Check if any ancestor has a class using jQuery

There are many ways to filter for element ancestors.

if ($elem.closest('.parentClass').length /* > 0*/) {/*...*/}
if ($elem.parents('.parentClass').length /* > 0*/) {/*...*/}
if ($elem.parents().hasClass('parentClass')) {/*...*/}
if ($('.parentClass').has($elem).length /* > 0*/) {/*...*/}
if ($'.parentClass *')) {/*...*/} 

Beware, closest() method includes element itself while checking for selector.

Alternatively, if you have a unique selector matching the $elem, e.g #myElem, you can use:

if ($('.parentClass:has(#myElem)').length /* > 0*/) {/*...*/}
if(document.querySelector('.parentClass #myElem')) {/*...*/}

If you want to match an element depending any of its ancestor class for styling purpose only, just use a CSS rule:

.parentClass #myElem { /* CSS property set */ }

in a "using" block is a SqlConnection closed on return or exception?

  1. Yes
  2. Yes.

Either way, when the using block is exited (either by successful completion or by error) it is closed.

Although I think it would be better to organize like this because it's a lot easier to see what is going to happen, even for the new maintenance programmer who will support it later:

using (SqlConnection connection = new SqlConnection(connectionString)) 
    int employeeID = findEmployeeID();    
        SqlCommand command = new SqlCommand("UpdateEmployeeTable", connection);
        command.CommandType = CommandType.StoredProcedure;
        command.Parameters.Add(new SqlParameter("@EmployeeID", employeeID));
        command.CommandTimeout = 5;

    catch (Exception) 
        /*Handle error*/ 

How can I open a URL in Android's web browser from my application?

Simple, website view via intent,

Intent viewIntent = new Intent("android.intent.action.VIEW", Uri.parse(""));

use this simple code toview your website in android app.

Add internet permission in manifest file,

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

internal/modules/cjs/loader.js:582 throw err

I got the same error:

 nodemon -w server.js server.js

[nodemon] 2.0.2
[nodemon] reading config .\nodemon.json
[nodemon] to restart at any time, enter `rs`
[nodemon] or send SIGHUP to 19248 to restart
[nodemon] ignoring: .\node_modules/**/* .\.next/**/*
[nodemon] watching dir(s): server.js
[nodemon] watching extensions: js,json
[nodemon] starting `node server.js index.js`
[nodemon] forking
[nodemon] child pid: 18840
[nodemon] watching 30 files
    throw err;

Error: Cannot find module 'D:\Programming\01a.nextjs\project\index.js'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:794:15)
    at Function.Module._load (internal/modules/cjs/loader.js:687:27)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1025:10)
    at internal/main/run_main_module.js:17:11 {
  requireStack: []
[nodemon] app crashed - waiting for file changes before starting...

I followed all the advises from here, but none of them worked for me. What I found is that I moved the server.js in his own folder server/server.js, but in package.json I forgot to make the change from this:

 "dev": "nodemon -w server.js server.js",
 "build": "next build",
 "start": "NODE_ENV=production node server.js"

to this:

"dev": "nodemon -w server/server.js server/server.js",
"build": "next build",
"start": "NODE_ENV=production node server/server.js"

After I made this change and restart the server with npm run dev everything worked fine.

.mp4 file not playing in chrome

After running into the same issue - here're some of my thoughts:

  • due to Chrome removing support for h264, on some machines, mp4 videos encoded with it will either not work (throwing an Parser error when viewing under Firebug/Network tab - consistent with issue submitted here), or crash the browser, depending upon the encoding settings
  • it isn't consistent - it entirely depends upon the codecs installed on the computer - while I didn't encounter this issue on my machine, we did have one in the office where the issue occurred (and thus we used this one for testing)
  • it might to do with Quicktime / divX settings (the machine in question had an older version of Quicktime than my native one - we didn't want to loose our testing pc though, so we didn't update it).

As it affects only Chrome (other browsers work fine with VideoForEverybody solution) the solution I've used is:

for every mp4 file, create a Theora encoded mp4 file (example.mp4 -> example_c.mp4) apply following js:

if (
        $(this).attr('src', $(this).attr('src').replace(".mp4", "_c.mp4"));

Unfortunately it's a bad Chrome hack, but hey, at least it works.

Source: user: eithedog

This also can help: chrome could play html5 mp4 video but html5test said chrome did not support mp4 video codec

Also check your version of crome here: html5test

Jquery function return value

I'm not entirely sure of the general purpose of the function, but you could always do this:

function getMachine(color, qty) {
    var retval;
    $("#getMachine li").each(function() {
        var thisArray = $(this).text().split("~");
        if(thisArray[0] == color&& qty>= parseInt(thisArray[1]) && qty<= parseInt(thisArray[2])) {
            retval = thisArray[3];
            return false;
    return retval;

var retval = getMachine(color, qty);

Why does the order in which libraries are linked sometimes cause errors in GCC?

You may can use -Xlinker option.

g++ -o foobar  -Xlinker -start-group  -Xlinker libA.a -Xlinker libB.a -Xlinker libC.a  -Xlinker -end-group 

is ALMOST equal to

g++ -o foobar  -Xlinker -start-group  -Xlinker libC.a -Xlinker libB.a -Xlinker libA.a  -Xlinker -end-group 

Careful !

  1. The order within a group is important ! Here's an example: a debug library has a debug routine, but the non-debug library has a weak version of the same. You must put the debug library FIRST in the group or you will resolve to the non-debug version.
  2. You need to precede each library in the group list with -Xlinker

What's the right way to pass form element state to sibling/parent elements?

I'm surprised that there are no answers with a straightforward idiomatic React solution at the moment I'm writing. So here's the one (compare the size and complexity to others):

class P extends React.Component {
    state = { foo : "" };

        const { foo } = this.state;

        return (
                <C1 value={ foo } onChange={ x => this.setState({ foo : x })} />
                <C2 value={ foo } />

const C1 = ({ value, onChange }) => (
    <input type="text"
           value={ value }
           onChange={ e => onChange( ) } />

const C2 = ({ value }) => (
    <div>Reacting on value change: { value }</div>

I'm setting the state of a parent element from a child element. This seems to betray the design principle of React: single-direction data flow.

Any controlled input (idiomatic way of working with forms in React) updates the parent state in its onChange callback and still doesn't betray anything.

Look carefully at C1 component, for instance. Do you see any significant difference in the way how C1 and built-in input component handle the state changes? You should not, because there is none. Lifting up the state and passing down value/onChange pairs is idiomatic for raw React. Not usage of refs, as some answers suggest.

AngularJS - How can I do a redirect with a full page load?

After searching and giving hit and trial session I am able to solove it by first specifying url like

$window.location.href = '/#/home/stats';

then reload


How to fix 'Unchecked runtime.lastError: The message port closed before a response was received' chrome issue?

I disabled Chrome extension "Coupons at Checkout" and this problem was solved.

How to fire a change event on a HTMLSelectElement if the new value is the same as the old?

For this problem, I have finally put a new <i> tag to refresh the select instead. Don't try to trigger an event if the selected option is the same that the one already selected.

enter image description here

If user click on the "refresh" button, I trigger the onchange event of my select with :

const refreshEquipeEl = document.getElementById("refreshEquipe1");

function onClickRefreshEquipe(event){
    let event2 = new Event('change');
refreshEquipeEl.onclick = onClickRefreshEquipe;

This way, I don't need to try select the same option in my select.

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

I am just curious why the official docs are so ignored which elaborate the details meticulously already.

But if you'd like to understand the cases, please refer to duffymo's answer.

The Java Naming and Directory InterfaceTM (JNDI) is an application programming interface (API) that provides naming and directory functionality to applications written using the JavaTM programming language. It is defined to be independent of any specific directory service implementation. Thus a variety of directories--new, emerging, and already deployed--can be accessed in a common way.

And its architecture

enter image description here

And normally how you use it.

How to delete specific rows and columns from a matrix in a smarter way?

You can use

t1<- t1[-4:-6,-7:-9]  


t1 <- t1[-(4:6), -(7:9)]


t1 <- t1[-c(4, 5, 6), -c(7, 8, 9)]

You can pass vectors to select rows/columns to be deleted. First two methods are useful if you are trying to delete contiguous rows/columns. Third method is useful if You are trying to delete discrete rows/columns.

> t1 <- array(1:20, dim=c(10,10));

> t1[-c(1, 4, 6, 7, 9), -c(2, 3, 8, 9)]

     [,1] [,2] [,3] [,4] [,5] [,6]
[1,]    2   12    2   12    2   12
[2,]    3   13    3   13    3   13
[3,]    5   15    5   15    5   15
[4,]    8   18    8   18    8   18
[5,]   10   20   10   20   10   20

MySQL: Get column name or alias from query

You could also use MySQLdb.cursors.DictCursor. This turns your result set into a python list of python dictionaries, although it uses a special cursor, thus technically less portable than the accepted answer. Not sure about speed. Here's the edited original code that uses this.

#!/usr/bin/python -u

import MySQLdb
import MySQLdb.cursors

# connect to mysql

    db = MySQLdb.connect(host='myhost', user='myuser', passwd='mypass', db='mydb', cursorclass=MySQLdb.cursors.DictCursor)
except MySQLdb.Error, e:
    print 'Error %d: %s' % (e.args[0], e.args[1])

# query select from table

cursor = db.cursor()

sql = 'SELECT ext, SUM(size) AS totalsize, COUNT(*) AS filecount FROM fileindex GROUP BY ext ORDER BY totalsize DESC;'

all_rows = cursor.fetchall()

print len(all_rows) # How many rows are returned.
for row in all_rows: # While loops always make me shudder!
    print '%s %s %s\n' % (row['ext'], row['totalsize'], row['filecount'])


Standard dictionary functions apply, for example, len(row[0]) to count the number of columns for the first row, list(row[0]) for a list of column names (for the first row), etc. Hope this helps!

Remove leading comma from a string


str = str.replace(/^,/, '');

I'll be back.

How to replace all spaces in a string

Pure Javascript, without regular expression:

var result = replaceSpacesText.split(" ").join("");

What does CultureInfo.InvariantCulture mean?

According to Microsoft:

The CultureInfo.InvariantCulture property is neither a neutral nor a specific culture. It is the third type of culture that is culture-insensitive. It is associated with the English language but not with a country or region.


So InvariantCulture is similair to culture "en-US" but not exactly the same. If you write:

var d = DateTime.Now;
var s1 = d.ToString(CultureInfo.InvariantCulture);   // "05/21/2014 22:09:28"
var s2 = d.ToString(new CultureInfo("en-US"));       // "5/21/2014 10:09:28 PM"

then s1 and s2 will have a similar format but InvariantCulture adds leading zeroes and "en-US" uses AM or PM.

So InvariantCulture is better for internal usage when you e.g save a date to a text-file or parses data. And a specified CultureInfo is better when you present data (date, currency...) to the end-user.

Constructors in Go

There are some equivalents of constructors for when the zero values can't make sensible default values or for when some parameter is necessary for the struct initialization.

Supposing you have a struct like this :

type Thing struct {
    Name  string
    Num   int

then, if the zero values aren't fitting, you would typically construct an instance with a NewThing function returning a pointer :

func NewThing(someParameter string) *Thing {
    p := new(Thing)
    p.Name = someParameter
    p.Num = 33 // <- a very sensible default value
    return p

When your struct is simple enough, you can use this condensed construct :

func NewThing(someParameter string) *Thing {
    return &Thing{someParameter, 33}

If you don't want to return a pointer, then a practice is to call the function makeThing instead of NewThing :

func makeThing(name string) Thing {
    return Thing{name, 33}

Reference : Allocation with new in Effective Go.

Change DIV content using ajax, php and jQuery


function getSummary(id)

     type: "GET",
     url: 'Your URL',
     data: "id=" + id, // appears as $_GET['id'] @ your backend side
     success: function(data) {
           // data is ur summary



And add onclick event in your lists

<a onclick="getSummary('1')">View Text</a>
<div id="#summary">This text will be replaced when the onclick event (link is clicked) is triggered.</div>

How to find out what the date was 5 days ago?

define('SECONDS_PER_DAY', 86400);
$days_ago = date('Y-m-d', time() - 5 * SECONDS_PER_DAY);

Other than that, you can use strtotime for any date:

$days_ago = date('Y-m-d', strtotime('January 18, 2034') - 5 * SECONDS_PER_DAY);

Or, as you used, mktime:

$days_ago = date('Y-m-d', mktime(0, 0, 0, 12, 2, 2008) - 5 * SECONDS_PER_DAY);

Well, you get it. The key is to remove enough seconds from the timestamp.

How can I change the image of an ImageView?

If you created imageview using xml file then follow the steps.

Solution 1:

Step 1: Create an XML file




Step 2: create an Activity

ImageView img= (ImageView) findViewById(;

Solution 2:

If you created imageview from Java Class

ImageView img = new ImageView(this);

Changing selection in a select with the Chosen plugin

From the "Updating Chosen Dynamically" section in the docs: You need to trigger the 'chosen:updated' event on the field

$(document).ready(function() {


    $('button').click(function() {


NOTE: versions prior to 1.0 used the following:


Regex to extract substring, returning 2 results for some reason

I think your problem is that the match method is returning an array. The 0th item in the array is the original string, the 1st thru nth items correspond to the 1st through nth matched parenthesised items. Your "alert()" call is showing the entire array.

How to get All input of POST in Laravel

There seems to be a major mistake in almost all the current answers in that they show BOTH GET and POST data. Not ONLY POST data.

The issue with your code as the accepted answer mentioned is that you did not import the facade. This can imported by adding the following at the top:

use Request;

public function add_question(Request $request)
    return Request::post();

You can also use the global request method like so (mentioned by @Canaan Etai), with no import required:


However, a better approach to importing Request in a controller method is by dependency injection as mentioned in @shuvrow answer:

use Illuminate\Http\Request;

public function add_question(Request $request)
    return $request->post();

More information about DI can be found here:

In either case, you should use:

// Show only POST data
$request->post(); // DI
request()->post(); // global method
Request::post(); // facade

// Show only GET data
$request->query(); // DI
request()->query(); // global method
Request::query(); // facade

// Show all data (i.e. both GET and POST data)
$request->all(); // DI
request()->all(); // global method
Request::all(); // facade

filtering NSArray into a new NSArray in Objective-C

Another category method you could use:

- (NSArray *) filteredArrayUsingBlock:(BOOL (^)(id obj))block {
    NSIndexSet *const filteredIndexes = [self indexesOfObjectsPassingTest:^BOOL (id _Nonnull obj, NSUInteger idx, BOOL *_Nonnull stop) {
                                       return block(obj);

    return [self objectsAtIndexes:filteredIndexes];

How to select records without duplicate on just one field in SQL?

Duplicate rows can be removed for Complex Queries by,

First storing the result to a #TempTable or @TempTableVariable

Delete from #TempTable or @TempTableVariable where your condition

Then select the rest of the data.

If need to create a row number create an identity column.


from s in context.shift
where !context.employeeshift.Any(es=>(es.shiftid==s.shiftid)&&(es.empid==57))
select s;

Hope this helps

Why would anybody use C over C++?

I like minimalism & simplicity.

Plotting a 3d cube, a sphere and a vector in Matplotlib

My answer is an amalgamation of the above two with extension to drawing sphere of user-defined opacity and some annotation. It finds application in b-vector visualization on a sphere for magnetic resonance image (MRI). Hope you find it useful:

from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure()
ax = fig.gca(projection='3d')

# draw sphere
u, v = np.mgrid[0:2*np.pi:50j, 0:np.pi:50j]
x = np.cos(u)*np.sin(v)
y = np.sin(u)*np.sin(v)
z = np.cos(v)
# alpha controls opacity
ax.plot_surface(x, y, z, color="g", alpha=0.3)

# a random array of 3D coordinates in [-1,1]
bvecs= np.random.randn(20,3)

# tails of the arrows
tails= np.zeros(len(bvecs))

# heads of the arrows with adjusted arrow head length
ax.quiver(tails,tails,tails,bvecs[:,0], bvecs[:,1], bvecs[:,2],
          length=1.0, normalize=True, color='r', arrow_length_ratio=0.15)


ax.set_title('b-vectors on unit sphere')

Hide console window from Process.Start C#

I had a similar issue when attempting to start a process without showing the console window. I tested with several different combinations of property values until I found one that exhibited the behavior I wanted.

Here is a page detailing why the UseShellExecute property must be set to false.

Under Remarks section on page:

If the UseShellExecute property is true or the UserName and Password properties are not null, the CreateNoWindow property value is ignored and a new window is created.

ProcessStartInfo startInfo = new ProcessStartInfo();
startInfo.FileName = fullPath;
startInfo.Arguments = args;
startInfo.RedirectStandardOutput = true;
startInfo.RedirectStandardError = true;
startInfo.UseShellExecute = false;
startInfo.CreateNoWindow = true;

Process processTemp = new Process();
processTemp.StartInfo = startInfo;
processTemp.EnableRaisingEvents = true;
catch (Exception e)

Convert seconds to HH-MM-SS with JavaScript?

After looking at all the answers and not being happy with most of them, this is what I came up with. I know I am very late to the conversation, but here it is anyway.

function secsToTime(secs){
  var time = new Date(); 
  // create Date object and set to today's date and time
  time.setHours(parseInt(secs/3600) % 24);
  time.setMinutes(parseInt(secs/60) % 60);
  time = time.toTimeString().split(" ")[0];
  // time.toString() = "HH:mm:ss GMT-0800 (PST)"
  // time.toString().split(" ") = ["HH:mm:ss", "GMT-0800", "(PST)"]
  // time.toTimeString().split(" ")[0]; = "HH:mm:ss"
  return time;

I create a new Date object, change the time to my parameters, convert the Date Object to a time string, and removed the additional stuff by splitting the string and returning only the part that need.

I thought I would share this approach, since it removes the need for regex, logic and math acrobatics to get the results in "HH:mm:ss" format, and instead it relies on built in methods.

You may want to take a look at the documentation here:

JavaScript push to array

object["property"] = value;

or = value;

Object and Array in JavaScript are different in terms of usage. Its best if you understand them:

Object vs Array: JavaScript

What reference do I need to use Microsoft.Office.Interop.Excel in .NET?

Make sure your project is 32 bit.

I had this problem, as soon as I ticked "Prefer 32 bit and rebuilt" all the Office Interop assemblies where available in Reference->Assemblies->Search "Office".

How can I view an old version of a file with Git?

You can also specify a commit hash (often also called commit ID) with the git show command.

In a nutshell

git show <commitHash>:/path/to/file

Step by step

  1. Show the log of all the changes for a given file with git log /path/to/file
  2. In the list of changes shown, it shows the commit hash such as commit 06c98... (06c98... being the commit hash)
  3. Copy the commit hash
  4. Run the command git show <commitHash>:/path/to/file using the commit hashof step 3 & the path/to/file of step 1.

Note: adding the ./ when specifying a relative path seems important, i.e. git show b2f8be577166577c59b55e11cfff1404baf63a84:./flight-simulation/src/main/components/nav-horiz.html.

@Nullable annotation usage

Different tools may interpret the meaning of @Nullable differently. For example, the Checker Framework and FindBugs handle @Nullable differently.

How do I check if a cookie exists?

If you're using jQuery, you can use the jquery.cookie plugin.

Getting the value for a particular cookie is done as follows:

$.cookie('MyCookie'); // Returns the cookie value

Export to CSV via PHP

Just like @Dampes8N said:

$result = mysql_query($sql,$conecction);
$fp = fopen('file.csv', 'w');
while($row = mysql_fetch_assoc($result)){
    fputcsv($fp, $row);

Hope this helps.