Programs & Examples On #Windows nt

Windows NT is a family of modern, commercial, portable, shared-source, hybrid-kernel operating systems developed by Microsoft.

Android EditText delete(backspace) key event

Belated but it may help new visitors, use TextWatcher() instead will help alot and also it will work for both soft and hard keyboard as well.

 editText.addTextChangedListener(new TextWatcher() {
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
                if (charSequence.length() > 0) {
                    //Here it means back button is pressed and edit text is now empty
                } else {
                   //Here edit text has some text

            public void afterTextChanged(Editable editable) {

How to create a Jar file in Netbeans

I also tried to make an executable jar file that I could run with the following command:

java -jar <jarfile>

After some searching I found the following link:

Packaging and Deploying Desktop Java Applications

I set the project's main class:

  1. Right-click the project's node and choose Properties
  2. Select the Run panel and enter the main class in the Main Class field
  3. Click OK to close the Project Properties dialog box
  4. Clean and build project

Then in the fodler dist the newly created jar should be executable with the command I mentioned above.

Aligning text and image on UIButton with imageEdgeInsets and titleEdgeInsets

The swift 4.2 version of solution would be the following:

let spacing: CGFloat = 10 // the amount of spacing to appear between image and title
self.button?.imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: spacing)
self.button?.titleEdgeInsets = UIEdgeInsets(top: 0, left: spacing, bottom: 0, right: 0)

How can I split a shell command over multiple lines when using an IF statement?

For Windows/WSL/Cygwin etc users:

Make sure that your line endings are standard Unix line feeds, i.e. \n (LF) only.

Using Windows line endings \r\n (CRLF) line endings will break the command line break.

This is because having \ at the end of a line with Windows line ending translates to \ \r \n.
As Mark correctly explains above:

The line-continuation will fail if you have whitespace after the backslash and before the newline.

This includes not just space () or tabs (\t) but also the carriage return (\r).

pandas dataframe columns scaling with sklearn

I know it's a very old comment, but still:

Instead of using single bracket (dfTest['A']), use double brackets (dfTest[['A']]).

i.e: min_max_scaler.fit_transform(dfTest[['A']]).

I believe this will give the desired result.

Check if a temporary table exists and delete if it exists before creating a temporary table

I cannot reproduce the error.

Perhaps I'm not understanding the problem.

The following works fine for me in SQL Server 2005, with the extra "foo" column appearing in the second select result:

IF OBJECT_ID('tempdb..#Results') IS NOT NULL DROP TABLE #Results
CREATE TABLE #Results ( Company CHAR(3), StepId TINYINT, FieldId TINYINT )
select company, stepid, fieldid from #Results
select company, stepid, fieldid, foo from #Results
IF OBJECT_ID('tempdb..#Results') IS NOT NULL DROP TABLE #Results

Converting any object to a byte array in java

What you want to do is called "serialization". There are several ways of doing it, but if you don't need anything fancy I think using the standard Java object serialization would do just fine.

Perhaps you could use something like this?

package com.example;


public class Serializer {

    public static byte[] serialize(Object obj) throws IOException {
        try(ByteArrayOutputStream b = new ByteArrayOutputStream()){
            try(ObjectOutputStream o = new ObjectOutputStream(b)){
            return b.toByteArray();

    public static Object deserialize(byte[] bytes) throws IOException, ClassNotFoundException {
        try(ByteArrayInputStream b = new ByteArrayInputStream(bytes)){
            try(ObjectInputStream o = new ObjectInputStream(b)){
                return o.readObject();


There are several improvements to this that can be done. Not in the least the fact that you can only read/write one object per byte array, which might or might not be what you want.

Note that "Only objects that support the interface can be written to streams" (see

Since you might run into it, the continuous allocation and resizing of the might turn out to be quite the bottle neck. Depending on your threading model you might want to consider reusing some of the objects.

For serialization of objects that do not implement the Serializable interface you either need to write your own serializer, for example using the read*/write* methods of and the get*/put* methods of java.nio.ByteBuffer perhaps together with reflection, or pull in a third party dependency.

This site has a list and performance comparison of some serialization frameworks. Looking at the APIs it seems Kryo might fit what you need.

CSS3 animate border color

You can try this also...

button {
  background: none;
  border: 0;
  box-sizing: border-box;
  margin: 1em;
  padding: 1em 2em;
  box-shadow: inset 0 0 0 2px #f45e61;
  color: #f45e61;
  font-size: inherit;
  font-weight: 700;
  vertical-align: middle;
  position: relative;
button::before, button::after {
  box-sizing: inherit;
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;

.draw {
  -webkit-transition: color 0.25s;
  transition: color 0.25s;
.draw::before, .draw::after {
  border: 2px solid transparent;
  width: 0;
  height: 0;
.draw::before {
  top: 0;
  left: 0;
.draw::after {
  bottom: 0;
  right: 0;
.draw:hover {
  color: #60daaa;
.draw:hover::before, .draw:hover::after {
  width: 100%;
  height: 100%;
.draw:hover::before {
  border-top-color: #60daaa;
  border-right-color: #60daaa;
  -webkit-transition: width 0.25s ease-out, height 0.25s ease-out 0.25s;
  transition: width 0.25s ease-out, height 0.25s ease-out 0.25s;
.draw:hover::after {
  border-bottom-color: #60daaa;
  border-left-color: #60daaa;
  -webkit-transition: border-color 0s ease-out 0.5s, width 0.25s ease-out 0.5s, height 0.25s ease-out 0.75s;
  transition: border-color 0s ease-out 0.5s, width 0.25s ease-out 0.5s, height 0.25s ease-out 0.75s;
<section class="buttons">
  <button class="draw">Draw</button>

Permission denied (publickey) when SSH Access to Amazon EC2 instance

This has happened to me multiple times. I have used Amazon Linux AMI 2013.09.2 and Ubuntu Server 12.04.3 LTS which are both on the free tier.

Every time I have launched an instance I have permission denied show up. I haven't verified this but my theory is that the server is not completely set up before I try to ssh into it. After a few tries with permission denied, I wait a few minutes and then I am able to connect. If you are having this problem I suggest waiting five minutes and trying again.

Setting the default page for ASP.NET (Visual Studio) server configuration

This One Method For Published Solution To Show SpeciFic Page on startup.

Here Is the Route Example to Redirect to Specific Page...

public class RouteConfig
    public static void RegisterRoutes(RouteCollection routes)

            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
            namespaces: new[] { "YourSolutionName.Controllers" }

By Default Home Controllers Index method is executed when application is started, Here You Can Define yours.

Note : I am Using Visual Studio 2013 and "YourSolutionName" is to changed to your project Name..

Is it a good practice to use an empty URL for a HTML form's action attribute? (action="")

I think it's best to explicitly state where the form posts. If you want to be totally safe, enter the same URL the form is on in the action attribute if you want it to submit back to itself. Although mainstream browsers evaluate "" to the same page, you can't guarantee that non-mainstream browsers will.

And of course, the entire URL including GET data like Juddling points out.

How do I get the time of day in javascript/Node.js?

var date = new Date();
var year = date.getFullYear();
var month = date.getMonth() + 1;
month = (month < 10 ? "0" : "") + month;
var hour = date.getHours();
hour = (hour < 10 ? "0" : "") + hour;
var day  = date.getDate();
day = (hour > 12 ? "" : "") + day - 1;
day = (day < 10 ? "0" : "") + day;
x = ":"
console.log( month + x + day + x + year )

It will display the date in the month, day, then the year

Is it possible to install both 32bit and 64bit Java on Windows 7?

To install 32-bit Java on Windows 7 (64-bit OS + Machine). You can do:

1) Download JDK:
2) Download JRE:

3) System variable create: C:\program files (x86)\java\jre6\bin\

4) Anywhere you type java -version

it use 32-bit on (64-bit). I have to use this because lots of third party libraries do not work with 64-bit. Java wake up from the hell, give us peach :P. Go-language is killer.

How do I create a pause/wait function using Qt?

From Qt5 onwards we can also use

Static Public Members of QThread

void    msleep(unsigned long msecs)
void    sleep(unsigned long secs)
void    usleep(unsigned long usecs)

<ng-container> vs <template>

A use case for it when you want to use a table with *ngIf and *ngFor - As putting a div in td/th will make the table element misbehave -. I faced this problem and that was the answer.

How do I remove all null and empty string values from an object?

There is a very simple way to remove NULL values from JSON object. By default JSON object includes NULL values. Following can be used to remove NULL from JSON string

JsonConvert.SerializeObject(yourClassObject, new JsonSerializerSettings() {
                                       NullValueHandling = NullValueHandling.Ignore})) 

How to get response status code from jQuery.ajax?

Came across this old thread searching for a similar solution myself and found the accepted answer to be using .complete() method of jquery ajax. I quote the notice on jquery website here:

The jqXHR.success(), jqXHR.error(), and jqXHR.complete() callbacks are deprecated as of jQuery 1.8. To prepare your code for their eventual removal, use jqXHR.done(),, and jqXHR.always() instead.

To know the status code of a ajax response, one can use the following code:

$.ajax( url [, settings ] )
.always(function (jqXHR) {

Works similarily for .done() and .fail()

Call removeView() on the child's parent first

Here is my solution.

Lets say you have two TextViews and put them on a LinearLayout (named ll). You'll put this LinerLayout on another LinerLayout.

< lm Linear Layout> 
       < ll Linear Layout> 
             <name Text view>
             </name Text view>
             <surname Text view>
             </surname Text view>
       </ll Linear Layout> 
</lm Linear Layout> 

When you want to create this structure you need to give parent as inheritance.

If you want use it in an onCreate method this will enough.

Otherwise here is solition:

LinerLayout lm = new LinearLayout(this); // You can use getApplicationContext() also
LinerLayout ll = new LinearLayout(lm.getContext());
TextView name = new TextView(ll.getContext());
TextView surname = new TextView(ll.getContext());

What are the undocumented features and limitations of the Windows FINDSTR command?

/D tip for multiple directories: put your directory list before the search string. These all work:

findstr /D:dir1;dir2 "searchString" *.*
findstr /D:"dir1;dir2" "searchString" *.*
findstr /D:"\path\dir1\;\path\dir2\" "searchString" *.*

As expected, the path is relative to location if you don't start the directories with \. Surrounding the path with " is optional if there are no spaces in the directory names. The ending \ is optional. The output of location will include whatever path you give it. It will work with or without surrounding the directory list with ".

Missing Microsoft RDLC Report Designer in Visual Studio

I had the same problem, after install the MS VS Community 2015, I didn't find the RDLC files neither the Report Viewer component, I solve the problem by going in the Control Panel (Windows) -> Programs -> Try to uninstall the MS VS Community and choose MODIFY, in this moment you will be able to Check the Microsoft SQL Server Data Tools.

That is it!

How to concatenate properties from multiple JavaScript objects

function collect(a, b, c){
    var d = {};

    for(p in a){
        d[p] = a[p];
    for(p in b){
        d[p] = b[p];
    for(p in c){
        d[p] = c[p];

    return d;

Understanding the set() function

As +Volatility and yourself pointed out, sets are unordered. If you need the elements to be in order, just call sorted on the set:

>>> y = [1, 1, 6, 6, 6, 6, 6, 8, 8]
>>> sorted(set(y))
[1, 6, 8]

Android ListView in fragment example

Your Fragment can subclass ListFragment.
And onCreateView() from ListFragment will return a ListView you can then populate.

Error:Cannot fit requested classes in a single dex file.Try supplying a main-dex list. # methods: 72477 > 65536

I solved my same problem like this way, you need to follow 2 simple step. I'm AndroidX user so for me, first I implement this dependencies in build.gradle file in my project in dependencies section.

implementation 'androidx.multidex:multidex:2.0.1'

dependencies {
//for multidex
implementation 'androidx.multidex:multidex:2.0.1'


after add this dependencies in your build.gradle file then sync your project again

Now add in the "defaultConfig" section:

multiDexEnabled true

defaultConfig {
    applicationId "com.papel.helper"
    minSdkVersion 16
    targetSdkVersion 28
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

    multiDexEnabled true

Now Rebuild your project again and Run :)

Is it possible to decrypt SHA1

SHA1 is a cryptographic hash function, so the intention of the design was to avoid what you are trying to do.

However, breaking a SHA1 hash is technically possible. You can do so by just trying to guess what was hashed. This brute-force approach is of course not efficient, but that's pretty much the only way.

So to answer your question: yes, it is possible, but you need significant computing power. Some researchers estimate that it costs $70k - $120k.

As far as we can tell today, there is also no other way but to guess the hashed input. This is because operations such as mod eliminate information from your input. Suppose you calculate mod 5 and you get 0. What was the input? Was it 0, 5 or 500? You see, you can't really 'go back' in this case.

jQuery: select an element's class and id at the same time?

It will work when adding space between id and class identifier

$("#countery .save")...

postgreSQL - psql \i : how to execute script in a given path

Postgres started on Linux/Unix. I suspect that reversing the slash with fix it.

\i somedir/script2.sql 

If you need to fully qualify something

\i c:/somedir/script2.sql

If that doesn't fix it, my next guess would be you need to escape the backslash.

\i somedir\\script2.sql

Structs data type in php?

Only associative arrays are structs in PHP.

And you can't make them strict on their own.

But you can sort of fake structure strictness with classes and interfaces, but beware that unlike structures, class instances are not passed in arguments, their identifiers are!

You can define a struct through an interface (or at least close to it)

Structs enforce a certain structure on an object.

PHP (<= 7.3) does not have native structs, but you can get around it with interfaces and type hinting:

interface FooStruct 
    public function name() : string;
interface BarStruct 
    public function id() : int;
interface MyStruct 
   public function foo() : FooStruct;
   public function bar() : BarStruct;

Any class implementing MyStruct will be a MyStruct.

The way it's build up is not up to the struct, it just ensures that the data returned is correct.

What about setting data?

Setting struct data is problematic as we end up with getters and setters and it's something that is close to an anemic object or a DTO and is considered an anti-pattern by some people

Wrong example:

interface FooStruct 
    public function getName() : string;
    public function setName(string $value) : FooStruct;
interface BarStruct 
    public function getId() : int;
    public function setId(int $value) : BarStruct;
interface MyStruct 
   public function getFoo() : FooStruct;
   public function setFoo(FooStruct $value) : MyStruct;
   public function getBar() : BarStruct;
   public function setBar(BarStruct $value) : MyStruct;

Then we end up with class implementations that might be mutable, and a struct must not mutate, this is to make it a "data type", just like int, string. Yet there's no way to restrict that with interfaces in PHP, meaning people will be able to implement your struct interface in a class that is not a struct. Make sure to keep the instance immutable

Also a struct may then be instantiated without the correct data and trigger errors when trying to access the data.

An easy and reliable way to set data in a PHP struct class is through its constructor

interface FooStruct 
    public function name() : string;
interface BarStruct 
    public function id() : int;
interface MyStruct 
   public function foo() : FooStruct;
   public function bar() : BarStruct;

class Foo implements FooStruct 
   protected $name;
   public function __construct(string $name)
       $this->name = $name;
   public function name() : string
       return $this->name;

class Bar implements BarStruct 
   protected $id;
   public function __construct(string $id)
       $this->id = $id;
   public function id() : int
       return $this->id;

class My implements MyStruct 
   protected $foo, $bar;
   public function __construct(FooStruct $foo, BarStruct $bar)
       $this->foo = $foo;
       $this->bar = $bar;
   public function foo() : FooStruct
       return $this->foo;
   public function bar() : BarStruct
       return $this->bar;

Type hinting using interfaces: (if your IDE supports it)

If you don't mind not having the strict type checking, then another way would be using interfaces or classes with comments for the IDE.

 * Interface My
 * @property Foo $foo
 * @property Bar $bar
interface My 


 * Interface Foo
 * @property string|integer $id
 * @property string $name
interface Foo 


 * Interface Bar
 * @property integer $id
interface Bar


The reason to use interfaces instead of classes is for the same reason why interfaces exist in the first place, because then many classes with many implementations can have this same structure and each method/function that uses it will support every class with this interface.

This depends on your IDE, so you might need to use classes instead or just live without it.

Note: Remember that you have to validate/sanitize the data in the instance elsewhere in the code to match the comment.

React-Router External link

There is no need to use <Link /> component from react-router.

If you want to go to external link use an anchor tag.

<a target="_blank" href="">Policies</a>

BeautifulSoup Grab Visible Webpage Text

from bs4 import BeautifulSoup
from bs4.element import Comment
import urllib.request
import re
import ssl

def tag_visible(element):
    if in ['style', 'script', 'head', 'title', 'meta', '[document]']:
        return False
    if isinstance(element, Comment):
        return False
    if re.match(r"[\n]+",str(element)): return False
    return True
def text_from_html(url):
    body = urllib.request.urlopen(url,context=ssl._create_unverified_context()).read()
    soup = BeautifulSoup(body ,"lxml")
    texts = soup.findAll(text=True)
    visible_texts = filter(tag_visible, texts)  
    text = u",".join(t.strip() for t in visible_texts)
    text = text.lstrip().rstrip()
    text = text.split(',')
    clean_text = ''
    for sen in text:
        if sen:
            sen = sen.rstrip().lstrip()
            clean_text += sen+','
    return clean_text
url = ''

I'm getting favicon.ico error

Try this add "icon" with your stylesheet Maybe it solve your error "favicon.ico:1 not found "

OR First Try to understand about favicon.enter image description here SET your favicon icon file in your folder. You can generate your favicon using "".

Why my $.ajax showing "preflight is invalid redirect error"?

I had the same error, though the problem was that I had a typo in the url

url: ''

The API had a redirect to another domain for all URL's that is wrong (404 errors).

So fixing the typo to the correct URL fixed it for me.

How to access parent scope from within a custom directive *with own scope* in AngularJS?

 scope: false
 transclude: false

and you will have the same scope(with parent element)


There are a lot of ways how to access parent scope depending on this two options scope& transclude.

SSL "Peer Not Authenticated" error with HttpClient 4.1

This is thrown when

... the peer was not able to identify itself (for example; no certificate, the particular cipher suite being used does not support authentication, or no peer authentication was established during SSL handshaking) this exception is thrown.

Probably the cause of this exception (where is the stacktrace) will show you why this exception is thrown. Most likely the default keystore shipped with Java does not contain (and trust) the root certificate of the TTP that is being used.

The answer is to retrieve the root certificate (e.g. from your browsers SSL connection), import it into the cacerts file and trust it using keytool which is shipped by the Java JDK. Otherwise you will have to assign another trust store programmatically.

Fit Image into PictureBox

First off, in order to have any image "resize" to fit a picturebox, you can set the PictureBox.SizeMode = PictureBoxSizeMode.StretchImage

If you want to do clipping of the image beforehand (i.e. cut off sides or top and bottom), then you need to clearly define what behavior you want (start at top, fill the height of the pciturebox and crop the rest, or start at the bottom, fill the height of the picturebox to the top, etc), and it should be fairly simple to use the Height / Width properties of both the picturebox and the image to clip the image and get the effect you are looking for.

How to check if a view controller is presented modally or pushed on a navigation stack?

Swift 4

var isModal: Bool {
    return presentingViewController != nil ||
           navigationController?.presentingViewController?.presentedViewController === navigationController ||
           tabBarController?.presentingViewController is UITabBarController

Where are Docker images stored on the host machine?

When using Docker for Mac Application, it appears that the containers are stored within the VM located at:


UPDATE (Courtesy of mmorin):

As of Jan 15 2019 it seems there is only this file:


that contains the Docker Disk and all the images and containers within it.

Launch Image does not show up in my iOS App

For some reason, I had to change the asset catalog location to "relative to project" for this to work.

I had also deleted the app from my phone and reinstalled, but it was probably the "relative to project" that did it.

exec failed because the name not a valid identifier?

Try this instead in the end:

exec (@query)

If you do not have the brackets, SQL Server assumes the value of the variable to be a stored procedure name.


EXECUTE sp_executesql @query

And it should not be because of FULL JOIN.
But I hope you have already created the temp tables: #TrafficFinal, #TrafficFinal2, #TrafficFinal3 before this.

Please note that there are performance considerations between using EXEC and sp_executesql. Because sp_executesql uses forced statement caching like an sp.
More details here.

On another note, is there a reason why you are using dynamic sql for this case, when you can use the query as is, considering you are not doing any query manipulations and executing it the way it is?

How to show Snackbar when Activity starts?

I have had trouble myself displaying Snackbar until now. Here is the simplest way to display a Snackbar. To display it as your Main Activity Starts, just put these two lines inside your OnCreate()

    Snackbar snackbar = Snackbar.make(findViewById(, "Welcome To Main Activity", Snackbar.LENGTH_LONG);;

P.S. Just make sure you have imported the Android Design Support.(As mentioned in the question).

For Kotlin,

Snackbar.make(findViewById(, message, Snackbar.LENGTH_SHORT).show()

How do I convert datetime to ISO 8601 in PHP

You can try this way:

$datetime = new DateTime('2010-12-30 23:21:46');

echo $datetime->format(DATE_ATOM);

How to use Servlets and Ajax?

Indeed, the keyword is "ajax": Asynchronous JavaScript and XML. However, last years it's more than often Asynchronous JavaScript and JSON. Basically, you let JS execute an asynchronous HTTP request and update the HTML DOM tree based on the response data.

Since it's pretty a tedious work to make it to work across all browsers (especially Internet Explorer versus others), there are plenty of JavaScript libraries out which simplifies this in single functions and covers as many as possible browser-specific bugs/quirks under the hoods, such as jQuery, Prototype, Mootools. Since jQuery is most popular these days, I'll use it in the below examples.

Kickoff example returning String as plain text

Create a /some.jsp like below (note: the code snippets in this answer doesn't expect the JSP file being placed in a subfolder, if you do so, alter servlet URL accordingly from "someservlet" to "${pageContext.request.contextPath}/someservlet"; it's merely omitted from the code snippets for brevity):

<!DOCTYPE html>
<html lang="en">
        <title>SO question 4112686</title>
        <script src=""></script>
            $(document).on("click", "#somebutton", function() { // When HTML DOM "click" event is invoked on element with ID "somebutton", execute the following function...
                $.get("someservlet", function(responseText) {   // Execute Ajax GET request on URL of "someservlet" and execute the following function with Ajax response text...
                    $("#somediv").text(responseText);           // Locate HTML DOM element with ID "somediv" and set its text content with the response text.
        <button id="somebutton">press here</button>
        <div id="somediv"></div>

Create a servlet with a doGet() method which look like this:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String text = "some text";

    response.setContentType("text/plain");  // Set content type of the response so that jQuery knows what it can expect.
    response.setCharacterEncoding("UTF-8"); // You want world domination, huh?
    response.getWriter().write(text);       // Write response body.

Map this servlet on an URL pattern of /someservlet or /someservlet/* as below (obviously, the URL pattern is free to your choice, but you'd need to alter the someservlet URL in JS code examples over all place accordingly):

package com.example;

public class SomeServlet extends HttpServlet {
    // ...

Or, when you're not on a Servlet 3.0 compatible container yet (Tomcat 7, Glassfish 3, JBoss AS 6, etc or newer), then map it in web.xml the old fashioned way (see also our Servlets wiki page):


Now open the http://localhost:8080/context/test.jsp in the browser and press the button. You'll see that the content of the div get updated with the servlet response.

Returning List<String> as JSON

With JSON instead of plaintext as response format you can even get some steps further. It allows for more dynamics. First, you'd like to have a tool to convert between Java objects and JSON strings. There are plenty of them as well (see the bottom of this page for an overview). My personal favourite is Google Gson. Download and put its JAR file in /WEB-INF/lib folder of your webapplication.

Here's an example which displays List<String> as <ul><li>. The servlet:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    List<String> list = new ArrayList<>();
    String json = new Gson().toJson(list);


The JS code:

$(document).on("click", "#somebutton", function() {  // When HTML DOM "click" event is invoked on element with ID "somebutton", execute the following function...
    $.get("someservlet", function(responseJson) {    // Execute Ajax GET request on URL of "someservlet" and execute the following function with Ajax response JSON...
        var $ul = $("<ul>").appendTo($("#somediv")); // Create HTML <ul> element and append it to HTML DOM element with ID "somediv".
        $.each(responseJson, function(index, item) { // Iterate over the JSON array.
            $("<li>").text(item).appendTo($ul);      // Create HTML <li> element, set its text content with currently iterated item and append it to the <ul>.

Do note that jQuery automatically parses the response as JSON and gives you directly a JSON object (responseJson) as function argument when you set the response content type to application/json. If you forget to set it or rely on a default of text/plain or text/html, then the responseJson argument wouldn't give you a JSON object, but a plain vanilla string and you'd need to manually fiddle around with JSON.parse() afterwards, which is thus totally unnecessary if you set the content type right in first place.

Returning Map<String, String> as JSON

Here's another example which displays Map<String, String> as <option>:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    Map<String, String> options = new LinkedHashMap<>();
    options.put("value1", "label1");
    options.put("value2", "label2");
    options.put("value3", "label3");
    String json = new Gson().toJson(options);


And the JSP:

$(document).on("click", "#somebutton", function() {               // When HTML DOM "click" event is invoked on element with ID "somebutton", execute the following function...
    $.get("someservlet", function(responseJson) {                 // Execute Ajax GET request on URL of "someservlet" and execute the following function with Ajax response JSON...
        var $select = $("#someselect");                           // Locate HTML DOM element with ID "someselect".
        $select.find("option").remove();                          // Find all child elements with tag name "option" and remove them (just to prevent duplicate options when button is pressed again).
        $.each(responseJson, function(key, value) {               // Iterate over the JSON object.
            $("<option>").val(key).text(value).appendTo($select); // Create HTML <option> element, set its value with currently iterated key and its text content with currently iterated item and finally append it to the <select>.


<select id="someselect"></select>

Returning List<Entity> as JSON

Here's an example which displays List<Product> in a <table> where the Product class has the properties Long id, String name and BigDecimal price. The servlet:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    List<Product> products = someProductService.list();
    String json = new Gson().toJson(products);


The JS code:

$(document).on("click", "#somebutton", function() {        // When HTML DOM "click" event is invoked on element with ID "somebutton", execute the following function...
    $.get("someservlet", function(responseJson) {          // Execute Ajax GET request on URL of "someservlet" and execute the following function with Ajax response JSON...
        var $table = $("<table>").appendTo($("#somediv")); // Create HTML <table> element and append it to HTML DOM element with ID "somediv".
        $.each(responseJson, function(index, product) {    // Iterate over the JSON array.
            $("<tr>").appendTo($table)                     // Create HTML <tr> element, set its text content with currently iterated item and append it to the <table>.
                .append($("<td>").text(        // Create HTML <td> element, set its text content with id of currently iterated product and append it to the <tr>.
                .append($("<td>").text(      // Create HTML <td> element, set its text content with name of currently iterated product and append it to the <tr>.
                .append($("<td>").text(product.price));    // Create HTML <td> element, set its text content with price of currently iterated product and append it to the <tr>.

Returning List<Entity> as XML

Here's an example which does effectively the same as previous example, but then with XML instead of JSON. When using JSP as XML output generator you'll see that it's less tedious to code the table and all. JSTL is this way much more helpful as you can actually use it to iterate over the results and perform server side data formatting. The servlet:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    List<Product> products = someProductService.list();

    request.setAttribute("products", products);
    request.getRequestDispatcher("/WEB-INF/xml/products.jsp").forward(request, response);

The JSP code (note: if you put the <table> in a <jsp:include>, it may be reusable elsewhere in a non-ajax response):

<?xml version="1.0" encoding="UTF-8"?>
<%@page contentType="application/xml" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="" %>
<%@taglib prefix="fmt" uri="" %>
        <c:forEach items="${products}" var="product">
                <td><c:out value="${}" /></td>
                <td><fmt:formatNumber value="${product.price}" type="currency" currencyCode="USD" /></td>

The JS code:

$(document).on("click", "#somebutton", function() {             // When HTML DOM "click" event is invoked on element with ID "somebutton", execute the following function...
    $.get("someservlet", function(responseXml) {                // Execute Ajax GET request on URL of "someservlet" and execute the following function with Ajax response XML...
        $("#somediv").html($(responseXml).find("data").html()); // Parse XML, find <data> element and append its HTML to HTML DOM element with ID "somediv".

You'll by now probably realize why XML is so much more powerful than JSON for the particular purpose of updating a HTML document using Ajax. JSON is funny, but after all generally only useful for so-called "public web services". MVC frameworks like JSF use XML under the covers for their ajax magic.

Ajaxifying an existing form

You can use jQuery $.serialize() to easily ajaxify existing POST forms without fiddling around with collecting and passing the individual form input parameters. Assuming an existing form which works perfectly fine without JavaScript/jQuery (and thus degrades gracefully when enduser has JavaScript disabled):

<form id="someform" action="someservlet" method="post">
    <input type="text" name="foo" />
    <input type="text" name="bar" />
    <input type="text" name="baz" />
    <input type="submit" name="submit" value="Submit" />

You can progressively enhance it with ajax as below:

$(document).on("submit", "#someform", function(event) {
    var $form = $(this);

    $.post($form.attr("action"), $form.serialize(), function(response) {
        // ...

    event.preventDefault(); // Important! Prevents submitting the form.

You can in the servlet distinguish between normal requests and ajax requests as below:

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String foo = request.getParameter("foo");
    String bar = request.getParameter("bar");
    String baz = request.getParameter("baz");

    boolean ajax = "XMLHttpRequest".equals(request.getHeader("X-Requested-With"));

    // ...

    if (ajax) {
        // Handle ajax (JSON or XML) response.
    } else {
        // Handle regular (JSP) response.

The jQuery Form plugin does less or more the same as above jQuery example, but it has additional transparent support for multipart/form-data forms as required by file uploads.

Manually sending request parameters to servlet

If you don't have a form at all, but just wanted to interact with the servlet "in the background" whereby you'd like to POST some data, then you can use jQuery $.param() to easily convert a JSON object to an URL-encoded query string.

var params = {
    foo: "fooValue",
    bar: "barValue",
    baz: "bazValue"

$.post("someservlet", $.param(params), function(response) {
    // ...

The same doPost() method as shown here above can be reused. Do note that above syntax also works with $.get() in jQuery and doGet() in servlet.

Manually sending JSON object to servlet

If you however intend to send the JSON object as a whole instead of as individual request parameters for some reason, then you'd need to serialize it to a string using JSON.stringify() (not part of jQuery) and instruct jQuery to set request content type to application/json instead of (default) application/x-www-form-urlencoded. This can't be done via $.post() convenience function, but needs to be done via $.ajax() as below.

var data = {
    foo: "fooValue",
    bar: "barValue",
    baz: "bazValue"

    type: "POST",
    url: "someservlet",
    contentType: "application/json", // NOT dataType!
    data: JSON.stringify(data),
    success: function(response) {
        // ...

Do note that a lot of starters mix contentType with dataType. The contentType represents the type of the request body. The dataType represents the (expected) type of the response body, which is usually unnecessary as jQuery already autodetects it based on response's Content-Type header.

Then, in order to process the JSON object in the servlet which isn't being sent as individual request parameters but as a whole JSON string the above way, you only need to manually parse the request body using a JSON tool instead of using getParameter() the usual way. Namely, servlets don't support application/json formatted requests, but only application/x-www-form-urlencoded or multipart/form-data formatted requests. Gson also supports parsing a JSON string into a JSON object.

JsonObject data = new Gson().fromJson(request.getReader(), JsonObject.class);
String foo = data.get("foo").getAsString();
String bar = data.get("bar").getAsString();
String baz = data.get("baz").getAsString();
// ...

Do note that this all is more clumsy than just using $.param(). Normally, you want to use JSON.stringify() only if the target service is e.g. a JAX-RS (RESTful) service which is for some reason only capable of consuming JSON strings and not regular request parameters.

Sending a redirect from servlet

Important to realize and understand is that any sendRedirect() and forward() call by the servlet on an ajax request would only forward or redirect the ajax request itself and not the main document/window where the ajax request originated. JavaScript/jQuery would in such case only retrieve the redirected/forwarded response as responseText variable in the callback function. If it represents a whole HTML page and not an ajax-specific XML or JSON response, then all you could do is to replace the current document with it.;

Note that this doesn't change the URL as enduser sees in browser's address bar. So there are issues with bookmarkability. Therefore, it's much better to just return an "instruction" for JavaScript/jQuery to perform a redirect instead of returning the whole content of the redirected page. E.g. by returning a boolean, or an URL.

String redirectURL = "";

Map<String, String> data = new HashMap<>();
data.put("redirect", redirectURL);
String json = new Gson().toJson(data);

function(responseJson) {
    if (responseJson.redirect) {
        window.location = responseJson.redirect;

    // ...

See also:

Using print statements only to debug

A simple way to do this is to call a logging function:

DEBUG = True

def log(s):
    if DEBUG:
        print s

log("hello world")

Then you can change the value of DEBUG and run your code with or without logging.

The standard logging module has a more elaborate mechanism for this.

How to verify Facebook access token?

Exchange Access Token for Mobile Number and Country Code (Server Side OR Client Side)

You can get the mobile number with your access_token with this API Maybe, once you have the mobile number and the id, you can work with it to verify the user with your server & database.

xxxxxxxxxx above is the Access Token

Example Response :

   "id": "61940819992708",
   "phone": {
      "number": "+91XX82923912",
      "country_prefix": "91",
      "national_number": "XX82923912"

Exchange Auth Code for Access Token (Server Side)

If you have an Auth Code instead, you can first get the Access Token with this API -|yyyyyyyyyy|zzzzzzzzzz

xxxxxxxxxx, yyyyyyyyyy and zzzzzzzzzz above are the Auth Code, App ID and App Secret respectively.

Example Response

   "id": "619XX819992708",
   "access_token": "EMAWdcsi711meGS2qQpNk4XBTwUBIDtqYAKoZBbBZAEZCZAXyWVbqvKUyKgDZBniZBFwKVyoVGHXnquCcikBqc9ROF2qAxLRrqBYAvXknwND3dhHU0iLZCRwBNHNlyQZD",
   "token_refresh_interval_sec": XX92000

Note - This is preferred on the server-side since the API requires the APP Secret which is not meant to be shared for security reasons.

Good Luck.

How to detect browser using angularjs?

There is a library ng-device-detector which makes detecting entities like browser, os easy.

Here is tutorial that explains how to use this library. Detect OS, browser and device in AngularJS


You need to add re-tree.js and ng-device-detector.js scripts into your html

Inject "ng.deviceDetector" as dependency in your module.

Then inject "deviceDetector" service provided by the library into your controller or factory where ever you want the data.

"deviceDetector" contains all data regarding browser, os and device.

Do we need type="text/css" for <link> in HTML5

For LINK elements the content-type is determined in the HTTP-response so the type attribute is superfluous. This is OK for all browsers.

How to make a shape with left-top round rounded corner and left-bottom rounded corner?

It looks like a bug

Finally I have to write something like this:

 <stroke android:width="3dp"

 <padding android:left="1dp"

 <corners android:radius="1dp"
  android:bottomRightRadius="2dp" android:bottomLeftRadius="0dp" 
  android:topLeftRadius="2dp" android:topRightRadius="0dp"/> 

I have to specify android:bottomRightRadius="2dp" for left-bottom rounded corner (another bug here).

How to HTML encode/escape a string? Is there a built-in?

In Ruby on Rails 3 HTML will be escaped by default.

For non-escaped strings use:

<%= raw "<p>hello world!</p>" %>

Java int to String - Integer.toString(i) vs new Integer(i).toString()

Simple way is just concatenate "" with integer:

int i = 100;

String s = "" + i;

now s will have 100 as string value.

When maven says "resolution will not be reattempted until the update interval of MyRepo has elapsed", where is that interval specified?

If you are using Eclipse then go to Windows -> Preferences -> Maven and uncheck the "Do not automatically update dependencies from remote repositories" checkbox.

This works with Maven 3 as well.


If you are doing in code then first check for table in database by using query SELECT table_name FROM user_tables WHERE table_name = 'XYZ'

if record found then truncate table otherwise create Table

Work like Create or Replace.

List all files and directories in a directory + subdirectories

If you don't have access to a subfolder inside the directory tree, Directory.GetFiles stops and throws the exception resulting in a null value in the receiving string[].

Here, see this answer

It manages the exception inside the loop and keep on working untill the entire folder is traversed.

Reliable way to convert a file to a byte[]

All these answers with .ReadAllBytes(). Another, similar (I won't say duplicate, since they were trying to refactor their code) question was asked on SO here: Best way to read a large file into a byte array in C#?

A comment was made on one of the posts regarding .ReadAllBytes():

File.ReadAllBytes throws OutOfMemoryException with big files (tested with 630 MB file 
and it failed) – juanjo.arana Mar 13 '13 at 1:31

A better approach, to me, would be something like this, with BinaryReader:

public static byte[] FileToByteArray(string fileName)
    byte[] fileData = null;

    using (FileStream fs = File.OpenRead(fileName)) 
        var binaryReader = new BinaryReader(fs); 
        fileData = binaryReader.ReadBytes((int)fs.Length); 
    return fileData;

But that's just me...

Of course, this all assumes you have the memory to handle the byte[] once it is read in, and I didn't put in the File.Exists check to ensure the file is there before proceeding, as you'd do that before calling this code.

jQuery.each - Getting li elements inside an ul

First I think you need to fix your lists, as the first node of a <ul> must be a <li> (stackoverflow ref). Once that is setup you can do this:

// note this array has outer scope
var phrases = [];

        // this is inner scope, in reference to the .phrase element
        var phrase = '';
            // cache jquery var
            var current = $(this);
            // check if our current li has children (sub elements)
            // if it does, skip it
            // ps, you can work with this by seeing if the first child
            // is a UL with blank inside and odd your custom BLANK text
            if(current.children().size() > 0) {return true;}
            // add current text to our current phrase
            phrase += current.text();
        // now that our current phrase is completely build we add it to our outer array
    // note the comma in the alert shows separate phrases

Working jsfiddle.

One thing is if you get the .text() of an upper level li you will get all sub level text with it.

Keeping an array will allow for many multiple phrases to be extracted.


This should work better with an empty UL with no LI:

// outer scope
var phrases = [];

    // inner scope
    var phrase = '';
        // cache jquery object
        var current = $(this);
        // check for sub levels
        if(current.children().size() > 0) {
            // check is sublevel is just empty UL
            var emptyULtest = current.children().eq(0); 
            if('ul') && $.trim(emptyULtest.text())==""){
                phrase += ' -BLANK- '; //custom blank text
                return true;   
            } else {
             // else it is an actual sublevel with li's
             return true;   
        // if it gets to here it is actual li
        phrase += current.text();
// note the comma to separate multiple phrases

Laravel: Error [PDOException]: Could not Find Driver in PostgreSQL

Be sure to configure the 'default' key in app/config/database.php

For postgres, this would be 'default' => 'postgres',

If you are receiving a [PDOException] could not find driver error, check to see if you have the correct PHP extensions installed. You need and installed and enabled. Instructions on how to do this vary between operating systems.

For Windows, the pgsql extensions should come pre-downloaded with the official PHP distribution. Just edit your php.ini and uncomment the lines and

Also, in php.ini, make sure extension_dir is set to the proper directory. It should be a folder called extensions or ext or similar inside your PHP install directory.

Finally, copy libpq.dll from C:\wamp\bin\php\php5.*\ into C:\wamp\bin\apache*\bin and restart all services through the WampServer interface.

If you still get the exception, you may need to add the postgres \bin directory to your PATH:

  1. System Properties -> Advanced tab -> Environment Variables
  2. In 'System variables' group on lower half of window, scroll through and find the PATH entry.
  3. Select it and click Edit
  4. At the end of the existing entry, put the full path to your postgres bin directory. The bin folder should be located in the root of your postgres installation directory.
  5. Restart any open command prompts, or to be certain, restart your computer.

This should hopefully resolve any problems. For more information see:

htaccess redirect if URL contains a certain string

If url contains a certen string, redirect to index.php . You need to match against the %{REQUEST_URI} variable to check if the url contains a certen string.

To redirect to /index.php if the uri contains bar anywhere in the uri string , you can use this :

RewriteEngine on

RewriteCond %{REQUEST_URI} bar
RewriteRule ^ /index.php [L,R]

How to start new activity on button click

Start another activity from this activity and u can pass parameters via Bundle Object also.

Intent intent = new Intent(getBaseContext(), YourActivity.class);
intent.putExtra("USER_NAME", "[email protected]");

Retrive data in another activity (YourActivity)

String s = getIntent().getStringExtra("USER_NAME");

this.getClass().getClassLoader().getResource("...") and NullPointerException

I had the same issue working on a project with Maven. Here how I fixed it: I just put the sources (images, musics and other stuffs) in the resources directory:


I created the same structure for the packages in the resources directory too. For example:

If my class is on


In the resources directory I put one package with the same name


So I use


Find the last time table was updated

If you're talking about last time the table was updated in terms of its structured has changed (new column added, column changed etc.) - use this query:

SELECT name, [modify_date] FROM sys.tables

If you're talking about DML operations (insert, update, delete), then you either need to persist what that DMV gives you on a regular basis, or you need to create triggers on all tables to record that "last modified" date - or check out features like Change Data Capture in SQL Server 2008 and newer.

Getting "TypeError: failed to fetch" when the request hasn't actually failed

If your are invoking fetch on a localhost server, use non-SSL unless you have a valid certificate for localhost. fetch will fail on an invalid or self signed certificate especially on localhost.

Why javascript getTime() is not a function?

For all those who came here and did indeed use Date typed Variables, here is the solution I found. It does also apply to TypeScript.

I was facing this error because I tried to compare two dates using the following Method

var res = dat1.getTime() > dat2.getTime(); // or any other comparison operator

However Im sure I used a Date object, because Im using angularjs with typescript, and I got the data from a typed API call.

Im not sure why the error is raised, but I assume that because my Object was created by JSON deserialisation, possibly the getTime() method was simply not added to the prototype.


In this case, recreating a date-Object based on your dates will fix the issue.

var res = new Date(dat1).getTime() > new Date(dat2).getTime()


I was right about this. Types will be cast to the according type but they wont be instanciated. Hence there will be a string cast to a date, which will obviously result in a runtime exception.

The trick is, if you use interfaces with non primitive only data such as dates or functions, you will need to perform a mapping after your http request.

class Details {
    description: string;
    date: Date;
    score: number;
    approved: boolean;

    constructor(data: any) {
      Object.assign(this, data);

and to perform the mapping:

public getDetails(id: number): Promise<Details> {
    return this.http
               .map(response => new Details(response.json()))

for arrays use:

public getDetails(): Promise<Details[]> {
    return this.http
               .map(response => {
                   const array = JSON.parse(response.json()) as any[];
                   const details = => new Details(data));
                   return details;

For credits and further information about this topic follow the link.

GCC dump preprocessor defines

Yes, use -E -dM options instead of -c. Example (outputs them to stdout):

 gcc -dM -E - < /dev/null

For C++

 g++ -dM -E -x c++ - < /dev/null

From the gcc manual:

Instead of the normal output, generate a list of `#define' directives for all the macros defined during the execution of the preprocessor, including predefined macros. This gives you a way of finding out what is predefined in your version of the preprocessor. Assuming you have no file foo.h, the command

touch foo.h; cpp -dM foo.h

will show all the predefined macros.

If you use -dM without the -E option, -dM is interpreted as a synonym for -fdump-rtl-mach.

Check if value exists in column in VBA

Simplest is to use Match

If Not IsError(Application.Match(ValueToSearchFor, RangeToSearchIn, 0)) Then
    ' String is in range

getting the screen density programmatically in android?

public static String getDensity(Context context) {
    String r;
    DisplayMetrics metrics = new DisplayMetrics();

    if (!(context instanceof Activity)) {
        r = "hdpi";
    } else {
        Activity activity = (Activity) context;

        if (metrics.densityDpi <= DisplayMetrics.DENSITY_LOW) {
            r = "ldpi";
        } else if (metrics.densityDpi <= DisplayMetrics.DENSITY_MEDIUM) {
            r = "mdpi";
        } else {
            r = "hdpi";

    return r;

Checking whether a string starts with XXXX

I did a little experiment to see which of these methods

  • string.startswith('hello')
  • string.rfind('hello') == 0
  • string.rpartition('hello')[0] == ''
  • string.rindex('hello') == 0

are most efficient to return whether a certain string begins with another string.

Here is the result of one of the many test runs I've made, where each list is ordered to show the least time it took (in seconds) to parse 5 million of each of the above expressions during each iteration of the while loop I used:

['startswith: 1.37', 'rpartition: 1.38', 'rfind: 1.62', 'rindex: 1.62']
['startswith: 1.28', 'rpartition: 1.44', 'rindex: 1.67', 'rfind: 1.68']
['startswith: 1.29', 'rpartition: 1.42', 'rindex: 1.63', 'rfind: 1.64']
['startswith: 1.28', 'rpartition: 1.43', 'rindex: 1.61', 'rfind: 1.62']
['rpartition: 1.48', 'startswith: 1.48', 'rfind: 1.62', 'rindex: 1.67']
['startswith: 1.34', 'rpartition: 1.43', 'rfind: 1.64', 'rindex: 1.64']
['startswith: 1.36', 'rpartition: 1.44', 'rindex: 1.61', 'rfind: 1.63']
['startswith: 1.29', 'rpartition: 1.37', 'rindex: 1.64', 'rfind: 1.67']
['startswith: 1.34', 'rpartition: 1.44', 'rfind: 1.66', 'rindex: 1.68']
['startswith: 1.44', 'rpartition: 1.41', 'rindex: 1.61', 'rfind: 2.24']
['startswith: 1.34', 'rpartition: 1.45', 'rindex: 1.62', 'rfind: 1.67']
['startswith: 1.34', 'rpartition: 1.38', 'rindex: 1.67', 'rfind: 1.74']
['rpartition: 1.37', 'startswith: 1.38', 'rfind: 1.61', 'rindex: 1.64']
['startswith: 1.32', 'rpartition: 1.39', 'rfind: 1.64', 'rindex: 1.61']
['rpartition: 1.35', 'startswith: 1.36', 'rfind: 1.63', 'rindex: 1.67']
['startswith: 1.29', 'rpartition: 1.36', 'rfind: 1.65', 'rindex: 1.84']
['startswith: 1.41', 'rpartition: 1.44', 'rfind: 1.63', 'rindex: 1.71']
['startswith: 1.34', 'rpartition: 1.46', 'rindex: 1.66', 'rfind: 1.74']
['startswith: 1.32', 'rpartition: 1.46', 'rfind: 1.64', 'rindex: 1.74']
['startswith: 1.38', 'rpartition: 1.48', 'rfind: 1.68', 'rindex: 1.68']
['startswith: 1.35', 'rpartition: 1.42', 'rfind: 1.63', 'rindex: 1.68']
['startswith: 1.32', 'rpartition: 1.46', 'rfind: 1.65', 'rindex: 1.75']
['startswith: 1.37', 'rpartition: 1.46', 'rfind: 1.74', 'rindex: 1.75']
['startswith: 1.31', 'rpartition: 1.48', 'rfind: 1.67', 'rindex: 1.74']
['startswith: 1.44', 'rpartition: 1.46', 'rindex: 1.69', 'rfind: 1.74']
['startswith: 1.44', 'rpartition: 1.42', 'rfind: 1.65', 'rindex: 1.65']
['startswith: 1.36', 'rpartition: 1.44', 'rfind: 1.64', 'rindex: 1.74']
['startswith: 1.34', 'rpartition: 1.46', 'rfind: 1.61', 'rindex: 1.74']
['startswith: 1.35', 'rpartition: 1.56', 'rfind: 1.68', 'rindex: 1.69']
['startswith: 1.32', 'rpartition: 1.48', 'rindex: 1.64', 'rfind: 1.65']
['startswith: 1.28', 'rpartition: 1.43', 'rfind: 1.59', 'rindex: 1.66']

I believe that it is pretty obvious from the start that the startswith method would come out the most efficient, as returning whether a string begins with the specified string is its main purpose.

What surprises me is that the seemingly impractical string.rpartition('hello')[0] == '' method always finds a way to be listed first, before the string.startswith('hello') method, every now and then. The results show that using str.partition to determine if a string starts with another string is more efficient then using both rfind and rindex.

Another thing I've noticed is that string.rindex('hello') == 0 and string.rindex('hello') == 0 have a good battle going on, each rising from fourth to third place, and dropping from third to fourth place, which makes sense, as their main purposes are the same.

Here is the code:

from time import perf_counter

string = 'hello world'
places = dict()

while True:
    start = perf_counter()
    for _ in range(5000000):
    end = perf_counter()
    places['startswith'] = round(end - start, 2)

    start = perf_counter()
    for _ in range(5000000):
        string.rfind('hello') == 0
    end = perf_counter()
    places['rfind'] = round(end - start, 2)

    start = perf_counter()
    for _ in range(5000000):
        string.rpartition('hello')[0] == ''
    end = perf_counter()
    places['rpartition'] = round(end - start, 2)

    start = perf_counter()
    for _ in range(5000000):
        string.rindex('hello') == 0
    end = perf_counter()
    places['rindex'] = round(end - start, 2)
    print([f'{b}: {str(a).ljust(4, "4")}' for a, b in sorted(i[::-1] for i in places.items())])

Create zip file and ignore directory structure

Alternatively, you could create a temporary symbolic link to your file:

ln -s /data/to/zip/data.txt data.txt
zip /dir/to/file/newZip !$
rm !$

This works also for a directory.

How can I echo a newline in a batch file?

Here you go, create a .bat file with the following in it :

@echo off
REM Creating a Newline variable (the two blank lines are required!)
set NLM=^

set NL=^^^%NLM%%NLM%^%NLM%%NLM%
REM Example Usage:
echo There should be a newline%NL%inserted here.


You should see output like the following:

There should be a newline
inserted here.

Press any key to continue . . .

You only need the code between the REM statements, obviously.

Content Type text/xml; charset=utf-8 was not supported by service

I've seen this behavior today when the

   <service name="A.B.C.D" behaviorConfiguration="returnFaults">
        <endpoint contract="A.B.C.ID" binding="basicHttpBinding" address=""/>

was missing from the web.config. The service.svc file was there and got served. It took a while to realize that the problem was not in the binding configuration it self...

Automatically start forever (node) on system restart

I tried lots of the above answers. None of them worked for me. My app is installed in /home and as user, not as root. This probably means that when the above mentioned start scripts run, /home is not mounted yet, so the app is not started.

Then I found these instructions by Digital Ocean:

Using PM2 as explained was very simple and works perfectly: My virtual servers had two physical crashes since - downtime was only about a minute.

How to find all occurrences of a substring?

You can use re.finditer() for non-overlapping matches.

>>> import re
>>> aString = 'this is a string where the substring "is" is repeated several times'
>>> print [(a.start(), a.end()) for a in list(re.finditer('is', aString))]
[(2, 4), (5, 7), (38, 40), (42, 44)]

but won't work for:

In [1]: aString="ababa"

In [2]: print [(a.start(), a.end()) for a in list(re.finditer('aba', aString))]
Output: [(0, 3)]

How to tell if UIViewController's view is visible

You want to use the UITabBarController's selectedViewController property. All view controllers attached to a tab bar controller have a tabBarController property set, so you can, from within any of the view controllers' code:

if([[[self tabBarController] selectedViewController] isEqual:self]){
     //we're in the active controller
     //we are not

Show a number to two decimal places

$number = sprintf('%0.2f', $numbers); // 520.89898989 -> 520.89

This will give you 2 number after decimal.

Cannot use object of type stdClass as array?

When you try to access it as $result['context'], you treating it as an array, the error it's telling you that you are actually dealing with an object, then you should access it as $result->context

Check if user is using IE

Update to SpiderCode's answer to fix issues where the string 'MSIE' returns -1 but it matches 'Trident'. It used to return NAN, but now returns 11 for that version of IE.

   function msieversion() {
       var ua = window.navigator.userAgent;
       var msie = ua.indexOf("MSIE ");
       if (msie > -1) {
           return ua.substring(msie + 5, ua.indexOf(".", msie));
       } else if (navigator.userAgent.match(/Trident.*rv\:11\./)) {
           return 11;
       } else {
           return false;

What is the way of declaring an array in JavaScript?

There are a number of ways to create arrays.

The traditional way of declaring and initializing an array looks like this:

var a = new Array(5); // declare an array "a", of size 5
a = [0, 0, 0, 0, 0];  // initialize each of the array's elements to 0


// declare and initialize an array in a single statement
var a = new Array(0, 0, 0, 0, 0); 

How can I make a ComboBox non-editable in .NET?

To make the text portion of a ComboBox non-editable, set the DropDownStyle property to "DropDownList". The ComboBox is now essentially select-only for the user. You can do this in the Visual Studio designer, or in C# like this:

stateComboBox.DropDownStyle = ComboBoxStyle.DropDownList;

Link to the documentation for the ComboBox DropDownStyle property on MSDN.

Android widget: How to change the text of a button

This may be off topic, but for those who are struggling on how to exactly change also the font of the button text (that was my case and Skatephone's answer helped me) here's how I did it (if you made buttons ind design mode):

First we need to have the button's string name "converted" (it's a foul way to explain, but straightforward) into java from the xml, and so we paste the aforementioned code into our

IMPORTANT! place the code under the OnCreate method!

import android.widget.RemoteViews;

RemoteViews remoteViews = new RemoteViews(getPackageName(), R.layout.my_layout);
remoteViews.setTextViewText(, "Set button text here");

Keep in mind:

my_layout has to be substituted with the xml file where your buttons are

Counter has to be substituted with the id name of your button ("@+id/ButtonName")

if you want to change the button text just insert the text in place of "Set button text here"

here comes the part where you change the font:

Now that you "converted" from xml to java, you can set a Typeface method for TextView. Paste the following code exactly under the previous one just described above

TextView txt = (TextView) findViewById(;
        Typeface font = Typeface.createFromAsset(getAssets(), "fonts/MyFontName.ttf");

where in place of text_your_text_view_id you put your button's id name (like as previous code) and in place of MyFontName.ttf you put your desired font

WARNING! This assumes you already put your desired font into the assets/font folder. e.g. assets/fonts/MyFontName.ttf

How to create a stopwatch using JavaScript?

This is my simple take on this question, I hope it helps someone out oneday, somewhere...

let output = document.getElementById('stopwatch');
let ms = 0;
let sec = 0;
let min = 0;

function timer() {
    if(ms >= 100){
        ms = 0
    if(sec === 60){
        sec = 0
    if(min === 60){
        ms, sec, min = 0;

    //Doing some string interpolation
    let milli = ms < 10 ? `0`+ ms : ms;
    let seconds = sec < 10 ? `0`+ sec : sec;
    let minute = min < 10 ? `0` + min : min;

    let timer= `${minute}:${seconds}:${milli}`;
    output.innerHTML =timer;
//Start timer
function start(){
 time = setInterval(timer,10);
//stop timer
function stop(){
//reset timer
function reset(){
    ms = 0;
    sec = 0;
    min = 0;

    output.innerHTML = `00:00:00`
const startBtn = document.getElementById('startBtn');
const stopBtn =  document.getElementById('stopBtn');
const resetBtn = document.getElementById('resetBtn');

    <p class="stopwatch" id="stopwatch">
        <!-- stopwatch goes here -->
    <button class="btn-start" id="startBtn">Start</button>
    <button class="btn-stop" id="stopBtn">Stop</button>
    <button class="btn-reset" id="resetBtn">Reset</button>

Set new id with jQuery

Use .val() not attr('value').

XPath to return only elements containing the text, and not its parents

Do you want to find elements that contain "match", or that equal "match"?

This will find elements that have text nodes that equal 'match' (matches none of the elements because of leading and trailing whitespace in random2):


This will find all elements that have text nodes that equal "match", after removing leading and trailing whitespace(matches random2):


This will find all elements that contain 'match' in the text node value (matches random2 and random3):


This XPATH 2.0 solution uses the matches() function and a regex pattern that looks for text nodes that contain 'match' and begin at the start of the string(i.e. ^) or a word boundary (i.e. \W) and terminated by the end of the string (i.e. $) or a word boundary. The third parameter i evaluates the regex pattern case-insensitive. (matches random2)


Sublime Text 2 - View whitespace characters

I know this is an old thread, but I like my own plugin that can cycle through whitespace modes (none, selection, and all) via a single shortcut. It also provides menu items under a View | Whitespace menu.

Hopefully people will find this useful - it is used by a lot of people :)

Setting the height of a SELECT in IE

You can use a replacement: jQuery Chosen. It looks pretty awesome.

hardcoded string "row three", should use @string resource

You can go to Design mode and select "Fix" at the bottom of the warning. Then a pop up will appear (seems like it's going to register the new string) and voila, the error is fixed.

How to get all keys with their values in redis

I have written a small code for this particular requirement using hiredis , please find the code with a working example at

Here is the code that I have written,

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "hiredis.h"

int main(void)
        unsigned int i,j=0;char **str1;
        redisContext *c; char *t;
        redisReply *reply, *rep;

        struct timeval timeout = { 1, 500000 }; // 1.5 seconds
        c = redisConnectWithTimeout((char*)"", 6903, timeout);
        if (c->err) {
                printf("Connection error: %s\n", c->errstr);

        reply = redisCommand(c,"keys *");
        while ( reply->element[j]->str != NULL)
                rep = redisCommand(c,"GET  %s", reply->element[j]->str);
                if (strstr(rep->str,"ERR Operation against a key holding"))
                        printf("%s\t\t%s\n",  reply->element[j]->str,rep->str);
                printf("%s\t\t%s\n",  reply->element[j]->str,rep->str);

How can I display a messagebox in ASP.NET?

Using AJAX Modal Popup and creating a Message Box Class:

Messsage Box Class:

public class MessageBox
    ModalPopupExtender _modalPop;
    Page _page;
    object _sender;
    Panel _pnl;

    public enum Buttons
    public enum DefaultButton
    public enum MessageBoxIcon


    public MessageBox(Page page, object sender, Panel pnl)
        _page = page;
        _sender = sender;
        _pnl = pnl;
        _modalPop = new ModalPopupExtender();

        _modalPop.ID = "popUp";
        _modalPop.PopupControlID = "ModalPanel";


    public void Show(String strTitle, string strMessage, Buttons buttons, DefaultButton defaultbutton, MessageBoxIcon msbi)
        MasterPage mPage = _page.Master;
        Label lblTitle = null;
        Label lblError = null;
        Button btn1 = null;
        Button btn2 = null;
        Button btn3 = null;
        Image imgIcon = null;

        lblTitle = ((Default)_page.Master).messageBoxTitle;
        lblError = ((Default)_page.Master).messageBoxMsg;
        btn1 = ((Default)_page.Master).button1;
        btn2 = ((Default)_page.Master).button2;
        btn3 = ((Default)_page.Master).button3;
        imgIcon = ((Default)_page.Master).messageBoxIcon;

        lblTitle.Text = strTitle;
        lblError.Text = strMessage;

        btn1.CssClass = "btn btn-default";
        btn2.CssClass = "btn btn-default";
        btn3.CssClass = "btn btn-default";

        switch (msbi)
            case MessageBoxIcon.Asterisk:
                //imgIcon.ImageUrl = "~/img/asterisk.jpg";
            case MessageBoxIcon.Exclamation:
                //imgIcon.ImageUrl = "~/img/exclamation.jpg";
            case MessageBoxIcon.Hand:
            case MessageBoxIcon.Information:
            case MessageBoxIcon.None:
            case MessageBoxIcon.Question:
            case MessageBoxIcon.Warning:
        switch (buttons)
            case Buttons.AbortRetryIgnore:
                btn1.Text = "Abort";
                btn2.Text = "Retry";
                btn3.Text = "Ignore";
                btn1.Visible = true;
                btn2.Visible = true;
                btn3.Visible = true;


            case Buttons.OK:
                btn1.Text = "OK";
                btn1.Visible = true;
                btn2.Visible = false;
                btn3.Visible = false;

            case Buttons.OKCancel:
                btn1.Text = "OK";
                btn2.Text = "Cancel";
                btn1.Visible = true;
                btn2.Visible = true;
                btn3.Visible = false;

            case Buttons.RetryCancel:
                btn1.Text = "Retry";
                btn2.Text = "Cancel";
                btn1.Visible = true;
                btn2.Visible = true;
                btn3.Visible = false;

            case Buttons.YesNo:
                btn1.Text = "No";
                btn2.Text = "Yes";
                btn1.Visible = true;
                btn2.Visible = true;
                btn3.Visible = false;

            case Buttons.YesNoCancel:
                btn1.Text = "Yes";
                btn2.Text = "No";
                btn3.Text = "Cancel";
                btn1.Visible = true;
                btn2.Visible = true;
                btn3.Visible = true;

        if (defaultbutton == DefaultButton.Button1)
            btn1.CssClass = "btn btn-primary";
            btn2.CssClass = "btn btn-default";
            btn3.CssClass = "btn btn-default";

        else if (defaultbutton == DefaultButton.Button2)
            btn1.CssClass = "btn btn-default";
            btn2.CssClass = "btn btn-primary";
            btn3.CssClass = "btn btn-default";

        else if (defaultbutton == DefaultButton.Button3)
            btn1.CssClass = "btn btn-default";
            btn2.CssClass = "btn btn-default";
            btn3.CssClass = "btn btn-primary";


    private void FirePopUp()
        _modalPop.TargetControlID = ((Button)_sender).ID;
        _modalPop.DropShadow = true;
        _modalPop.OkControlID = //btn 1 / 2 / 3;
        _modalPop.CancelControlID = //btn 1 / 2 / 3;
        _modalPop.BackgroundCssClass = "modalBackground";


In my MasterPage code:

  #region AlertBox
    public Button button1
        { return this.btn1; }
    public Button button2
        { return this.btn2; }
    public Button button3
        { return this.btn1; }

    public Label messageBoxTitle
        { return this.lblMessageBoxTitle; }

    public Label messageBoxMsg
        { return this.lblMessage; }

    public Image messageBoxIcon
        { return this.img; }

    public DialogResult res
        get { return res; }
        set { res = value; }


In my MasterPage aspx:

On the header add reference (just for some style)

<link href="" rel="stylesheet">

On the Content:

<asp:Panel ID="ModalPanel" runat="server" style="display: none; position: absolute; top:0;">
        <asp:Panel ID="pnlAlertBox" runat="server" >
        <div class="modal-dialog" >
            <div ID="modalContent" runat="server" class="modal-content">
                <div class="modal-header">  
                    <h4 class="modal-title" id="myModalLabel">
                         <asp:Label ID="lblMessageBoxTitle" runat="server" Text="This is the MessageBox Caption"></asp:Label>
                <div ID="modalbody" class="modal-body" style="width:800px; height:600px">
                    <asp:Image ID="img" runat="server" Height="20px" Width="20px"/>
                    <asp:Label ID="lblMessage" runat="server" Text="Here Goes My Message"></asp:Label>
                <div class="modal-footer">
                    <asp:Button ID="btn1" runat="server" OnClick="btn_Click" CssClass="btn btn-default" Text="Another Button" />
                    <asp:Button ID="btn2" runat="server" OnClick="btn_Click" CssClass="btn btn-default" Text="Cancel" />
                    <asp:Button ID="btn3" runat="server" OnClick="btn_Click" CssClass="btn btn-primary" Text="Ok" />

And to call it from a button, button code:

protected void btnTest_Click(object sender, EventArgs e)
            MessageBox msgBox = new MessageBox(this, sender, aPanel);
            msgBox.Show("This is my Caption", "this is my message", MessageBox.Buttons.AbortRetryIgnore, MessageBox.DefaultButton.Button1, MessageBox.MessageBoxIcon.Asterisk);


Oracle date format picture ends before converting entire input string

What you're trying to insert is not a date, I think, but a string. You need to use to_date() function, like this:

insert into table t1 (id, date_field) values (1, to_date('20.06.2013', ''));

Device not detected in Eclipse when connected with USB cable

On a kitkat Google Nexus 7, I tired everything here, and did not succeed. The device did previously connect properly to this computer.

Then I hit settings - developer-options - Revoke USB debugging authorisations and confirmed that I really did want to revoke them.

I unplugged and plugged the USB. The tablet beeped and asked if wanted to authorise the computer for debugging. I said "Yes" and everything worked again.

click command in selenium webdriver does not work

Thanks for all the answers everyone! I have found a solution, turns out I didn't provide enough code in my question.

The problem was NOT with the click() function after all, but instead related to cas authentication used with my project. In Selenium IDE my login test executed a "open" command to the following location,


That worked. I exported the test to Selenium webdriver which naturally preserved that location. The command in Selenium Webdriver was,

driver.get(baseUrl + "/cas/login?service=https%1A%2F%8FAPPNAME%2FMOREURL%2Fj_spring_cas_security");

For reasons I have yet to understand the above failed. When I changed it to,

driver.get(baseUrl + "MOREURL/");

The click command suddenly started to work... I will edit this answer if I can figure out why exactly this is.

Note: I obscured the URLs used above to protect my company's product.

A valid provisioning profile for this executable was not found for debug mode

After select auto manager signing

You may still need to check the selection in settings. Sometime, it's not correct there.

enter image description here

Spring Boot - Handle to Hibernate SessionFactory

Great work Andreas. I created a bean version so the SessionFactory could be autowired.

import javax.persistence.EntityManagerFactory;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;


private EntityManagerFactory entityManagerFactory;

public SessionFactory getSessionFactory() {
    if (entityManagerFactory.unwrap(SessionFactory.class) == null) {
        throw new NullPointerException("factory is not a hibernate factory");
    return entityManagerFactory.unwrap(SessionFactory.class);

Python Dictionary contains List as Value - How to update?

why not just skip .get altogether and do something like this?:

for x in range(len(dictionary["C1"]))
    dictionary["C1"][x] += 10

IF-THEN-ELSE statements in postgresql

In general, an alternative to case when ... is coalesce(nullif(x,bad_value),y) (that cannot be used in OP's case). For example,

select coalesce(nullif(y,''),x), coalesce(nullif(x,''),y), *
from (     (select 'abc' as x, '' as y)
 union all (select 'def' as x, 'ghi' as y)
 union all (select '' as x, 'jkl' as y)
 union all (select null as x, 'mno' as y)
 union all (select 'pqr' as x, null as y)
) q


 coalesce | coalesce |  x  |  y  
 abc      | abc      | abc | 
 ghi      | def      | def | ghi
 jkl      | jkl      |     | jkl
 mno      | mno      |     | mno
 pqr      | pqr      | pqr | 
(5 rows)

List all sequences in a Postgres db 8.1 with SQL

This statement lists the table and column that is associated with each sequence:


    SELECT t.relname as related_table, 
           a.attname as related_column,
           s.relname as sequence_name
    FROM pg_class s 
      JOIN pg_depend d ON d.objid = s.oid 
      JOIN pg_class t ON d.objid = s.oid AND d.refobjid = t.oid 
      JOIN pg_attribute a ON (d.refobjid, d.refobjsubid) = (a.attrelid, a.attnum)
      JOIN pg_namespace n ON n.oid = s.relnamespace 
    WHERE s.relkind     = 'S' 

  AND n.nspname     = 'public'

more see here link to answer

Cannot find pkg-config error


Get AVG ignoring Null or Zero values

You already attempt to filter out NULL values with NOT NULL. I have changed this to IS NOT NULL in the WHERE clause so it will execute. We can refactor this by removing the ISNULL function in the AVG method. Also, I doubt you'll actually need bigint so we can remove the cast.

SELECT distinct
     AVG(a.SecurityW) as Average1
     ,AVG(a.TransferW) as Average2
     ,AVG(a.StaffW) as Average3
FROM Table1 a,  Table2 b
WHERE a.SecurityW <> 0 AND a.SecurityW IS NOT NULL
AND a.TransferW<> 0 AND a.TransferWIS IS NOT NULL
AND a.StaffW<> 0 AND a.StaffWIS IS NOT NULL
AND MONTH(a.ActualTime) = 4
AND YEAR(a.ActualTime) = 2013

Use of 'const' for function parameters

Being a VB.NET programmer that needs to use a C++ program with 50+ exposed functions, and a .h file that sporadically uses the const qualifier, it is difficult to know when to access a variable using ByRef or ByVal.

Of course the program tells you by generating an exception error on the line where you made the mistake, but then you need to guess which of the 2-10 parameters is wrong.

So now I have the distasteful task of trying to convince a developer that they should really define their variables (in the .h file) in a manner that allows an automated method of creating all of the VB.NET function definitions easily. They will then smugly say, "read the ... documentation."

I have written an awk script that parses a .h file, and creates all of the Declare Function commands, but without an indicator as to which variables are R/O vs R/W, it only does half the job.


At the encouragement of another user I am adding the following;

Here is an example of a (IMO) poorly formed .h entry;

typedef int (EE_STDCALL *Do_SomethingPtr)( int smfID, const char* cursor_name, const char* sql );

The resultant VB from my script;

    Declare Function Do_Something Lib "SomeOther.DLL" (ByRef smfID As Integer, ByVal cursor_name As String, ByVal sql As String) As Integer

Note the missing "const" on the first parameter. Without it, a program (or another developer) has no Idea the 1st parameter should be passed "ByVal." By adding the "const" it makes the .h file self documenting so that developers using other languages can easily write working code.

html text input onchange event

Well unless I misunderstand you can just use the onChange attribute:

<input type="text" onChange="return bar()">

Note: in FF 3 (at least) this is not called until some the user has confirmed they are changed either by clicking away from the element, clicking enter, or other.

Check for false

If you want it to check explicit for it to not be false (boolean value) you have to use

if(borrar() !== false)

But in JavaScript we usually use falsy and truthy and you could use


but then values 0, '', null, undefined, null and NaN would not generate the alert.

The following values are always falsy:

,0 (zero)
,'' or "" (empty string)

Everything else is truthy. That includes:

'0' (a string containing a single zero)
,'false' (a string containing the text “false”)
,[] (an empty array)
,{} (an empty object)
,function(){} (an “empty” function)


As an extra perk to convert any value to true or false (boolean type), use double exclamation mark:

!![] === true
!!'false' === true
!!false === false
!!undefined === false

Unmount the directory which is mounted by sshfs in Mac

sudo diskutil unmount force PATH 

Works every time :)
Notice the force tag

How to open a URL in a new Tab using JavaScript or jQuery?

 var url = "";, '_blank');

How to call a SOAP web service on Android

It's true that due to it's overhead SOAP is not the best choice for data exchange with mobile devices. However, you might find yourself in situation in which you do not control the format of server output.

So, if you have to stick with SOAP, there is a kSOAP2 library patched for Android here:

How to symbolicate crash log Xcode?

Writing this answer as much for the community as for myself.

If there ever are problems symbolicating a crash report, one can overcome them as follows:

  1. Create a separate folder, copy and from the corresponding .xcarchive into the folder. Also copy the .crash report into the folder.

  2. Open the crash report in TextEdit or elsewhere, go to the Binary Images: section, and copy the first address there (e.g. 0xd7000).

  3. cd into the folder. Now you can run the following command:

    xcrun atos -o -arch arm64 -l 0xd7000 0x0033f9bb

This will symbolicate the symbol at address 0x0033f9bb. Please make sure to pick the correct value for the -arch option (can be obtaned from the first line in the Binary Images: section, or figured out from the Hardware Model: in the crash report and the app's supported archs).

You can also copy the necessary addresses (e.g. a thread call stack) from the crash report directly into a text file (in TextEdit, hold Option and select the necessary text block, or copy and cut), to get something like this:


Now you can save this into a text file, e.g. addr.txt, and run the following command:

xcrun atos -o -arch arm64 -l 0xd7000 -f addr.txt

This will give a nice symbolication for all the addresses at once.


Before doing the above, it's worth checking that everything is set up correctly (as atos will happily report something for basically any supplied address).

To do the checking, open the crash report, and go to the end of the call stack for Thread 0. The first line from the end to list your app (usually the second one), e.g.:

34  Foo                    0x0033f9bb 0xd7000 + 2525627

should be the main() call. Symbolicating the address (0x0033f9bb in this case) as described above should confirm that this is indeed main() and not some random method or function.

If the address is not that of main(), check your load address (-l option) and arch (-arch option).


If the above doesn't work due to bitcode, download the dSYM for your build from iTunes Connect, extract the executable binary from the dSYM (Finder > Show Package Contents), copy it into the directory, and use it (i.e. Foo) as the argument to atos, instead of the

How to check if a char is equal to an empty space?

To compare character you use the == operator:

if (c == ' ')

Detect all changes to a <input type="text"> (immediately) using JQuery

Add this code somewhere, this will do the trick.

var originalVal = $.fn.val;
$.fn.val = function(){
    var result =originalVal.apply(this,arguments);
        $(this).change(); // OR with custom event $(this).trigger('value-changed');
    return result;

Found this solution at val() doesn't trigger change() in jQuery

LoDash: Get an array of values from an array of object properties

And if you need to extract several properties from each object, then

let newArr =, o => _.pick(o, ['name', 'surname', 'rate']));

Reading a simple text file

Having a file in your assets folder requires you to use this piece of code in order to get files from the assets folder:


In this example, getAssets() returns an AssetManager instance and then you're free to use whatever method you want from the AssetManager API.

How to find index of list item in Swift?

For custom class, you need to implement the Equatable protocol.

import Foundation

func ==(l: MyClass, r: MyClass) -> Bool {
  return ==

class MyClass: Equtable {
    init(id: String) {
        self.msgID = id

    let msgID: String

let item = MyClass(3)
let itemList = [MyClass(1), MyClass(2), item]
let idx = itemList.indexOf(item)


Removing html5 required attribute with jQuery

Even though the ID selector is the simplest, you can also use the name selector as below:


For more see:

Angular 2 - Checking for server errors from subscribe

You can achieve with following way

        result => {
        error => {
            this.errors = error

if (!this.errors) {
    //route to new page

Converting Columns into rows with their respective data in sql server

i solved the query this way

    ca.ID, ca.[Name]
FROM [Emp2]
         ('ID' , cast(ID as varchar)),
         ('[Name]' , Name)

  ) as CA (ID, Name)

output look like

  ID     Name
------ --------------------------------------------------
ID     1
[Name] Joy
ID     2
[Name] jean
ID     4
[Name] paul

How does String substring work in Swift

I had the same initial reaction. I too was frustrated at how syntax and objects change so drastically in every major release.

However, I realized from experience how I always eventually suffer the consequences of trying to fight "change" like dealing with multi-byte characters which is inevitable if you're looking at a global audience.

So I decided to recognize and respect the efforts exerted by Apple engineers and do my part by understanding their mindset when they came up with this "horrific" approach.

Instead of creating extensions which is just a workaround to make your life easier (I'm not saying they're wrong or expensive), why not figure out how Strings are now designed to work.

For instance, I had this code which was working on Swift 2.2:

let rString = cString.substringToIndex(2)
let gString = (cString.substringFromIndex(2) as NSString).substringToIndex(2)
let bString = (cString.substringFromIndex(4) as NSString).substringToIndex(2)

and after giving up trying to get the same approach working e.g. using Substrings, I finally understood the concept of treating Strings as a bidirectional collection for which I ended up with this version of the same code:

let rString = String(cString.characters.prefix(2))
cString = String(cString.characters.dropFirst(2))
let gString = String(cString.characters.prefix(2))
cString = String(cString.characters.dropFirst(2))
let bString = String(cString.characters.prefix(2))

I hope this contributes...

If else in stored procedure sql server

You can try below Procedure Sql:

@ParLngId int output
    -- Min will return only 1 value, if 'Extranet Client' is found
    -- IsNull will take care of 'Extranet Client' not found, returning 0 instead of Null
    -- But T_Param must be a Master Table with ParStrNom having a Unique Index, if so Min is not reqd at all
    -- But 'PHY', 'Extranet Client' suggests that Unique Key has 2 columns, not just ParStrNom

    SET @ParLngId = IsNull((Select Min (ParLngId) from T_Param where ParStrNom = 'Extranet Client'), 0);

    -- Nothing changed below

    if  (@ParLngId = 0)
            Insert Into T_Param values ('PHY', 'Extranet Client', Null, Null, 'T', 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 1, NULL, NULL, NULL)
            SET @ParLngId = @@IDENTITY

    Return  @ParLngId

Check if a process is running or not on Windows with Python

You can not rely on lock files in Linux or Windows. I would just bite the bullet and iterate through all the running programs. I really do not believe it will be as "expensive" as you think. psutil is an excellent cross-platform python module cable of enumerating all the running programs on a system.

import psutil    
"someProgram" in ( for p in psutil.process_iter())

How can I pass a reference to a function, with parameters?

The following is equivalent to your second code block:

var f = function () {
        //Some logic here...

var fr = f;


If you want to actually pass a reference to a function to some other function, you can do something like this:

function fiz(x, y, z) {
    return x + y + z;

// elsewhere...

function foo(fn, p, q, r) {
    return function () {
        return fn(p, q, r);

// finally...

f = foo(fiz, 1, 2, 3);
f(); // returns 6

You're almost certainly better off using a framework for this sort of thing, though.

How do I shrink my SQL Server Database?

Not sure how practical this would be, and depending on the size of the database, number of tables and other complexities, but I:

  1. defrag the physical drive
  2. create a new database according to my requirements, space, percentage growth, etc
  3. use the simple ssms task to import all tables from the old db to the new db
  4. script out the indexes for all tables on the old database, and then recreate the indexes on the new database. expand as needed for foreign keys etc.
  5. rename databases as needed, confirm successful, delete old

Select from table by knowing only date without time (ORACLE)

DATE is a reserved keyword in Oracle, so I'm using column-name your_date instead.

If you have an index on your_date, I would use

WHERE your_date >= TO_DATE('2010-08-03', 'YYYY-MM-DD')
  AND your_date <  TO_DATE('2010-08-04', 'YYYY-MM-DD')


WHERE your_date BETWEEN TO_DATE('2010-08-03', 'YYYY-MM-DD')
                    AND TO_DATE('2010-08-03 23:59:59', 'YYYY-MM-DD HH24:MI:SS')

If there is no index or if there are not too many records

WHERE TRUNC(your_date) = TO_DATE('2010-08-03', 'YYYY-MM-DD')

should be sufficient. TRUNC without parameter removes hours, minutes and seconds from a DATE.

If performance really matters, consider putting a Function Based Index on that column:

CREATE INDEX trunc_date_idx ON t1(TRUNC(your_date));

How do I disable Git Credential Manager for Windows?

In case you do not want to remove or uninstall the credentials manager: see for the solution that worked for me.

Explanations, etc. in that page (linked to prevent duplicate content in the same website family).

TL;DR: this now sits on top of my automated bash scripts:

# next env var doesn't help...
export GIT_SSH_COMMAND='ssh -oBatchMode=yes'
# these should shut up git asking, but only partly: the X-windows-like dialog doesn't pop up no more, but ...
export GIT_ASKPASS=echo
export SSH_ASKPASS=echo
# We needed to find *THIS* to shut up the bloody git-for-windows credential manager: 
export GCM_INTERACTIVE=never

The final nail in the coffin of that credentials manager was the unique bit (GCM_INTERACTIVE) in Martin Ba's answer above: How do I disable Git Credential Manager for Windows?

How to open local files in Swagger-UI

My environment,
Firefox 45.9 , Windows 7
swagger-ui ie 3.x

I did the unzip and the petstore comes up fine in a Firefox tab. I then opened a new Firefox tab and went to File > Open File and opened my swagger.json file. The file comes up clean, ie as a file.

I then copied the 'file location' from Firefox ( ie the URL location eg: file:///D:/My%20Applications/Swagger/swagger-ui-master/dist/MySwagger.json ).

I then went back to the swagger UI tab and pasted the file location text into the swagger UI explore window and my swagger came up clean.

Hope this helps.

Multiple select in Visual Studio?

I couldn't find anything built in, which is sad. There is this functionality in CodeRush though.

With Notepad++, this feature comes in built in. Just turn on multi-editing from

Setting > Preferences > Editing > Multi-Editing Settings

But its not as intuitive as MS Word which lets you select two words by double clicking on them (after Ctrl of course).

library not found for -lPods

I tried EVERY answer in this thread to no avail. Finally resolved my issue by matching the "Pre-Configuration Build Products Path" in my target project with the value in the Pods project. Turns out they were building to two different output locations. None of the other suggestions in this thread were relevant for me. Would be great if XCode gave a useful error description (like WHY it can't use the lib - File Not Found, No matching architecture found, etc.).

installing python packages without internet and using source code as .tar.gz and .whl

We have a similar situation at work, where the production machines have no access to the Internet; therefore everything has to be managed offline and off-host.

Here is what I tried with varied amounts of success:

  1. basket which is a small utility that you run on your internet-connected host. Instead of trying to install a package, it will instead download it, and everything else it requires to be installed into a directory. You then move this directory onto your target machine. Pros: very easy and simple to use, no server headaches; no ports to configure. Cons: there aren't any real showstoppers, but the biggest one is that it doesn't respect any version pinning you may have; it will always download the latest version of a package.

  2. Run a local pypi server. Used pypiserver and devpi. pypiserver is super simple to install and setup; devpi takes a bit more finagling. They both do the same thing - act as a proxy/cache for the real pypi and as a local pypi server for any home-grown packages. localshop is a new one that wasn't around when I was looking, it also has the same idea. So how it works is your internet-restricted machine will connect to these servers, they are then connected to the Internet so that they can cache and proxy the actual repository.

The problem with the second approach is that although you get maximum compatibility and access to the entire repository of Python packages, you still need to make sure any/all dependencies are installed on your target machines (for example, any headers for database drivers and a build toolchain). Further, these solutions do not cater for non-pypi repositories (for example, packages that are hosted on github).

We got very far with the second option though, so I would definitely recommend it.

Eventually, getting tired of having to deal with compatibility issues and libraries, we migrated the entire circus of servers to commercially supported docker containers.

This means that we ship everything pre-configured, nothing actually needs to be installed on the production machines and it has been the most headache-free solution for us.

We replaced the pypi repositories with a local docker image server.

Cannot declare instance members in a static class in C#

As John Weldon said all members must be static in a static class. Try

public static class employee
     static NameValueCollection appSetting = ConfigurationManager.AppSettings;    


How to get a user's time zone?

Xcode 8.2.1 • Swift 3.0.2


Locale.current.regionCode           // "US"
Locale.current.languageCode         // "en"
Locale.current.currencyCode         // "USD"
Locale.current.currencySymbol       // "$"
Locale.current.groupingSeparator    // ","
Locale.current.decimalSeparator     // "."
Locale.current.usesMetricSystem     // false

Locale.windowsLocaleCode(fromIdentifier: "pt_BR")                   //  1,046
Locale.identifier(fromWindowsLocaleCode: 1046) ?? ""                // "pt_BR"
Locale.windowsLocaleCode(fromIdentifier: Locale.current.identifier) //  1,033 Note: I am in Brasil but I use "en_US" format with all my devices
Locale.windowsLocaleCode(fromIdentifier: "en_US")                                   // 1,033
Locale.identifier(fromWindowsLocaleCode: 1033) ?? ""                                // "en_US"

Locale(identifier: "en_US_POSIX").localizedString(forLanguageCode: "pt")            // "Portuguese"
Locale(identifier: "en_US_POSIX").localizedString(forRegionCode: "br")              // "Brazil"
Locale(identifier: "en_US_POSIX").localizedString(forIdentifier: "pt_BR")           // "Portuguese (Brazil)"

TimeZone.current.localizedName(for: .standard, locale: .current) ?? ""              // "Brasilia Standard Time"
TimeZone.current.localizedName(for: .shortStandard, locale: .current) ?? ""         // "GMT-3
TimeZone.current.localizedName(for: .daylightSaving, locale: .current) ?? ""        // "Brasilia Summer Time"
TimeZone.current.localizedName(for: .shortDaylightSaving, locale: .current) ?? ""   // "GMT-2"
TimeZone.current.localizedName(for: .generic, locale: .current) ?? ""               // "Brasilia Time"
TimeZone.current.localizedName(for: .shortGeneric, locale: .current) ?? ""          // "Sao Paulo Time"

var timeZone: String {
    return TimeZone.current.localizedName(for: TimeZone.current.isDaylightSavingTime() ?
                                               .daylightSaving :
                                          locale: .current) ?? "" }

timeZone       // "Brasilia Summer Time"

Get class labels from Keras functional model

To map predicted classes and filenames using ImageDataGenerator, I use:

# Data generator and prediction
test_datagen = ImageDataGenerator(rescale=1./255)
test_generator = test_datagen.flow_from_directory(
        target_size=(150, 150),
pred = model.predict_generator(test_generator, steps=len(test_generator), verbose=0)
# Get classes by max element in np (as a list)
classes = list(np.argmax(pred, axis=1))
# Get filenames (set shuffle=false in generator is important)
filenames = test_generator.filenames

I can loop over predicted classes and the associated filename using:

for f in zip(classes, filenames):

How to create a directory in Java?

Just wanted to point out to everyone calling File.mkdir() or File.mkdirs() to be careful the File object is a directory and not a file. For example if you call mkdirs() for the path /dir1/dir2/file.txt, it will create a folder with the name file.txt which is probably not what you wanted. If you are creating a new file and also want to automatically create parent folders you can do something like this:

            File file = new File(filePath);
            if (file.getParentFile() != null) {

how to parse a "dd/mm/yyyy" or "dd-mm-yyyy" or "dd-mmm-yyyy" formatted date string using JavaScript or jQuery

You might want to use helper library like which wraps the native javascript date object for easier manipulations

Then you can do things like:

var day = moment("12-25-1995", "MM-DD-YYYY");


var day = moment("25/12/1995", "DD/MM/YYYY");

then operate on the date

day.add('days', 7)

and to get the native javascript date


Android Gradle Could not reserve enough space for object heap

I ran into the same issue, here's my post:

Android Studio - Gradle build failing - Java Heap Space

exec summary: Windows looks for the file here:


So create that file, and add a line like this:

org.gradle.jvmargs=-XX\:MaxHeapSize\=256m -Xmx256m

as per @Faiz Siddiqui post

twitter bootstrap navbar fixed top overlapping site

This issue is known and there's a workaround in the twitter bootstrap site:

When you affix the navbar, remember to account for the hidden area underneath. Add 40px or more of padding to the <body>. Be sure to add this after the core Bootstrap CSS and before the optional responsive CSS.

This worked for me:

body { padding-top: 40px; }

Get the correct week number of a given date

This is the way:

public int GetWeekNumber()
    CultureInfo ciCurr = CultureInfo.CurrentCulture;
    int weekNum = ciCurr.Calendar.GetWeekOfYear(DateTime.Now, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
    return weekNum;

Most important for is the CalendarWeekRule parameter.

See here:;k(TargetFrameworkMoniker-.NETFramework

What is a provisioning profile used for when developing iPhone applications?

A Quote from : iPhone Developer Program (~8MB PDF)

A provisioning profile is a collection of digital entities that uniquely ties developers and devices to an authorized iPhone Development Team and enables a device to be used for testing. A Development Provisioning Profile must be installed on each device on which you wish to run your application code. Each Development Provisioning Profile will contain a set of iPhone Development Certificates, Unique Device Identifiers and an App ID. Devices specified within the provisioning profile can be used for testing only by those individuals whose iPhone Development Certificates are included in the profile. A single device can contain multiple provisioning profiles.

JavaScript variable number of arguments to function

Use the arguments object when inside the function to have access to all arguments passed in.

Python - Get Yesterday's date as a string in YYYY-MM-DD format

>>> import datetime

How to edit .csproj file

You can right click the project file, select "Unload project" then you can open the file directly for editing by selecting "Edit project name.csproj".

You will have to load the project back after you have saved your changes in order for it to compile.

See How to: Unload and Reload Projects on MSDN.

Since project files are XML files, you can also simply edit them using any text editor that supports Unicode (notepad, notepad++ etc...)

However, I would be very reluctant to edit these files by hand - use the Solution explorer for this if at all possible. If you have errors and you know how to fix them manually, go ahead, but be aware that you can completely ruin the project file if you don't know exactly what you are doing.

filters on ng-model in an input

I believe that the intention of AngularJS inputs and the ngModel direcive is that invalid input should never end up in the model. The model should always be valid. The problem with having invalid model is that we might have watchers that fire and take (inappropriate) actions based on invalid model.

As I see it, the proper solution here is to plug into the $parsers pipeline and make sure that invalid input doesn't make it into the model. I'm not sure how did you try to approach things or what exactly didn't work for you with $parsers but here is a simple directive that solves your problem (or at least my understanding of the problem):

app.directive('customValidation', function(){
   return {
     require: 'ngModel',
     link: function(scope, element, attrs, modelCtrl) {

       modelCtrl.$parsers.push(function (inputValue) {

         var transformedInput = inputValue.toLowerCase().replace(/ /g, ''); 

         if (transformedInput!=inputValue) {

         return transformedInput;         

As soon as the above directive is declared it can be used like so:

<input ng-model="sth" ng-trim="false" custom-validation>

As in solution proposed by @Valentyn Shybanov we need to use the ng-trim directive if we want to disallow spaces at the beginning / end of the input.

The advantage of this approach is 2-fold:

  • Invalid value is not propagated to the model
  • Using a directive it is easy to add this custom validation to any input without duplicating watchers over and over again

Using CookieContainer with WebClient class

This one is just extension of article you found.

public class WebClientEx : WebClient
    public WebClientEx(CookieContainer container)
        this.container = container;

    public CookieContainer CookieContainer
            get { return container; }
            set { container= value; }

    private CookieContainer container = new CookieContainer();

    protected override WebRequest GetWebRequest(Uri address)
        WebRequest r = base.GetWebRequest(address);
        var request = r as HttpWebRequest;
        if (request != null)
            request.CookieContainer = container;
        return r;

    protected override WebResponse GetWebResponse(WebRequest request, IAsyncResult result)
        WebResponse response = base.GetWebResponse(request, result);
        return response;

    protected override WebResponse GetWebResponse(WebRequest request)
        WebResponse response = base.GetWebResponse(request);
        return response;

    private void ReadCookies(WebResponse r)
        var response = r as HttpWebResponse;
        if (response != null)
            CookieCollection cookies = response.Cookies;

SOAP-UI - How to pass xml inside parameter

To send CDATA in a request object use the SoapObject.setInnerText("..."); method.

Using sudo with Python script

To pass the password to sudo's stdin:

#!/usr/bin/env python
from subprocess import Popen, PIPE

sudo_password = 'mypass'
command = 'mount -t vboxsf myfolder /home/myuser/myfolder'.split()

p = Popen(['sudo', '-S'] + command, stdin=PIPE, stderr=PIPE,
sudo_prompt = p.communicate(sudo_password + '\n')[1]

Note: you could probably configure passwordless sudo or SUDO_ASKPASS command instead of hardcoding your password in the source code.

htmlentities() vs. htmlspecialchars()


  • Sometimes you're writing XML data, and you can't use HTML entities in a XML file.
  • Because htmlentities substitutes more characters than htmlspecialchars. This is unnecessary, makes the PHP script less efficient and the resulting HTML code less readable.

htmlentities is only necessary if your pages use encodings such as ASCII or LATIN-1 instead of UTF-8 and you're handling data with an encoding different from the page's.

Does Python have a string 'contains' substring method?

in Python strings and lists

Here are a few useful examples that speak for themselves concerning the in method:

"foo" in "foobar"

"foo" in "Foobar"

"foo" in "Foobar".lower()

"foo".capitalize() in "Foobar"

"foo" in ["bar", "foo", "foobar"]

"foo" in ["fo", "o", "foobar"]

["foo" in a for a in ["fo", "o", "foobar"]]
[False, False, True]

Caveat. Lists are iterables, and the in method acts on iterables, not just strings.

Floating point inaccuracy examples

How's this for an explantation to the layman. One way computers represent numbers is by counting discrete units. These are digital computers. For whole numbers, those without a fractional part, modern digital computers count powers of two: 1, 2, 4, 8. ,,, Place value, binary digits, blah , blah, blah. For fractions, digital computers count inverse powers of two: 1/2, 1/4, 1/8, ... The problem is that many numbers can't be represented by a sum of a finite number of those inverse powers. Using more place values (more bits) will increase the precision of the representation of those 'problem' numbers, but never get it exactly because it only has a limited number of bits. Some numbers can't be represented with an infinite number of bits.


OK, you want to measure the volume of water in a container, and you only have 3 measuring cups: full cup, half cup, and quarter cup. After counting the last full cup, let's say there is one third of a cup remaining. Yet you can't measure that because it doesn't exactly fill any combination of available cups. It doesn't fill the half cup, and the overflow from the quarter cup is too small to fill anything. So you have an error - the difference between 1/3 and 1/4. This error is compounded when you combine it with errors from other measurements.

Display open transactions in MySQL

Although there won't be any remaining transaction in the case, as @Johan said, you can see the current transaction list in InnoDB with the query below if you want.

SELECT * FROM information_schema.innodb_trx\G

From the document:

The INNODB_TRX table contains information about every transaction (excluding read-only transactions) currently executing inside InnoDB, including whether the transaction is waiting for a lock, when the transaction started, and the SQL statement the transaction is executing, if any.

How to sort the letters in a string alphabetically in Python

Sorted() solution can give you some unexpected results with other strings.

List of other solutions:

Sort letters and make them distinct:

>>> s = "Bubble Bobble"
>>> ''.join(sorted(set(s.lower())))
' belou'

Sort letters and make them distinct while keeping caps:

>>> s = "Bubble Bobble"
>>> ''.join(sorted(set(s)))
' Bbelou'

Sort letters and keep duplicates:

>>> s = "Bubble Bobble"
>>> ''.join(sorted(s))
' BBbbbbeellou'

If you want to get rid of the space in the result, add strip() function in any of those mentioned cases:

>>> s = "Bubble Bobble"
>>> ''.join(sorted(set(s.lower()))).strip()

Adding Counter in shell script

Try this:

while true; do
  if /home/hadoop/latest/bin/hadoop fs -ls /apps/hdtech/bds/quality-rt/dt=$DATE_YEST_FORMAT2 then
       echo "Files Present" | mailx -s "File Present"  -r [email protected] [email protected]
  elif [[ "$counter" -gt 20 ]]; then
       echo "Counter limit reached, exit script."
       exit 1
       let counter++
       echo "Sleeping for another half an hour" | mailx -s "Time to Sleep Now"  -r [email protected] [email protected]
       sleep 1800


  • break - if files are present, it will break and allow the script to process the files.
  • [[ "$counter" -gt 20 ]] - if the counter variable is greater than 20, the script will exit.
  • let counter++ - increments the counter by 1 at each pass.

'typeid' versus 'typeof' in C++

You can use Boost demangle to accomplish a nice looking name:

#include <boost/units/detail/utility.hpp>

and something like

To_main_msg_evt ev("Failed to initialize cards in " + boost::units::detail::demangle(typeid(*_IO_card.get()).name()) + ".\n", true, this);

Binding an enum to a WinForms combo box, and then setting it

 public static void FillByEnumOrderByNumber<TEnum>(this System.Windows.Forms.ListControl ctrl, TEnum enum1, bool showValueInDisplay = true) where TEnum : struct
        if (!typeof(TEnum).IsEnum) throw new ArgumentException("An Enumeration type is required.", "enumObj");

        var values = from TEnum enumValue in Enum.GetValues(typeof(TEnum))
                         KeyValuePair<TEnum, string>(   (enumValue), enumValue.ToString());

        ctrl.DataSource = values
            .OrderBy(x => x.Key)


        ctrl.DisplayMember = "Value";
        ctrl.ValueMember = "Key";

        ctrl.SelectedValue = enum1;
    public static void  FillByEnumOrderByName<TEnum>(this System.Windows.Forms.ListControl ctrl, TEnum enum1, bool showValueInDisplay = true  ) where TEnum : struct
        if (!typeof(TEnum).IsEnum) throw new ArgumentException("An Enumeration type is required.", "enumObj");

        var values = from TEnum enumValue in Enum.GetValues(typeof(TEnum))
                         KeyValuePair<TEnum,string> ( (enumValue),  enumValue.ToString()  );

        ctrl.DataSource = values

        ctrl.DisplayMember = "Value";
        ctrl.ValueMember = "Key";

        ctrl.SelectedValue = enum1;

.net Core 2.0 - Package was restored using .NetFramework 4.6.1 instead of target framework .netCore 2.0. The package may not be fully compatible

For me, I had ~6 different Nuget packages to update and when I selected Microsoft.AspNetCore.All first, I got the referenced error.

I started at the bottom and updated others first (EF Core, EF Design Tools, etc), then when the only one that was left was Microsoft.AspNetCore.All it worked fine.

Insert PHP code In WordPress Page and Post


there are 3 steps to run PHP code inside post or page.

  1. In functions.php file (in your theme) add new function

  2. In functions.php file (in your theme) register new shortcode which call your function:

add_shortcode( 'SHORCODE_NAME', 'FUNCTION_NAME' );
  1. use your new shortcode

Example #1: just display text.

In functions:

function simple_function_1() {
    return "Hello World!";

add_shortcode( 'own_shortcode1', 'simple_function_1' );

In post/page:



Hello World!

Example #2: use for loop.

In functions:

function simple_function_2() {
    $output = "";
    for ($number = 1; $number < 10; $number++) {    
        // Append numbers to the string
        $output .= "$number<br>";
    return "$output";

add_shortcode( 'own_shortcode2', 'simple_function_2' );

In post/page:




Example #3: use shortcode with arguments

In functions:

function simple_function_3($name) {
    return "Hello $name";

add_shortcode( 'own_shortcode3', 'simple_function_3' );

In post/page:

[own_shortcode3 name="John"]


Hello John

Example #3 - without passing arguments

In post/page:




What is let-* in Angular 2 templates?

update Angular 5

ngOutletContext was renamed to ngTemplateOutletContext

See also


Templates (<template>, or <ng-template> since 4.x) are added as embedded views and get passed a context.

With let-col the context property $implicit is made available as col within the template for bindings. With let-foo="bar" the context property bar is made available as foo.

For example if you add a template

<ng-template #myTemplate let-col let-foo="bar">

<!-- render above template with a custom context -->
<ng-template [ngTemplateOutlet]="myTemplate"
                                           $implicit: 'some col value',
                                           bar: 'some bar value'

See also this answer and ViewContainerRef#createEmbeddedView.

*ngFor also works this way. The canonical syntax makes this more obvious

<ng-template ngFor let-item [ngForOf]="items" let-i="index" let-odd="odd">

where NgFor adds the template as embedded view to the DOM for each item of items and adds a few values (item, index, odd) to the context.

See also Using $implict to pass multiple parameters

php Replacing multiple spaces with a single space

preg_replace("/[[:blank:]]+/"," ",$input)

How to increase heap size for jBoss server

I have mentioned the configuration changes needed for the increase of heap size in Windows or Linux environments.



Check for the following line,


and change it accordingly to suit your heap size needs

-Xms1303m: initial heap size in megabytes
-Xmx1303m: maximum heap size in megabytes

JAVA_OPTS="-Xms1024M -Xmx2048M -XX:MaxPermSize=2048M -XX:MaxHeapSize=2048M"



JAVA_OPTS="-Xms1024M -Xmx2048M -XX:MaxPermSize=2048M -XX:MaxHeapSize=2048M"

Now restart the server and it will work without prompting any heap size errors.

For more information you can refer this link below.

Jenkins: Can comments be added to a Jenkinsfile?

The Jenkinsfile is written in groovy which uses the Java (and C) form of comments:

/* this
   is a
   multi-line comment */

// this is a single line comment

Simple conversion between java.util.Date and XMLGregorianCalendar

Why not use an external binding file to tell XJC to generate java.util.Date fields instead of XMLGregorianCalendar?

Also see How do I map xs:date to java.util.Date? Blog

Get the last day of the month in SQL

This query can also be used.


SELECT DATEADD(DAY, - DAY(@SelectedDate), DATEADD(MONTH, 1 , @SelectedDate)) EndOfMonth

How to execute .sql file using powershell?

if(Test-Path "C:\Program Files\Microsoft SQL Server\MSSQL11.SQLEXPRESS") { #Sql Server 2012
    Import-Module SqlPs -DisableNameChecking
    C: # Switch back from SqlServer
} else { #Sql Server 2008
    Add-PSSnapin SqlServerCmdletSnapin100 # here live Invoke-SqlCmd

Invoke-Sqlcmd -InputFile "MySqlScript.sql" -ServerInstance "Database name" -ErrorAction 'Stop' -Verbose -QueryTimeout 1800 # 30min


if not exists (select * from sysobjects where name='cars' and xtype='U')
    create table cars (
        Name varchar(64) not null

The above will create a table called cars if the table does not already exist.

How do you create optional arguments in php?

If you don't know how many attributes need to be processed, you can use the variadic argument list token(...) introduced in PHP 5.6 (see full documentation here).


function <functionName> ([<type> ]...<$paramName>) {}

For example:

function someVariadricFunc(...$arguments) {
  foreach ($arguments as $arg) {
    // do some stuff with $arg...

someVariadricFunc();           // an empty array going to be passed
someVariadricFunc('apple');    // provides a one-element array
someVariadricFunc('apple', 'pear', 'orange', 'banana');

As you can see, this token basically turns all parameters to an array, which you can process in any way you like.

Should I call Close() or Dispose() for stream objects?

This is an old question, but you can now write using statements without needing to block each one. They will be disposed of in reverse order when the containing block is finished.

using var responseStream = response.GetResponseStream();
using var reader = new StreamReader(responseStream);
using var writer = new StreamWriter(filename);

int chunkSize = 1024;
while (!reader.EndOfStream)
    char[] buffer = new char[chunkSize];
    int count = reader.Read(buffer, 0, chunkSize);
    if (count != 0)
        writer.Write(buffer, 0, count);

Prevent flicker on webkit-transition of webkit-transform

For a more detailed explanation, check out this post:

I would definitely avoid applying it to the entire body. The key is to make sure whatever specific element you plan on transforming in the future starts out rendered in 3d so the browsers doesn't have to switch in and out of rendering modes. Adding

-webkit-transform: translateZ(0) 

(or either of the options already mentioned) to the animated element will accomplish this.

Ignoring a class property in Entity Framework 4.1 Code First

As of EF 5.0, you need to include the System.ComponentModel.DataAnnotations.Schema namespace.

What is an example of the Liskov Substitution Principle?

A great example illustrating LSP (given by Uncle Bob in a podcast I heard recently) was how sometimes something that sounds right in natural language doesn't quite work in code.

In mathematics, a Square is a Rectangle. Indeed it is a specialization of a rectangle. The "is a" makes you want to model this with inheritance. However if in code you made Square derive from Rectangle, then a Square should be usable anywhere you expect a Rectangle. This makes for some strange behavior.

Imagine you had SetWidth and SetHeight methods on your Rectangle base class; this seems perfectly logical. However if your Rectangle reference pointed to a Square, then SetWidth and SetHeight doesn't make sense because setting one would change the other to match it. In this case Square fails the Liskov Substitution Test with Rectangle and the abstraction of having Square inherit from Rectangle is a bad one.

enter image description here

Y'all should check out the other priceless SOLID Principles Motivational Posters.

How can I run Tensorboard on a remote server?

Another option if you can't get it working for some reason is to simply mount a logdir directory on your filesystem with sshfs:

sshfs user@host:/home/user/project/summary_logs ~/summary_logs

and then run Tensorboard locally.

Set the value of an input field

If the field for whatever reason only has a name attribute and nothing else, you can try this:

document.getElementsByName("INPUTNAME")[0].value = "TEXT HERE";

How to multiply all integers inside list

The simplest way to me is:

map((2).__mul__, [1, 2, 3])

SQL DATEPART(dw,date) need monday = 1 and sunday = 7

Try this:

          @addDate AS DATE, 
          @numDays AS INT

    WHILE @numDays > 0 BEGIN
        SET @addDate = DATEADD(day, 1, @addDate)    
        IF DATENAME(DW, @addDate) <> 'sunday' BEGIN
            SET @numDays = @numDays - 1 


SET versus SELECT when assigning variables?

Quote, which summarizes from this article:

  1. SET is the ANSI standard for variable assignment, SELECT is not.
  2. SET can only assign one variable at a time, SELECT can make multiple assignments at once.
  3. If assigning from a query, SET can only assign a scalar value. If the query returns multiple values/rows then SET will raise an error. SELECT will assign one of the values to the variable and hide the fact that multiple values were returned (so you'd likely never know why something was going wrong elsewhere - have fun troubleshooting that one)
  4. When assigning from a query if there is no value returned then SET will assign NULL, where SELECT will not make the assignment at all (so the variable will not be changed from its previous value)
  5. As far as speed differences - there are no direct differences between SET and SELECT. However SELECT's ability to make multiple assignments in one shot does give it a slight speed advantage over SET.

Set icon for Android application

It's better to do this through Android Studio rather than the file browser as it updates all icon files with the correct resolution for each.

To do so go to menu File ? New ? Image Asset. This will open a new dialogue and then make sure Launcher Icons is selected (Which it is by default) and then browse to the directory of your icon (it doesn't have to be in the project resources) and then once selected make sure other settings are to your liking and hit done.

Now all resolutions are saved into their respective folders, and you don't have to worry about copying it yourself or using tools, etc.

Enter image description here

Don't forget "Shape - none" for a transparent background.

Please don't edit my answer without asking.

Print the data in ResultSet along with column names

For those who wanted more better version of the resultset printing as util class This was really helpful for printing resultset and does many things from a single util... thanks to Hami Torun!

In this class printResultSet uses ResultSetMetaData in a generic way have a look at it..

import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.StringJoiner;

public final class DBTablePrinter {

     * Column type category for CHAR, VARCHAR
     * and similar text columns.
    public static final int CATEGORY_STRING = 1;
     * Column type category for TINYINT, SMALLINT,
     * INT and BIGINT columns.
    public static final int CATEGORY_INTEGER = 2;
     * Column type category for REAL, DOUBLE,
     * and DECIMAL columns.
    public static final int CATEGORY_DOUBLE = 3;
     * Column type category for date and time related columns like
    public static final int CATEGORY_DATETIME = 4;
     * Column type category for BOOLEAN columns.
    public static final int CATEGORY_BOOLEAN = 5;
     * Column type category for types for which the type name
     * will be printed instead of the content, like BLOB,
     * BINARY, ARRAY etc.
    public static final int CATEGORY_OTHER = 0;
     * Default maximum number of rows to query and print.
    private static final int DEFAULT_MAX_ROWS = 10;
     * Default maximum width for text columns
     * (like a VARCHAR) column.
    private static final int DEFAULT_MAX_TEXT_COL_WIDTH = 150;

     * Overloaded method that prints rows from table tableName
     * to standard out using the given database connection
     * conn. Total number of rows will be limited to
     * {@link #DEFAULT_MAX_ROWS} and
     * {@link #DEFAULT_MAX_TEXT_COL_WIDTH} will be used to limit
     * the width of text columns (like a VARCHAR column).
     * @param conn      Database connection object (java.sql.Connection)
     * @param tableName Name of the database table
    public static void printTable(Connection conn, String tableName) {
        printTable(conn, tableName, DEFAULT_MAX_ROWS, DEFAULT_MAX_TEXT_COL_WIDTH);

     * Overloaded method that prints rows from table tableName
     * to standard out using the given database connection
     * conn. Total number of rows will be limited to
     * maxRows and
     * {@link #DEFAULT_MAX_TEXT_COL_WIDTH} will be used to limit
     * the width of text columns (like a VARCHAR column).
     * @param conn      Database connection object (java.sql.Connection)
     * @param tableName Name of the database table
     * @param maxRows   Number of max. rows to query and print
    public static void printTable(Connection conn, String tableName, int maxRows) {
        printTable(conn, tableName, maxRows, DEFAULT_MAX_TEXT_COL_WIDTH);

     * Overloaded method that prints rows from table tableName
     * to standard out using the given database connection
     * conn. Total number of rows will be limited to
     * maxRows and
     * maxStringColWidth will be used to limit
     * the width of text columns (like a VARCHAR column).
     * @param conn              Database connection object (java.sql.Connection)
     * @param tableName         Name of the database table
     * @param maxRows           Number of max. rows to query and print
     * @param maxStringColWidth Max. width of text columns
    public static void printTable(Connection conn, String tableName, int maxRows, int maxStringColWidth) {
        if (conn == null) {
            System.err.println("DBTablePrinter Error: No connection to database (Connection is null)!");
        if (tableName == null) {
            System.err.println("DBTablePrinter Error: No table name (tableName is null)!");
        if (tableName.length() == 0) {
            System.err.println("DBTablePrinter Error: Empty table name!");
        if (maxRows 
     * ResultSet to standard out using {@link #DEFAULT_MAX_TEXT_COL_WIDTH}
     * to limit the width of text columns.
     * @param rs The ResultSet to print
    public static void printResultSet(ResultSet rs) {
        printResultSet(rs, DEFAULT_MAX_TEXT_COL_WIDTH);

     * Overloaded method to print rows of a 
     * ResultSet to standard out using maxStringColWidth
     * to limit the width of text columns.
     * @param rs                The ResultSet to print
     * @param maxStringColWidth Max. width of text columns
    public static void printResultSet(ResultSet rs, int maxStringColWidth) {
        try {
            if (rs == null) {
                System.err.println("DBTablePrinter Error: Result set is null!");
            if (rs.isClosed()) {
                System.err.println("DBTablePrinter Error: Result Set is closed!");
            if (maxStringColWidth  columns = new ArrayList(columnCount);

            // List of table names. Can be more than one if it is a joined
            // table query
            List tableNames = new ArrayList(columnCount);

            // Get the columns and their meta data.
            // NOTE: columnIndex for rsmd.getXXX methods STARTS AT 1 NOT 0
            for (int i = 1; i  maxStringColWidth) {
                                value = value.substring(0, maxStringColWidth - 3) + "...";

                    // Adjust the column width
                    c.setWidth(value.length() > c.getWidth() ? value.length() : c.getWidth());
                } // END of for loop columnCount

            } // END of while (

            At this point we have gone through meta data, get the
            columns and created all Column objects, iterated over the
            ResultSet rows, populated the column values and adjusted
            the column widths.
            We cannot start printing just yet because we have to prepare
            a row separator String.

            // For the fun of it, I will use StringBuilder
            StringBuilder strToPrint = new StringBuilder();
            StringBuilder rowSeparator = new StringBuilder();

            Prepare column labels to print as well as the row separator.
            It should look something like this:
            +--------+------------+------------+-----------+  (row separator)
            | EMP_NO | BIRTH_DATE | FIRST_NAME | LAST_NAME |  (labels row)
            +--------+------------+------------+-----------+  (row separator)

            // Iterate over columns
            for (Column c : columns) {
                int width = c.getWidth();

                // Center the column label
                String toPrint;
                String name = c.getLabel();
                int diff = width - name.length();

                if ((diff % 2) == 1) {
                    // diff is not divisible by 2, add 1 to width (and diff)
                    // so that we can have equal padding to the left and right
                    // of the column label.

                int paddingSize = diff / 2; // InteliJ says casting to int is redundant.

                // Cool String repeater code thanks to user102008 at

                String padding = new String(new char[paddingSize]).replace("\0", " ");

                toPrint = "| " + padding + name + padding + " ";
                // END centering the column label


                rowSeparator.append(new String(new char[width + 2]).replace("\0", "-"));

            String lineSeparator = System.getProperty("line.separator");

            // Is this really necessary ??
            lineSeparator = lineSeparator == null ? "\n" : lineSeparator;


            strToPrint.insert(0, rowSeparator);

            StringJoiner sj = new StringJoiner(", ");
            for (String name : tableNames) {

            String info = "Printing " + rowCount;
            info += rowCount > 1 ? " rows from " : " row from ";
            info += tableNames.size() > 1 ? "tables " : "table ";
            info += sj.toString();


            // Print out the formatted column labels

            String format;

            // Print out the rows
            for (int i = 0; i 
     * Integers should not be truncated so column widths should
     * be adjusted without a column width limit. Text columns should be
     * left justified and can be truncated to a max. column width etc...


* See also: * java.sql.Types * * @param type Generic SQL type * @return The category this type belongs to */ private static int whichCategory(int type) { switch (type) { case Types.BIGINT: case Types.TINYINT: case Types.SMALLINT: case Types.INTEGER: return CATEGORY_INTEGER; case Types.REAL: case Types.DOUBLE: case Types.DECIMAL: return CATEGORY_DOUBLE; case Types.DATE: case Types.TIME: case Types.TIME_WITH_TIMEZONE: case Types.TIMESTAMP: case Types.TIMESTAMP_WITH_TIMEZONE: return CATEGORY_DATETIME; case Types.BOOLEAN: return CATEGORY_BOOLEAN; case Types.VARCHAR: case Types.NVARCHAR: case Types.LONGVARCHAR: case Types.LONGNVARCHAR: case Types.CHAR: case Types.NCHAR: return CATEGORY_STRING; default: return CATEGORY_OTHER; } } /** * Represents a database table column. */ private static class Column { /** * Column label. */ private String label; /** * Generic SQL type of the column as defined in * * java.sql.Types * . */ private int type; /** * Generic SQL type name of the column as defined in * * java.sql.Types * . */ private String typeName; /** * Width of the column that will be adjusted according to column label * and values to be printed. */ private int width = 0; /** * Column values from each row of a ResultSet. */ private List values = new ArrayList(); /** * Flag for text justification using String.format. * Empty string ("") to justify right, * dash (-) to justify left. * * @see #justifyLeft() */ private String justifyFlag = ""; /** * Column type category. The columns will be categorised according * to their column types and specific needs to print them correctly. */ private int typeCategory = 0; /** * Constructs a new Column with a column label, * generic SQL type and type name (as defined in * * java.sql.Types * ) * * @param label Column label or name * @param type Generic SQL type * @param typeName Generic SQL type name */ public Column(String label, int type, String typeName) { this.label = label; this.type = type; this.typeName = typeName; } /** * Returns the column label * * @return Column label */ public String getLabel() { return label; } /** * Returns the generic SQL type of the column * * @return Generic SQL type */ public int getType() { return type; } /** * Returns the generic SQL type name of the column * * @return Generic SQL type name */ public String getTypeName() { return typeName; } /** * Returns the width of the column * * @return Column width */ public int getWidth() { return width; } /** * Sets the width of the column to width * * @param width Width of the column */ public void setWidth(int width) { this.width = width; } /** * Adds a String representation (value) * of a value to this column object's {@link #values} list. * These values will come from each row of a * * ResultSet * of a database query. * * @param value The column value to add to {@link #values} */ public void addValue(String value) { values.add(value); } /** * Returns the column value at row index i. * Note that the index starts at 0 so that getValue(0) * will get the value for this column from the first row * of a * ResultSet. * * @param i The index of the column value to get * @return The String representation of the value */ public String getValue(int i) { return values.get(i); } /** * Returns the value of the {@link #justifyFlag}. The column * values will be printed using String.format and * this flag will be used to right or left justify the text. * * @return The {@link #justifyFlag} of this column * @see #justifyLeft() */ public String getJustifyFlag() { return justifyFlag; } /** * Sets {@link #justifyFlag} to "-" so that * the column value will be left justified when printed with * String.format. Typically numbers will be right * justified and text will be left justified. */ public void justifyLeft() { this.justifyFlag = "-"; } /** * Returns the generic SQL type category of the column * * @return The {@link #typeCategory} of the column */ public int getTypeCategory() { return typeCategory; } /** * Sets the {@link #typeCategory} of the column * * @param typeCategory The type category */ public void setTypeCategory(int typeCategory) { this.typeCategory = typeCategory; } } }

This is the scala version of doing this... which will print column names and data as well in a generic way...

def printQuery(res: ResultSet): Unit = {
    val rsmd = res.getMetaData
    val columnCount = rsmd.getColumnCount
    var rowCnt = 0
    val s = StringBuilder.newBuilder
    while ( {

      if (rowCnt == 0) {
        s.append("| ")
        for (i <- 1 to columnCount) {
          val name = rsmd.getColumnName(i)
          s.append("| ")
      rowCnt += 1
      s.append("| ")
      for (i <- 1 to columnCount) {
        if (i > 1)
          s.append(" | ")
      s.append(" |")
    System.out.println(s"TOTAL: $rowCnt rows")

FORCE INDEX in MySQL - where do I put it?

The syntax for index hints is documented here:

FORCE INDEX goes right after the table reference:

    SELECT owner_id,
    FROM db_products FORCE INDEX (products_start_time)
    ORDER BY start_time DESC
) as resultstable
WHERE resultstable.closed = 0
      AND = 1
      AND resultstable.approved = 1
      AND resultstable.deleted = 0
      AND resultstable.creation_in_progress = 0
GROUP BY resultstable.owner_id
ORDER BY start_time DESC


If you're using ORDER BY before GROUP BY to get the latest entry per owner_id, you're using a nonstandard and undocumented behavior of MySQL to do that.

There's no guarantee that it'll continue to work in future versions of MySQL, and the query is likely to be an error in any other RDBMS.

Search the tag for many explanations of better solutions for this type of query.

How to find elements with 'value=x'?

Value exactly equal to 123:


Full reference:

Adding an onclick event to a table row

I try to figure out how to get a better result with pure JS and i get something this:


const tbody = document.getElementById("tbody");
let rowSelected;

tbody.onclick = (e) => {
  for (let i = 0; i < e.path.length; ++i) {
    if (e.path[i].tagName == "TR") {

function selectRow(r) {
  if (rowSelected !== undefined) = "white";

  rowSelected = r; = "dodgerblue";

And now you can use the variable rowSelected in other function like you want or call another function after set the style

ListView item background via custom selector

I've been frustrated by this myself and finally solved it. As Romain Guy hinted to, there's another state, "android:state_selected", that you must use. Use a state drawable for the background of your list item, and use a different state drawable for listSelector of your list:


<?xml version="1.0" encoding="utf-8"?>


<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="">
    <item android:state_selected="true" android:drawable="@color/android:transparent" />
    <item android:drawable="@drawable/listitem_normal" />

layout.xml that includes the ListView:



<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="">
    <item android:state_pressed="true" android:drawable="@drawable/listitem_pressed" />
    <item android:state_focused="true" android:drawable="@drawable/listitem_selected" />

Where is the documentation for the values() method of Enum?

You can't see this method in javadoc because it's added by the compiler.

Documented in three places :

The compiler automatically adds some special methods when it creates an enum. For example, they have a static values method that returns an array containing all of the values of the enum in the order they are declared. This method is commonly used in combination with the for-each construct to iterate over the values of an enum type.

  • Enum.valueOf class
    (The special implicit values method is mentioned in description of valueOf method)

All the constants of an enum type can be obtained by calling the implicit public static T[] values() method of that type.

The values function simply list all values of the enumeration.

Show only two digit after decimal

double i2=i/60000;
DecimalFormat dtime = new DecimalFormat("#.##"); 
i2= Double.valueOf(dtime.format(time));

Is there a way to avoid null check before the for-each loop iteration starts?

How much shorter do you want it to be? It is only an extra 2 lines AND it is clear and concise logic.

I think the more important thing you need to decide is if null is a valid value or not. If they are not valid, you should write you code to prevent it from happening. Then you would not need this kind of check. If you go get an exception while doing a foreach loop, that is a sign that there is a bug somewhere else in your code.

How to scroll to specific item using jQuery?

I did this combination. its work for me. but facing one issue if click move that div size is too large that scenerio scroll not down to this particular div.

 var scrollDownTo =$("#show_question_" + nQueId).position().top;
            scrollTop: scrollDownTo
            }, 1000, function(){


How can I convert the "arguments" object to an array in JavaScript?

Benshmarck 3 methods :

function test()
  console.log(arguments.length + ' Argument(s)');

  var i = 0;
  var loop = 1000000;
  var t =;
  while(i < loop)
  {, 0); 
  console.log( - t);

  i = 0,
  t =;
  while(i < loop)
      Array.apply(null, arguments);
  console.log( - t);

  i = 0,
  t =;
  while(i < loop)
      arguments.length == 1 ? [arguments[0]] : Array.apply(null, arguments);
  console.log( - t);

test(42, 44);
test(42, 44, 88, 64, 10, 64, 700, 15615156, 4654, 9);
test(42, 'truc', 44, '47', 454, 88, 64, '@ehuehe', 10, 64, 700, 15615156, 4654, 9,97,4,94,56,8,456,156,1,456,867,5,152489,74,5,48479,89,897,894,894,8989,489,489,4,489,488989,498498);


0 Argument(s)
1 Argument(s)
2 Argument(s)
10 Argument(s)
40 Argument(s)

Enjoy !

How to include js file in another js file?

You need to write a document.write object:

document.write('<script type="text/javascript" src="file.js" ></script>');

and place it in your main javascript file

How to convert wstring into string?

Default encoding on:

  • Windows UTF-16.
  • Linux UTF-8.
  • MacOS UTF-8.

My solution Steps, includes null chars \0 (avoid truncated). Without using functions on windows.h header:

  1. Add Macros to detect Platform. Windows/Linux and others
  1. Create function to convert std::wstring to std::string and inverse std::string to std::wstring
  1. Create function for print
  1. Print std::string/ std::wstring

Check RawString Literals. Raw String Suffix.

Linux Code. Print directly std::string using std::cout, Default Encoding on Linux is UTF-8, no need extra functions.

On Windows if you need to print unicode. We can use WriteConsole for print unicode chars from std::wstring.

Finally on Windows. You need a powerfull and complete view support for unicode chars in console. I recommend Windows Terminal


  • Tested on Microsoft Visual Studio 2019 with VC++; std=c++17. (Windows Project)
  • Tested on using Clang compiler; std=c++17.

Q. Why you not use <codecvt> header functions and classes?.
A. Deprecate Removed or deprecated features impossible build on VC++, but no problems on g++. I prefer 0 warnings and headaches.

Q. std ::wstring is cross platform?
A. No. std::wstring uses wchar_t elements. On Windows wchar_t size is 2 bytes, each character is stored in UTF-16 units, if character is bigger than U+FFFF, the character is represented in two UTF-16 units(2 wchar_t elements) called surrogate pairs. On Linux wchar_t size is 4 bytes each character is stored in one wchar_t element, no needed surrogate pairs. Check Standard data types on UNIX, Linux, and Windowsl.

Q. std ::string is cross platform?
A. Yes. std::string uses char elements. char type is guaranted that is same byte size in most compilers. char type size is 1 byte. Check Standard data types on UNIX, Linux, and Windowsl.

Full example code

#include <iostream>
#include <set>
#include <string>
#include <locale>

#if (_WIN32)
#include <Windows.h>
#include <conio.h>
#define DLLIMPORT _declspec(dllimport)
#define DLLEXPORT _declspec(dllexport)
#define NOMINMAX

#elif defined(__EMSCRIPTEN__)
#include <emscripten/emscripten.h>
#include <emscripten/bind.h>
#include <unistd.h>
#include <termios.h>
#define DLLCALL
#define DLLEXPORT __attribute__((visibility("default")))
#define DLLPRIVATE __attribute__((visibility("hidden")))

// LINUX - Ubuntu, Fedora, , Centos, Debian, RedHat
#elif (__LINUX__ || __gnu_linux__ || __linux__ || __linux || linux)
#include <unistd.h>
#include <termios.h>
#define DLLEXPORT __attribute__((visibility("default")))
#define DLLPRIVATE __attribute__((visibility("hidden")))
#define CoTaskMemAlloc(p) malloc(p)
#define CoTaskMemFree(p) free(p)

#elif (__ANDROID__ || ANDROID)
#define DLLCALL
#define DLLEXPORT __attribute__((visibility("default")))
#define DLLPRIVATE __attribute__((visibility("hidden")))

#elif defined(__APPLE__)
#include <unistd.h>
#include <termios.h>
#define DLLCALL
#define DLLEXPORT __attribute__((visibility("default")))
#define DLLPRIVATE __attribute__((visibility("hidden")))
#include "TargetConditionals.h"
#define IOS_PLATFORM 1



typedef std::string String;
typedef std::wstring WString;

#define EMPTY_STRING u8""s
#define EMPTY_WSTRING L""s

using namespace std::literals::string_literals;

class Strings
    static String WideStringToString(const WString& wstr)
        if (wstr.empty())
            return String();
        size_t pos;
        size_t begin = 0;
        String ret;

        int size;
        pos = wstr.find(static_cast<wchar_t>(0), begin);
        while (pos != WString::npos && begin < wstr.length())
            WString segment = WString(&wstr[begin], pos - begin);
            size = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, &segment[0], segment.size(), NULL, 0, NULL, NULL);
            String converted = String(size, 0);
            WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, &segment[0], segment.size(), &converted[0], converted.size(), NULL, NULL);
            ret.append({ 0 });
            begin = pos + 1;
            pos = wstr.find(static_cast<wchar_t>(0), begin);
        if (begin <= wstr.length())
            WString segment = WString(&wstr[begin], wstr.length() - begin);
            size = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, &segment[0], segment.size(), NULL, 0, NULL, NULL);
            String converted = String(size, 0);
            WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, &segment[0], segment.size(), &converted[0], converted.size(), NULL, NULL);
        size_t size;
        pos = wstr.find(static_cast<wchar_t>(0), begin);
        while (pos != WString::npos && begin < wstr.length())
            WString segment = WString(&wstr[begin], pos - begin);
            size = wcstombs(nullptr, segment.c_str(), 0);
            String converted = String(size, 0);
            wcstombs(&converted[0], segment.c_str(), converted.size());
            ret.append({ 0 });
            begin = pos + 1;
            pos = wstr.find(static_cast<wchar_t>(0), begin);
        if (begin <= wstr.length())
            WString segment = WString(&wstr[begin], wstr.length() - begin);
            size = wcstombs(nullptr, segment.c_str(), 0);
            String converted = String(size, 0);
            wcstombs(&converted[0], segment.c_str(), converted.size());
        static_assert(false, "Unknown Platform");
        return ret;

    static WString StringToWideString(const String& str)
        if (str.empty())
            return WString();

        size_t pos;
        size_t begin = 0;
        WString ret;
        int size = 0;
        pos = str.find(static_cast<char>(0), begin);
        while (pos != std::string::npos) {
            std::string segment = std::string(&str[begin], pos - begin);
            std::wstring converted = std::wstring(segment.size() + 1, 0);
            size = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, &segment[0], segment.size(), &converted[0], converted.length());
            ret.append({ 0 });
            begin = pos + 1;
            pos = str.find(static_cast<char>(0), begin);
        if (begin < str.length()) {
            std::string segment = std::string(&str[begin], str.length() - begin);
            std::wstring converted = std::wstring(segment.size() + 1, 0);
            size = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, segment.c_str(), segment.size(), &converted[0], converted.length());

        size_t size;
        pos = str.find(static_cast<char>(0), begin);
        while (pos != String::npos)
            String segment = String(&str[begin], pos - begin);
            WString converted = WString(segment.size(), 0);
            size = mbstowcs(&converted[0], &segment[0], converted.size());
            ret.append({ 0 });
            begin = pos + 1;
            pos = str.find(static_cast<char>(0), begin);
        if (begin < str.length())
            String segment = String(&str[begin], str.length() - begin);
            WString converted = WString(segment.size(), 0);
            size = mbstowcs(&converted[0], &segment[0], converted.size());
        static_assert(false, "Unknown Platform");
        return ret;

enum class ConsoleTextStyle
    DEFAULT = 0,
    BOLD = 1,
    FAINT = 2,
    ITALIC = 3,
    UNDERLINE = 4,
    SLOW_BLINK = 5,
    RAPID_BLINK = 6,
    REVERSE = 7,

enum class ConsoleForeground
    DEFAULT = 39,
    BLACK = 30,
    DARK_RED = 31,
    DARK_GREEN = 32,
    DARK_YELLOW = 33,
    DARK_BLUE = 34,
    DARK_MAGENTA = 35,
    DARK_CYAN = 36,
    GRAY = 37,
    DARK_GRAY = 90,
    RED = 91,
    GREEN = 92,
    YELLOW = 93,
    BLUE = 94,
    MAGENTA = 95,
    CYAN = 96,
    WHITE = 97

enum class ConsoleBackground
    DEFAULT = 49,
    BLACK = 40,
    DARK_RED = 41,
    DARK_GREEN = 42,
    DARK_YELLOW = 43,
    DARK_BLUE = 44,
    DARK_MAGENTA = 45,
    DARK_CYAN = 46,
    GRAY = 47,
    DARK_GRAY = 100,
    RED = 101,
    GREEN = 102,
    YELLOW = 103,
    BLUE = 104,
    MAGENTA = 105,
    CYAN = 106,
    WHITE = 107

class Console
    static void EnableVirtualTermimalProcessing()
        HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
        DWORD dwMode = 0;
        GetConsoleMode(hOut, &dwMode);
            SetConsoleMode(hOut, dwMode);

    static void ResetTerminalFormat()
        std::cout << u8"\033[0m";

    static void SetVirtualTerminalFormat(ConsoleForeground foreground, ConsoleBackground background, std::set<ConsoleTextStyle> styles)
        String format = u8"\033[";
        if (styles.size() > 0)
            for (auto it = styles.begin(); it != styles.end(); ++it)
        std::cout << format;
    static void Clear()

        static_assert(false, "Unknown Platform");

    static void Write(const String& s, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
        SetVirtualTerminalFormat(foreground, background, styles);
        String str = s;
        WString unicode = Strings::StringToWideString(str);
        WriteConsole(GetStdHandle(STD_OUTPUT_HANDLE), unicode.c_str(), static_cast<DWORD>(unicode.length()), nullptr, nullptr);
        std::cout << str;
        static_assert(false, "Unknown Platform");


    static void WriteLine(const String& s, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
        Write(s, foreground, background, styles);
        std::cout << std::endl;

    static void Write(const WString& s, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
        SetVirtualTerminalFormat(foreground, background, styles);
        WString str = s;

        WriteConsole(GetStdHandle(STD_OUTPUT_HANDLE), str.c_str(), static_cast<DWORD>(str.length()), nullptr, nullptr);
        std::cout << Strings::WideStringToString(str);
        static_assert(false, "Unknown Platform");


    static void WriteLine(const WString& s, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
        Write(s, foreground, background, styles);
        std::cout << std::endl;

    static void WriteLine()
        std::cout << std::endl;

    static void Pause()
        char c;
            c = getchar();
            std::cout << "Press Key " << std::endl;
        } while (c != 64);
        std::cout << "KeyPressed" << std::endl;

    static int PauseAny(bool printWhenPressed = false, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
        int ch;
        ch = _getch();
        struct termios oldt, newt;
        tcgetattr(STDIN_FILENO, &oldt);
        newt = oldt;
        newt.c_lflag &= ~(ICANON | ECHO);
        tcsetattr(STDIN_FILENO, TCSANOW, &newt);
        ch = getchar();
        tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
        static_assert(false, "Unknown Platform");
        if (printWhenPressed)
            Console::Write(String(1, ch), foreground, background, styles);
        return ch;

int main()
    auto str = u8"\0Hello\0123456789?????????123456789??"s;//
    WString wstr = L"\0Hello\0123456789?????????123456789??"s;
    WString wstrResult = Strings::StringToWideString(str);
    String strResult = Strings::WideStringToString(wstr);
    bool equals1 = wstr == wstrResult;
    bool equals2 = str == strResult;

    Console::WriteLine(u8"¦ Converted Strings printed with Console::WriteLine"s, ConsoleForeground::GREEN);
    Console::WriteLine(wstrResult, ConsoleForeground::BLUE);//Printed OK on Windows/Linux.
    Console::WriteLine(strResult, ConsoleForeground::BLUE);//Printed OK on Windows/Linux.
    Console::WriteLine(u8"¦ Converted Strings printed with std::cout/std::wcout"s, ConsoleForeground::GREEN);
    std::cout << strResult << std::endl;//Printed OK on Linux. BAD on Windows.
    std::wcout << wstrResult << std::endl; //Printed BAD on Windows/Linux.
    Console::WriteLine(u8"Press any key to exit"s, ConsoleForeground::DARK_GRAY);


You cant test this code on


Using Windows Terminal WindowsTerminal

Using cmd/powershell enter image description here capture
enter image description here

SQL Server returns error "Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'." in Windows application

If your issue is with linked servers, you need to look at a few things.

First, your users need to have delegation enabled and if the only thing that's changed, it'l likely they do. Otherwise you can uncheck the "Account is sensitive and cannot be delegated" checkbox is the user properties in AD.

Second, your service account(s) must be trusted for delegation. Since you recently changed your service account I suspect this is the culprit. (

You mentioned that you might have some SPN issues, so be sure to set the SPN for both endpoints, otherwise you will not be able to see the delegation tab in AD. Also make sure you're in advanced view in "Active Directory Users and Computers."

If you still do not see the delegation tab, even after correcting your SPN, make sure your domain not in 2000 mode. If it is, you can "raise domain function level."

At this point, you can now mark the account as trusted for delegation:

In the details pane, right-click the user you want to be trusted for delegation, and click Properties.

Click the Delegation tab, select the Account is trusted for delegation check box, and then click OK.

Finally you will also need to set all the machines as trusted for delegation.

Once you've done this, reconnect to your sql server and test your liked servers. They should work.

How to give color to each class in scatter plot in R?

Here is an example that I built based on this page.

library(e1071); library(ggplot2)

mysvm      <- svm(Species ~ ., iris)
Predicted  <- predict(mysvm, iris)

mydf = cbind(iris, Predicted)
qplot(Petal.Length, Petal.Width, colour = Species, shape = Predicted, 
   data = iris)

This gives you the output. You can easily spot the misclassified species from this figure.

enter image description here

invalid command code ., despite escaping periods, using sed

Probably your new domain contain / ? If so, try using separator other than / in sed, e.g. #, , etc.

find ./ -type f -exec sed -i '' {} \;

It would also be good to enclose s/// in single quote rather than double quote to avoid variable substitution or any other unexpected behaviour

android.content.res.Resources$NotFoundException: String resource ID #0x0

The evaluated value for settext was integer so it went to see a resource attached to it but it was not found, you wanted to set text so it should be string so convert integer into string by attaching .toStringe or String.valueOf(int) will solve your problem!

Making PHP var_dump() values display one line per value

Use output buffers:

    var_dump($_SERVER) ;
    $dump = ob_get_contents();

    echo "<pre> $dump </pre>";

Yet another option would be to use Output buffering and convert all the newlines in the dump to <br> elements, e.g.

var_dump($_SERVER) ;
echo nl2br(ob_get_clean());

db.collection is not a function when using MongoClient v3.0

I encountered the same thing. In package.json, change mongodb line to "mongodb": "^2.2.33". You will need to npm uninstall mongodb; then npm install to install this version.

This resolved the issue for me. Seems to be a bug or docs need to be updated.

Circular dependency in Spring

If two beans are dependent on each other then we should not use Constructor injection in both the bean definitions. Instead we have to use setter injection in any one of the beans. (of course we can use setter injection n both the bean definitions, but constructor injections in both throw 'BeanCurrentlyInCreationException'

Refer Spring doc at ""

What is for Python what 'explode' is for PHP?

The alternative for explode in php is split.

The first parameter is the delimiter, the second parameter the maximum number splits. The parts are returned without the delimiter present (except possibly the last part). When the delimiter is None, all whitespace is matched. This is the default.

>>> "Rajasekar SP".split()
['Rajasekar', 'SP']

>>> "Rajasekar SP".split('a',2)
['R','j','sekar SP']

Get size of an Iterable in Java

java 8 and above, false).count();

How do I set an ASP.NET Label text from code behind on page load?

In your ASP.NET page:

<asp:Label ID="UserNameLabel" runat="server" />

In your code behind (assuming you're using C#):

function Page_Load(object sender, EventArgs e)
    if (!Page.IsPostBack)
       UserNameLabel.Text = "User Name";

Node.js: Python not found exception due to node-sass and node-gyp

I found the same issue with Node 12.19.0 and yarn 1.22.5 on Windows 10. I fixed the problem by installing latest stable python 64-bit with adding the path to Environment Variables during python installation. After python installation, I restarted my machine for env vars.

Save child objects automatically using JPA Hibernate

in your setChilds, you might want to try looping thru the list and doing something like

child.parent = this;

you also should set up the cascade on the parent to the appropriate values.

Image Processing: Algorithm Improvement for 'Coca-Cola Can' Recognition

Looking at shape

Take a gander at the shape of the red portion of the can/bottle. Notice how the can tapers off slightly at the very top whereas the bottle label is straight. You can distinguish between these two by comparing the width of the red portion across the length of it.

Looking at highlights

One way to distinguish between bottles and cans is the material. A bottle is made of plastic whereas a can is made of aluminum metal. In sufficiently well-lit situations, looking at the specularity would be one way of telling a bottle label from a can label.

As far as I can tell, that is how a human would tell the difference between the two types of labels. If the lighting conditions are poor, there is bound to be some uncertainty in distinguishing the two anyways. In that case, you would have to be able to detect the presence of the transparent/translucent bottle itself.

Button Center CSS

Consider adding this to your CSS to resolve the problem:

.btn {
  width: 20%;
  margin-left: 40%;
  margin-right: 30%;

Already defined in .obj - no double inclusions

This is one of the method to overcome this issue.

  • Just put the prototype in the header files and include the header files in the .cpp files as shown below.


#include <boost/asio.hpp>

class SocketClient // Or whatever the name is... {

// ...

    bool read(int, char*); // Or whatever the name is...

//  ... };



bool SocketClient::read(int, char*)
    // Implementation  goes here...


#include <iostream>
#include <string>
#include <sstream>
#include <boost/asio.hpp>
#include <boost/thread/thread.hpp>
#include "client.h"
//              ^^ Notice this!


int main()

Can I call jQuery's click() to follow an <a> link if I haven't bound an event handler to it with bind or click already?

If you need this feature for one case or very few cases (your whole application is not requiring this feature). I would rather leave jQuery as is (for many reasons, including being able to update to newer versions, CDN, etc.) and have the following workaround:

// For modern browsers

// Relying on Paul Irish's conditional class names,
// <>
// (via HTML5 Boilerplate, <>) where
// each Internet Explorer version gets a class of its version
$("html.ie7").length && (function(){
    var eleOnClickattr = $(ele).attr("onclick")

How can I measure the similarity between two images?

You can use Siamese Network to see if the two images are similar or dissimilar following this tutorial. This tutorial cluster the similar images whereas you can use L2 distance to measure the similarity of two images.