Programs & Examples On #Httplistenerrequest

Understanding dispatch_async

All of the DISPATCH_QUEUE_PRIORITY_X queues are concurrent queues (meaning they can execute multiple tasks at once), and are FIFO in the sense that tasks within a given queue will begin executing using "first in, first out" order. This is in comparison to the main queue (from dispatch_get_main_queue()), which is a serial queue (tasks will begin executing and finish executing in the order in which they are received).

So, if you send 1000 dispatch_async() blocks to DISPATCH_QUEUE_PRIORITY_DEFAULT, those tasks will start executing in the order you sent them into the queue. Likewise for the HIGH, LOW, and BACKGROUND queues. Anything you send into any of these queues is executed in the background on alternate threads, away from your main application thread. Therefore, these queues are suitable for executing tasks such as background downloading, compression, computation, etc.

Note that the order of execution is FIFO on a per-queue basis. So if you send 1000 dispatch_async() tasks to the four different concurrent queues, evenly splitting them and sending them to BACKGROUND, LOW, DEFAULT and HIGH in order (ie you schedule the last 250 tasks on the HIGH queue), it's very likely that the first tasks you see starting will be on that HIGH queue as the system has taken your implication that those tasks need to get to the CPU as quickly as possible.

Note also that I say "will begin executing in order", but keep in mind that as concurrent queues things won't necessarily FINISH executing in order depending on length of time for each task.

As per Apple:

A concurrent dispatch queue is useful when you have multiple tasks that can run in parallel. A concurrent queue is still a queue in that it dequeues tasks in a first-in, first-out order; however, a concurrent queue may dequeue additional tasks before any previous tasks finish. The actual number of tasks executed by a concurrent queue at any given moment is variable and can change dynamically as conditions in your application change. Many factors affect the number of tasks executed by the concurrent queues, including the number of available cores, the amount of work being done by other processes, and the number and priority of tasks in other serial dispatch queues.

Basically, if you send those 1000 dispatch_async() blocks to a DEFAULT, HIGH, LOW, or BACKGROUND queue they will all start executing in the order you send them. However, shorter tasks may finish before longer ones. Reasons behind this are if there are available CPU cores or if the current queue tasks are performing computationally non-intensive work (thus making the system think it can dispatch additional tasks in parallel regardless of core count).

The level of concurrency is handled entirely by the system and is based on system load and other internally determined factors. This is the beauty of Grand Central Dispatch (the dispatch_async() system) - you just make your work units as code blocks, set a priority for them (based on the queue you choose) and let the system handle the rest.

So to answer your above question: you are partially correct. You are "asking that code" to perform concurrent tasks on a global concurrent queue at the specified priority level. The code in the block will execute in the background and any additional (similar) code will execute potentially in parallel depending on the system's assessment of available resources.

The "main" queue on the other hand (from dispatch_get_main_queue()) is a serial queue (not concurrent). Tasks sent to the main queue will always execute in order and will always finish in order. These tasks will also be executed on the UI Thread so it's suitable for updating your UI with progress messages, completion notifications, etc.

Can I limit the length of an array in JavaScript?

You need to actually use the shortened array after you remove items from it. You are ignoring the shortened array.

You convert the cookie into an array. You reduce the length of the array and then you never use that shortened array. Instead, you just use the old cookie (the unshortened one).

You should convert the shortened array back to a string with .join(",") and then use it for the new cookie instead of using old_cookie which is not shortened.

You may also not be using .splice() correctly, but I don't know exactly what your objective is for shortening the array. You can read about the exact function of .splice() here.

AngularJS: factory $http.get JSON file

I wanted to note that the fourth part of Accepted Answer is wrong .

theApp.factory('mainInfo', function($http) { 

var obj = {content:null};

$http.get('content.json').success(function(data) {
    // you can do some processing here
    obj.content = data;

return obj;    

The above code as @Karl Zilles wrote will fail because obj will always be returned before it receives data (thus the value will always be null) and this is because we are making an Asynchronous call.

The details of similar questions are discussed in this post

In Angular, use $promise to deal with the fetched data when you want to make an asynchronous call.

The simplest version is

theApp.factory('mainInfo', function($http) { 
    return {
        get:  function(){
            $http.get('content.json'); // this will return a promise to controller

// and in controller

mainInfo.get().then(function(response) { 
    $ =;

The reason I don't use success and error is I just found out from the doc, these two methods are deprecated.

The $http legacy promise methods success and error have been deprecated. Use the standard then method instead.

How do I find the duplicates in a list and create another list with them?

Here's a neat and concise solution -

for x in set(li):

li = list(set(li))

Returning null in a method whose signature says return int?

int is a primitive, null is not a value that it can take on. You could change the method return type to return java.lang.Integer and then you can return null, and existing code that returns int will get autoboxed.

Nulls are assigned only to reference types, it means the reference doesn't point to anything. Primitives are not reference types, they are values, so they are never set to null.

Using the object wrapper java.lang.Integer as the return value means you are passing back an Object and the object reference can be null.

A regex for version number parsing

I've seen a lot of answers, but... i have a new one. It works for me at least. I've added a new restriction. Version numbers can't start (major, minor or patch) with any zeros followed by others.

01.0.0 is not valid 1.0.0 is valid 10.0.10 is valid 1.0.0000 is not valid


It's based in a previous one. But i see this solution better... for me ;)


downloading all the files in a directory with cURL

What about something like this:

for /f %%f in ('curl -s -l -u user:pass') do curl -O -u user:pass

FB OpenGraph og:image not pulling images (possibly https?)

I had similar problems. I removed the property="og:image:secure_url" and now it will scrub with just og:image. Sometimes, less is more

&& (AND) and || (OR) in IF statements

Java has 5 different boolean compare operators: &, &&, |, ||, ^

& and && are "and" operators, | and || "or" operators, ^ is "xor"

The single ones will check every parameter, regardless of the values, before checking the values of the parameters. The double ones will first check the left parameter and its value and if true (||) or false (&&) leave the second one untouched. Sound compilcated? An easy example should make it clear:

Given for all examples:

 String aString = null;


 if (aString != null & aString.equals("lala"))

Both parameters are checked before the evaluation is done and a NullPointerException will be thrown for the second parameter.

 if (aString != null && aString.equals("lala"))

The first parameter is checked and it returns false, so the second paramter won't be checked, because the result is false anyway.

The same for OR:

 if (aString == null | !aString.equals("lala"))

Will raise NullPointerException, too.

 if (aString == null || !aString.equals("lala"))

The first parameter is checked and it returns true, so the second paramter won't be checked, because the result is true anyway.

XOR can't be optimized, because it depends on both parameters.

Usage of sys.stdout.flush() method

Python's standard out is buffered (meaning that it collects some of the data "written" to standard out before it writes it to the terminal). Calling sys.stdout.flush() forces it to "flush" the buffer, meaning that it will write everything in the buffer to the terminal, even if normally it would wait before doing so.

Here's some good information about (un)buffered I/O and why it's useful:
Buffered vs unbuffered IO

Can not run Java Applets in Internet Explorer 11 using JRE 7u51

For Windows 8.1 Users.... there is a little note on the java download site which says:

"Downloading and installing Java will only work in Desktop mode on Windows 8 and Windows 8.1. See the Java on Windows 8 FAQ for more detailed information."

Unfortunately, "Desktop mode" is not the default mode in Windows 8.1. After installing java and wasting 2hours trying to get java working with IE11, I went back to oracles site...paid a bit more attention to that warning!! switched to Desktop mode, and reinstalled java... hey presto it worked.

Furious, that java download does not work with the default config of Windows 8.1, don't know who to be more angry with? Oracle or Microsoft? ( or me for skimming over the warning..)

Android getting value from selected radiobutton

Thanks a lot to Chris.

This is my solution:

RadioGroup radgroup_opcionesEventos = null;

 private static String[] arrayEventos = {
            "Congestión", "Derrumbe", "Accidente"
    protected void onCreate(Bundle savedInstanceState)
        radgroup_opcionesEventos = (RadioGroup)findViewById(;
        int i=0;//
        for(String evento : arrayEventos) {
            //RadioButton nuevoRadio = crearRadioButton(evento);//a.old.ln
            RadioButton nuevoRadio = crearRadioButton(evento,i);//

        RadioButton primerRadio = (RadioButton) radgroup_opcionesEventos.getChildAt(0);

private RadioButton crearRadioButton(String evento, int n)
        //RadioButton nuevoRadio = new RadioButton(this);//a.old.ln
        RadioButton nuevoRadio = new RadioButton(getApplicationContext());//

        LinearLayout.LayoutParams params = new RadioGroup.LayoutParams(
        return nuevoRadio;

    protected void onResume()
        radgroup_opcionesEventos.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                RadioButton radioButton = (RadioButton) group.findViewById(checkedId);
                //int mySelectedIndex = (int) radioButton.getTag();
                String mySelectedIndex = radioButton.getTag().toString();

CMake is not able to find BOOST libraries

Long answer to short, if you install boost in custom path, all header files must in ${path}/boost/.

if you want to konw why cmake can't find the requested Boost libraries after you have set BOOST_ROOT/BOOST_INCLUDEDIR, you can check cmake install location path_to_cmake/share/cmake-xxx/Modules/FindBoost.

cmake which will find Boost_INCLUDE_DIR in boost/config.hpp in BOOST_ROOT. That means your boost header file must in ${path}/boost/, any other format (such as ${path}/boost-x.y.z) will not be suitable for find_package in CMakeLists.txt.

Binding select element to object in Angular

You Can Select the Id using a Function

<option *ngFor="#c of countries" (change)="onchange(">{{}}</option>

Resolve Javascript Promise outside function scope

I've put together a gist that does that job:

here's how you should use it:

import ExternalizedPromiseCreator from '../externalized-promise';

describe('ExternalizedPromise', () => {
  let fn: jest.Mock;
  let deferredFn: jest.Mock;
  let neverCalledFn: jest.Mock;
  beforeEach(() => {
    fn = jest.fn();
    deferredFn = jest.fn();
    neverCalledFn = jest.fn();

  it('resolve should resolve the promise', done => {
    const externalizedPromise = ExternalizedPromiseCreator.create(() => fn());

      .then(() => deferredFn())
      .catch(() => neverCalledFn())
      .then(() => {



First Heroku deploy failed `error code=H10`

In my case there was no start command in the script section of package.json file. When I created the package.json file with npm init I did not create a start script command. So I went to the package.json file, under scripts I added a new entry:

 "scripts": {
    "start": "node index.js"

Saved it and uploaded to Heroku and it worked

How to set thymeleaf th:field value from other variable

It has 2 possible solutions:

1) You can set it in the view by javascript... (not recomended)

<input class="form-control"

<script type="text/javascript">
        document.getElementById("tbFormControll").value = "default";

2) Or the better solution is to set the value in the model, that you attach to the view in GET operation by a controller. You can also change the value in the controller, just make a Java object from $ and call setClientName.

public class FormControllModel {
    private String clientName = "default";
    public String getClientName () {
        return clientName;
    public void setClientName (String value) {
        clientName = value;

I hope it helps.

Binding a generic list to a repeater - ASP.NET

Code Behind:

public class Friends
    public string   ID      { get; set; }
    public string   Name    { get; set; }
    public string   Image   { get; set; }

protected void Page_Load(object sender, EventArgs e)
        List <Friends> friendsList = new List<Friends>();

        foreach (var friend  in friendz)
                new Friends { ID =, Name = }    


        this.rptFriends.DataSource = friendsList;

.aspx Page

<asp:Repeater ID="rptFriends" runat="server">
                <table border="0" cellpadding="0" cellspacing="0">
                        <td><%# Eval("ID") %></td>
                        <td><%# Eval("Name") %></td>

How to get a list of column names

$db = sqlite_open('mysqlitedb');
$cols = sqlite_fetch_column_types('form name'$db, SQLITE_ASSOC);
foreach ($cols as $column => $type) {
  echo "Column: $column  Type: $type\n";

Reversing a string in C

Since you say you want to get fancy, perhaps you'll want to exchange your characters using an XOR swap.

python socket.error: [Errno 98] Address already in use

There is obviously another process listening on the port. You might find out that process by using the following command:

$ lsof -i :8000

or change your tornado app's port. tornado's error info not Explicitly on this.

How do you clear a slice in Go?

It all depends on what is your definition of 'clear'. One of the valid ones certainly is:

slice = slice[:0]

But there's a catch. If slice elements are of type T:

var slice []T

then enforcing len(slice) to be zero, by the above "trick", doesn't make any element of


eligible for garbage collection. This might be the optimal approach in some scenarios. But it might also be a cause of "memory leaks" - memory not used, but potentially reachable (after re-slicing of 'slice') and thus not garbage "collectable".

Why am I getting AttributeError: Object has no attribute

These kind of bugs are common when Python multi-threading. What happens is that, on interpreter tear-down, the relevant module (myThread in this case) goes through a sort-of del myThread.

The call self.sample() is roughly equivalent to myThread.__dict__["sample"](self). But if we're during the interpreter's tear-down sequence, then its own dictionary of known types might've already had myThread deleted, and now it's basically a NoneType - and has no 'sample' attribute.

How to regex in a MySQL query

I think you can use REGEXP instead of LIKE

SELECT trecord FROM `tbl` WHERE (trecord REGEXP '^ALA[0-9]')

git remote prune – didn't show as many pruned branches as I expected

When you use git push origin :staleStuff, it automatically removes origin/staleStuff, so when you ran git remote prune origin, you have pruned some branch that was removed by someone else. It's more likely that your co-workers now need to run git prune to get rid of branches you have removed.

So what exactly git remote prune does? Main idea: local branches (not tracking branches) are not touched by git remote prune command and should be removed manually.

Now, a real-world example for better understanding:

You have a remote repository with 2 branches: master and feature. Let's assume that you are working on both branches, so as a result you have these references in your local repository (full reference names are given to avoid any confusion):

  • refs/heads/master (short name master)
  • refs/heads/feature (short name feature)
  • refs/remotes/origin/master (short name origin/master)
  • refs/remotes/origin/feature (short name origin/feature)

Now, a typical scenario:

  1. Some other developer finishes all work on the feature, merges it into master and removes feature branch from remote repository.
  2. By default, when you do git fetch (or git pull), no references are removed from your local repository, so you still have all those 4 references.
  3. You decide to clean them up, and run git remote prune origin.
  4. git detects that feature branch no longer exists, so refs/remotes/origin/feature is a stale branch which should be removed.
  5. Now you have 3 references, including refs/heads/feature, because git remote prune does not remove any refs/heads/* references.

It is possible to identify local branches, associated with remote tracking branches, by branch.<branch_name>.merge configuration parameter. This parameter is not really required for anything to work (probably except git pull), so it might be missing.

(updated with example & useful info from comments)

How to pass arguments and redirect stdin from a file to program run in gdb?

Start GDB on your project.

  1. Go to project directory, where you've already compiled the project executable. Issue the command gdb and the name of the executable as below:

    gdb projectExecutablename

This starts up gdb, prints the following: GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1 Copyright (C) 2016 Free Software Foundation, Inc. ................................................. Type "apropos word" to search for commands related to "word"... Reading symbols from projectExecutablename...done. (gdb)

  1. Before you start your program running, you want to set up your breakpoints. The break command allows you to do so. To set a breakpoint at the beginning of the function named main:

    (gdb) b main

  2. Once you've have the (gdb) prompt, the run command starts the executable running. If the program you are debugging requires any command-line arguments, you specify them to the run command. If you wanted to run my program on the "xfiles" file (which is in a folder "mulder" in the project directory), you'd do the following:

    (gdb) r mulder/xfiles

Hope this helps.

Disclaimer: This solution is not mine, it is adapted from This short guide to gdb was, most probably, developed at Stanford University.

How can I run an EXE program from a Windows Service using C#?

i have tried this article Code Project, it is working fine for me. I have used the code too. article is excellent in explanation with screenshot.

I am adding necessary explanation to this scenario

You have just booted up your computer and are about to log on. When you log on, the system assigns you a unique Session ID. In Windows Vista, the first User to log on to the computer is assigned a Session ID of 1 by the OS. The next User to log on will be assigned a Session ID of 2. And so on and so forth. You can view the Session ID assigned to each logged on User from the Users tab in Task Manager. enter image description here

But your windows service is brought under session ID of 0. This session is isolated from other sessions. This ultimately prevent the windows service to invoke the application running under user session's like 1 or 2.

In order to invoke the application from windows service you need to copy the control from winlogon.exe which acts as present logged user as shown in below screenshot. enter image description here

Important codes

// obtain the process id of the winlogon process that 
// is running within the currently active session
Process[] processes = Process.GetProcessesByName("winlogon");
foreach (Process p in processes)
    if ((uint)p.SessionId == dwSessionId)
        winlogonPid = (uint)p.Id;

// obtain a handle to the winlogon process
hProcess = OpenProcess(MAXIMUM_ALLOWED, false, winlogonPid);

// obtain a handle to the access token of the winlogon process
if (!OpenProcessToken(hProcess, TOKEN_DUPLICATE, ref hPToken))
    return false;

// Security attibute structure used in DuplicateTokenEx and   CreateProcessAsUser
// I would prefer to not have to use a security attribute variable and to just 
// simply pass null and inherit (by default) the security attributes
// of the existing token. However, in C# structures are value types and   therefore
// cannot be assigned the null value.
sa.Length = Marshal.SizeOf(sa);

// copy the access token of the winlogon process; 
// the newly created token will be a primary token
if (!DuplicateTokenEx(hPToken, MAXIMUM_ALLOWED, ref sa, 
    (int)TOKEN_TYPE.TokenPrimary, ref hUserTokenDup))
      return false;

 si.cb = (int)Marshal.SizeOf(si);

// interactive window station parameter; basically this indicates 
// that the process created can display a GUI on the desktop
si.lpDesktop = @"winsta0\default";

// flags that specify the priority and creation method of the process

// create a new process in the current User's logon session
 bool result = CreateProcessAsUser(hUserTokenDup,  // client's access token
                            null,             // file to execute
                            applicationName,  // command line
                            ref sa,           // pointer to process    SECURITY_ATTRIBUTES
                            ref sa,           // pointer to thread SECURITY_ATTRIBUTES
                            false,            // handles are not inheritable
                            dwCreationFlags,  // creation flags
                            IntPtr.Zero,      // pointer to new environment block 
                            null,             // name of current directory 
                            ref si,           // pointer to STARTUPINFO structure
                            out procInfo      // receives information about new process

Search for string within text column in MySQL

you mean:

SELECT * FROM items WHERE items.xml LIKE '%123456%'

How do I declare a model class in my Angular 2 component using TypeScript?

The problem lies that you haven't added Model to either the bootstrap (which will make it a singleton), or to the providers array of your component definition:

    selector: "testWidget",
    template: "<div>This is a test and {{param1}} is my param.</div>",
    providers : [

export class testWidget {
    constructor(private model: Model) {}

And yes, you should define Model above the Component. But better would be to put it in his own file.

But if you want it to be just a class from which you can create multiple instances, you better just use new.

    selector: "testWidget",
    template: "<div>This is a test and {{param1}} is my param.</div>"

export class testWidget {

    private model: Model = new Model();

    constructor() {}

javascript regex : only english letters allowed

Another option is to use the case-insensitive flag i, then there's no need for the extra character range A-Z.

var reg = /^[a-z]+$/i;
console.log( reg.test("somethingELSE") ); //true
console.log( "somethingELSE".match(reg)[0] ); //"somethingELSE"

Here's a DEMO on how this regex works with test() and match().

How to vertically align text in input type="text"?

IF vertical align won't work use padding. padding-top: 10px; it will shift the text to the bottom or padding-bottom: 10px; to shift the text in the text box to top

adjust the padding size till it suit the size you want. Thats the hack

How to get Printer Info in .NET?

It's been a long time since I've worked in a Windows environment, but I would suggest that you look at using WMI.

How do I programmatically change file permissions?

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.attribute.PosixFileAttributes;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;
import java.util.Set;

public class FileAndDirectory1 {
    public static void main(String[] args) {
        File file = new File("fileTest1.txt");
        try {
                //PosixFilePermission is an enum class, PosixFilePermissions is a final class
                //create file permissions from string
                Set<PosixFilePermission> filePermissions = PosixFilePermissions.fromString("---------"/* "rwxrwxrwx" */);
                FileAttribute<?> permissions = PosixFilePermissions.asFileAttribute(filePermissions);
                Files.createFile(file.toPath(), permissions);
                // printing the permissions associated with the file
                System.out.println("Executable: " + file.canExecute());
                System.out.println("Readable: " + file.canRead());
                System.out.println("Writable: "+ file.canWrite());

                //modify permissions
                //get the permission using file attributes
                Set<PosixFilePermission> perms = Files.readAttributes(file.toPath(), PosixFileAttributes.class).permissions();

                Files.setPosixFilePermissions(file.toPath(), perms);

                System.out.println("Executable: " + file.canExecute());
                System.out.println("Readable: " + file.canRead());
                System.out.println("Writable: "+ file.canWrite());

        } catch (IOException e) {
        Path path = Paths.get(String.valueOf(file));

Align button to the right

<div class="container-fluid">
  <div class="row">
    <h3 class="one">Text</h3>
    <button class="btn btn-secondary ml-auto">Button</button>

.ml-auto is Bootstraph 4's non-flexbox way of aligning things.

How to save data in an android app

OP is asking for a "save" function, which is more than just preserving data across executions of the program (which you must do for the app to be worth anything.)

I recommend saving the data in a file on the sdcard which allows you to not only recall it later, but allows the user to mount the device as an external drive on their own computer and grab the data for use in other places.

So you really need a multi-point system:

1) Implement onSaveInstanceState(). In this method, you're passed a Bundle, which is basically like a dictionary. Store as much information in the bundle as would be needed to restart the app exactly where it left off. In your onCreate() method, check for the passed-in bundle to be non-null, and if so, restore the state from the bundle.

2) Implement onPause(). In this method, create a SharedPreferences editor and use it to save whatever state you need to start the app up next time. This mainly consists of the users' preferences (hence the name), but anything else relavent to the app's start-up state should go here as well. I would not store scores here, just the stuff you need to restart the app. Then, in onCreate(), whenever there's no bundle object, use the SharedPreferences interface to recall those settings.

3a) As for things like scores, you could follow Mathias's advice above and store the scores in the directory returned in getFilesDir(), using openFileOutput(), etc. I think this directory is private to the app and lives in main storage, meaning that other apps and the user would not be able to access the data. If that's ok with you, then this is probably the way to go.

3b) If you do want other apps or the user to have direct access to the data, or if the data is going to be very large, then the sdcard is the way to go. Pick a directory name like com/user1446371/basketballapp/ to avoid collisions with other applications (unless you're sure that your app name is reasonably unique) and create that directory on the sdcard. As Mathias pointed out, you should first confirm that the sdcard is mounted.

File sdcard = Environment.getExternalStorageDirectory();
if( sdcard == null || !sdcard.isDirectory()) {
    fail("sdcard not available");
File datadir = new File(sdcard, "com/user1446371/basketballapp/");
if( !datadir.exists() && !datadir.mkdirs() ) {
    fail("unable to create data directory");
if( !datadir.isDirectory() ) {
    fail("exists, but is not a directory");
// Now use regular java I/O to read and write files to data directory

I recommend simple CSV files for your data, so that other applications can read them easily.

Obviously, you'll have to write activities that allow "save" and "open" dialogs. I generally just make calls to the openintents file manager and let it do the work. This requires that your users install the openintents file manager to make use of these features, however.

event.preventDefault() vs. return false

Basically, this way you combine things because jQuery is a framework which mostly focuses on HTML elements, you basically preventing the default, but at the same time, you stop propagation to bubble up.

So we can simply say, return false in jQuery is equal to:

return false is e.preventDefault AND e.stopPropagation

But also don't forget it's all in jQuery or DOM related functions, when you run it on the element, basically, it prevents everything from firing including the default behaviour and propagation of the event.

Basically before starting using return false;, first understand what e.preventDefault(); and e.stopPropagation(); do, then if you think you need both at the same time, then simply use it.

So basically this code below:

$('div').click(function () {
  return false;

is equal to this code:

$('div').click(function (event) {

Programmatically Add CenterX/CenterY Constraints

Programmatically you can do it by adding the following constraints.

NSLayoutConstraint *constraintHorizontal = [NSLayoutConstraint constraintWithItem:self  

NSLayoutConstraint *constraintVertical = [NSLayoutConstraint constraintWithItem:self

What is the simplest method of inter-process communication between 2 C# processes?


it's just way more easy to make a shared file if possible!

File.AppendAllText("sharedFile.txt", "payload text here");
// in

Why is my CSS bundling not working with a bin deployed MVC4 app?

I was facing this problem while deploying the code in Azure websites. it did worked when I deployed build from and wasn't when I tried to publish the build from visual studio 2013. the main problem was CSS Minification. I totally agree with 1st response to this question. but thought of sharing solution that worked for me, may be it will help you in fixing it.

basically when we deploy through VSO it generates minification files for css, js by kicking in system.web.Optimization, but when we do publish build from VS 2013 we have to take care of the below. bundling-and-minification 1. make sure the folder structure and your bundler naming convention should be different. something like this.

bundles.Add(new StyleBundle("~/Content/materialize/mcss").Include(

2. add at the bottom of your bundleconfig definition

public static void RegisterBundles(BundleCollection bundles)
  bundles.Add(new ScriptBundle("~/bundles/jquery").Include(

   // Code removed for clarity.
   BundleTable.EnableOptimizations = true;

3. make sure to add debug false in web.config (when you start local debuging VS2013 will give you a popup saying that you need to make sure to putting it back before deploying into prod. that itself explains much.

  <compilation debug="true" />
  <!-- Lines removed for clarity. -->

How to change ViewPager's page?

Supplemental answer

I was originally having trouble getting a reference to the ViewPager from other class methods because the addOnTabSelectedListener made an anonymous inner class, which in turn required the ViewPager variable to be declared final. The solution was to use a class member variable and not use the anonymous inner class.

public class MainActivity extends AppCompatActivity {

    TabLayout tabLayout;
    ViewPager viewPager;

    protected void onCreate(Bundle savedInstanceState) {

        Toolbar toolbar = (Toolbar) findViewById(;

        tabLayout = (TabLayout) findViewById(;
        tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
        tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
        tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));

        viewPager = (ViewPager) findViewById(;
        final PagerAdapter adapter = new PagerAdapter(getSupportFragmentManager(), tabLayout.getTabCount());
        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));

        // don't use an anonymous inner class here


    TabLayout.OnTabSelectedListener tabListener = new TabLayout.OnTabSelectedListener() {

        public void onTabSelected(TabLayout.Tab tab) {

        public void onTabUnselected(TabLayout.Tab tab) {


        public void onTabReselected(TabLayout.Tab tab) {


    // The view pager can now be accessed here, too.
    public void someMethod() {


How to downgrade python from 3.7 to 3.6

create a virtual environment, install then switch to python 3.6.5

$ conda create -n tensorflow python=3.7
$ conda activate tensorflow
$ conda install python=3.6.5
$ pip install tensorflow

activate the environment when you would want to use tensorflow

Gradle Build Android Project "Could not resolve all dependencies" error

compileSdkVersion 17
targetSdkVersion 17

change the compile version from 18 to 17

compile ""
compile ""

How to reset Django admin password?

This is very good question.

python changepassword user_name

Example :-

python changepassword mickey

How to get value of a div using javascript

To put it short 'value' is not an valid attribute of div. So it's absolutely correct to return undefined.

What you could do was something in the line of using one of the HTML5 attributes 'data-*'

<div id="demo" align="center"  data-value="1">

And the script would be:

var val = document.getElementById('demo').getAttribute('data-value');

This should work in most modern browsers Just remember to put your doctype as <!DOCTYPE html> to get it valid

How do I reference to another (open or closed) workbook, and pull values back, in VBA? - Excel 2007

You will have to open the file in one way or another if you want to access the data within it. Obviously, one way is to open it in your Excel application instance, e.g.:-

(untested code)

Dim wbk As Workbook
Set wbk = Workbooks.Open("C:\myworkbook.xls")

' now you can manipulate the data in the workbook anyway you want, e.g. '

Dim x As Variant
x = wbk.Worksheets("Sheet1").Range("A6").Value

Call wbk.Worksheets("Sheet2").Range("A1:G100").Copy
Call ThisWorbook.Worksheets("Target").Range("A1").PasteSpecial(xlPasteValues)
Application.CutCopyMode = False

' etc '

Call wbk.Close(False)

Another way to do it would be to use the Excel ADODB provider to open a connection to the file and then use SQL to select data from the sheet you want, but since you are anyway working from within Excel I don't believe there is any reason to do this rather than just open the workbook. Note that there are optional parameters for the Workbooks.Open() method to open the workbook as read-only, etc.

refresh div with jquery

I tried the first solution and it works but the end user can easily identify that the div's are refreshing as it is fadeIn(), without fade in i tried .toggle().toggle() and it works perfect. you can try like this


it works perfectly for me as i'm developing a messenger and need to minimize and maximize the chat box's and this does it best rather than the above code.

Set element width or height in Standards Mode

Try declaring the unit of width: = "400px"; // width in PIXELS

How to import multiple csv files in a single load?

Note that you can use other tricks like :

-- One or more wildcard:
--  braces and brackets   

Python Brute Force algorithm

Use itertools.product, combined with itertools.chain to put the various lengths together:

from itertools import chain, product
def bruteforce(charset, maxlength):
    return (''.join(candidate)
        for candidate in chain.from_iterable(product(charset, repeat=i)
        for i in range(1, maxlength + 1)))


>>> list(bruteforce('abcde', 2))
['a', 'b', 'c', 'd', 'e', 'aa', 'ab', 'ac', 'ad', 'ae', 'ba', 'bb', 'bc', 'bd', 'be', 'ca', 'cb', 'cc', 'cd', 'ce', 'da', 'db', 'dc', 'dd', 'de', 'ea', 'eb', 'ec', 'ed', 'ee']

This will efficiently produce progressively larger words with the input sets, up to length maxlength.

Do not attempt to produce an in-memory list of 26 characters up to length 10; instead, iterate over the results produced:

for attempt in bruteforce(string.ascii_lowercase, 10):
    # match it against your password, or whatever
    if matched:

How to run a cron job on every Monday, Wednesday and Friday?

The rule would be:

0 19 * * 1,3,5

I suggest that you use for having a very convenient GUI to create your rules in the future :)

AngularJs: How to set radio button checked based on model

Just do something like this,<input type="radio" ng-disabled="loading" name="dateRange" ng-model="filter.DateRange" value="1" ng-checked="(filter.DateRange == 1)"/>

Could not find a version that satisfies the requirement tensorflow

For version TensorFlow 2.2:

  1. Make sure you have python 3.8

try: python --version

or python3 --version

or py --version

  1. Upgrade the pip of the python which has version 3.8

try: python3 -m pip install --upgrade pip

or python -m pip install --upgrade pip

or py -m pip install --upgrade pip

  1. Install TensorFlow:

try: python3 -m pip install TensorFlow

or python -m pip install TensorFlow

or py -m pip install TensorFlow

  1. Make sure to run the file with the correct python:

try: python3

or python

or py

Android: Clear the back stack

I tried all solutions and none worked individually for me. My Solution is :

Declare Activity A as SingleTop by using [android:launchMode="singleTop"] in Android manifest.

Now add the following flags while launching A from anywhere. It will clear the stack.

Intent in = new Intent(mContext, A.class);

How to set the maximum memory usage for JVM?

use the arguments -Xms<memory> -Xmx<memory>. Use M or G after the numbers for indicating Megs and Gigs of bytes respectively. -Xms indicates the minimum and -Xmx the maximum.

Visual Studio Code - Convert spaces to tabs

File -> Preferences -> Settings or just press Ctrl + , and search for spaces, then just deactivate this option:

enter image description here

I had to reopen the file so the changes would take effect.

save a pandas.Series histogram plot to file

Use the Figure.savefig() method, like so:

ax = s.hist()  # s is an instance of Series
fig = ax.get_figure()

It doesn't have to end in pdf, there are many options. Check out the documentation.

Alternatively, you can use the pyplot interface and just call the savefig as a function to save the most recently created figure:

import matplotlib.pyplot as plt
plt.savefig('path/to/figure.pdf')  # saves the current figure

Fastest way to convert JavaScript NodeList to Array?

NodeList.prototype.forEach = Array.prototype.forEach;

Now you can do document.querySelectorAll('div').forEach(function()...)

Multi value Dictionary

Dictionary<T1, Tuple<T2, T3>>

Edit: Sorry - I forgot you don't get Tuples until .NET 4.0 comes out. D'oh!

How to make rpm auto install dependencies

Step1: copy all the rpm pkg in given locations

Step2: if createrepo is not already installed, as it will not be by default, install it.

[root@pavangildamysql1 8.0.11_rhel7]# yum install createrepo

Step3: create repository metedata and give below permission

[root@pavangildamysql1 8.0.11_rhel7]# chown -R root.root /scratch/PVN/8.0.11_rhel7
[root@pavangildamysql1 8.0.11_rhel7]# createrepo /scratch/PVN/8.0.11_rhel7
Spawning worker 0 with 3 pkgs
Spawning worker 1 with 3 pkgs
Spawning worker 2 with 3 pkgs
Spawning worker 3 with 2 pkgs
Workers Finished
Saving Primary metadata
Saving file lists metadata
Saving other metadata
Generating sqlite DBs
Sqlite DBs complete
[root@pavangildamysql1 8.0.11_rhel7]# chmod -R o-w+r /scratch/PVN/8.0.11_rhel7

Step4: Create repository file with following contents at /etc/yum.repos.d/mysql.repo

name=My Awesome Repo

Step5 Run this command to install

[root@pavangildamysql1 local]# yum --nogpgcheck localinstall mysql-commercial-server-8.0.11-1.1.el7.x86_64.rpm

Fastest way to extract frames using ffmpeg?

I tried it. 3600 frame in 32 seconds. your method is really slow. You should try this.

ffmpeg -i file.mpg -s 240x135 -vf fps=1 %d.jpg

if else statement in AngularJS templates

I agree that a ternary is extremely clean. Seems that it is very situational though as somethings I need to display div or p or table , so with a table I don't prefer a ternary for obvious reasons. Making a call to a function is typically ideal or in my case I did this:

<div ng-controller="TopNavCtrl">
        <div ng-if=" ==='servername'">
            <table class="table">
                <tr ng-repeat="(group, status) in user.groups">
                    <th style="width: 250px">{{ group }}</th>
                    <td><input type="checkbox" ng-model="user.groups[group]" /></td>
       <div ng-if=" ==='otherservername'">
            <table class="table">
                <tr ng-repeat="(group, status) in user.groups">
                    <th style="width: 250px">{{ group }}</th>
                    <td><input type="checkbox" ng-model="user.groups[group]" /></td>

How to darken an image on mouseover?

Create black png with lets say 50% transparency. Overlay this on mouseover.

What is better, adjacency lists or adjacency matrices for graph problems in C++?

It depends on what you're looking for.

With adjacency matrices you can answer fast to questions regarding if a specific edge between two vertices belongs to the graph, and you can also have quick insertions and deletions of edges. The downside is that you have to use excessive space, especially for graphs with many vertices, which is very inefficient especially if your graph is sparse.

On the other hand, with adjacency lists it is harder to check whether a given edge is in a graph, because you have to search through the appropriate list to find the edge, but they are more space efficient.

Generally though, adjacency lists are the right data structure for most applications of graphs.

Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/JDBC_DBO]]

After spending lot of time on internet. I found that NONE of the option worked for I tried Right click on the server -> Clean. didn't work.

What worked is:

You just to add<absolute-ordering/> tag to your web.xml just under the <display-name> tag and it should work.for more detail click here

UnicodeDecodeError: 'charmap' codec can't decode byte X in position Y: character maps to <undefined>

The file in question is not using the CP1252 encoding. It's using another encoding. Which one you have to figure out yourself. Common ones are Latin-1 and UTF-8. Since 0x90 doesn't actually mean anything in Latin-1, UTF-8 (where 0x90 is a continuation byte) is more likely.

You specify the encoding when you open the file:

file = open(filename, encoding="utf8")

MySQL, Concatenate two columns

You can use the CONCAT function like this:



To get that result you can try this:

SET @rn := 0;

SELECT CONCAT(`SUBJECT`,'-',`YEAR`,'-',LPAD(@rn := @rn+1,3,'0'))
FROM `table`

How to find the last day of the month from date?

Try this , if you are using PHP 5.3+,

$a_date = "2009-11-23";
$date = new DateTime($a_date);
$date->modify('last day of this month');
echo $date->format('Y-m-d');

For finding next month last date, modify as follows,

 $date->modify('last day of 1 month');
 echo $date->format('Y-m-d');

and so on..

How do I import the javax.servlet API in my Eclipse project?

I know this is an old post. However, I observed another instance where in the project already has Tomcat added but we still get this error. Did this to resolve that:
Alt + Enter
Project Facets
On the right, next to details, is another tab "Runtimes". The installed tomcat server will be listed there. Select it.
Save the configuration and DONE!

Hope this helps someone.

JQuery Datatables : Cannot read property 'aDataSort' of undefined

I faced the same problem, the following changes solved my problem.

$(document).ready(function() {
     $('.datatable').dataTable( {
            bSort: false,
            aoColumns: [ { sWidth: "45%" }, { sWidth: "45%" }, { sWidth: "10%", bSearchable: false, bSortable: false } ],
        "scrollY":        "200px",
        "scrollCollapse": true,
        "info":           true,
        "paging":         true
    } );
} );

the aoColumns array describes the width of each column and its sortable properties.

Another thing to mention this error will also appear when you order by a column number that does not exist.

Understanding the grid classes ( col-sm-# and col-lg-# ) in Bootstrap 3


I took another look at the docs and it appears I overlooked a section which talks specifically about this.

The answers to my questions:

  1. Yes, they are meant to apply only to specific ranges, rather than everything above a certain width.

  2. Yes, the classes are meant to be combined.

  3. It appears that this is appropriate in certain cases but not others because the col-# classes are basically equivalent to col-xsm-# or, widths above 0px (all widths).

Other than reading the docs too quickly, I think I was confused because I came into Bootstrap 3 with a "Bootstrap 2 mentality". Specifically, I was using the (optional) responsive styles (bootstrap-responsive.css) in v2 and v3 is quite different (for the better IMO).

UPDATE for stable release:

This question was originally written when RC1 was out. They made some major changes in RC2 so for anyone reading this now, not everything mentioned above still applies.

As of when I'm currently writing this, the col-*-# classes DO seem to apply upwards. So for example, if you want an element to be 12 columns (full width) for phones, but two 6 columns (half page) for tablets and up, you would do something like this:

<div class="col-xs-12 col-sm-6"> ... //NO NEED FOR col-md-6 or col-lg-6

(They also added an additional xs break point after this question was written.)

How can I use a C++ library from node.js?

Try shelljs to call c/c++ program or shared libraries by using node program from linux/unix . node-cmd an option in windows. Both packages basically enable us to call c/c++ program similar to the way we call from terminal/command line.

Eg in ubuntu:

const shell = require('shelljs');

shell.exec("command or script name");

In windows:

const cmd = require('node-cmd');'command here');

Note: shelljs and node-cmd are for running os commands, not specific to c/c++.

Maven 3 Archetype for Project With Spring, Spring MVC, Hibernate, JPA

A great Spring MVC quickstart archetype is available on GitHub, courtesy of kolorobot. Good instructions are provided on how to install it to your local Maven repo and use it to create a new Spring MVC project. He’s even helpfully included the Tomcat 7 Maven plugin in the archetypical project so that the newly created Spring MVC can be run from the command line without having to manually deploy it to an application server.

Kolorobot’s example application includes the following:

  • No-xml Spring MVC 3.2 web application for Servlet 3.0 environment
  • Apache Tiles with configuration in place,
  • Bootstrap
  • JPA 2.0 (Hibernate/HSQLDB)
  • JUnit/Mockito
  • Spring Security 3.1

Get Folder Size from Windows Command Line

I suggest to download utility DU from the Sysinternals Suite provided by Microsoft at this link

usage: du [-c] [-l <levels> | -n | -v] [-u] [-q] <directory>
   -c     Print output as CSV.
   -l     Specify subdirectory depth of information (default is all levels).
   -n     Do not recurse.
   -q     Quiet (no banner).
   -u     Count each instance of a hardlinked file.
   -v     Show size (in KB) of intermediate directories.

C:\SysInternals>du -n d:\temp

Du v1.4 - report directory disk usage
Copyright (C) 2005-2011 Mark Russinovich
Sysinternals -

Files:        26
Directories:  14
Size:         28.873.005 bytes
Size on disk: 29.024.256 bytes

While you are at it, take a look at the other utilities. They are a life-saver for every Windows Professional

Positioning <div> element at center of screen

Alternative solution that doesn't use position absolute:
I see a lot of position absolute answers. I couldn't use position absolute without breaking something else. So for those that couldn't as well, here is what I did: (posted in response to another question).

The solution only focuses on vertically centering because my children elements were already horizontally centered but same could be applied if you couldn't horizontally center them in another way.

How can I get the index from a JSON object with value?

Function base solution for get index from a JSON object with value by VanillaJS.


    var data= [{_x000D_
      "name": "placeHolder",_x000D_
      "section": "right"_x000D_
    }, {_x000D_
      "name": "Overview",_x000D_
      "section": "left"_x000D_
    }, {_x000D_
      "name": "ByFunction",_x000D_
      "section": "left"_x000D_
    }, {_x000D_
      "name": "Time",_x000D_
      "section": "left"_x000D_
    }, {_x000D_
      "name": "allFit",_x000D_
      "section": "left"_x000D_
    }, {_x000D_
      "name": "allbMatches",_x000D_
      "section": "left"_x000D_
    }, {_x000D_
      "name": "allOffers",_x000D_
      "section": "left"_x000D_
    }, {_x000D_
      "name": "allInterests",_x000D_
      "section": "left"_x000D_
    }, {_x000D_
      "name": "allResponses",_x000D_
      "section": "left"_x000D_
    }, {_x000D_
      "name": "divChanged",_x000D_
      "section": "right"_x000D_
    // create function_x000D_
    function findIndex(jsonData, findThis){_x000D_
      var indexNum = jsonData.findIndex(obj =>;  _x000D_
    //Output of result_x000D_
          console.log(" Array Index number: " + indexNum + " , value of " + findThis );_x000D_
    /* call function */_x000D_
    findIndex(data, "allOffers");
Output of index number : <h1 id="output"></h1>

How to resolve Unable to load authentication plugin 'caching_sha2_password' issue

You need just to delete your older connector and download new version (mysql-connector-java-5.1.46)

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

Probably there are many processes that use sources compiled, could be a server, an old maven instruction or IDE. Sure terminate all processes, stop the server and then execute maven again. If the problem persists, you should close java.exe process.


Where does linux store my syslog?

You have to tell the system what information to log and where to put the info. Logging is configured in the /etc/rsyslog.conf file, then restart rsyslog to load the new config. The default logging rules are usually in a /etc/rsyslog.d/50-default.conf file.

PHP code is not being executed, instead code shows on the page

In case we are in the same page do following

sudo apt-get install php -y sudo apt-get install php-{bcmath,bz2,intl,gd,mbstring,mysql,zip,fpm} -y

To enable PHP 7.2 FPM in Apache2 do:

a2enmod proxy_fcgi setenvif

a2enconf php7.2-fpm

update 2: Apache downloads .php file instead of rendering

After that, I faced above issue. There are similar questions like this.

I don't know why but it only happened for my .php files in /var/www/html/ root folder. everything was ok for sub-directories. (for example wordpress and phpmyadmin worked fine)

So here is my solution. I decided to enable php module. so I ran this command:

a2enmod php7.2

but I got this errors:

Considering dependency mpm_prefork for php7.2: Considering conflict mpm_event for mpm_prefork: ERROR: Module mpm_event is enabled - cannot proceed due to conflicts. It needs to be disabled first! Considering conflict mpm_worker for mpm_prefork: ERROR: Could not enable dependency mpm_prefork for php7.2, aborting

so I decided to disable mpm by running following commands:

sudo a2dismod mpm_prefork
sudo a2dismod mpm_worker
sudo a2dismod mpm_event

then restart apache:

systemctl restart apache2

then enable php7.2 (my installed version):

sudo a2enmod php7.2

and right now everything works fine.

How to hide underbar in EditText

You have to set a minWidth too, otherwise the cursor will disappear if the text is empty.


Is it possible to create a 'link to a folder' in a SharePoint document library?

i couldn't change the permissions on the sharepoint i'm using but got a round it by uploading .url files with the drag and drop multiple files uploader.

Using the normal upload didn't work because they are intepreted by the file open dialog when you try to open them singly so it just tries to open the target not the .url file.

.url files can be made by saving a favourite with internet exploiter.

How to force Sequential Javascript Execution?

In your example, the first function does actually complete before the second function is started. setTimeout does not hold execution of the function until the timeout is reached, it will simply start a timer in the background and execute your alert statement after the specified time.

There is no native way of doing a "sleep" in JavaScript. You could write a loop that checks for the time, but that will put a lot of strain on the client. You could also do the Synchronous AJAX call, as emacsian described, but that will put extra load on your server. Your best bet is really to avoid this, which should be simple enough for most cases once you understand how setTimeout works.

Transaction isolation levels relation with locks on table

I want to understand the lock each transaction isolation takes on the table

For example, you have 3 concurrent processes A, B and C. A starts a transaction, writes data and commit/rollback (depending on results). B just executes a SELECT statement to read data. C reads and updates data. All these process work on the same table T.

  • READ UNCOMMITTED - no lock on the table. You can read data in the table while writing on it. This means A writes data (uncommitted) and B can read this uncommitted data and use it (for any purpose). If A executes a rollback, B still has read the data and used it. This is the fastest but most insecure way to work with data since can lead to data holes in not physically related tables (yes, two tables can be logically but not physically related in real-world apps =\).
  • READ COMMITTED - lock on committed data. You can read the data that was only committed. This means A writes data and B can't read the data saved by A until A executes a commit. The problem here is that C can update data that was read and used on B and B client won't have the updated data.
  • REPEATABLE READ - lock on a block of SQL(which is selected by using select query). This means B reads the data under some condition i.e. WHERE aField > 10 AND aField < 20, A inserts data where aField value is between 10 and 20, then B reads the data again and get a different result.
  • SERIALIZABLE - lock on a full table(on which Select query is fired). This means, B reads the data and no other transaction can modify the data on the table. This is the most secure but slowest way to work with data. Also, since a simple read operation locks the table, this can lead to heavy problems on production: imagine that T table is an Invoice table, user X wants to know the invoices of the day and user Y wants to create a new invoice, so while X executes the read of the invoices, Y can't add a new invoice (and when it's about money, people get really mad, especially the bosses).

I want to understand where we define these isolation levels: only at JDBC/hibernate level or in DB also

Using JDBC, you define it using Connection#setTransactionIsolation.

Using Hibernate:

<property name="hibernate.connection.isolation">2</property>



Hibernate configuration is taken from here (sorry, it's in Spanish).

By the way, you can set the isolation level on RDBMS as well:

and on and on...

Can Python test the membership of multiple values in a list?

The Python parser evaluated that statement as a tuple, where the first value was 'a', and the second value is the expression 'b' in ['b', 'a', 'foo', 'bar'] (which evaluates to True).

You can write a simple function do do what you want, though:

def all_in(candidates, sequence):
    for element in candidates:
        if element not in sequence:
            return False
    return True

And call it like:

>>> all_in(('a', 'b'), ['b', 'a', 'foo', 'bar'])

Sending email with PHP from an SMTP server

ini_set("SMTP", "");
ini_set("sendmail_from", "[email protected]");

$message = "The mail message was sent with the following mail setting:\r\nSMTP =\r\nsmtp_port = 25\r\nsendmail_from = [email protected]";

$headers = "From: [email protected]";

mail("[email protected]", "Testing", $message, $headers);
echo "Check your email now....&lt;BR/>";

or, for more details, read on.

Python - Check If Word Is In A String

If matching a sequence of characters is not sufficient and you need to match whole words, here is a simple function that gets the job done. It basically appends spaces where necessary and searches for that in the string:

def smart_find(haystack, needle):
    if haystack.startswith(needle+" "):
        return True
    if haystack.endswith(" "+needle):
        return True
    if haystack.find(" "+needle+" ") != -1:
        return True
    return False

This assumes that commas and other punctuations have already been stripped out.

How can I convert integer into float in Java?

You shouldn't use float unless you have to. In 99% of cases, double is a better choice.

int x = 1111111111;
int y = 10000;
float f = (float) x / y;
double d = (double) x / y;
System.out.println("f= "+f);
System.out.println("d= "+d);


f= 111111.12
d= 111111.1111

Following @Matt's comment.

float has very little precision (6-7 digits) and shows significant rounding error fairly easily. double has another 9 digits of accuracy. The cost of using double instead of float is notional in 99% of cases however the cost of a subtle bug due to rounding error is much higher. For this reason, many developers recommend not using floating point at all and strongly recommend BigDecimal.

However I find that double can be used in most cases provided sensible rounding is used.

In this case, int x has 32-bit precision whereas float has a 24-bit precision, even dividing by 1 could have a rounding error. double on the other hand has 53-bit of precision which is more than enough to get a reasonably accurate result.

Initializing array of structures

It's a designated initializer, introduced with the C99 standard; it allows you to initialize specific members of a struct or union object by name. my_data is obviously a typedef for a struct type that has a member name of type char * or char [N].

Unable to connect to SQL Express "Error: 26-Error Locating Server/Instance Specified)

I had a similar problem which was solved by going to the "SQL Server Configuration Manager" and making sure that the "SQL Server Browser" was configured to start automatically and was started.

I came across this solution in the answer of this forum post:

I hope this helps somebody out there.

Specified cast is not valid.. how to resolve this

If you are expecting double, decimal, float, integer why not use the one which accomodates all namely decimal (128 bits are enough for most numbers you are looking at).

instead of (double)value use decimal.Parse(value.ToString()) or Convert.ToDecimal(value)

What are the options for storing hierarchical data in a relational database?

If your database supports arrays, you can also implement a lineage column or materialized path as an array of parent ids.

Specifically with Postgres you can then use the set operators to query the hierarchy, and get excellent performance with GIN indices. This makes finding parents, children, and depth pretty trivial in a single query. Updates are pretty manageable as well.

I have a full write up of using arrays for materialized paths if you're curious.

Adding a 'share by email' link to website

<a target="_blank" title="Share this page" href="[INSERT URL]&title=[INSERT TITLE]&summary=[INSERT SUMMARY]&img=[INSERT IMAGE URL]&pageInfo=%7B%22hostname%22%3A%22[INSERT DOMAIN NAME]%22%2C%22publisher%22%3A%22[INSERT PUBLISHERID]%22%7D"><img width="86" height="25" alt="Share this page" src=""></a>


First, insert these lines wherever you want within your newsletter code. Then:

  1. Change "INSERT URL" to whatever website holds the shared content.
  2. Change "INSERT TITLE" to the title of the article.
  3. Change "INSERT SUMMARY" to a short summary of the article.
  4. Change "INSERT IMAGE URL" to an image that will be shared with the rest of the content.
  5. Change "INSERT DOMAIN NAME" to your domain name.
  6. Change "INSERT PUBLISHERID" to your publisher ID (if you have an account, if not, remove "[INSERT PUBLISHERID]" or sign up!)

If you are using this on an email newsletter, make sure you add our sharing buttons to the destination page. This will ensure that you get complete sharing analytics for your page. Make sure you replace "INSERT PUBLISHERID" with your own.

Change placeholder text

Try accessing the placeholder attribute of the input and change its value like the following:

$('#some_input_id').attr('placeholder','New Text Here');

Can also clear the placeholder if required like:


What is a smart pointer and when should I use one?

Smart Pointers are those where you don't have to worry about Memory De-Allocation, Resource Sharing and Transfer.

You can very well use these pointer in the similar way as any allocation works in Java. In java Garbage Collector does the trick, while in Smart Pointers, the trick is done by Destructors.

Postgres ERROR: could not open file for reading: Permission denied

for macbook first i opened terminal then type

open /tmp

or in finder directory you directly enter command+shift+g then type /tmp in go to the folder.

it opens temp folder in finder. then i paste copied csv file into this folder.then again i go to postgres terminal and typed below command and then it is copied my csv data into db table

\copy recharge_operator FROM '/private/tmp/operator.csv' DELIMITER ',' CSV;

How to make a JSON call to a url?

Because the URL isn't on the same domain as your website, you need to use JSONP.

For example: (In jQuery):

    function(data) { ... }

This works by creating a <script> tag like this one:

<script src="" type="text/javascript"></script>

Their server then emits Javascript that calls someFunction with the data to retrieve.
`someFunction is an internal callback generated by jQuery that then calls your callback.

access key and value of object using *ngFor

I think Object.keys is the best solution to this problem. For anyone that comes across this answer and is trying to find out why Object.keys is giving them ['0', '1'] instead of ['key1', 'key2'], a cautionary tale - beware the difference between "of" and "in":

I was already using Object.keys, something similar to this:

interface demo {
    key: string;
    value: string;

createDemo(mydemo: any): Array<demo> {
    const tempdemo: Array<demo> = [];

    // Caution: use "of" and not "in"
    for (const key of Object.keys(mydemo)) {
            { key: key, value: mydemo[key]}

    return tempdemo;

However, instead of

for (const key OF Object.keys(mydemo)) {

I had inadvertently wrote

for (const key IN Object.keys(mydemo)) {

which "worked" perfectly fine without any error and returned

[{key: '0', value: undefined}, {key: '1', value: undefined}]

That cost me about 2 hours googling and cursing..

(slaps forehead)

Change the Arrow buttons in Slick slider

This worked for me:

Hide the default buttons in CSS and use:

<!-- In HTML: -->
<p class="left">left</p>
<p class="right">right</p>

/* In the JS file */
  arrows: false



How to return JSon object

You only have one row to serialize. Try something like this :

List<results> resultRows = new List<results>

resultRows.Add(new results{id = 1, value="ABC", info="ABC"});
resultRows.Add(new results{id = 2, value="XYZ", info="XYZ"});

string json = JavaScriptSerializer.Serialize(new { results = resultRows});
  • Edit to match OP's original json output

** Edit 2 : sorry, but I missed that he was using JSON.NET. Using the JavaScriptSerializer the above code produces this result :


When to use Spring Security`s antMatcher()?

You need antMatcher for multiple HttpSecurity, see Spring Security Reference:

5.7 Multiple HttpSecurity

We can configure multiple HttpSecurity instances just as we can have multiple <http> blocks. The key is to extend the WebSecurityConfigurationAdapter multiple times. For example, the following is an example of having a different configuration for URL’s that start with /api/.

public class MultiHttpSecurityConfig {
  public void configureGlobal(AuthenticationManagerBuilder auth) { 1
              .withUser("admin").password("password").roles("USER", "ADMIN");

  @Order(1)                                                        2
  public static class ApiWebSecurityConfigurationAdapter extends WebSecurityConfigurerAdapter {
      protected void configure(HttpSecurity http) throws Exception {
              .antMatcher("/api/**")                               3

  @Configuration                                                   4
  public static class FormLoginWebSecurityConfigurerAdapter extends WebSecurityConfigurerAdapter {

      protected void configure(HttpSecurity http) throws Exception {

1 Configure Authentication as normal

2 Create an instance of WebSecurityConfigurerAdapter that contains @Order to specify which WebSecurityConfigurerAdapter should be considered first.

3 The http.antMatcher states that this HttpSecurity will only be applicable to URLs that start with /api/

4 Create another instance of WebSecurityConfigurerAdapter. If the URL does not start with /api/ this configuration will be used. This configuration is considered after ApiWebSecurityConfigurationAdapter since it has an @Order value after 1 (no @Order defaults to last).

In your case you need no antMatcher, because you have only one configuration. Your modified code:

        .somethingElse() // for /high_level_url_A/**
        .somethingElse() // for /high_level_url_B/**

How can I uninstall npm modules in Node.js?

In case you are on Windows, run CMD as administrator and type:

npm -g uninstall <package name>

What is the difference between rb and r+b modes in file objects

r opens for reading, whereas r+ opens for reading and writing. The b is for binary.

This is spelled out in the documentation:

The most commonly-used values of mode are 'r' for reading, 'w' for writing (truncating the file if it already exists), and 'a' for appending (which on some Unix systems means that all writes append to the end of the file regardless of the current seek position). If mode is omitted, it defaults to 'r'. The default is to use text mode, which may convert '\n' characters to a platform-specific representation on writing and back on reading. Thus, when opening a binary file, you should append 'b' to the mode value to open the file in binary mode, which will improve portability. (Appending 'b' is useful even on systems that don’t treat binary and text files differently, where it serves as documentation.) See below for more possible values of mode.

Modes 'r+', 'w+' and 'a+' open the file for updating (note that 'w+' truncates the file). Append 'b' to the mode to open the file in binary mode, on systems that differentiate between binary and text files; on systems that don’t have this distinction, adding the 'b' has no effect.

SQL: How to to SUM two values from different tables

you can also try this in sql-server !!

select, + as mytotal from [dbo].[cash] a join [dbo].[cheque] b on 


or try using sum,union

select sum(total)  as mytotal,city
    select * from cash union
    select * from cheque
) as vij
group by city 

Unzip All Files In A Directory

If the files are gzip'd. Then just use:

gunzip -rfk .

from the root directory to recursively extract files in respective directories by keeping the original ones (or remove -k to delete them)

Multidimensional arrays in Swift

You are creating an array of three elements and assigning all three to the same thing, which is itself an array of three elements (three Doubles).

When you do the modifications you are modifying the floats in the internal array.

Android Bitmap to Base64 String

All of these answers are inefficient as they needlessly decode to a bitmap and then recompress the bitmap. When you take a photo on Android, it is stored as a jpeg in the temp file you specify when you follow the android docs.

What you should do is directly convert that file to a Base64 string. Here is how to do that in easy copy-paste (in Kotlin). Note you must close the base64FilterStream to truly flush its internal buffer.

fun convertImageFileToBase64(imageFile: File): String {

    return FileInputStream(imageFile).use { inputStream ->
        ByteArrayOutputStream().use { outputStream ->
            Base64OutputStream(outputStream, Base64.DEFAULT).use { base64FilterStream ->

As a bonus, your image quality should be slightly improved, due to bypassing the re-compressing.

Run a single migration file

Please notice that instead of script/runner, you may have to use rails runner on new rails environments.

UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only

This is the normal behavior and the reason is that your sqlCommandHandlerService.persist method needs a TX when being executed (because it is marked with @Transactional annotation). But when it is called inside processNextRegistrationMessage, because there is a TX available, the container doesn't create a new one and uses existing TX. So if any exception occurs in sqlCommandHandlerService.persist method, it causes TX to be set to rollBackOnly (even if you catch the exception in the caller and ignore it).

To overcome this you can use propagation levels for transactions. Have a look at this to find out which propagation best suits your requirements.

Update; Read this!

Well after a colleague came to me with a couple of questions about a similar situation, I feel this needs a bit of clarification.
Although propagations solve such issues, you should be VERY careful about using them and do not use them unless you ABSOLUTELY understand what they mean and how they work. You may end up persisting some data and rolling back some others where you don't expect them to work that way and things can go horribly wrong.

EDIT Link to current version of the documentation

How to return values in javascript

function myFunction(value1,value2,value3)
     return {val2: value2, val3: value3};

How to destroy Fragment?

If you are in the fragment itself, you need to call this. Your fragment needs to be the fragment that is being called. Enter code:


or if you are using supportLib, then you need to call:


How do I get the serial key for Visual Studio Express?

I have an improvement on the answer @DewiMorgan gave for VS 2008 express. I have since confirmed it also works on VS 2005 express.
It lets you run the software without it EVER requiring registration, and also makes it so you don't have to manually delete the key every 30 days. It does this by preventing the key from ever being written.

(Deleting the correct key can also let you avoid registering VS 2015 "Community Edition," but using permissions to prevent the key being written will make the IDE crash, so I haven't found a great solution for it yet.)

The directions assume Visual C# Express 2008, but this works on all the other visual studio express apps I can find.

  1. Open regedit, head to HKEY_CURRENT_USER\Software\Microsoft\VCSExpress\9.0\Registration.
  2. Delete the value Params. picture of me deleting the value 'Params' in the registry.
  3. Right click on the key 'Registration' in the tree, and click permissions.
  4. Click Advanced...
  5. Go to the permissions tab, and uncheck the box labeled Inherit from parent the permission entries that apply to child objects. Include these with entries explicitly defined here. me unchecking the box
  6. In the dialog that opens, click copy.
    the security dialog that pops up
    Note that in Windows 7 (and 8/8.1, I think), it appears the copy button was renamed to add, as in add inherited permissions as explicit permissions.

    In Windows 10, it appears things changed again. @ravuya says that you might have to manually re-create some of the permissions, as the registry editor no longer offers this exact functionality directly. I don't use Windows very much anymore, so I'll defer to them:

    On Win10, there is a button called "Disable Inheritance" that does the same thing as the checkbox mentioned in step 5. It is necessary to create new permissions just for Registration, instead of inheriting those permissions from an upstream registry key.

  7. Hit OK in the 'Advanced' window.
  8. Back in the first permissions window, click your user, and uncheck Full Control. Me unchecking 'full control'

  9. Do the same thing for the Administrators group. Me unchecking 'full control' for the Administrators group

  10. Hit OK or Apply. Congratulations, you will never again be plagued by the registration nag, and just like WinRAR, your trial will never expire.

You may have to do the same thing for other (non-Visual C#) programs, like Visual Basic express or Visual C++ express.

It has been reported by @IronManMark20 in the comments that simply deleting the registry key works and that Visual Studio does not attempt to re-create the key. I am not sure if I believe this because when I installed VS on a clean windows installation, the key was not created until I ran VS at least once. But for what it's worth, that may be an option as well.

POST request with JSON body

// Example API call
$data = array(array (
    "REGION" => "MUMBAI",
    "LOCATION" => "NA",
    "STORE" => "AMAZON"));
// json encode data
$authToken = "xxxxxxxxxx";
$data_string = json_encode($data); 
// set up the curl resource
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "");   
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Content-Length: ' . strlen($data_string) ,
    'API-TOKEN-KEY:'.$authToken ));   // API-TOKEN-KEY is keyword so change according to ur key word. like authorization 
// execute the request
$output = curl_exec($ch);
//echo $output;
// Check for errors
if($output === FALSE){
echo($output) . PHP_EOL;
// close curl resource to free up system resources

How to resolve "local edit, incoming delete upon update" message

If you haven't made any changes inside the conflicted directory, you can also rm -rf conflicts_in_here/ and then svn up. This worked for me at least.

How to remove a newline from a string in Bash

echo "|$COMMAND|"|tr '\n' ' '

will replace the newline (in POSIX/Unix it's not a carriage return) with a space.

To be honest I would think about switching away from bash to something more sane though. Or avoiding generating this malformed data in the first place.

Hmmm, this seems like it could be a horrible security hole as well, depending on where the data is coming from.

HTTP Error 401.2 - Unauthorized You are not authorized to view this page due to invalid authentication headers

Open Project properties by selecting project then go to

View>Properties Windows

and make sure Anonymous Authentication is Enabled

enter image description here

Add multiple items to already initialized arraylist in java

What is the "source" of those integer? If it is something that you need to hard code in your source code, you may do


How can I get the Windows last reboot reason

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

How do I comment out a block of tags in XML?

Here for commenting we have to write like below:

<!-- Your comment here -->

Shortcuts for IntelliJ Idea and Eclipse

For Windows & Linux:

Shortcut for Commenting a single line:

Ctrl + /

Shortcut for Commenting multiple lines:

Ctrl + Shift + /

For Mac:

Shortcut for Commenting a single line:

cmnd + /

Shortcut for Commenting multiple lines:

cmnd + Shift + /

One thing you have to keep in mind that, you can't comment an attribute of an XML tag. For Example:

    android:textStyle="bold" />

Here, TextView is a XML Tag and text is an attribute of that tag. You can't comment attributes of an XML Tag. You have to comment the full XML Tag. For Example:

    android:textStyle="bold" />-->

Does dispatch_async(dispatch_get_main_queue(), ^{...}); wait until done?

Your proposed doCalculationsAndUpdateUIs does data processing and dispatches UI updates to the main queue. I presume that you have dispatched doCalculationsAndUpdateUIs to a background queue when you first called it.

While technically fine, that's a little fragile, contingent upon your remembering to dispatch it to the background every time you call it: I would, instead, suggest that you do your dispatch to the background and dispatch back to the main queue from within the same method, as it makes the logic unambiguous and more robust, etc.

Thus it might look like:

- (void)doCalculationsAndUpdateUIs {

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, NULL), ^{

        // DATA PROCESSING 1 

        dispatch_async(dispatch_get_main_queue(), ^{
            // UI UPDATION 1

        /* I expect the control to come here after UI UPDATION 1 */

        // DATA PROCESSING 2

        dispatch_async(dispatch_get_main_queue(), ^{
            // UI UPDATION 2

        /* I expect the control to come here after UI UPDATION 2 */

        // DATA PROCESSING 3

        dispatch_async(dispatch_get_main_queue(), ^{
            // UI UPDATION 3

In terms of whether you dispatch your UI updates asynchronously with dispatch_async (where the background process will not wait for the UI update) or synchronously with dispatch_sync (where it will wait for the UI update), the question is why would you want to do it synchronously: Do you really want to slow down the background process as it waits for the UI update, or would you like the background process to carry on while the UI update takes place.

Generally you would dispatch the UI update asynchronously with dispatch_async as you've used in your original question. Yes, there certainly are special circumstances where you need to dispatch code synchronously (e.g. you're synchronizing the updates to some class property by performing all updates to it on the main queue), but more often than not, you just dispatch the UI update asynchronously and carry on. Dispatching code synchronously can cause problems (e.g. deadlocks) if done sloppily, so my general counsel is that you should probably only dispatch UI updates synchronously if there is some compelling need to do so, otherwise you should design your solution so you can dispatch them asynchronously.

In answer to your question as to whether this is the "best way to achieve this", it's hard for us to say without knowing more about the business problem being solved. For example, if you might be calling this doCalculationsAndUpdateUIs multiple times, I might be inclined to use my own serial queue rather than a concurrent global queue, in order to ensure that these don't step over each other. Or if you might need the ability to cancel this doCalculationsAndUpdateUIs when the user dismisses the scene or calls the method again, then I might be inclined to use a operation queue which offers cancelation capabilities. It depends entirely upon what you're trying to achieve.

But, in general, the pattern of asynchronously dispatching a complicated task to a background queue and then asynchronously dispatching the UI update back to the main queue is very common.

intellij incorrectly saying no beans of type found for autowired repository

just add below two annotations to your POJO.

public class YourClass {

How to get a key in a JavaScript object by its value?

Really straightforward.

const CryptoEnum = Object.freeze({
                    "Bitcoin": 0, "Ethereum": 1, 
                    "Filecoin": 2, "Monero": 3, 
                    "EOS": 4, "Cardano": 5, 
                    "NEO": 6, "Dash": 7, 
                    "Zcash": 8, "Decred": 9 

// output => "Bitcoin"

Error: Cannot match any routes. URL Segment: - Angular 2

Solved myself. Done some small structural changes also. Route from Component1 to Component2 is done by a single <router-outlet>. Component2 to Comonent3 and Component4 is done by multiple <router-outlet name= "xxxxx"> The resulting contents are :


    <a routerLink="/two" class="dash-item">Go to 2</a>


 <a [routerLink]="['/two', {outlets: {'nameThree': ['three']}}]">In Two...Go to 3 ...       </a>
 <a [routerLink]="['/two', {outlets: {'nameFour': ['four']}}]">   In Two...Go to 4 ...</a>

 <router-outlet name="nameThree"></router-outlet>
 <router-outlet name="nameFour"></router-outlet>

The '/two' represents the parent component and ['three']and ['four'] represents the link to the respective children of component2 . Component3.html and Component4.html are the same as in the question.


const routes: Routes = [
    path: '',
    redirectTo: 'one',
    pathMatch: 'full'
    path: 'two',
    component: ClassTwo, children: [

            path: 'three',
            component: ClassThree,
            outlet: 'nameThree'
            path: 'four',
            component: ClassFour,
            outlet: 'nameFour'

How do I make an html link look like a button?

Use this class. It will make your link look the same as a button when applied using the button class on an a tag.



.button {
    display: inline-block;
    outline: none;
    cursor: pointer;
    border: solid 1px #da7c0c;
    background: #478dad;
    text-align: center;
    text-decoration: none;
    font: 14px/100% Arial, Helvetica, sans-serif;
    padding: .5em 2em .55em;
    text-shadow: 0 1px 1px rgba(0,0,0,.3);
    -webkit-border-radius: .5em; 
    -moz-border-radius: .5em;
    border-radius: .3em;
    -webkit-box-shadow: 0 1px 2px rgba(0,0,0,.2);
    -moz-box-shadow: 0 1px 2px rgba(0,0,0,.2);
    box-shadow: 0 1px 2px rgba(0,0,0,.2);
.button:hover {
    background: #f47c20;
    background: -webkit-gradient(linear, left top, left bottom, from(#f88e11), to(#f06015));
    background: -moz-linear-gradient(top,  #f88e11,  #f06015);
    filter:  progid:DXImageTransform.Microsoft.gradient(startColorstr='#f88e11', endColorstr='#f06015');
.button:active {
    position: relative;
    top: 1px;

How to disable HTML button using JavaScript?

<button disabled=true>text here</button>

You can still use an attribute. Just use the 'disabled' attribute instead of 'value'.

Load CSV file with Spark

Are you sure that all the lines have at least 2 columns? Can you try something like, just to check?:

sc.textFile("file.csv") \
    .map(lambda line: line.split(",")) \
    .filter(lambda line: len(line)>1) \
    .map(lambda line: (line[0],line[1])) \

Alternatively, you could print the culprit (if any):

sc.textFile("file.csv") \
    .map(lambda line: line.split(",")) \
    .filter(lambda line: len(line)<=1) \

What is the format for the PostgreSQL connection string / URL?


How to properly use jsPDF library

Shouldn't you also be using the jspdf.plugin.from_html.js library? Besides the main library (jspdf.js), you must use other libraries for "special operations" (like jspdf.plugin.addimage.js for using images). Check

Align text in a table header

Try to use text-align in style attribute to align center.

<th class="not_mapped_style" style="text-align:center">DisplayName</th>

Using the AND and NOT Operator in Python

You should write :

if (self.a != 0) and (self.b != 0) :

"&" is the bit wise operator and does not suit for boolean operations. The equivalent of "&&" is "and" in Python.

A shorter way to check what you want is to use the "in" operator :

if 0 not in (self.a, self.b) :

You can check if anything is part of a an iterable with "in", it works for :

  • Tuples. I.E : "foo" in ("foo", 1, c, etc) will return true
  • Lists. I.E : "foo" in ["foo", 1, c, etc] will return true
  • Strings. I.E : "a" in "ago" will return true
  • Dict. I.E : "foo" in {"foo" : "bar"} will return true

As an answer to the comments :

Yes, using "in" is slower since you are creating an Tuple object, but really performances are not an issue here, plus readability matters a lot in Python.

For the triangle check, it's easier to read :

0 not in (self.a, self.b, self.c)


(self.a != 0) and (self.b != 0) and (self.c != 0) 

It's easier to refactor too.

Of course, in this example, it really is not that important, it's very simple snippet. But this style leads to a Pythonic code, which leads to a happier programmer (and losing weight, improving sex life, etc.) on big programs.

MySQL - Rows to Columns

I make that into Group By hostId then it will show only first row with values,

A   B  C
1  10
2      3

Model summary in pytorch

While you will not get as detailed information about the model as in Keras' model.summary, simply printing the model will give you some idea about the different layers involved and their specifications.

For instance:

from torchvision import models
model = models.vgg16()

The output in this case would be something as follows:

  (features): Sequential (
    (0): Conv2d(3, 64, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (1): ReLU (inplace)
    (2): Conv2d(64, 64, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (3): ReLU (inplace)
    (4): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
    (5): Conv2d(64, 128, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (6): ReLU (inplace)
    (7): Conv2d(128, 128, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (8): ReLU (inplace)
    (9): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
    (10): Conv2d(128, 256, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (11): ReLU (inplace)
    (12): Conv2d(256, 256, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (13): ReLU (inplace)
    (14): Conv2d(256, 256, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (15): ReLU (inplace)
    (16): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
    (17): Conv2d(256, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (18): ReLU (inplace)
    (19): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (20): ReLU (inplace)
    (21): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (22): ReLU (inplace)
    (23): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
    (24): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (25): ReLU (inplace)
    (26): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (27): ReLU (inplace)
    (28): Conv2d(512, 512, kernel_size=(3, 3), stride=(1, 1), padding=(1, 1))
    (29): ReLU (inplace)
    (30): MaxPool2d (size=(2, 2), stride=(2, 2), dilation=(1, 1))
  (classifier): Sequential (
    (0): Dropout (p = 0.5)
    (1): Linear (25088 -> 4096)
    (2): ReLU (inplace)
    (3): Dropout (p = 0.5)
    (4): Linear (4096 -> 4096)
    (5): ReLU (inplace)
    (6): Linear (4096 -> 1000)

Now you could, as mentioned by Kashyap, use the state_dict method to get the weights of the different layers. But using this listing of the layers would perhaps provide more direction is creating a helper function to get that Keras like model summary! Hope this helps!

Localhost not working in chrome and firefox

Changing my LAN network settings to not automatically detect a proxy server worked for me BUT resetting your Windows network stack may help.

See The Nuclear Option: Resetting The Crap Out Of Your Network Adapters in Vista from Scott Hanselman.

comparing two strings in ruby

var1 is a regular string, whereas var2 is an array, this is how you should compare (in this case):

puts var1 == var2[0]

How to get a vCard (.vcf file) into Android contacts from website

There is now an import functionality on Android ICS 4.0.4.

First you must save your .vcf file on a storage (USB storage, or SDcard). Android will scan the selected storage to detect any .vcf file and will import it on the selected address book. The functionality is in the option menu of your contact list.

!Note: Be careful while doing this! Android will import EVERYTHING that is a .vcf in your storage. It's all or nothing, and the consequence can be trashing your address book.

Having trouble setting working directory

The command setwd("~/") should set your working directory to your home directory. You might be experiencing problems because the OS you are using does not recognise "~/" as your home directory: this might be because of the OS, or it might be because of not having set that as your home directory elsewhere.

As you have tagged the post using RStudio:

  • In the bottom right window move the tab over to 'files'.
  • Navigate through there to whichever folder you were planning to use as your working directory.
  • Under 'more' click 'set as working directory'

You will now have set the folder as your working directory. Use the command getwd() to get the working directory as it is now set, and save that as a variable string at the top of your script. Then use setwd with that string as the argument, so that each time you run the script you use the same directory.

For example at the top of my script I would have:

work_dir <- "C:/Users/john.smith/Documents"

How to get the HTML for a DOM element in javascript

You'll want something like this for it to be cross browser.

function OuterHTML(element) {
    var container = document.createElement("div");

    return container.innerHTML;

Add ... if string is too long PHP

You can achieve the desired trim in this way too:

mb_strimwidth("Hello World", 0, 10, "...");


  • Hello World: the string to trim.
  • 0: number of characters from the beginning of the string.
  • 10: the length of the trimmed string.
  • ...: an added string at the end of the trimmed string.

This will return Hello W....

Notice that 10 is the length of the truncated string + the added string!


To avoid truncating words:

In case of presenting text excerpts, probably truncating a word should be avoided. If there is no hard requirement on the length of the truncated text, apart from wordwrap() mentioned here, one can use the following to truncate and prevent cutting the last word as well.

$text = "Knowledge is a natural right of every human being of which no one
has the right to deprive him or her under any pretext, except in a case where a
person does something which deprives him or her of that right. It is mere
stupidity to leave its benefits to certain individuals and teams who monopolize
these while the masses provide the facilities and pay the expenses for the
establishment of public sports.";

// we don't want new lines in our preview
$text_only_spaces = preg_replace('/\s+/', ' ', $text);

// truncates the text
$text_truncated = mb_substr($text_only_spaces, 0, mb_strpos($text_only_spaces, " ", 50));

// prevents last word truncation
$preview = trim(mb_substr($text_truncated, 0, mb_strrpos($text_truncated, " ")));

In this case, $preview will be "Knowledge is a natural right of every human being".

Live code example:

How to kill a child process after a given timeout in Bash?

(As seen in: BASH FAQ entry #68: "How do I run a command, and have it abort (timeout) after N seconds?")

If you don't mind downloading something, use timeout (sudo apt-get install timeout) and use it like: (most Systems have it already installed otherwise use sudo apt-get install coreutils)

timeout 10 ping

If you don't want to download something, do what timeout does internally:

( cmdpid=$BASHPID; (sleep 10; kill $cmdpid) & exec ping )

In case that you want to do a timeout for longer bash code, use the second option as such:

( cmdpid=$BASHPID; 
    (sleep 10; kill $cmdpid) \
   & while ! ping -w 1 
         echo crap; 
     done )

Removing spaces from a variable input using PowerShell 4.0

The Replace operator means Replace something with something else; do not be confused with removal functionality.

Also you should send the result processed by the operator to a variable or to another operator. Neither .Replace(), nor -replace modifies the original variable.

To remove all spaces, use 'Replace any space symbol with empty string'

$string = $string -replace '\s',''

To remove all spaces at the beginning and end of the line, and replace all double-and-more-spaces or tab symbols to spacebar symbol, use

$string = $string -replace '(^\s+|\s+$)','' -replace '\s+',' '

or the more native System.String method

$string = $string.Trim()

Regexp is preferred, because ' ' means only 'spacebar' symbol, and '\s' means 'spacebar, tab and other space symbols'. Note that $string.Replace() does 'Normal' replace, and $string -replace does RegEx replace, which is more heavy but more functional.

Note that RegEx have some special symbols like dot (.), braces ([]()), slashes (\), hats (^), mathematical signs (+-) or dollar signs ($) that need do be escaped. ( '' -replace '\.','-' => 'my-space-com'. A dollar sign with a number (ex $1) must be used on a right part with care

'2033' -replace '(\d+)',$( 'Data: $1')
Data: 2033

UPDATE: You can also use $str = $str.Trim(), along with TrimEnd() and TrimStart(). Read more at System.String MSDN page.

SQL Server 2008: How to query all databases sizes?

with fs
    select database_id, type, size * 8.0 / 1024 size
    from sys.master_files
    (select sum(size) from fs where type = 0 and fs.database_id = db.database_id) DataFileSizeMB,
    (select sum(size) from fs where type = 1 and fs.database_id = db.database_id) LogFileSizeMB
from sys.databases db

Xpath: select div that contains class AND whose specific child element contains text

You can use ancestor. I find that this is easier to read because the element you are actually selecting is at the end of the path.

//span[contains(text(),'someText')]/ancestor::div[contains(@class, 'measure-tab')]

Iterate through <select> options

After try several code, and still not working, I go to official documentation of select2.js. here the link:

from that the way to clear selection select2 js is:


What is the shortcut in IntelliJ IDEA to find method / functions?

Intellij v 13.1.4, OSX

The Open Symbol keyboard shortcut is command+shift+s

How to read and write excel file

A simple CSV file should suffice

Check whether an input string contains a number in javascript

You can also try lodash:

const isNumeric = number => 
  _.isFinite(_.parseInt(number)) && !_.isNaN(_.parseInt(number))

Flutter : Vertically center column

Solution as proposed by Aziz would be:


It would not be in the exact center because of padding:

padding: new EdgeInsets.all(25.0),

To make exactly center Column - at least in this case - you would need to remove padding.

nginx: how to create an alias url route?

server {
  root /path/to/root;
  location / {
    # bla bla
  location /demo {
    alias /path/to/root/production/folder/here;

If you need to use try_files inside /demo you'll need to replace alias with a root and do a rewrite because of the bug explained here

jQuery show/hide not working


$( '.expand' ).click(function() {_x000D_
  $( '.img_display_content' ).toggle();_x000D_
.wrap {_x000D_
.img_display_header {_x000D_
    border:#333 solid 1px;_x000D_
    margin-bottom: 2px;_x000D_
.expand {_x000D_
 height: 100%;_x000D_
.img_display_content {_x000D_
    width: 100%;_x000D_
    height:100px;   _x000D_
    margin-top: -2px;_x000D_
<script src=""></script>_x000D_
<div class="wrap">_x000D_
<div class="img_display_header">_x000D_
<div class="expand">+</div>_x000D_
<div class="img_display_content"></div>_x000D_
"Display or hide the matched elements."

This is much shorter in code than using show() and hide() methods.

IF EXISTS condition not working with PLSQL

IF EXISTS() is semantically incorrect. EXISTS condition can be used only inside a SQL statement. So you might rewrite your pl/sql block as follows:

  l_exst number(1);
  select case 
           when exists(select ce.s_regno 
                         from courseoffering co
                         join co_enrolment ce
                           on ce.co_id = co.co_id
                        where ce.s_regno=403 
                          and ce.coe_completionstatus = 'C' 
                          and ce.c_id = 803
                          and rownum = 1
           then 1
           else 0
         end  into l_exst
  from dual;

  if l_exst = 1 
    DBMS_OUTPUT.put_line('YES YOU CAN');
    DBMS_OUTPUT.put_line('YOU CANNOT'); 
  end if;

Or you can simply use count function do determine the number of rows returned by the query, and rownum=1 predicate - you only need to know if a record exists:

  l_exst number;
   select count(*) 
     into l_exst
     from courseoffering co
          join co_enrolment ce
            on ce.co_id = co.co_id
    where ce.s_regno=403 
      and ce.coe_completionstatus = 'C' 
      and ce.c_id = 803
      and rownum = 1;

  if l_exst = 0
    DBMS_OUTPUT.put_line('YOU CANNOT');
    DBMS_OUTPUT.put_line('YES YOU CAN');
  end if;

C pointers and arrays: [Warning] assignment makes pointer from integer without a cast

In this case a[4] is the 5th integer in the array a, ap is a pointer to integer, so you are assigning an integer to a pointer and that's the warning.
So ap now holds 45 and when you try to de-reference it (by doing *ap) you are trying to access a memory at address 45, which is an invalid address, so your program crashes.

You should do ap = &(a[4]); or ap = a + 4;

In c array names decays to pointer, so a points to the 1st element of the array.
In this way, a is equivalent to &(a[0]).

How to find the number of days between two dates

The DATEDIFF function is use to calculate the number of days between the required date

Example if you are diff current date from given date in string format

SELECT * , DATEDIFF(CURDATE(),STR_TO_DATE('01/11/2017', '%m/%d/%Y')) AS days FROM consignments WHERE code = '1610000154'

Here, STR_TO_DATE () : Take a string and returns a date specified by a format mask;

For your example :

SELECT dtCreated
    , bActive
    , dtLastPaymentAttempt
    , dtLastUpdated
    , dtLastVisit
    , DATEDIFF(dtLastUpdated, dtCreated) as Difference
FROM Customers
WHERE (bActive = 'true') 
    AND (dtLastUpdated > '2012-01-01 00:00:00')

Tested on mysql server 5.7.17

How to extract public key using OpenSSL?

If your looking how to copy an Amazon AWS .pem keypair into a different region do the following:

openssl rsa -in .ssh/amazon-aws.pem -pubout > .ssh/


aws ec2 import-key-pair --key-name amazon-aws --public-key-material '$(cat .ssh/' --region us-west-2

React proptype array with shape

And there it is... right under my nose:

From the react docs themselves:

// An array of a certain type
    optionalArrayOf: React.PropTypes.arrayOf(React.PropTypes.number),

curl: (35) SSL connect error

If you are using curl versions curl-7.19.7-46.el6.x86_64 or older. Please provide an option as -k1 (small K1).

How can I edit a view using phpMyAdmin 3.2.4?

Just export you view and you will have all SQL need to make some change on it.

Just need to add your change in SQL query for the view and change :


ERROR! MySQL manager or server PID file could not be found! QNAP

I ended up figuring this out on my own.

In searching for my logs I went into

cd /usr/local/mysql/var

In there I found the file named [MyNAS].pid (replace [MyNAS] with the name of your NAS.

I then ran the following to remove the file

rm -rf /usr/local/mysql/var/[MyNAS].pid

I then restarted mysql

[/usr/local/mysql/var] # /etc/init.d/ restart        
Try to shutting down MySQL
ERROR! MySQL manager or server PID file could not be found!
Starting MySQL. SUCCESS! 

I tested everything and it all works like a charm again!

Difference between HashSet and HashMap?

As the names imply, a HashMap is an associative Map (mapping from a key to a value), a HashSet is just a Set.

How can I tell how many objects I've stored in an S3 bucket?

You can download and install s3 browser from When you select a bucket in the center right corner you can see the number of files in the bucket. But, the size it shows is incorrect in the current version.


ORA-01438: value larger than specified precision allows for this column

From (the definitive resource outside of Oracle Support):

ORA-01438: value larger than specified precision allowed for this column
Cause: When inserting or updating records, a numeric value was entered that exceeded the precision defined for the column.
Action: Enter a value that complies with the numeric column's precision, or use the MODIFY option with the ALTER TABLE command to expand the precision.

ORA-06512: at stringline string
Cause: Backtrace message as the stack is unwound by unhandled exceptions.
Action: Fix the problem causing the exception or write an exception handler for this condition. Or you may need to contact your application administrator or DBA.

Warning: mysqli_real_escape_string() expects exactly 2 parameters, 1 given... what I do wrong?

mysqli_real_escape_string function requires the connection to your database.

$username = mysqli_real_escape_string($your_connection, $_POST['username']);

P.S.: Do not mix mysql_ functions* and mysqli_ functions*. Please use mysqli_* functions or PDO because mysql_* functions are deprecated and will be removed in the future.

Using if elif fi in shell scripts

This is working for me,

 # cat
 echo "You have provided the following arguments $arg1 $arg2 $arg3"
 if [ "$arg1" = "$arg2" ] && [ "$arg1" != "$arg3" ]
     echo "Two of the provided args are equal."
     exit 3
 elif [ $arg1 == $arg2 ] && [ $arg1 = $arg3 ]
     echo "All of the specified args are equal"
     exit 0
     echo "All of the specified args are different"
     exit 4

 # ./
 You have provided the following arguments
 All of the specified args are equal

You can add set -x in script to troubleshoot the errors.

How do you return the column names of a table?

SELECT @col= COALESCE(@col, '') + ',' + COLUMN_NAME
SELECT @col;

How do I initialize the base (super) class?

Python (until version 3) supports "old-style" and new-style classes. New-style classes are derived from object and are what you are using, and invoke their base class through super(), e.g.

class X(object):
  def __init__(self, x):

  def doit(self, bar):

class Y(X):
  def __init__(self):
    super(Y, self).__init__(123)

  def doit(self, foo):
    return super(Y, self).doit(foo)

Because python knows about old- and new-style classes, there are different ways to invoke a base method, which is why you've found multiple ways of doing so.

For completeness sake, old-style classes call base methods explicitly using the base class, i.e.

def doit(self, foo):
  return X.doit(self, foo)

But since you shouldn't be using old-style anymore, I wouldn't care about this too much.

Python 3 only knows about new-style classes (no matter if you derive from object or not).

Looping through all the properties of object php

Here is another way to express the object property.

foreach ($obj as $key=>$value) {
    echo "$key => $obj[$key]\n";

Get the last insert id with doctrine 2?

If you're not using entities but Native SQL as shown here then you might want to get the last inserted id as shown below:


For databases with sequences such as PostgreSQL please note that you can provide the sequence name as the first parameter of the lastInsertId method.

$entityManager->getConnection()->lastInsertId($seqName = 'my_sequence')

For more information take a look at the code on GitHub here and here.

How to read specific lines from a file (by line number)?

if you want line 7

line = open("file.txt", "r").readlines()[7]

Which is a better way to check if an array has more than one element?

isset() only checks if a variable is set.. Has got nothing to do with size or what the array contains

Cannot implicitly convert type from Task<>

You need to make TestGetMethod async too and attach await in front of GetIdList(); will unwrap the task to List<int>, So if your helper function is returning Task make sure you have await as you are calling the function async too.

public Task<List<int>> TestGetMethod()
    return GetIdList();

async Task<List<int>> GetIdList()
    using (HttpClient proxy = new HttpClient())
        string response = await proxy.GetStringAsync("");
        List<int> idList = JsonConvert.DeserializeObject<List<int>>();
        return idList;

Another option

public async void TestGetMethod(List<int> results)
    results = await GetIdList(); // await will unwrap the List<int>

How to create a DataFrame from a text file in Spark

I know I am quite late to answer this but I have come up with a different answer:

val rdd = sc.textFile("/home/training/mydata/file.txt")

val text =",")).map(arrays=>(ararys(0),arrays(1))).toDF("id","name").show 

"OSError: [Errno 1] Operation not permitted" when installing Scrapy in OSX 10.11 (El Capitan) (System Integrity Protection)

Tried a combination of some answers and this eventually worked:

sudo -H pip install --upgrade --ignore-installed awsebcli


Convert integer to hexadecimal and back again


int myInt = 2934;
string myHex = myInt.ToString("X");  // Gives you hexadecimal
int myNewInt = Convert.ToInt32(myHex, 16);  // Back to int again.

See How to: Convert Between Hexadecimal Strings and Numeric Types (C# Programming Guide) for more information and examples.

How to add bootstrap in angular 6 project?

npm install --save bootstrap

afterwards, inside angular.json (previously .angular-cli.json) inside the project's root folder, find styles and add the bootstrap css file like this:

for angular 6

"styles": [

for angular 7

"styles": [

How to replace special characters in a string?

string Output = Regex.Replace(Input, @"([ a-zA-Z0-9&, _]|^\s)", "");

Here all the special characters except space, comma, and ampersand are replaced. You can also omit space, comma and ampersand by the following regular expression.

string Output = Regex.Replace(Input, @"([ a-zA-Z0-9_]|^\s)", "");

Where Input is the string which we need to replace the characters.

Get escaped URL parameter

function getURLParameters(paramName) 
        var sURL = window.document.URL.toString();  
    if (sURL.indexOf("?") > 0)
       var arrParams = sURL.split("?");         
       var arrURLParams = arrParams[1].split("&");      
       var arrParamNames = new Array(arrURLParams.length);
       var arrParamValues = new Array(arrURLParams.length);     
       var i = 0;
       for (i=0;i<arrURLParams.length;i++)
        var sParam =  arrURLParams[i].split("=");
        arrParamNames[i] = sParam[0];
        if (sParam[1] != "")
            arrParamValues[i] = unescape(sParam[1]);
            arrParamValues[i] = "No Value";

       for (i=0;i<arrURLParams.length;i++)
                if(arrParamNames[i] == paramName){
                return arrParamValues[i];
       return "No Parameters Found";


Gradle's dependency cache may be corrupt (this sometimes occurs after a network connection timeout.)

check out distributionUrl setting in I changed https to http, then my problem was solved.

Java generics: multiple generic parameters?

You can declare multiple type variables on a type or method. For example, using type parameters on the method:

<P, Q> int f(Set<P>, Set<Q>) {
  return 0;

Pycharm and sys.argv arguments

Notice that for some unknown reason, it is not possible to add command line arguments in the PyCharm Edu version. It can be only done in Professional and Community editions.

Load image from resources

You can always use System.Resources.ResourceManager which returns the cached ResourceManager used by this class. Since chan1 and chan2 represent two different images, you may use System.Resources.ResourceManager.GetObject(string name) which returns an object matching your input with the project resources


object O = Resources.ResourceManager.GetObject("chan1"); //Return an object from the image chan1.png in the project
channelPic.Image = (Image)O; //Set the Image property of channelPic to the returned object as Image

Notice: Resources.ResourceManager.GetObject(string name) may return null if the string specified was not found in the project resources.

I hope you find this helpful :)

Where can I find documentation on formatting a date in JavaScript?

JsSimpleDateFormat is a library that can format the date object and parse the formatted string back to Date object. It uses the Java format (SimpleDateFormat class). The name of months and days can be localized.


var sdf = new JsSimpleDateFormat("EEEE, MMMM dd, yyyy");
var formattedString = sdf.format(new Date());
var dateObject = sdf.parse("Monday, June 29, 2009");

Nullable DateTime conversion

You might want to do it like this:

DateTime? lastPostDate =  (DateTime?)(reader.IsDbNull(3) ? null : reader[3]); 

The problem you are having is that the ternary operator wants a viable cast between the left and right sides. And null can't be cast to DateTime.

Note the above works because both sides of the ternary are object's. The object is explicitly cast to DateTime? which works: as long as reader[3] is in fact a date.

Instagram how to get my user id from username?

Very late answer but I think this is the best answer of this topic. Hope this is useful.

You can get user info when a request is made with the url below:{username}/?__a=1


This url will get all information about a user whose username is therock

Update i June-20-2019, the API is public now. No authentication required.

Update in December-11-2018, I needed to confirm that this endpoint still work. You need to login before sending request to this site because it's not public endpoint anymore. The login step is easy also. This is my demo:

Update in Apr-17-2018, it's look like this endpoint still working (but its not public endpoint anymore), you must send a request with extra information to that endpoint. (Press F12 to open developer toolbar, then click to Network Tab and trace the request.)

Sorry because I'm too busy. Hope this information help you guys. Hmm, feel free to give me a down-vote if you want.

Update in Apr-12-2018, cameronjonesweb said that this endpoint doesn't work anymore. When he/she trying to access this endpoint, 403 status code return.

apache and httpd running but I can't see my website

Did you restart the server after you changed the config file?

Can you telnet to the server from a different machine?

Can you telnet to the server from the server itself?

telnet <ip address> 80

telnet localhost 80

Node.js Web Application examples/tutorials

The closest thing is likely Dav Glass's experimental work using node.js, express and YUI3. Basically, he explains how YUI3 is used to render markup on the server side, then sent to the client where binding to event and data occurs. The beauty is YUI3 is used as-is on both the client and the server. Makes a lot of sense. The one big issue is there is not yet a production ready server-side DOM library.


Debug message "Resource interpreted as other but transferred with MIME type application/javascript"

It seems like a bug in Safari's cache handling policies.

Workaround in apache:

Header unset ETag
Header unset Last-Modified

The APK file does not exist on disk

In my case, I was using a special character in my app file path. I closed the Android Studio and removed the ' character from my app file path. Everything worked fine when I reopned the project.

Assembly - JG/JNLE/JL/JNGE after CMP

Wikibooks has a fairly good summary of jump instructions. Basically, there's actually two stages:

cmp_instruction op1, op2

Which sets various flags based on the result, and

jmp_conditional_instruction address

which will execute the jump based on the results of those flags.

Compare (cmp) will basically compute the subtraction op1-op2, however, this is not stored; instead only flag results are set. So if you did cmp eax, ebx that's the same as saying eax-ebx - then deciding based on whether that is positive, negative or zero which flags to set.

More detailed reference here.

In Swift how to call method with parameters on GCD main thread?

Don't forget to weakify self if you are using self inside of the closure.

dispatch_async(dispatch_get_main_queue(),{ [weak self] () -> () in
    if let strongSelf = self {

Detect URLs in text with JavaScript

There is existing npm package: url-regex, just install it with yarn add url-regex or npm install url-regex and use as following:

const urlRegex = require('url-regex');

const replaced = 'Find me at and also at or at'
  .replace(urlRegex({strict: false}), function(url) {
     return '<a href="' + url + '">' + url + '</a>';

How to redirect output to a file and stdout

You can do that for your entire script by using something like that at the beginning of your script :

#!/usr/bin/env bash

test x$1 = x$'\x00' && shift || { set -o pipefail ; ( exec 2>&1 ; $0 $'\x00' "$@" ) | tee mylogfile ; exit $? ; }

# do whaetever you want

This redirect both stderr and stdout outputs to the file called mylogfile and let everything goes to stdout at the same time.

It is used some stupid tricks :

  • use exec without command to setup redirections,
  • use tee to duplicates outputs,
  • restart the script with the wanted redirections,
  • use a special first parameter (a simple NUL character specified by the $'string' special bash notation) to specify that the script is restarted (no equivalent parameter may be used by your original work),
  • try to preserve the original exit status when restarting the script using the pipefail option.

Ugly but useful for me in certain situations.

Websocket connections with Postman

Postman doesn't support it, but WebSocket King does.

enter image description here

How can I give the Intellij compiler more heap space?

GWT in Intellij 12

FWIW, I was getting a similar error with my GWT application during 'Build | Rebuild Project'.

This was caused by Intellij doing a full GWT compile which I didn't like because it is also a very lengthy process.

I disabled GWT compile by turning off the module check boxes under 'Project Structure | Facets | GWT'.

Alternatively there is a 'Compiler maximum heap size' setting in that location as well.

How to prevent column break within an element?

This works for me in 2015 :

li {_x000D_
  -webkit-column-break-inside: avoid;_x000D_
  /* Chrome, Safari, Opera */_x000D_
  page-break-inside: avoid;_x000D_
  /* Firefox */_x000D_
  break-inside: avoid;_x000D_
  /* IE 10+ */_x000D_
.x {_x000D_
  -moz-column-count: 3;_x000D_
  column-count: 3;_x000D_
  width: 30em;_x000D_
<div class='x'>_x000D_
    <li>Number one</li>_x000D_
    <li>Number two</li>_x000D_
    <li>Number three</li>_x000D_
    <li>Number four is a bit longer</li>_x000D_
    <li>Number five</li>_x000D_

How to reference image resources in XAML?

If the image is in your resources folder and its build action is set to Resource. You can reference the image in XAML as follows:


Assuming you do not have any folder structure under the Resources folder and it is an application. For example I use:


when I have a folder named RibbonImages under Resources folder.

Extract the first word of a string in a SQL Server query

I wanted to do something like this without making a separate function, and came up with this simple one-line approach:

SET @test = 'First Second'

SELECT SUBSTRING(@test,1,(CHARINDEX(' ',@test + ' ')-1))

This would return the result "First"

It's short, just not as robust, as it assumes your string doesn't start with a space. It will handle one-word inputs, multi-word inputs, and empty string or NULL inputs.

How to add click event to a iframe with JQuery

Solution that work for me :

var editorInstance = CKEDITOR.instances[this.editorId];

            editorInstance.on('focus', function(e) {



What are the default access modifiers in C#?

Namespace level: internal

Type level: private