Programs & Examples On #Coding efficiency

How to check if a file exists in a folder?

To check file exists or not you can use


Forward host port to docker container

If MongoDB and RabbitMQ are running on the Host, then the port should already exposed as it is not within Docker.

You do not need the -p option in order to expose ports from container to host. By default, all port are exposed. The -p option allows you to expose a port from the container to the outside of the host.

So, my guess is that you do not need -p at all and it should be working fine :)

How to properly add cross-site request forgery (CSRF) token using PHP

For security code, please don't generate your tokens this way: $token = md5(uniqid(rand(), TRUE));

Try this out:

Generating a CSRF Token


if (empty($_SESSION['token'])) {
    $_SESSION['token'] = bin2hex(random_bytes(32));
$token = $_SESSION['token'];

Sidenote: One of my employer's open source projects is an initiative to backport random_bytes() and random_int() into PHP 5 projects. It's MIT licensed and available on Github and Composer as paragonie/random_compat.

PHP 5.3+ (or with ext-mcrypt)

if (empty($_SESSION['token'])) {
    if (function_exists('mcrypt_create_iv')) {
        $_SESSION['token'] = bin2hex(mcrypt_create_iv(32, MCRYPT_DEV_URANDOM));
    } else {
        $_SESSION['token'] = bin2hex(openssl_random_pseudo_bytes(32));
$token = $_SESSION['token'];

Verifying the CSRF Token

Don't just use == or even ===, use hash_equals() (PHP 5.6+ only, but available to earlier versions with the hash-compat library).

if (!empty($_POST['token'])) {
    if (hash_equals($_SESSION['token'], $_POST['token'])) {
         // Proceed to process the form data
    } else {
         // Log this as a warning and keep an eye on these attempts

Going Further with Per-Form Tokens

You can further restrict tokens to only be available for a particular form by using hash_hmac(). HMAC is a particular keyed hash function that is safe to use, even with weaker hash functions (e.g. MD5). However, I recommend using the SHA-2 family of hash functions instead.

First, generate a second token for use as an HMAC key, then use logic like this to render it:

<input type="hidden" name="token" value="<?php
    echo hash_hmac('sha256', '/my_form.php', $_SESSION['second_token']);
?>" />

And then using a congruent operation when verifying the token:

$calc = hash_hmac('sha256', '/my_form.php', $_SESSION['second_token']);
if (hash_equals($calc, $_POST['token'])) {
    // Continue...

The tokens generated for one form cannot be reused in another context without knowing $_SESSION['second_token']. It is important that you use a separate token as an HMAC key than the one you just drop on the page.

Bonus: Hybrid Approach + Twig Integration

Anyone who uses the Twig templating engine can benefit from a simplified dual strategy by adding this filter to their Twig environment:

    new \Twig_SimpleFunction(
        function($lock_to = null) {
            if (empty($_SESSION['token'])) {
                $_SESSION['token'] = bin2hex(random_bytes(32));
            if (empty($_SESSION['token2'])) {
                $_SESSION['token2'] = random_bytes(32);
            if (empty($lock_to)) {
                return $_SESSION['token'];
            return hash_hmac('sha256', $lock_to, $_SESSION['token2']);

With this Twig function, you can use both the general purpose tokens like so:

<input type="hidden" name="token" value="{{ form_token() }}" />

Or the locked down variant:

<input type="hidden" name="token" value="{{ form_token('/my_form.php') }}" />

Twig is only concerned with template rendering; you still must validate the tokens properly. In my opinion, the Twig strategy offers greater flexibility and simplicity, while maintaining the possibility for maximum security.

Single-Use CSRF Tokens

If you have a security requirement that each CSRF token is allowed to be usable exactly once, the simplest strategy regenerate it after each successful validation. However, doing so will invalidate every previous token which doesn't mix well with people who browse multiple tabs at once.

Paragon Initiative Enterprises maintains an Anti-CSRF library for these corner cases. It works with one-use per-form tokens, exclusively. When enough tokens are stored in the session data (default configuration: 65535), it will cycle out the oldest unredeemed tokens first.

How can I include all JavaScript files in a directory via JavaScript file?

Another option that is pretty short:

<script type="text/javascript">
  url: "/js/partials",
  success: function(data){
        // will loop through 
        var partial= $(this).attr("href");
        $.getScript( "/js/partials/" + partial, function( data, textStatus, jqxhr ) {});

ADB Android Device Unauthorized

After having spent over an hour going in rounds swearing at Samsung (mostly), Google, and who not, here are my findings, that finally helped me get the device recognized:

  • On Device:
    • Set developer mode
    • Allow USB debugging
    • Default USB configuration > Select USB tethering
    • Connect device to PC USB
  • On PC:
    • Elevated cmd/ps prompt (maybe not mandatory, but that was my drill)
    • adb kill-server (precede with .\ in ps)
    • adb start-server (while device connected) > watch for prompt on device
  • On device:
    • Always allow connections from this computer > Yes
  • On PC:
    • adb devices gets the following output:
List of devices attached
278c250cce217ece        device

How can I loop through a C++ map of maps?

Old question but the remaining answers are outdated as of C++11 - you can use a ranged based for loop and simply do:

std::map<std::string, std::map<std::string, std::string>> mymap;

for(auto const &ent1 : mymap) {
  // ent1.first is the first key
  for(auto const &ent2 : ent1.second) {
    // ent2.first is the second key
    // ent2.second is the data

this should be much cleaner than the earlier versions, and avoids unnecessary copies.

Some favour replacing the comments with explicit definitions of reference variables (which get optimised away if unused):

for(auto const &ent1 : mymap) {
  auto const &outer_key = ent1.first;
  auto const &inner_map = ent1.second;
  for(auto const &ent2 : inner_map) {
    auto const &inner_key   = ent2.first;
    auto const &inner_value = ent2.second;

Laravel Eloquent Join vs Inner Join?

I'm sure there are other ways to accomplish this, but one solution would be to use join through the Query Builder.

If you have tables set up something like this:



votes, comments and status_updates (3 tables)

In your User model:

class User extends Eloquent {
    public function friends()
        return $this->hasMany('Friend');

In your Friend model:

class Friend extends Eloquent {
    public function user()
        return $this->belongsTo('User');

Then, to gather all the votes for the friends of the user with the id of 1, you could run this query:

$user = User::find(1);
$friends_votes = $user->friends()
    ->with('user') // bring along details of the friend
    ->join('votes', 'votes.user_id', '=', 'friends.friend_id')
    ->get(['votes.*']); // exclude extra details from friends table

Run the same join for the comments and status_updates tables. If you would like votes, comments, and status_updates to be in one chronological list, you can merge the resulting three collections into one and then sort the merged collection.


To get votes, comments, and status updates in one query, you could build up each query and then union the results. Unfortunately, this doesn't seem to work if we use the Eloquent hasMany relationship (see comments for this question for a discussion of that problem) so we have to modify to queries to use where instead:

$friends_votes = 
    ->join('votes', 'votes.user_id', '=', 'friends.friend_id');

$friends_comments = 
    ->join('comments', 'comments.user_id', '=', 'friends.friend_id');

$friends_status_updates = 
    ->join('friends', 'status_updates.user_id', '=', 'friends.friend_id');

$friends_events = 

At this point, though, our query is getting a bit hairy, so a polymorphic relationship with and an extra table (like DefiniteIntegral suggests below) might be a better idea.

Passing an array of data as an input parameter to an Oracle procedure

This is one way to do it:

SQL> set serveroutput on
  2  /

Type created

  2  BEGIN
  3    FOR i IN 1..t_in.count LOOP
  4      dbms_output.put_line(t_in(i));
  5    END LOOP;
  6  END;
  7  /

Procedure created

  2    v_t MyType;
  3  BEGIN
  4    v_t := MyType();
  5    v_t.EXTEND(10);
  6    v_t(1) := 'this is a test';
  7    v_t(2) := 'A second test line';
  8    testing(v_t);
  9  END;
 10  /

this is a test
A second test line

To expand on my comment to @dcp's answer, here's how you could implement the solution proposed there if you wanted to use an associative array:

  4    PROCEDURE pp (inp p_type);
  5  END p;
  6  /

Package created
  2    PROCEDURE pp (inp p_type) IS
  3    BEGIN
  4      FOR i IN 1..inp.count LOOP
  5        dbms_output.put_line(inp(i));
  6      END LOOP;
  7    END pp;
  8  END p;
  9  /

Package body created
  2    v_t p.p_type;
  3  BEGIN
  4    v_t(1) := 'this is a test of p';
  5    v_t(2) := 'A second test line for p';
  6    p.pp(v_t);
  7  END;
  8  /

this is a test of p
A second test line for p

PL/SQL procedure successfully completed


This trades creating a standalone Oracle TYPE (which cannot be an associative array) with requiring the definition of a package that can be seen by all in order that the TYPE it defines there can be used by all.

Why both no-cache and no-store should be used in HTTP response?

I must clarify that no-cache does not mean do not cache. In fact, it means "revalidate with server" before using any cached response you may have, on every request.

must-revalidate, on the other hand, only needs to revalidate when the resource is considered stale.

If the server says that the resource is still valid then the cache can respond with its representation, thus alleviating the need for the server to resend the entire resource.

no-store is effectively the full do not cache directive and is intended to prevent storage of the representation in any form of cache whatsoever.

I say whatsoever, but note this in the RFC 2616 HTTP spec:

History buffers MAY store such responses as part of their normal operation

But this is omitted from the newer RFC 7234 HTTP spec in potentially an attempt to make no-store stronger, see:

Keyboard shortcut to comment lines in Sublime Text 2

I'd like to add, that on my mac by default block comment toggle shortcut is cmd+alt+/

Generate a range of dates using SQL

About a year and a half too late, but for posterity here is a version for Teradata:

SELECT calendar_date 
WHERE SYS_CALENDAR.Calendar.calendar_date between '2010-01-01' (date) and '2010-01-03' (date)

Format bytes to kilobytes, megabytes, gigabytes

try this ;)

function bytesToSize($bytes) {
                $sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
                if ($bytes == 0) return 'n/a';
                $i = intval(floor(log($bytes) / log(1024)));
                if ($i == 0) return $bytes . ' ' . $sizes[$i]; 
                return round(($bytes / pow(1024, $i)),1,PHP_ROUND_HALF_UP). ' ' . $sizes[$i];
echo bytesToSize(10000050300);

How to fix missing dependency warning when using useEffect React Hook?

you try this way

const fetchBusinesses = () => {
    return fetch("theURL", {method: "GET"}
      .then(res => normalizeResponseErrors(res))
      .then(res => {
        return res.json();
      .then(rcvdBusinesses => {
        // some stuff
      .catch(err => {
        // some error handling


useEffect(() => {

it's work for you. But my suggestion is try this way also work for you. It's better than before way. I use this way:

useEffect(() => {
        const fetchBusinesses = () => {
    return fetch("theURL", {method: "GET"}
      .then(res => normalizeResponseErrors(res))
      .then(res => {
        return res.json();
      .then(rcvdBusinesses => {
        // some stuff
      .catch(err => {
        // some error handling
      }, []);

if you get data on the base of specific id then add in callback useEffect [id] then cannot show you warning React Hook useEffect has a missing dependency: 'any thing'. Either include it or remove the dependency array

Changing Font Size For UITableView Section Headers

While mosca1337's answer is a correct solution, be careful with that method. For a header with text longer than one line, you will have to perform the calculations of the height of the header in tableView:heightForHeaderInSection: which can be cumbersome.

A much preferred method is to use the appearance API:

[[UILabel appearanceWhenContainedIn:[UITableViewHeaderFooterView class], nil] setFont:[UIFont boldSystemFontOfSize:28]];

This will change the font, while still leaving the table to manage the heights itself.

For optimal results, subclass the table view, and add it to the containment chain (in appearanceWhenContainedIn:) to make sure the font is only changed for the specific table views.

Unable to load DLL 'SQLite.Interop.dll'

This is what worked for me.

  1. With Visual Studio open, search and install SQLite.Core via the NUGET Package manager.
  2. Go to Solution Explorer in VS, Right click your PROJECT NAME-->ADD-->NEW FOLDER
  3. Name the folder x64
  4. Repeat the process and add folder and name it x86
  5. Right click the x64 folder-->ADD-->EXISTING ITEM Then browse to the DEBUG FOLDER. You will find the x64 folder. Open it and select the "SQLite.Interop.dll" file then hit OK.
  6. Repeat step 5 for the x86 folder.
  7. Right click the DLL that you just added and select PROPERTIES. In the option Copy to Output Directory, choose Copy always.
  8. Repeat step 7 for both DLLs in x64 and x86 folder.

Next time you build the project and take to another computer, it should work fine.

Should I use past or present tense in git commit messages?

Stick with the present tense imperative because

  • it's good to have a standard
  • it matches tickets in the bug tracker which naturally have the form "implement something", "fix something", or "test something."

CURRENT_DATE/CURDATE() not working as default DATE value

----- 2016-07-04 MariaDB 10.2.1 -- Release Note -- -----

Support for DEFAULT with expressions (MDEV-10134).

----- 2018-10-22 8.0.13 General Availability -- -- -----

MySQL now supports use of expressions as default values in data type specifications. This includes the use of expressions as default values for the BLOB, TEXT, GEOMETRY, and JSON data types, which previously could not be assigned default values at all. For details, see Data Type Default Values.

A fatal error occurred while creating a TLS client credential. The internal error state is 10013

I found this here:

"Correct file permissions Correct the permissions on the c:\ProgramData\Microsoft\Crypto\RSA\MachineKeys folder:

Everyone Access: Special Applies to 'This folder only' Network Service Access: Read & Execute Applies to 'This folder, subfolders and files' Administrators Access: Full Control Applies to 'This folder, subfolder and files' System Access: Full control Applies to 'This folder, subfolder and Files' IUSR Access: Full Control Applies to 'This folder, subfolder and files' The internal error state is 10013 After these changes, restart the server. The 10013 errors should disappear."

How to disable copy/paste from/to EditText

If you are using API level 11 or above then you can stop copy,paste,cut and custom context menus from appearing by.

edittext.setCustomSelectionActionModeCallback(new ActionMode.Callback() {

            public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
                return false;

            public void onDestroyActionMode(ActionMode mode) {                  

            public boolean onCreateActionMode(ActionMode mode, Menu menu) {
                return false;

            public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
                return false;

Returning false from onCreateActionMode(ActionMode, Menu) will prevent the action mode from being started(Select All, Cut, Copy and Paste actions).

Why doesn't Mockito mock static methods?

As an addition to the Gerold Broser's answer, here an example of mocking a static method with arguments:

class Buddy {
  static String addHello(String name) {
    return "Hello " + name;


void testMockStaticMethods() {
  assertThat(Buddy.addHello("John")).isEqualTo("Hello John");

  try (MockedStatic<Buddy> theMock = Mockito.mockStatic(Buddy.class)) {
    theMock.when(() -> Buddy.addHello("John")).thenReturn("Guten Tag John");
    assertThat(Buddy.addHello("John")).isEqualTo("Guten Tag John");

  assertThat(Buddy.addHello("John")).isEqualTo("Hello John");

Docker Error bind: address already in use

maybe it is too rude, but works for me. restart docker service itself

sudo service docker restart

hope it works for you also!

Loop through files in a folder using VBA?

Dir function loses focus easily when I handle and process files from other folders.

I've gotten better results with the component FileSystemObject.

Full example is given here:

Don't forget to set a reference in the Visual Basic Editor to Microsoft Scripting Runtime (by using Tools > References)

Give it a try!

Proper way of checking if row exists in table in PL/SQL block

select max( 1 )
  into my_if_has_data
  from MY_TABLE    X
 where X.my_field   = my_condition
   and rownum       = 1;

Not iterating through all records.

If MY_TABLE has no data, then my_if_has_data sets to null.

Linux command line howto accept pairing for bluetooth device without pin

follow steps (CentOs):

  1. bluetoothctl
  2. devices
  3. scan on
  4. pair 34:88:5D:51:5A:95 (34:88:5D:51:5A:95 is my device code,replace it with yours)
  5. trust 34:88:5D:51:5A:95
  6. connect 34:88:5D:51:5A:95

If you want more details

How to include External CSS and JS file in Laravel 5


If you have a external .css or .js file to add into your page!

My version : Laravel Framework 5.7

If you want to add a External .js file..

  1. Copy your External codes.
  2. Run command npm install in your terminal.
  3. When the above command is executed you can see a folder named node_modules.
  4. Then go to resources/js.
  5. Open file app.js.
  6. Scroll down to the bottom and paste your External JS.
  7. Finally run command npm run dev in your terminal.

your scripts will be updated and its compiled and moved to public/js/app.js . by adding a .js file in public folder will not effect on your page.

If you want to add a External .css file..

  1. Copy your External styles.
  2. Run command npm install in your terminal.
  3. When the above command is executed you can see a folder named node_modules.
  4. Then go to resources/sass.
  5. Open file app.scss.
  6. Scroll down to the bottom and paste your External Styles.
  7. Finally run command npm run dev in your terminal.

your scripts will be updated and its compiled and moved to public/css/app.css . by adding a .css file in public folder will not effect on your page.

  • Easiest and the safest way to add your external .css and .js.

Laravel JavaScript & CSS Scaffolding

YouTube Compiling Assets

How to update all MySQL table rows at the same time?

just use UPDATE query without condition like this

 UPDATE tablename SET online_status=0;

Multiple controllers with AngularJS in single page app

<div class="widget" ng-controller="widgetController">
    <p>Stuff here</p>

<div class="menu" ng-controller="menuController">
    <p>Other stuff here</p>
///////////////// OR ////////////

  <div class="widget" ng-controller="widgetController">
    <p>Stuff here</p>
    <div class="menu" ng-controller="menuController">
        <p>Other stuff here</p>

menuController have access for menu div. And widgetController have access to both.

Code-first vs Model/Database-first

Code-first appears to be the rising star. I had a quick look at Ruby on Rails, and their standard is code-first, with database migrations.

If you are building an MVC3 application, I believe Code first has the following advantages:

  • Easy attribute decoration - You can decorate fields with validation, require, etc.. attributes, it's quite awkward with EF modelling
  • No weird modelling errors - EF modelling often has weird errors, such as when you try to rename an association property, it needs to match the underlying meta-data - very inflexible.
  • Not awkward to merge - When using code version control tools such as mercurial, merging .edmx files is a pain. You're a programmer used to C#, and there you are merging a .edmx. Not so with code-first.
  • Contrast back to Code first and you have complete control without all the hidden complexities and unknowns to deal with.
  • I recommend you use the Package Manager command line tool, don't even use the graphical tools to add a new controller to scaffold views.
  • DB-Migrations - Then you can also Enable-Migrations. This is so powerful. You make changes to your model in code, and then the framework can keep track of schema changes, so you can seamlessly deploy upgrades, with schema versions automatically upgraded (and downgraded if required). (Not sure, but this probably does work with model-first too)


The question also asks for a comparison of code-first to EDMX model/db-first. Code-first can be used for both of these approaches too:

How do I keep Python print from adding newlines or spaces?

Regain control of your console! Simply:

from __past__ import printf

where contains:

import sys
def printf(fmt, *varargs):
    sys.stdout.write(fmt % varargs)


>>> printf("Hello, world!\n")
Hello, world!
>>> printf("%d %d %d\n", 0, 1, 42)
0 1 42
>>> printf('a'); printf('b'); printf('c'); printf('\n')

Bonus extra: If you don't like print >> f, ..., you can extending this caper to fprintf(f, ...).

MySQL 1062 - Duplicate entry '0' for key 'PRIMARY'

You need to specify the primary key as auto-increment

CREATE TABLE `momento_distribution`
     `momento_id`       INT(11) NOT NULL AUTO_INCREMENT,
     `momento_idmember` INT(11) NOT NULL,
     `created_at`       DATETIME DEFAULT NULL,
     `updated_at`       DATETIME DEFAULT NULL,
     `unread`           TINYINT(1) DEFAULT '1',
     `accepted`         VARCHAR(10) NOT NULL DEFAULT 'pending',
     `ext_member`       VARCHAR(255) DEFAULT NULL,
     PRIMARY KEY (`momento_id`, `momento_idmember`),
     KEY `momento_distribution_FI_2` (`momento_idmember`),
     KEY `accepted` (`accepted`, `ext_member`)

With regards to comment below, how about:

ALTER TABLE `momento_distribution`

A PRIMARY KEY is a unique index, so if it contains duplicates, you cannot assign the column to be unique index, so you may need to create a new column altogether

How do I generate a stream from a string?

Add this to a static string utility class:

public static Stream ToStream(this string str)
    MemoryStream stream = new MemoryStream();
    StreamWriter writer = new StreamWriter(stream);
    stream.Position = 0;
    return stream;

This adds an extension function so you can simply:

using (var stringStream = "My string".ToStream())
    // use stringStream

Android emulator doesn't take keyboard input - SDK tools rev 20

Google wanted to give some more headache to the developers.

So, what you have to do now is edit your AVD and add "Keyboard Support" for it in the Hardware section and change the value to "Yes"

What is the backslash character (\\)?

If double backslash looks weird to you, C# also allows verbatim string literals where the escaping is not required.

Console.WriteLine(@"Mango \ Nightangle");

Don't you just wish Java had something like this ;-)

Understanding the main method of python

Python does not have a defined entry point like Java, C, C++, etc. Rather it simply executes a source file line-by-line. The if statement allows you to create a main function which will be executed if your file is loaded as the "Main" module rather than as a library in another module.

To be clear, this means that the Python interpreter starts at the first line of a file and executes it. Executing lines like class Foobar: and def foobar() creates either a class or a function and stores them in memory for later use.

How to use OrderBy with findAll in Spring Data

public interface StudentDAO extends JpaRepository<StudentEntity, Integer> {
    public List<StudentEntity> findAllByOrderByIdAsc();

The code above should work. I'm using something similar:

public List<Pilot> findTop10ByOrderByLevelDesc();

It returns 10 rows with the highest level.

IMPORTANT: Since I've been told that it's easy to miss the key point of this answer, here's a little clarification:

findAllByOrderByIdAsc(); // don't miss "by"

Pointer-to-pointer dynamic two-dimensional array

The first method cannot be used to create dynamic 2D arrays because by doing:

int *board[4];

you essentially allocated an array of 4 pointers to int on stack. Therefore, if you now populate each of these 4 pointers with a dynamic array:

for (int i = 0; i < 4; ++i) {
  board[i] = new int[10];

what you end-up with is a 2D array with static number of rows (in this case 4) and dynamic number of columns (in this case 10). So it is not fully dynamic because when you allocate an array on stack you should specify a constant size, i.e. known at compile-time. Dynamic array is called dynamic because its size is not necessary to be known at compile-time, but can rather be determined by some variable in runtime.

Once again, when you do:

int *board[4];


const int x = 4; // <--- `const` qualifier is absolutely needed in this case!
int *board[x];

you supply a constant known at compile-time (in this case 4 or x) so that compiler can now pre-allocate this memory for your array, and when your program is loaded into the memory it would already have this amount of memory for the board array, that's why it is called static, i.e. because the size is hard-coded and cannot be changed dynamically (in runtime).

On the other hand, when you do:

int **board;
board = new int*[10];


int x = 10; // <--- Notice that it does not have to be `const` anymore!
int **board;
board = new int*[x];

the compiler does not know how much memory board array will require, and therefore it does not pre-allocate anything. But when you start your program, the size of array would be determined by the value of x variable (in runtime) and the corresponding space for board array would be allocated on so-called heap - the area of memory where all programs running on your computer can allocate unknown beforehand (at compile-time) amounts memory for personal usage.

As a result, to truly create dynamic 2D array you have to go with the second method:

int **board;
board = new int*[10]; // dynamic array (size 10) of pointers to int

for (int i = 0; i < 10; ++i) {
  board[i] = new int[10];
  // each i-th pointer is now pointing to dynamic array (size 10) of actual int values

We've just created an square 2D array with 10 by 10 dimensions. To traverse it and populate it with actual values, for example 1, we could use nested loops:

for (int i = 0; i < 10; ++i) {   // for each row
  for (int j = 0; j < 10; ++j) { // for each column
    board[i][j] = 1;

How to format DateTime to 24 hours time?


Set auto height and width in CSS/HTML for different screen sizes

Using bootstrap with a little bit of customization, the following seems to work for me:

I need 3 partitions in my container and I tried this:


.row.content {height: 100%; width:100%; position: fixed; }
.sidenav {
  padding-top: 20px;
  border: 1px solid #cecece;
  height: 100%;
.midnav {
  padding: 0px;


  <div class="container-fluid text-center"> 
    <div class="row content">
    <div class="col-md-2 sidenav text-left">Some content 1</div>
    <div class="col-md-9 midnav text-left">Some content 2</div>
    <div class="col-md-1 sidenav text-center">Some content 3</div>

Password Protect a SQLite DB. Is it possible?

Why do you need to encrypt the database? The user could easily disassemble your program and figure out the key. If you're encrypting it for network transfer, then consider using PGP instead of squeezing an encryption layer into a database layer.

Display Back Arrow on Toolbar

If your are using the just use:

Toolbar toolbar = findViewById(;

Then just define in the Manifest.xml the parent Activity.

      android:value=".ParentActivity" />

Instead if you are using a Toolbar and you want a custom behavior just use:


and in your Activity:

Toolbar toolbar = (Toolbar) findViewById(;
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {

Shell Script: How to write a string to file and to stdout on console?

You can use >> to print in another file.

echo "hello" >> logfile.txt

PowerShell - Start-Process and Cmdline Switches


If you run PowerShell from a cmd.exe window created by Powershell, the 2nd instance no longer waits for jobs to complete.

cmd>  PowerShell
PS> Start-Process cmd.exe -Wait 

Now from the new cmd window, run PowerShell again and within it start a 2nd cmd window: cmd2> PowerShell

PS> Start-Process cmd.exe -Wait

The 2nd instance of PowerShell no longer honors the -Wait request and ALL background process/jobs return 'Completed' status even thou they are still running !

I discovered this when my C# Explorer program is used to open a cmd.exe window and PS is run from that window, it also ignores the -Wait request. It appears that any PowerShell which is a 'win32 job' of cmd.exe fails to honor the wait request.

I ran into this with PowerShell version 3.0 on windows 7/x64

'python3' is not recognized as an internal or external command, operable program or batch file

You can also try this: Go to the path where Python is installed in your system. For me it was something like C:\Users\\Local Settings\Application Data\Programs\Python\Python37 In this folder, you'll find a python executable. Just create a duplicate and rename it to python3. Works every time.

enter image description here

Excel: Search for a list of strings within a particular string using array formulas?

In case others may find this useful: I found that by adding an initial empty cell to my list of search terms, a zero value will be returned instead of error.


NB: Column A has the search terms, B is the row number index.

Export javascript data to CSV file without server interaction

There's always the HTML5 download attribute :

This attribute, if present, indicates that the author intends the hyperlink to be used for downloading a resource so that when the user clicks on the link they will be prompted to save it as a local file.

If the attribute has a value, the value will be used as the pre-filled file name in the Save prompt that opens when the user clicks on the link.

var A = [['n','sqrt(n)']];

for(var j=1; j<10; ++j){ 
    A.push([j, Math.sqrt(j)]);

var csvRows = [];

for(var i=0, l=A.length; i<l; ++i){

var csvString = csvRows.join("%0A");
var a         = document.createElement('a');
a.href        = 'data:attachment/csv,' +  encodeURIComponent(csvString);      = '_blank';    = 'myFile.csv';



Tested in Chrome and Firefox, works fine in the newest versions (as of July 2013).
Works in Opera as well, but does not set the filename (as of July 2013).
Does not seem to work in IE9 (big suprise) (as of July 2013).

An overview over what browsers support the download attribute can be found Here
For non-supporting browsers, one has to set the appropriate headers on the serverside.

Apparently there is a hack for IE10 and IE11, which doesn't support the download attribute (Edge does however).

var A = [['n','sqrt(n)']];

for(var j=1; j<10; ++j){ 
    A.push([j, Math.sqrt(j)]);

var csvRows = [];

for(var i=0, l=A.length; i<l; ++i){

var csvString = csvRows.join("%0A");

if (window.navigator.msSaveOrOpenBlob) {
    var blob = new Blob([csvString]);
    window.navigator.msSaveOrOpenBlob(blob, 'myFile.csv');
} else {
    var a         = document.createElement('a');
    a.href        = 'data:attachment/csv,' +  encodeURIComponent(csvString);      = '_blank';    = 'myFile.csv';

If statement within Where clause

You can't use IF like that. You can do what you want with AND and OR:

SELECT t.first_name,
  FROM employeetable t
 WHERE ((status_flag = STATUS_ACTIVE   AND t.status = 'A')
     OR (status_flag = STATUS_INACTIVE AND t.status = 'T')
     OR (source_flag = SOURCE_FUNCTION AND t.business_unit = 'production')
     OR (source_flag = SOURCE_USER     AND t.business_unit = 'users'))
   AND t.first_name LIKE firstname
   AND t.last_name  LIKE lastname
   AND t.employid   LIKE employeeid;

Verify object attribute value with mockito

And very nice and clean solution in koltin from com.nhaarman.mockito_kotlin

verify(mock).execute(argThat {
    this.param = expected

Should a RESTful 'PUT' operation return something

Just as an empty Request body is in keeping with the original purpose of a GET request and empty response body is in keeping with the original purpose of a PUT request.

The Role Manager feature has not been enabled

If you got here because you're using the new ASP.NET Identity UserManager, what you're actually looking for is the RoleManager:

var roleManager = new RoleManager<IdentityRole>(new RoleStore<IdentityRole>(new ApplicationDbContext()));

roleManager will give you access to see if the role exists, create, etc, plus it is created for the UserManager

nodejs module.js:340 error: cannot find module

I had the same problem, but finally I tried copying the Node_modules folder in the same project folder, and it worked.

how to generate a unique token which expires after 24 hours?

There are two possible approaches; either you create a unique value and store somewhere along with the creation time, for example in a database, or you put the creation time inside the token so that you can decode it later and see when it was created.

To create a unique token:

string token = Convert.ToBase64String(Guid.NewGuid().ToByteArray());

Basic example of creating a unique token containing a time stamp:

byte[] time = BitConverter.GetBytes(DateTime.UtcNow.ToBinary());
byte[] key = Guid.NewGuid().ToByteArray();
string token = Convert.ToBase64String(time.Concat(key).ToArray());

To decode the token to get the creation time:

byte[] data = Convert.FromBase64String(token);
DateTime when = DateTime.FromBinary(BitConverter.ToInt64(data, 0));
if (when < DateTime.UtcNow.AddHours(-24)) {
  // too old

Note: If you need the token with the time stamp to be secure, you need to encrypt it. Otherwise a user could figure out what it contains and create a false token.

Does C# have an equivalent to JavaScript's encodeURIComponent()?

System.Uri.EscapeUriString() didn't seem to do anything, but System.Uri.EscapeDataString() worked for me.

.bashrc: Permission denied

.bashrc is not meant to be executed but sourced. Try this instead:

. ~/.bashrc


Django: Redirect to previous page after login

Django's built-in authentication works the way you want.

Their login pages include a next query string which is the page to return to after login.

Look at

How to access route, post, get etc. parameters in Zend Framework 2

The easiest way to do that would be to use the Params plugin, introduced in beta5. It has utility methods to make it easy to access different types of parameters. As always, reading the tests can prove valuable to understand how something is supposed to be used.

Get a single value

To get the value of a named parameter in a controller, you will need to select the appropriate method for the type of parameter you are looking for and pass in the name.


$this->params()->fromPost('paramname');   // From POST
$this->params()->fromQuery('paramname');  // From GET
$this->params()->fromRoute('paramname');  // From RouteMatch
$this->params()->fromHeader('paramname'); // From header
$this->params()->fromFiles('paramname');  // From file being uploaded


Default values

All of these methods also support default values that will be returned if no parameter with the given name is found.


$orderBy = $this->params()->fromQuery('orderby', 'name');

When visiting, $orderBy will have the value birthdate.
When visiting, $orderBy will have the default value name.

Get all parameters

To get all parameters of one type, just don't pass in anything and the Params plugin will return an array of values with their names as keys.


$allGetValues = $this->params()->fromQuery(); // empty method call

When visiting $allGetValues will be an array like

    'orderby' => 'birthdate',
    'filter'  => 'hasphone',


Not using Params plugin

If you check the source code for the Params plugin, you will see that it's just a thin wrapper around other controllers to allow for more consistent parameter retrieval. If you for some reason want/need to access them directly, you can see in the source code how it's done.


$this->getRequest()->getRequest('name', 'default');
$this->getEvent()->getRouteMatch()->getParam('name', 'default');

NOTE: You could have used the superglobals $_GET, $_POST etc., but that is discouraged.

Could not install packages due to a "Environment error :[error 13]: permission denied : 'usr/local/bin/f2py'"

It is always preferred to use a virtual environment ,Create your virtual environment using :

python -m venv <name_of_virtualenv>

go to your environment directory and activate your environment using below command on windows:


then simply use

pip install package_name

How do I right align div elements?

Other answers for this question are not so good since float:right can go outside of a parent div (overflow: hidden for parent sometimes might help) and margin-left: auto, margin-right: 0 for me didn't work in complex nested divs (I didn't investigate why).

I've figured out that for certain elements text-align: right works, assuming this works when the element and parent are both inline or inline-block.

Note: the text-align CSS property describes how inline content like text is aligned in its parent block element. text-align does not control the alignment of block elements itself, only their inline content.

An example:

<div style="display: block; width: 80%; min-width: 400px; background-color: #caa;">
    <div style="display: block; width: 100%">
        I'm parent
    <div style="display: inline-block; text-align: right; width: 100%">
        Caption for parent

Here's a JS Fiddle.

What are the differences between numpy arrays and matrices? Which one should I use?

Numpy matrices are strictly 2-dimensional, while numpy arrays (ndarrays) are N-dimensional. Matrix objects are a subclass of ndarray, so they inherit all the attributes and methods of ndarrays.

The main advantage of numpy matrices is that they provide a convenient notation for matrix multiplication: if a and b are matrices, then a*b is their matrix product.

import numpy as np

a = np.mat('4 3; 2 1')
b = np.mat('1 2; 3 4')
# [[4 3]
#  [2 1]]
# [[1 2]
#  [3 4]]
# [[13 20]
#  [ 5  8]]

On the other hand, as of Python 3.5, NumPy supports infix matrix multiplication using the @ operator, so you can achieve the same convenience of matrix multiplication with ndarrays in Python >= 3.5.

import numpy as np

a = np.array([[4, 3], [2, 1]])
b = np.array([[1, 2], [3, 4]])
# [[13 20]
#  [ 5  8]]

Both matrix objects and ndarrays have .T to return the transpose, but matrix objects also have .H for the conjugate transpose, and .I for the inverse.

In contrast, numpy arrays consistently abide by the rule that operations are applied element-wise (except for the new @ operator). Thus, if a and b are numpy arrays, then a*b is the array formed by multiplying the components element-wise:

c = np.array([[4, 3], [2, 1]])
d = np.array([[1, 2], [3, 4]])
# [[4 6]
#  [6 4]]

To obtain the result of matrix multiplication, you use (or @ in Python >= 3.5, as shown above):

# [[13 20]
#  [ 5  8]]

The ** operator also behaves differently:

# [[22 15]
#  [10  7]]
# [[16  9]
#  [ 4  1]]

Since a is a matrix, a**2 returns the matrix product a*a. Since c is an ndarray, c**2 returns an ndarray with each component squared element-wise.

There are other technical differences between matrix objects and ndarrays (having to do with np.ravel, item selection and sequence behavior).

The main advantage of numpy arrays is that they are more general than 2-dimensional matrices. What happens when you want a 3-dimensional array? Then you have to use an ndarray, not a matrix object. Thus, learning to use matrix objects is more work -- you have to learn matrix object operations, and ndarray operations.

Writing a program that mixes both matrices and arrays makes your life difficult because you have to keep track of what type of object your variables are, lest multiplication return something you don't expect.

In contrast, if you stick solely with ndarrays, then you can do everything matrix objects can do, and more, except with slightly different functions/notation.

If you are willing to give up the visual appeal of NumPy matrix product notation (which can be achieved almost as elegantly with ndarrays in Python >= 3.5), then I think NumPy arrays are definitely the way to go.

PS. Of course, you really don't have to choose one at the expense of the other, since np.asmatrix and np.asarray allow you to convert one to the other (as long as the array is 2-dimensional).

There is a synopsis of the differences between NumPy arrays vs NumPy matrixes here.

500 internal server error, how to debug

Try writing all the errors to a file.

error_reporting(-1); // reports all errors
ini_set("display_errors", "1"); // shows all errors
ini_set("log_errors", 1);
ini_set("error_log", "/tmp/php-error.log");

Something like that.

Tips for using Vim as a Java IDE?

Some tips:

  • Make sure you use vim (vi improved). Linux and some versions of UNIX symlink vi to vim.
  • You can get code completion with eclim
  • Or you can get vi functionality within Eclipse with viPlugin
  • Syntax highlighting is great with vim
  • Vim has good support for writing little macros like running ant/maven builds

Have fun :-)

What is Gradle in Android Studio?

DEFINITION:: Gradle can be described a structured building mechanism where it provides a developer the tools and flexibility to manage the resources of a project to create builds that are smaller in size, targeting specific requirements for certain devices of certain configurations


  1. minimumSdk
  2. maximumSdk
  3. targettedSdk
  4. versionCode
  5. versionName

LIBRARIES:: We can add android libraries or any other third party libraries in addition as per requirements easy which was a tedious task earlier. If the library does not fit for the existing project, The developer is shown a log where the person can find a appropriate solution to make changes to the project so that the library can be added. Its just one line of dependency


Combining build types with build flavours to get varities of build varients

 ====================                         ====================
|     BuildTypes     |                       |   ProductFlavours  |
 --------------------  ====================== --------------------
|  Debug,Production  |      ||       ||      | Paid,Free,Demo,Mock|
 ====================       ||       ||       ==================== 
                            ||       ||
                            VV       VV
|           DebugPaid, DebugFree, DebugDemo, DebugMock            |
|  ProductionPaid, ProductionFree, ProductionDemo, ProductionMock |


Gradle helps in reducing the size of the generated build by removing the unused resources also unused things from integrated libraries


We can Specify certain permissions for certain builds by adding certain permissions in certain scenarios based on requirements


We can manage generating build for certain devices that include certain densities and certain api levels. This helps in product deployments in app store according to requirements across multiple types of devices


Vogella Tutorials

Telnet is not recognized as internal or external command

  1. Open "Start" (Windows Button)
  2. Search for "Turn Windows features On or Off"
  3. Check "Telnet client" and check "Telnet server".

clearing a char array c

Try the following:


how to use JSON.stringify and json_decode() properly


Pandas column of lists, create a row for each list element

Pandas >= 0.25

Series and DataFrame methods define a .explode() method that explodes lists into separate rows. See the docs section on Exploding a list-like column.

df = pd.DataFrame({
    'var1': [['a', 'b', 'c'], ['d', 'e',], [], np.nan], 
    'var2': [1, 2, 3, 4]
        var1  var2
0  [a, b, c]     1
1     [d, e]     2
2         []     3
3        NaN     4


  var1  var2
0    a     1
0    b     1
0    c     1
1    d     2
1    e     2
2  NaN     3  # empty list converted to NaN
3  NaN     4  # NaN entry preserved as-is

# to reset the index to be monotonically increasing...

  var1  var2
0    a     1
1    b     1
2    c     1
3    d     2
4    e     2
5  NaN     3
6  NaN     4

Note that this also handles mixed columns of lists and scalars, as well as empty lists and NaNs appropriately (this is a drawback of repeat-based solutions).

However, you should note that explode only works on a single column (for now).

P.S.: if you are looking to explode a column of strings, you need to split on a separator first, then use explode. See this (very much) related answer by me.

How To Run PHP From Windows Command Line in WAMPServer

Try using batch file

  1. Open notepad
  2. type php -S localhost:8000
  3. save file as .bat extension, server.bat
  4. now click on server.bat file your server is ready on http://localhost:8000


if you got error php not recognize any internal or external command then goto environment variable and edit path to php.exe "C:\wamp\bin\php\php5.4.3"

Changing default startup directory for command prompt in Windows 7

"start in directory" command

cmd /K cd C:\WorkSpace

but if WorkSpace happens to be on different than C drive, console will be launched in default folder and then you still need to put D: to change drive To avoid this use cd with -d parameter

cmd /K cd -d D:\WorkSpace

create a shortcut and your fixed ;)

C++ "was not declared in this scope" compile error

grid is not present on nonrecursivecountcells's scope.

Either make grid a global array, or pass it as a parameter to the function.

Ansible: Set variable to file content

You can use the slurp module to fetch a file from the remote host: (Thanks to @mlissner for suggesting it)

  amazon_linux_ami: "ami-fb8e9292"
  user_data_file: ""
- name: Load data
    src: "{{ user_data_file }}"
  register: slurped_user_data
- name: Decode data and store as fact # You can skip this if you want to use the right hand side directly...
    user_data: "{{ slurped_user_data.content | b64decode }}"

How to download PDF automatically using js?

It is also possible to open the pdf link in a new window and let the browser handle the rest:, '_blank');


Troubleshooting "Illegal mix of collations" error in mysql

Sometimes it can be dangerous to convert charsets, specially on databases with huge amounts of data. I think the best option is to use the "binary" operator:

e.g : WHERE binary table1.column1 = binary table2.column1

Cannot overwrite model once compiled Mongoose

I have been experiencing this issue & it was not because of the schema definitions but rather of serverless offline mode - I just managed to resolve it with this:

serverless offline --skipCacheInvalidation

Which is mentioned here

Hopefully that helps someone else who is building their project on serverless and running offline mode.

Form/JavaScript not working on IE 11 with error DOM7011

Go to

Tools > Compatibility View settings > Uncheck the option "Display intranet sites in Compatibility View".

Click on Close. It may re-launch the page and then your problem would be resolved.

How to break out of jQuery each Loop

According to the documentation return false; should do the job.

We can break the $.each() loop [..] by making the callback function return false.

Return false in the callback:

function callback(indexInArray, valueOfElement) {
  var booleanKeepGoing;

  this; // == valueOfElement (casted to Object)

  return booleanKeepGoing; // optional, unless false 
                           // and want to stop looping

BTW, continue works like this:

Returning non-false is the same as a continue statement in a for loop; it will skip immediately to the next iteration.

How to Increase Import Size Limit in phpMyAdmin

go to your cpanel and search "ini editor". You'll get "Multiphp INI Editor" There you select your wordpress directory and put upload_max_filesize = 256M post_max_size = 256M memory_limit = 256M

enter image description here

Query EC2 tags from within instance

A variation on some of the answers above but this is how I got the value of a specific tag from the user-data script on an instance

REGION=$(curl http://instance-data/latest/meta-data/placement/availability-zone | sed 's/.$//')

INSTANCE_ID=$(curl -s http://instance-data/latest/meta-data/instance-id)

TAG_VALUE=$(aws ec2 describe-tags --region $REGION --filters "Name=resource-id,Values=$INSTANCE_ID" "Name=key,Values='<TAG_NAME_HERE>'" | jq -r '.Tags[].Value')

How do I check if a string contains a specific word?

Another option is to use the strstr() function. Something like:

if (strlen(strstr($haystack,$needle))>0) {
// Needle Found

Point to note: The strstr() function is case-sensitive. For a case-insensitive search, use the stristr() function.

How to filter keys of an object with lodash?

Just change filter to omitBy

const data = { aaa: 111, abb: 222, bbb: 333 };_x000D_
const result = _.omitBy(data, (value, key) => !key.startsWith("a"));_x000D_
<script src=""></script>

PySpark: withColumn() with two conditions and three outcomes

The withColumn function in pyspark enables you to make a new variable with conditions, add in the when and otherwise functions and you have a properly working if then else structure. For all of this you would need to import the sparksql functions, as you will see that the following bit of code will not work without the col() function. In the first bit, we declare a new column -'new column', and then give the condition enclosed in when function (i.e. fruit1==fruit2) then give 1 if the condition is true, if untrue the control goes to the otherwise which then takes care of the second condition (fruit1 or fruit2 is Null) with the isNull() function and if true 3 is returned and if false, the otherwise is checked again giving 0 as the answer.

from pyspark.sql import functions as F
    F.when(F.col('fruit1')==F.col('fruit2'), 1)
    .otherwise(F.when((F.col('fruit1').isNull()) | (F.col('fruit2').isNull()), 3))

class << self idiom in Ruby

I found a super simple explanation about class << self , Eigenclass and different type of methods.

In Ruby, there are three types of methods that can be applied to a class:

  1. Instance methods
  2. Singleton methods
  3. Class methods

Instance methods and class methods are almost similar to their homonymous in other programming languages.

class Foo  
  def an_instance_method  
    puts "I am an instance method"  
  def self.a_class_method  
    puts "I am a class method"  

foo =

def foo.a_singleton_method
  puts "I am a singletone method"

Another way of accessing an Eigenclass(which includes singleton methods) is with the following syntax (class <<):

foo =

class << foo
  def a_singleton_method
    puts "I am a singleton method"

now you can define a singleton method for self which is the class Foo itself in this context:

class Foo
  class << self
    def a_singleton_and_class_method
      puts "I am a singleton method for self and a class method for Foo"

How to add Button over image using CSS?

I like TryingToImprove's answer. I've essentially taken his answer and simplified it down to the barebones css to accomplish the same thing. I think it's a lot easier to chew on.


<div class="content">
    <img src=""/> 
    <a href="#">Counter-Strike 1.6 Steam</a>



.content a {

Working fiddle here.

What is the argument for printf that formats a long?

I think to answer this question definitively would require knowing the compiler name and version that you are using and the platform (CPU type, OS etc.) that it is compiling for.

javascript: detect scroll end

This will actually be the correct answer:

function scrolled(event) {
   const container =
   const {clientHeight, scrollHeight, scrollY: scrollTop} = container

   if (clientHeight + scrollY >= scrollHeight) {

The reason for using the event is up-to-date data, if you'll use a direct reference to the div you'll get outdated scrollY and will fail to detect the position correctly.

additional way is to wrap it in a setTimeout and wait till the data updates.

How to pass a value to razor variable from javascript variable?

I see that this problem was discussed some time ago, but if anyone 'll meet with this again, here is my solution:

In your *.cshtml View file:

var data = JsFunction("@Html.Raw(Model.Path)");
$(function () {
    $("#btn").click(function () {
        var model = { Id: '@Html.Raw(Model.Id)', Data: data }
            type: "POST",
            url: "/Controller/Action",
            data: model,
            datatype: "html",
            success: function() {

JavaScript variable model is something that I need to pass to Razor ViewModel. It can be done with ajax request. You just need to have proper argument/s in your action, that matches Json object created in JavaScript.

Hope it'll help someone!

How to fill a Javascript object literal with many static key/value pairs efficiently?

The syntax you wrote as first is not valid. You can achieve something using the follow:

var map =  {"aaa": "rrr", "bbb": "ppp" /* etc */ };

How to install mcrypt extension in xampp

Right from the PHP Docs: PHP 5.3 Windows binaries uses the static version of the MCrypt library, no DLL are needed.

But if you really want to download it, just go to the mcrypt sourceforge page

How to rsync only a specific list of files?

Edit: atp's answer below is better. Please use that one!

You might have an easier time, if you're looking for a specific list of files, putting them directly on the command line instead:

# rsync -avP -e ssh `cat deploy/rsync_include.txt` [email protected]:/var/www/

This is assuming, however, that your list isn't so long that the command line length will be a problem and that the rsync_include.txt file contains just real paths (i.e. no comments, and no regexps).

Extract only right most n letters from a string


String mystr = "PER 343573";
String number = mystr.Substring(mystr.Length-6);

EDIT: too slow...

How can I delete Docker's images?

Possible reason: The reason can be that this image is currently used by a running container. In such case, you can list running containers, stop the relevant container and then remove the image:

docker ps
docker stop <containerid>
docker rm <containerid>
docker rmi <imageid>

If you cannnot find container by docker ps, you can use this to list all already exited containers and remove them.

docker ps -a | grep 60afe4036d97
docker rm <containerid>

Note: Be careful of deleting all exited containers at once in case you use Volume-Only containers. These stay in Exit state, but contains useful data.

How to set up file permissions for Laravel?

Change the permissions for your project folder to enable read/write/exec for any user within the group owning the directory (which in your case is _www):

chmod -R 775 /path/to/your/project

Then add your OS X username to the _www group to allow it access to the directory:

sudo dseditgroup -o edit -a yourusername -t user _www

JNZ & CMP Assembly Instructions

At first it seems as if JNZ means jump if not Zero (0), as in jump if zero flag is 1/set.

But in reality it means Jump (if) not Zero (is set).

If 0 = not set and 1 = set then just remember:
JNZ Jumps if the zero flag is not set (0)

Cast object to T

You could require the type to be a reference type :

 private static T ReadData<T>(XmlReader reader, string value) where T : class
     object readData = reader.ReadContentAsObject();
     return (T)readData;

And then do another that uses value types and TryParse...

 private static T ReadDataV<T>(XmlReader reader, string value) where T : struct
     object readData = reader.ReadContentAsObject();
     int outInt;
     if(int.TryParse(readData, out outInt))
        return outInt

How to place the ~/.composer/vendor/bin directory in your PATH?

Detailed instructions:

in your ~/.bashrc add these lines:

export PATH="$PATH:~/.composer/vendor/bin"

Then reload:

source ~/.bashrc

Check if its added correctly:

echo $PATH


HTML Drag And Drop On Mobile Devices

here is my solution:

$(el).on('touchstart', function(e) {
    var link = $('a')  
    if(link.length > 0) {
        window.location.href = link.attr('href');

SQL: Combine Select count(*) from multiple tables

(select count(*) from foo1 where ID = '00123244552000258')
(select count(*) from foo2 where ID = '00123244552000258')
(select count(*) from foo3 where ID = '00123244552000258')

This is an easy way.

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

What is JNDI ?

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

What is its basic use?

Most of it is covered in the above answer but I would like to provide architecture here so that above will make more sense.

enter image description here

To use the JNDI, you must have the JNDI classes and one or more service providers. The Java 2 SDK, v1.3 includes three service providers for the following naming/directory services:

  1. Lightweight Directory Access Protocol (LDAP)
  2. Common Object Request Broker Architecture (CORBA) Common Object Services (COS) name service
  3. Java Remote Method Invocation (RMI) Registry

So basically you create objects and register them on the directory services which you can later do lookup and execute operation on.

"Missing return statement" within if / for / while

If you put return statement in if, while or for statement then it may or may not return value. If it will not go inside these statement then also that method should return some value ( that could be null). To ensure that, compiler will force you to write this return statement which is after if, while or for.

But if you write if / else block and each one of them is having return in it then compiler knows that either if or else will get execute and method will return a value. So this time compiler will not force you.


Fastest method of screen capturing on Windows

I use d3d9 to get the backbuffer, and save that to a png file using the d3dx library:

    IDirect3DSurface9 *surface ;

    // GetBackBuffer
    idirect3ddevice9->GetBackBuffer(0, 0, D3DBACKBUFFER_TYPE_MONO, &surface ) ;

    // save the surface
    D3DXSaveSurfaceToFileA( "filename.png", D3DXIFF_PNG, surface, NULL, NULL ) ;

    SAFE_RELEASE( surface ) ;

To do this you should create your swapbuffer with

d3dpps.SwapEffect = D3DSWAPEFFECT_COPY ; // for screenshots.

(So you guarantee the backbuffer isn't mangled before you take the screenshot).

Find mouse position relative to element

You can use getBoudingClientRect() of the relative parent.

document.addEventListener("mousemove", (e) => {
  let xCoord = e.clientX - + e.offsetX
  let yCoord = e.clientY - + e.offsetY
  console.log("xCoord", xCoord, "yCoord", yCoord)

Why boolean in Java takes only true or false? Why not 1 or 0 also?

Java, unlike languages like C and C++, treats boolean as a completely separate data type which has 2 distinct values: true and false. The values 1 and 0 are of type int and are not implicitly convertible to boolean.

How to downgrade tensorflow, multiple versions possible?

You can try to use the options of --no-cache-dir together with -I to overwrite the cache of the previous version and install the new version. For example:

pip3 install --no-cache-dir -I tensorflow==1.1

Then use the following command to check the version of tensorflow:

python3 -c ‘import tensorflow as tf; print(tf.__version__)’

It should show the right version got installed.

How to copy a file to multiple directories using the gnu cp command

ls -db di*/subdir | xargs -n 1 cp File

-b in case there is a space in directory name otherwise it will be broken as a different item by xargs, had this problem with the echo version

How do I position a div relative to the mouse pointer using jQuery?

You don not need to create a $(document).mousemove( function(e) {}) to handle mouse x,y. Get the event in the $.hover function and from there it is possible to get x and y positions of the mouse. See the code below:

    var pos = [e.pageX-150,e.pageY];
    $('foo1').dialog( "option", "position", pos );

What should be the package name of android app?

Visit and try to fill "Android package name". In some cases it can write error: "Invalid Android package name".

In it is written:

And although the application ID looks like a traditional Java package name, the naming rules for the application ID are a bit more restrictive:

  • It must have at least two segments (one or more dots).
  • Each segment must start with a letter.
  • All characters must be alphanumeric or an underscore [a-zA-Z0-9_].

So, "" and "" are errors.

String method cannot be found in a main class method

It seem like your Resort method doesn't declare a compareTo method. This method typically belongs to the Comparable interface. Make sure your class implements it.

Additionally, the compareTo method is typically implemented as accepting an argument of the same type as the object the method gets invoked on. As such, you shouldn't be passing a String argument, but rather a Resort.

Alternatively, you can compare the names of the resorts. For example

if (resortList[mid].getResortName().compareTo(resortName)>0)  

Setting graph figure size

The properties that can be set for a figure is referenced here.

You could then use:

figure_number = 1;
x      = 0;   % Screen position
y      = 0;   % Screen position
width  = 600; % Width of figure
height = 400; % Height of figure (by default in pixels)

figure(figure_number, 'Position', [x y width height]);

YouTube Autoplay not working

This code allows you to autoplay iframe video

<iframe src=""  width="560" height="315"  frameborder="0" allowfullscreen></iframe>

Here Is working fiddle

data.frame rows to a list

A more modern solution uses only purrr::transpose:

iris[1:2,] %>% purrr::transpose()
#> [[1]]
#> [[1]]$Sepal.Length
#> [1] 5.1
#> [[1]]$Sepal.Width
#> [1] 3.5
#> [[1]]$Petal.Length
#> [1] 1.4
#> [[1]]$Petal.Width
#> [1] 0.2
#> [[1]]$Species
#> [1] 1
#> [[2]]
#> [[2]]$Sepal.Length
#> [1] 4.9
#> [[2]]$Sepal.Width
#> [1] 3
#> [[2]]$Petal.Length
#> [1] 1.4
#> [[2]]$Petal.Width
#> [1] 0.2
#> [[2]]$Species
#> [1] 1

How do you comment out code in PowerShell?

You use the hash mark like this

# This is a comment in Powershell

Wikipedia has a good page for keeping track of how to do comments in several popular languages

Closing a file after File.Create


create write close

File.WriteAllBytes--   type binary


Set the value of an input field

It's simple; An example is:

<input type="text" id="example"> // Setup text field 
<script type="text/javascript"> 
var elem = document.getElementById("example"); // Get text field
elem.value = "My default value"; // Change field

Using import fs from 'fs'

Building on RobertoNovelo's answer:

import * as fs from 'fs';

is currently the simplest way to do it.

It was tested with a Node.js project (Node.js v10.15.3), with esm, allowing to use import.

How to turn off word wrapping in HTML?

You need to use the CSS white-space attribute.

In particular, white-space: nowrap and white-space: pre are the most commonly used values. The first one seems to be what you 're after.

vba: get unique values from array

There's no built-in functionality to remove duplicates from arrays. Raj's answer seems elegant, but I prefer to use dictionaries.

Dim d As Object
Set d = CreateObject("Scripting.Dictionary")
'Set d = New Scripting.Dictionary

Dim i As Long
For i = LBound(myArray) To UBound(myArray)
    d(myArray(i)) = 1
Next i

Dim v As Variant
For Each v In d.Keys()
    'd.Keys() is a Variant array of the unique values in myArray.
    'v will iterate through each of them.
Next v

EDIT: I changed the loop to use LBound and UBound as per Tomalak's suggested answer. EDIT: d.Keys() is a Variant array, not a Collection.

Difference between RUN and CMD in a Dockerfile

There has been enough answers on RUN and CMD. I just want to add a few words on ENTRYPOINT. CMD arguments can be overwritten by command line arguments, while ENTRYPOINT arguments are always used.

This article is a good source of information.

How to prevent Google Colab from disconnecting?

Well I am not a python guy nor I know what is the actual use of this 'Colab', I use it as a build system lol. And I used to setup ssh forwarding in it then put this code and just leave it running and yeah it works.

import getpass
authtoken = getpass.getpass()

POST data in JSON format

Using the new FormData object (and other ES6 stuff), you can do this to turn your entire form into JSON:

let data = {};
let formdata = new FormData(theform);
for (let tuple of formdata.entries()) data[tuple[0]] = tuple[1];

and then just xhr.send(JSON.stringify(data)); like in Jan's original answer.

Percentage width in a RelativeLayout


As pointed by @EmJiHash PercentRelativeLayout and PercentFrameLayout is deprecated in API level 26.0.0

Consider Using ConstraintLayout

Google introduced new API called



Add compile dependency like

compile ''

You can specify dimension in percentage so get both benefit of RelativeLayout and percentage


jQuery - getting custom attribute from selected option

Simpler syntax if one form.

var option = $('option:selected').attr('mytag')

... if more than one form.

var option = $('select#myform option:selected').attr('mytag')

How to use double or single brackets, parentheses, curly braces

  1. A single bracket ([) usually actually calls a program named [; man test or man [ for more info. Example:

    $ VARIABLE=abcdef
    $ if [ $VARIABLE == abcdef ] ; then echo yes ; else echo no ; fi
  2. The double bracket ([[) does the same thing (basically) as a single bracket, but is a bash builtin.

    $ VARIABLE=abcdef
    $ if [[ $VARIABLE == 123456 ]] ; then echo yes ; else echo no ; fi
  3. Parentheses (()) are used to create a subshell. For example:

    $ pwd
    $ (cd /tmp; pwd)
    $ pwd

    As you can see, the subshell allowed you to perform operations without affecting the environment of the current shell.

  4. (a) Braces ({}) are used to unambiguously identify variables. Example:

    $ VARIABLE=abcdef
    $ echo Variable: $VARIABLE
    Variable: abcdef
    $ echo Variable: $VARIABLE123456
    $ echo Variable: ${VARIABLE}123456
    Variable: abcdef123456

    (b) Braces are also used to execute a sequence of commands in the current shell context, e.g.

    $ { date; top -b -n1 | head ; } >logfile 
    # 'date' and 'top' output are concatenated, 
    # could be useful sometimes to hunt for a top loader )
    $ { date; make 2>&1; date; } | tee logfile
    # now we can calculate the duration of a build from the logfile

There is a subtle syntactic difference with ( ), though (see bash reference) ; essentially, a semicolon ; after the last command within braces is a must, and the braces {, } must be surrounded by spaces.

how to use a like with a join in sql?

If this is something you'll need to do often...then you may want to denormalize the relationship between tables A and B.

For example, on insert to table B, you could write zero or more entries to a juncion table mapping B to A based on partial mapping. Similarly, changes to either table could update this association.

This all depends on how frequently tables A and B are modified. If they are fairly static, then taking a hit on INSERT is less painful then repeated hits on SELECT.

How does one generate a random number in Apple's Swift language?

 let MAX : UInt32 = 9
 let MIN : UInt32 = 1

    func randomNumber()
    var random_number = Int(arc4random_uniform(MAX) + MIN)
    print ("random = ", random_number);

How to get the background color of an HTML element?

Simple solution

myDivObj = document.getElementById("myDivID")
let myDivObjBgColor = window.getComputedStyle(myDivObj).backgroundColor;

Now the background color is stored in the new variable.

Vue-router redirect on page not found (404)

@mani's Original answer is all you want, but if you'd also like to read it in official way, here's

Reference to Vue's official page:

Expected response code 250 but got code "530", with message "530 5.7.1 Authentication required

I see you have all the settings right. You just need to end the local web server and start it again with

php artisan serve

Everytime you change your .env file, you need tor restart the server for the new options to take effect.

Or clear and cache your configuration with

php artisan config:cache

How can I change the Y-axis figures into percentages in a barplot?

Borrowed from @Deena above, that function modification for labels is more versatile than you might have thought. For example, I had a ggplot where the denominator of counted variables was 140. I used her example thus:

scale_y_continuous(labels = function(x) paste0(round(x/140*100,1), "%"), breaks = seq(0, 140, 35))

This allowed me to get my percentages on the 140 denominator, and then break the scale at 25% increments rather than the weird numbers it defaulted to. The key here is that the scale breaks are still set by the original count, not by your percentages. Therefore the breaks must be from zero to the denominator value, with the third argument in "breaks" being the denominator divided by however many label breaks you want (e.g. 140 * 0.25 = 35).

Can anyone explain IEnumerable and IEnumerator to me?

for example, when to use it over foreach?

You don't use IEnumerable "over" foreach. Implementing IEnumerable makes using foreach possible.

When you write code like:

foreach (Foo bar in baz)

it's functionally equivalent to writing:

IEnumerator bat = baz.GetEnumerator();
while (bat.MoveNext())
   bar = (Foo)bat.Current

By "functionally equivalent," I mean that's actually what the compiler turns the code into. You can't use foreach on baz in this example unless baz implements IEnumerable.

IEnumerable means that baz implements the method

IEnumerator GetEnumerator()

The IEnumerator object that this method returns must implement the methods

bool MoveNext()


Object Current()

The first method advances to the next object in the IEnumerable object that created the enumerator, returning false if it's done, and the second returns the current object.

Anything in .Net that you can iterate over implements IEnumerable. If you're building your own class, and it doesn't already inherit from a class that implements IEnumerable, you can make your class usable in foreach statements by implementing IEnumerable (and by creating an enumerator class that its new GetEnumerator method will return).

What is a View in Oracle?

regular view----->short name for a query,no additional space is used here

Materialised view---->similar to creating table whose data will refresh periodically based on data query used for creating the view

Android get image path from drawable as string

I think you cannot get it as String but you can get it as int by get resource id:

int resId = this.getResources().getIdentifier("imageNameHere", "drawable", this.getPackageName());

Delete all SYSTEM V shared memory and semaphores on UNIX-like systems

This works on my Mac OS:

for n in `ipcs -b -m | egrep ^m | awk '{ print $2; }'`; do ipcrm -m $n; done

Convert multiple rows into one with comma as separator

You can use this query to do the above task:

SELECT @test = COALESCE(@test + ',', '') + field2 FROM #test
SELECT field2 = @test 

For detail and step by step explanation visit the following link

jquery draggable: how to limit the draggable area?

$(function() { $( "#draggable" ).draggable({ containment: "window" }); });

of this code does not display. Full code and Demo:

In order to limit the element inside its parent:

$( "#draggable" ).draggable({ containment: "window" });

php hide ALL errors

Use PHP error handling functions to handle errors. How you do it depends on your needs. This system will intercept all errors and forward it however you want it Or supress it if you ask it to do so

How is using OnClickListener interface different via XML and Java code?

These are exactly the same. android:onClick was added in API level 4 to make it easier, more Javascript-web-like, and drive everything from the XML. What it does internally is add an OnClickListener on the Button, which calls your DoIt method.

Here is what using a android:onClick="DoIt" does internally:

Button button= (Button) findViewById(;
button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {

The only thing you trade off by using android:onClick, as usual with XML configuration, is that it becomes a bit more difficult to add dynamic content (programatically, you could decide to add one listener or another depending on your variables). But this is easily defeated by adding your test within the DoIt method.

Simplest way to do a recursive self-join?

Using CTEs you can do it this way

        PersonID INT,
        Initials VARCHAR(20),
        ParentID INT

INSERT INTO @Table SELECT     2,'EB',1
INSERT INTO @Table SELECT     3,'MB',1
INSERT INTO @Table SELECT     4,'SW',2
INSERT INTO @Table SELECT     6,'IS',5


SELECT @PersonID = 1

;WITH Selects AS (
        SELECT *
        FROM    @Table
        WHERE   PersonID = @PersonID
        UNION ALL
        SELECT  t.*
        FROM    @Table t INNER JOIN
                Selects s ON t.ParentID = s.PersonID
FROm    Selects

How to use __DATE__ and __TIME__ predefined macros in as two integers, then stringify?

If you can use a C++ compiler to build the object file that you want to contain your version string, then we can do exactly what you want! The only magic here is that C++ allows you to use expressions to statically initialize an array, while C doesn't. The expressions need to be fully computable at compile time, but these expressions are, so it's no problem.

We build up the version string one byte at a time, and get exactly what we want.

// source file version_num.h




#endif // VERSION_NUM_H

// source file build_defs.h

#ifndef BUILD_DEFS_H

#define BUILD_DEFS_H

// Example of __DATE__ string: "Jul 27 2012"
//                              01234567890

#define BUILD_YEAR_CH0 (__DATE__[ 7])
#define BUILD_YEAR_CH1 (__DATE__[ 8])
#define BUILD_YEAR_CH2 (__DATE__[ 9])
#define BUILD_YEAR_CH3 (__DATE__[10])

#define BUILD_MONTH_IS_JAN (__DATE__[0] == 'J' && __DATE__[1] == 'a' && __DATE__[2] == 'n')
#define BUILD_MONTH_IS_FEB (__DATE__[0] == 'F')
#define BUILD_MONTH_IS_MAR (__DATE__[0] == 'M' && __DATE__[1] == 'a' && __DATE__[2] == 'r')
#define BUILD_MONTH_IS_APR (__DATE__[0] == 'A' && __DATE__[1] == 'p')
#define BUILD_MONTH_IS_MAY (__DATE__[0] == 'M' && __DATE__[1] == 'a' && __DATE__[2] == 'y')
#define BUILD_MONTH_IS_JUN (__DATE__[0] == 'J' && __DATE__[1] == 'u' && __DATE__[2] == 'n')
#define BUILD_MONTH_IS_JUL (__DATE__[0] == 'J' && __DATE__[1] == 'u' && __DATE__[2] == 'l')
#define BUILD_MONTH_IS_AUG (__DATE__[0] == 'A' && __DATE__[1] == 'u')
#define BUILD_MONTH_IS_SEP (__DATE__[0] == 'S')
#define BUILD_MONTH_IS_OCT (__DATE__[0] == 'O')
#define BUILD_MONTH_IS_NOV (__DATE__[0] == 'N')
#define BUILD_MONTH_IS_DEC (__DATE__[0] == 'D')

#define BUILD_MONTH_CH0 \

#define BUILD_MONTH_CH1 \
    ( \
        (BUILD_MONTH_IS_JAN) ? '1' : \
        (BUILD_MONTH_IS_FEB) ? '2' : \
        (BUILD_MONTH_IS_MAR) ? '3' : \
        (BUILD_MONTH_IS_APR) ? '4' : \
        (BUILD_MONTH_IS_MAY) ? '5' : \
        (BUILD_MONTH_IS_JUN) ? '6' : \
        (BUILD_MONTH_IS_JUL) ? '7' : \
        (BUILD_MONTH_IS_AUG) ? '8' : \
        (BUILD_MONTH_IS_SEP) ? '9' : \
        (BUILD_MONTH_IS_OCT) ? '0' : \
        (BUILD_MONTH_IS_NOV) ? '1' : \
        (BUILD_MONTH_IS_DEC) ? '2' : \
        /* error default */    '?' \

#define BUILD_DAY_CH0 ((__DATE__[4] >= '0') ? (__DATE__[4]) : '0')
#define BUILD_DAY_CH1 (__DATE__[ 5])

// Example of __TIME__ string: "21:06:19"
//                              01234567

#define BUILD_HOUR_CH0 (__TIME__[0])
#define BUILD_HOUR_CH1 (__TIME__[1])

#define BUILD_MIN_CH0 (__TIME__[3])
#define BUILD_MIN_CH1 (__TIME__[4])

#define BUILD_SEC_CH0 (__TIME__[6])
#define BUILD_SEC_CH1 (__TIME__[7])


    ((VERSION_MAJOR / 100) + '0'), \
    (((VERSION_MAJOR % 100) / 10) + '0'), \
    ((VERSION_MAJOR % 10) + '0')

#elif VERSION_MAJOR > 10

    ((VERSION_MAJOR / 10) + '0'), \
    ((VERSION_MAJOR % 10) + '0')


    (VERSION_MAJOR + '0')



    ((VERSION_MINOR / 100) + '0'), \
    (((VERSION_MINOR % 100) / 10) + '0'), \
    ((VERSION_MINOR % 10) + '0')

#elif VERSION_MINOR > 10

    ((VERSION_MINOR / 10) + '0'), \
    ((VERSION_MINOR % 10) + '0')


    (VERSION_MINOR + '0')


#endif // BUILD_DEFS_H

// source file main.c

#include "version_num.h"
#include "build_defs.h"

// want something like: 1.4.1432.2234

const unsigned char completeVersion[] =
    '-', 'V', '-',

#include <stdio.h>

int main(int argc, char **argv)
    printf("%s\n", completeVersion);
    // prints something similar to: 1.4-V-2013-05-09T15:34:49

This isn't exactly the format you asked for, but I still don't fully understand how you want days and hours mapped to an integer. I think it's pretty clear how to make this produce any desired string.

How to set upload_max_filesize in .htaccess?

If you are getting 500 - Internal server error that means you don't have permission to set these values by .htaccess. You have to contact your web server providers and ask to set AllowOverride Options for your host or to put these lines in their virtual host configuration file.

Get name of currently executing test in JUnit 4

I'd suggest you decouple the test method name from your test data set. I would model a DataLoaderFactory class which loads/caches the sets of test data from your resources, and then in your test case cam call some interface method which returns a set of test data for the test case. Having the test data tied to the test method name assumes the test data can only be used once, where in most case i'd suggest that the same test data in uses in multiple tests to verify various aspects of your business logic.

Overlay a background-image with an rgba background-color

/* Working method */_x000D_
.tinted-image {_x000D_
  background: _x000D_
    /* top, transparent red, faked with gradient */ _x000D_
      rgba(255, 0, 0, 0.45), _x000D_
      rgba(255, 0, 0, 0.45)_x000D_
    /* bottom, image */_x000D_
    height: 1280px;_x000D_
    width: 960px;_x000D_
    background-size: cover;_x000D_
.tinted-image p {_x000D_
    color: #fff;_x000D_
    padding: 100px;_x000D_
<div class="tinted-image">_x000D_
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laboriosam distinctio, temporibus tempora a eveniet quas  qui veritatis sunt perferendis harum!</p>_x000D_


Handling very large numbers in Python

The python interpreter will handle it for you, you just have to do your operations (+, -, *, /), and it will work as normal.

The int value is unlimited.

Careful when doing division, by default the quotient is turned into float, but float does not support such large numbers. If you get an error message saying float does not support such large numbers, then it means the quotient is too large to be stored in float you’ll have to use floor division (//).

It ignores any decimal that comes after the decimal point, this way, the result will be int, so you can have a large number result.



How can I uninstall Ruby on ubuntu?

This command should do the trick (provided that you installed it using a dpkg-based packet manager):

aptitude purge ruby

How do you use the Immediate Window in Visual Studio?

Use the Immediate Window to Execute Commands

The Immediate Window can also be used to execute commands. Just type a > followed by the command.

enter image description here

For example >shell cmd will start a command shell (this can be useful to check what environment variables were passed to Visual Studio, for example). >cls will clear the screen.

Here is a list of commands that are so commonly used that they have their own aliases:

How do I force Kubernetes to re-pull an image?

This answer aims to force an image pull in a situation where your node has already downloaded an image with the same name, therefore even though you push a new image to container registry, when you spin up some pods, your pod says "image already present".

For a case in Azure Container Registry (probably AWS and GCP also provides this):

  1. You can look to your Azure Container Registry and by checking the manifest creation date you can identify what image is the most recent one.

  2. Then, copy its digest hash (which has a format of

  3. You can scale down your current replica by running command below. Note that this will obviously stop your container and cause downtime.

kubectl scale --replicas=0 deployment <deployment-name> -n <namespace-name>
  1. Then you can get the copy of the deployment.yaml by running:
kubectl get deployments.apps <deployment-name> -o yaml > deployment.yaml
  1. Then change the line with image field from <image-name>:<tag> to <image-name>, save the file.

  2. Now you can scale up your replicas again. New image will be pulled with its unique digest.

Note: It is assumed that, imagePullPolicy: Always field is present in the container.

Split array into two parts without for loop in java

Use this code it works perfectly for odd or even list sizes. Hope it help somebody .

 int listSize = listOfArtist.size();
 int mid = 0;
 if (listSize % 2 == 0) {
    mid = listSize / 2;
    Log.e("Parting", "You entered an even number. mid " + mid
                    + " size is " + listSize);
 } else {
    mid = (listSize + 1) / 2;
    Log.e("Parting", "You entered an odd number. mid " + mid
                    + " size is " + listSize);
 //sublist returns List convert it into arraylist * very important
 leftArray = new ArrayList<ArtistModel>(listOfArtist.subList(0, mid));
 rightArray = new ArrayList<ArtistModel>(listOfArtist.subList(mid,

How to convert an ASCII character into an int in C

I agree to Ashot and Cwan, but maybe you like to convert an ascii-cipher like '7' into an int like 7?

Then I recoomend:

char seven = '7';
int i = seven - '0'; 

or, maybe you get a warning,

int i = (int) (seven - '0'); 

corrected after comments, thanks.

cannot find module "lodash"

The above error run the commend line\

please change the command $ node server it's working and server is started

Vector erase iterator

Because the method erase in vector return the next iterator of the passed iterator.

I will give example of how to remove element in vector when iterating.

void test_del_vector(){
    std::vector<int> vecInt{0, 1, 2, 3, 4, 5};

    //method 1
    for(auto it = vecInt.begin();it != vecInt.end();){
        if(*it % 2){// remove all the odds
            it = vecInt.erase(it); // note it will = next(it) after erase
        } else{

    // output all the remaining elements
    for(auto const& it:vecInt)std::cout<<it;

    // recreate vecInt, and use method 2
    vecInt = {0, 1, 2, 3, 4, 5};
    //method 2
    for(auto it=std::begin(vecInt);it!=std::end(vecInt);){
        if (*it % 2){
            it = vecInt.erase(it);

    // output all the remaining elements
    for(auto const& it:vecInt)std::cout<<it;

    // recreate vecInt, and use method 3
    vecInt = {0, 1, 2, 3, 4, 5};
    //method 3
    vecInt.erase(std::remove_if(vecInt.begin(), vecInt.end(),
                 [](const int a){return a % 2;}),

    // output all the remaining elements
    for(auto const& it:vecInt)std::cout<<it;


output aw below:


A more generate method:

template<class Container, class F>
void erase_where(Container& c, F&& f)
    c.erase(std::remove_if(c.begin(), c.end(),std::forward<F>(f)),

void test_del_vector(){
    std::vector<int> vecInt{0, 1, 2, 3, 4, 5};
    //method 4
    auto is_odd = [](int x){return x % 2;};
    erase_where(vecInt, is_odd);

    // output all the remaining elements
    for(auto const& it:vecInt)std::cout<<it;

Having links relative to root?

To give a URL to an image tag which locates images/ directory in the root like


you should give src URL starting with / as follows:

<img src="/images/logo.png"/>

This code works in any directories without any troubles even if you are in branches/europe/about.php still the logo can be seen right there.

How do I copy a string to the clipboard?

import wx

def ctc(text):

    if not wx.TheClipboard.IsOpened():
        data = wx.TextDataObject()


PHPMailer character encoding issues

To avoid problems of character encoding in sending emails using the class PHPMailer we can configure it to send it with UTF-8 character encoding using the "CharSet" parameter, as we can see in the following Php code:

$mail = new PHPMailer();
$mail->From = '[email protected]';
$mail->FromName = 'Mi nombre';
$mail->AddAddress('[email protected]');
$mail->Subject = 'Prueba';
$mail->Body = '';

// Active condition utf-8
$mail->CharSet = 'UTF-8';

// Send mail

What is the 'dynamic' type in C# 4.0 used for?

An example of use :

You consume many classes that have a commun property 'CreationDate' :

public class Contact
    // some properties

    public DateTime CreationDate { get; set; }        

public class Company
    // some properties

    public DateTime CreationDate { get; set; }


public class Opportunity
    // some properties

    public DateTime CreationDate { get; set; }


If you write a commun method that retrieves the value of the 'CreationDate' Property, you'd have to use reflection:

    static DateTime RetrieveValueOfCreationDate(Object item)
        return (DateTime)item.GetType().GetProperty("CreationDate").GetValue(item);

With the 'dynamic' concept, your code is much more elegant :

    static DateTime RetrieveValueOfCreationDate(dynamic item)
        return item.CreationDate;

Declare Variable for a Query String

Using EXEC

You can use following example for building SQL statement.

DECLARE @sqlCommand varchar(1000)
DECLARE @columnList varchar(75)
DECLARE @city varchar(75)
SET @columnList = 'CustomerID, ContactName, City'
SET @city = '''London'''
SET @sqlCommand = 'SELECT ' + @columnList + ' FROM customers WHERE City = ' + @city
EXEC (@sqlCommand)

Using sp_executesql

With using this approach you can ensure that the data values being passed into the query are the correct datatypes and avoind use of more quotes.

DECLARE @sqlCommand nvarchar(1000)
DECLARE @columnList varchar(75)
DECLARE @city varchar(75)
SET @columnList = 'CustomerID, ContactName, City'
SET @city = 'London'
SET @sqlCommand = 'SELECT ' + @columnList + ' FROM customers WHERE City = @city'
EXECUTE sp_executesql @sqlCommand, N'@city nvarchar(75)', @city = @city


Chart.js - Formatting Y axis

As Nevercom said the scaleLable should contain javascript so to manipulate the y value just apply the required formatting.

Note the the value is a string.

var options = {      
    scaleLabel : "<%= value + ' + two = ' + (Number(value) + 2)   %>"

jsFiddle example

if you wish to set a manual y scale you can use scaleOverride

var options = {      
    scaleLabel : "<%= value + ' + two = ' + (Number(value) + 2)   %>",

    scaleOverride: true,
    scaleSteps: 10,
    scaleStepWidth: 10,
    scaleStartValue: 0


jsFiddle example

Image encryption/decryption using AES256 symmetric block ciphers

AES encrypt/decrypt in android

String encData= encrypt("keykey".getBytes("UTF-16LE"), ("0123000000000215").getBytes("UTF-16LE"));

String decData= decrypt("keykey",Base64.decode(encData.getBytes("UTF-16LE"), Base64.DEFAULT));

encrypt function

private static String encrypt(byte[] key, byte[] clear) throws Exception
        MessageDigest md = MessageDigest.getInstance("md5");
        byte[] digestOfPassword = md.digest(key);

        SecretKeySpec skeySpec = new SecretKeySpec(digestOfPassword, "AES");
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding");
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        byte[] encrypted = cipher.doFinal(clear);
        return Base64.encodeToString(encrypted,Base64.DEFAULT);

decrypt function

private static String decrypt(String key, byte[] encrypted) throws Exception
        MessageDigest md = MessageDigest.getInstance("md5");
        byte[] digestOfPassword = md.digest(key.getBytes("UTF-16LE"));

        SecretKeySpec skeySpec = new SecretKeySpec(digestOfPassword, "AES");
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding");
        cipher.init(Cipher.DECRYPT_MODE, skeySpec);
        byte[] decrypted = cipher.doFinal(encrypted);
        return new String(decrypted, "UTF-16LE");

AES encrypt/decrypt in c#

 static void Main(string[] args)
            string enc = encryptAES("0123000000000215", "keykey");
            string dec = decryptAES(enc, "keykey");


encrypt function

 public static string encryptAES(string input, string key)
            var plain = Encoding.Unicode.GetBytes(input);

            // 128 bits
            AesCryptoServiceProvider provider = new AesCryptoServiceProvider();
            provider.KeySize = 128;
            provider.Mode = CipherMode.ECB;
            provider.Padding = PaddingMode.PKCS7;

            provider.Key = CalculateMD5Hash(key);

            var enc = provider.CreateEncryptor().TransformFinalBlock(plain, 0, plain.Length);
            return Convert.ToBase64String(enc);

decrypt function

public static string decryptAES(string encryptText, string key)
    byte[] enc = Convert.FromBase64String(encryptText);
    // 128 bits
    AesCryptoServiceProvider provider = new AesCryptoServiceProvider();
    provider.KeySize = 128;
    provider.Mode = CipherMode.ECB;
    provider.Padding = PaddingMode.PKCS7;

    provider.Key = CalculateMD5Hash(key);

    var dec = provider.CreateDecryptor().TransformFinalBlock(enc, 0, enc.Length);
    return Encoding.Unicode.GetString(dec);

create md5

 public static byte[] CalculateMD5Hash(string input)
            MD5 md5 = MD5.Create();
            byte[] inputBytes = Encoding.Unicode.GetBytes(input);
            return md5.ComputeHash(inputBytes);

How to use radio buttons in ReactJS?

Bootstrap guys, we do it like this:

export default function RadioButton({ onChange, option }) {
    const handleChange = event => {

    return (
            <div className="custom-control custom-radio">
                    id={ option.option }
                    onChange={ handleChange }
                    value = { }
                        htmlFor={ option.option }
                        { option.option }

How to add anything in <head> through jquery/javascript?

You can use innerHTML to just concat the extra field string;

document.head.innerHTML = document.head.innerHTML + '<link rel="stylesheet>...'

However, you can't guarantee that the extra things you add to the head will be recognised by the browser after the first load, and it's possible you will get a FOUC (flash of unstyled content) as the extra stylesheets are loaded.

I haven't looked at the API in years, but you could also use document.write, which is what was designed for this sort of action. However, this would require you to block the page from rendering until your initial AJAX request has completed.

Setting a div's height in HTML with CSS

Give this a try:

html, body,_x000D_
#left, #right {_x000D_
  height: 100%_x000D_
#left {_x000D_
  float: left;_x000D_
  width: 25%;_x000D_
#right {_x000D_
  width: 75%;_x000D_
    <div id="left">_x000D_
    <div id="right">_x000D_

How to create a custom navigation drawer in android

Android Navigation Drawer using Activity I just followed the example :

You just need few Customization:

public class MainActivity extends AppCompatActivity  {

public static final String AVATAR_URL = "";

private DrawerLayout drawerLayout;
private View content;
private Toolbar toolbar;
private NavigationView navigationView;
private ActionBarDrawerToggle drawerToggle;

protected void onCreate(Bundle savedInstanceState) {
    toolbar = (Toolbar) findViewById(;
    drawerLayout = (DrawerLayout) findViewById(;

    content = findViewById(;
    drawerToggle = setupDrawerToggle();
    final ImageView avatar = (ImageView) navigationView.getHeaderView(0).findViewById(;
    Picasso.with(this).load(AVATAR_URL).transform(new CircleTransform()).into(avatar);


private void initToolbar() {
    final Toolbar toolbar = (Toolbar) findViewById(;
    final ActionBar actionBar = getSupportActionBar();

    if (actionBar != null) {
private ActionBarDrawerToggle setupDrawerToggle() {
    return new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.drawer_open,  R.string.drawer_close);

protected void onPostCreate(Bundle savedInstanceState) {
    // Sync the toggle state after onRestoreInstanceState has occurred.

public void onConfigurationChanged(Configuration newConfig) {
    // Pass any configuration change to the drawer toggles
 private void setupDrawerLayout() {

    drawerLayout = (DrawerLayout) findViewById(;
    navigationView = (NavigationView) findViewById(;

    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {

        public boolean onNavigationItemSelected(MenuItem menuItem) {

            int id = menuItem.getItemId();

          switch (id) {
                    Intent i = new Intent(getApplicationContext(), MainActivity.class);
                    Intent j = new Intent(getApplicationContext(), SecondActivity.class);


        return true;

} Here is the xml Layout




            app:layout_scrollFlags="scroll|enterAlways|snap" />




Add drawer.xml in menu

<menu xmlns:android="">






To open and close drawer add this values in string.xml

<string name="drawer_open">Open</string>
<string name="drawer_close">Close</string>


enter code here


    android:text="[email protected]"

What's a clean way to stop mongod on Mac OS X?

Simple way is to get the process id of mongodb and kill it. Please note DO NOT USE kill -9 pid for this as it may cause damage to the database.

so, 1. get the pid of mongodb

$ pgrep mongo

you will get pid of mongo, Now

$ kill

You may use kill -15 as well

how to convert a string to date in mysql?

STR_TO_DATE('12/31/2011', '%m/%d/%Y')

What is the maximum number of characters that nvarchar(MAX) will hold?

2^31-1 bytes. So, a little less than 2^31-1 characters for varchar(max) and half that for nvarchar(max).

nchar and nvarchar

MySQL: Quick breakdown of the types of joins

I have 2 tables like this:

> SELECT * FROM table_a;
| id   | name |
|    1 | row1 |
|    2 | row2 |

> SELECT * FROM table_b;
| id   | name | aid  |
|    3 | row3 |    1 |
|    4 | row4 |    1 |
|    5 | row5 | NULL |

INNER JOIN cares about both tables

INNER JOIN cares about both tables, so you only get a row if both tables have one. If there is more than one matching pair, you get multiple rows.

> SELECT * FROM table_a a INNER JOIN table_b b ON;
| id   | name | id   | name | aid  |
|    1 | row1 |    3 | row3 | 1    |
|    1 | row1 |    4 | row4 | 1    |

It makes no difference to INNER JOIN if you reverse the order, because it cares about both tables:

> SELECT * FROM table_b b INNER JOIN table_a a ON;
| id   | name | aid  | id   | name |
|    3 | row3 | 1    |    1 | row1 |
|    4 | row4 | 1    |    1 | row1 |

You get the same rows, but the columns are in a different order because we mentioned the tables in a different order.

LEFT JOIN only cares about the first table

LEFT JOIN cares about the first table you give it, and doesn't care much about the second, so you always get the rows from the first table, even if there is no corresponding row in the second:

> SELECT * FROM table_a a LEFT JOIN table_b b ON;
| id   | name | id   | name | aid  |
|    1 | row1 |    3 | row3 | 1    |
|    1 | row1 |    4 | row4 | 1    |
|    2 | row2 | NULL | NULL | NULL |

Above you can see all rows of table_a even though some of them do not match with anything in table b, but not all rows of table_b - only ones that match something in table_a.

If we reverse the order of the tables, LEFT JOIN behaves differently:

> SELECT * FROM table_b b LEFT JOIN table_a a ON;
| id   | name | aid  | id   | name |
|    3 | row3 | 1    |    1 | row1 |
|    4 | row4 | 1    |    1 | row1 |
|    5 | row5 | NULL | NULL | NULL |

Now we get all rows of table_b, but only matching rows of table_a.

RIGHT JOIN only cares about the second table

a RIGHT JOIN b gets you exactly the same rows as b LEFT JOIN a. The only difference is the default order of the columns.

> SELECT * FROM table_a a RIGHT JOIN table_b b ON;
| id   | name | id   | name | aid  |
|    1 | row1 |    3 | row3 | 1    |
|    1 | row1 |    4 | row4 | 1    |
| NULL | NULL |    5 | row5 | NULL |

This is the same rows as table_b LEFT JOIN table_a, which we saw in the LEFT JOIN section.


> SELECT * FROM table_b b RIGHT JOIN table_a a ON;
| id   | name | aid  | id   | name |
|    3 | row3 | 1    |    1 | row1 |
|    4 | row4 | 1    |    1 | row1 |
| NULL | NULL | NULL |    2 | row2 |

Is the same rows as table_a LEFT JOIN table_b.

No join at all gives you copies of everything

If you write your tables with no JOIN clause at all, just separated by commas, you get every row of the first table written next to every row of the second table, in every possible combination:

> SELECT * FROM table_b b, table_a;
| id   | name | aid  | id   | name |
|    3 | row3 | 1    |    1 | row1 |
|    3 | row3 | 1    |    2 | row2 |
|    4 | row4 | 1    |    1 | row1 |
|    4 | row4 | 1    |    2 | row2 |
|    5 | row5 | NULL |    1 | row1 |
|    5 | row5 | NULL |    2 | row2 |

(This is from my blog post Examples of SQL join types)

is there something like isset of php in javascript/jQuery?

The problem is that passing an undefined variable to a function causes an error.

This means you have to run typeof before passing it as an argument.

The cleanest way I found to do this is like so:

function isset(v){
    if(v === 'undefined'){
        return false;
    return true;


  alert('is set');
} else {
  alert('not set');

Now the code is much more compact and readable.

This will still give an error if you try to call a variable from a non instantiated variable like:


thus before trying to run this you need to make sure the object is defined:

undefVar = isset(typeof(undefVar))?undefVar:{};

Best programming based games

Planetwars is a game specifically written for Google Ai Contest, bots are controlling fleets for conquering planets, they support many languages

Add a row number to result set of a SQL query

The typical pattern would be as follows, but you need to actually define how the ordering should be applied (since a table is, by definition, an unordered bag of rows):

SELECT t.A, t.B, t.C, number = ROW_NUMBER() OVER (ORDER BY t.A)
  FROM dbo.tableZ AS t

Not sure what the variables in your question are supposed to represent (they don't match).

Nodejs send file in response

You need use Stream to send file (archive) in a response, what is more you have to use appropriate Content-type in your response header.

There is an example function that do it:

const fs = require('fs');

// Where fileName is name of the file and response is Node.js Reponse. 
responseFile = (fileName, response) => {
  const filePath =  "/path/to/archive.rar" // or any file format

  // Check if file specified by the filePath exists 
  fs.exists(filePath, function(exists){
      if (exists) {     
        // Content-type is very interesting part that guarantee that
        // Web browser will handle response in an appropriate manner.
        response.writeHead(200, {
          "Content-Type": "application/octet-stream",
          "Content-Disposition": "attachment; filename=" + fileName
      } else {
        response.writeHead(400, {"Content-Type": "text/plain"});
        response.end("ERROR File does not exist");

The purpose of the Content-Type field is to describe the data contained in the body fully enough that the receiving user agent can pick an appropriate agent or mechanism to present the data to the user, or otherwise deal with the data in an appropriate manner.

"application/octet-stream" is defined as "arbitrary binary data" in RFC 2046, purpose of this content-type is to be saved to disk - it is what you really need.

"filename=[name of file]" specifies name of file which will be downloaded.

For more information please see this stackoverflow topic.

On select change, get data attribute value

You need to find the selected option:




although the first method is preferred.

Difference between == and ===

There are subtleties with Swifts === that go beyond mere pointer arithmetics. While in Objective-C you were able to compare any two pointers (i.e. NSObject *) with == this is no longer true in Swift since types play a much greater role during compilation.

A Playground will give you

1 === 2                    // false
1 === 1                    // true
let one = 1                // 1
1 === one                  // compile error: Type 'Int' does not conform to protocol 'AnyObject'
1 === (one as AnyObject)   // true (surprisingly (to me at least))

With strings we will have to get used to this:

var st = "123"                                 // "123"
var ns = (st as NSString)                      // "123"
st == ns                                       // true, content equality
st === ns                                      // compile error
ns === (st as NSString)                        // false, new struct
ns === (st as AnyObject)                       // false, new struct
(st as NSString) === (st as NSString)          // false, new structs, bridging is not "free" (as in "lunch")
NSString(string:st) === NSString(string:st)    // false, new structs
var st1 = NSString(string:st)                  // "123"
var st2 = st1                                  // "123"
st1 === st2                                    // true
var st3 = (st as NSString)                     // "123"
st1 === st3                                    // false
(st as AnyObject) === (st as AnyObject)        // false

but then you can also have fun as follows:

var st4 = st             // "123"
st4 == st                // true
st4 += "5"               // "1235"
st4 == st                // false, not quite a reference, copy on write semantics

I am sure you can think of a lot more funny cases :-)

Update for Swift 3 (as suggested by the comment from Jakub Truhlár)

1===2                                    // Compiler error: binary operator '===' cannot be applied to two 'Int' operands
(1 as AnyObject) === (2 as AnyObject)    // false
let two = 2
(2 as AnyObject) === (two as AnyObject)  // false (rather unpleasant)
(2 as AnyObject) === (2 as AnyObject)    // false (this makes it clear that there are new objects being generated)

This looks a little more consistent with Type 'Int' does not conform to protocol 'AnyObject', however we then get

type(of:(1 as AnyObject))                // _SwiftTypePreservingNSNumber.Type

but the explicit conversion makes clear that there might be something going on. On the String-side of things NSString will still be available as long as we import Cocoa. Then we will have

var st = "123"                                 // "123"
var ns = (st as NSString)                      // "123"
st == ns                                       // Compile error with Fixit: 'NSString' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?
st == ns as String                             // true, content equality
st === ns                                      // compile error: binary operator '===' cannot be applied to operands of type 'String' and 'NSString'
ns === (st as NSString)                        // false, new struct
ns === (st as AnyObject)                       // false, new struct
(st as NSString) === (st as NSString)          // false, new structs, bridging is not "free" (as in "lunch")
NSString(string:st) === NSString(string:st)    // false, new objects
var st1 = NSString(string:st)                  // "123"
var st2 = st1                                  // "123"
st1 === st2                                    // true
var st3 = (st as NSString)                     // "123"
st1 === st3                                    // false
(st as AnyObject) === (st as AnyObject)        // false

It is still confusing to have two String classes, but dropping the implicit conversion will probably make it a little more palpable.

Jackson JSON custom serialization for certain fields

Add a @JsonProperty annotated getter, which returns a String, for the favoriteNumber field:

public class Person {
    public String name;
    public int age;
    private int favoriteNumber;

    public Person(String name, int age, int favoriteNumber) { = name;
        this.age = age;
        this.favoriteNumber = favoriteNumber;

    public String getFavoriteNumber() {
        return String.valueOf(favoriteNumber);

    public static void main(String... args) throws Exception {
        Person p = new Person("Joe", 25, 123);
        ObjectMapper mapper = new ObjectMapper();
        // {"name":"Joe","age":25,"favoriteNumber":"123"}

How to resolve the error "Unable to access jarfile ApacheJMeter.jar errorlevel=1" while initiating Jmeter?

This error could also happen because of version mismatch of jmeter and java. As jmeter versions supports different java versions as below.

Image of java versions supported for jmeter versions

Download the zip accordingly and you are good to go.

How to get line count of a large file cheaply in Python?

If one wants to get the line count cheaply in Python in Linux, I recommend this method:

import os
print os.popen("wc -l file_path").readline().split()[0]

file_path can be both abstract file path or relative path. Hope this may help.

How to open the command prompt and insert commands using Java?

I know that people recommend staying away from rt.exec(String), but this works, and I don't know how to change it into the array version.

rt.exec("cmd.exe /c cd \""+new_dir+"\" & start cmd.exe /k \"java -flag -flag -cp terminal-based-program.jar\"");

Html.RenderPartial() syntax with Razor


Most efficient way to find smallest of 3 numbers Java?

Write a method minimum3 that returns the smallest of three floating-point numbers. Use the Math.min method to implement minimum3. Incorporate the method into an application that reads three values from the user, determines the smallest value and displays the result.

What is the default access specifier in Java?

If no access specifier is given, it's package-level access (there is no explicit specifier for this) for classes and class members. Interface methods are implicitly public.

Squaring all elements in a list

array = [1,2,3,4,5]
def square(array):
    result = map(lambda x: x * x,array)
    return list(result)

Log4j output not displayed in Eclipse console

I had the same error.

I am using Jboss 7.1 AS. In the configuration file - standalone.xml edit the following tag. (stop your server and edit)

            <level name="ALL"/>
                <handler name="CONSOLE"/>
                <handler name="FILE"/>

The ALL has the lowest possible rank and is intended to turn on all logging.

How to ignore certain files in Git

You can also use .gitattributes (instead of .gitignore) to exclude entire filetypes. The file is pretty self-explanatory, but I'm pasting the contents here for reference. Pay attention to the last line (*.class binary):

# Denote all files that are truly binary and should not be modified.
*.png binary
*.jpg binary
*.gif binary
*.ico binary
*.mo binary
*.pdf binary
*.phar binary
*.class binary

Getting title and meta tags from external website

Improved answer from @shamittomar above to get the meta tags (or the specified one from html source)

Can be improved further... the difference from php's default get_meta_tags is that it works even when there is unicode string

function getMetaTags($html, $name = null)
    $doc = new DOMDocument();
    try {
    } catch (Exception $e) {


    $metas = $doc->getElementsByTagName('meta');

    $data = [];
    for ($i = 0; $i < $metas->length; $i++)
        $meta = $metas->item($i);

        if (!empty($meta->getAttribute('name'))) {
            // will ignore repeating meta tags !!
            $data[$meta->getAttribute('name')] = $meta->getAttribute('content');

    if (!empty($name)) {
        return !empty($data[$name]) ? $data[$name] : false;

    return $data;

Regex not operator

No, there's no direct not operator. At least not the way you hope for.

You can use a zero-width negative lookahead, however:

\((?!2001)[0-9a-zA-z _\.\-:]*\)

The (?!...) part means "only match if the text following (hence: lookahead) this doesn't (hence: negative) match this. But it doesn't actually consume the characters it matches (hence: zero-width).

There are actually 4 combinations of lookarounds with 2 axes:

  • lookbehind / lookahead : specifies if the characters before or after the point are considered
  • positive / negative : specifies if the characters must match or must not match.

How can I wrap or break long text/word in a fixed width span?

In my case, display: block was breaking the design as intended.

The max-width property just saved me.

and for styling, you can use text-overflow: ellipsis as well.

my code was

max-width: 255px

List attributes of an object

vars(obj) returns the attributes of an object.

How do I convert between big-endian and little-endian values in C++?

On most POSIX systems (through it's not in the POSIX standard) there is the endian.h, which can be used to determine what encoding your system uses. From there it's something like this:

unsigned int change_endian(unsigned int x)
    unsigned char *ptr = (unsigned char *)&x;
    return (ptr[0] << 24) | (ptr[1] << 16) | (ptr[2] << 8) | ptr[3];

This swaps the order (from big endian to little endian):

If you have the number 0xDEADBEEF (on a little endian system stored as 0xEFBEADDE), ptr[0] will be 0xEF, ptr[1] is 0xBE, etc.

But if you want to use it for networking, then htons, htonl and htonll (and their inverses ntohs, ntohl and ntohll) will be helpful for converting from host order to network order.

Enabling WiFi on Android Emulator

Wifi is not available on the emulator if you are using below of API level 25.

When using an AVD with API level 25 or higher, the emulator provides a simulated Wi-Fi access point ("AndroidWifi"), and Android automatically connects to it.

More Information:

How to do SVN Update on my project using the command line

svn update /path/to/working/copy

If subversion is not in your PATH, then of course

/path/to/subversion/svn update /path/to/working/copy

or if you are in the current root directory of your svn repo (it contains a .svn subfolder), it's as simple as

svn update

How to add/subtract time (hours, minutes, etc.) from a Pandas DataFrame.Index whos objects are of type datetime.time?

Liam's link looks great, but also check out pandas.Timedelta - looks like it plays nicely with NumPy's and Python's time deltas.

pd.date_range('2014-01-01', periods=10) + pd.Timedelta(days=1)

How to check if variable's type matches Type stored in a variable

You need to see if the Type of your instance is equal to the Type of the class. To get the type of the instance you use the GetType() method:




should do it. Obviously you could use '==' to do your comparison if you prefer.

Statically rotate font-awesome icons

If you use Less you can directly use the following mixin:

.@{fa-css-prefix}-rotate-90  { .fa-icon-rotate(90deg, 1);  }

'namespace' but is used like a 'type'

I had this problem as I created a class "Response.cs" inside a folder named "Response". So VS was catching the new Response () as Folder/namespace.

So I changed the class name to StatusResponse.cs and called new StatusResponse().This solved the issue.

.htaccess rewrite to redirect root URL to subdirectory

try to use below lines in htaccess

Note: you may need to check what is the name of the default.html

default.html is the file that load by default in the root folder.


Redirect /default.html

How to insert new cell into UITableView in Swift

Here is your code for add data into both tableView:

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    @IBOutlet weak var table1Text: UITextField!
    @IBOutlet weak var table2Text: UITextField!
    @IBOutlet weak var table1: UITableView!
    @IBOutlet weak var table2: UITableView!

    var table1Data = ["a"]
    var table2Data = ["1"]

    override func viewDidLoad() {


    @IBAction func addData(sender: AnyObject) {

        //add your data into tables array from textField

        dispatch_async(dispatch_get_main_queue(), { () -> Void in
            //reload your tableView


    //delegate methods
    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if tableView == table1 {
            return table1Data.count
        }else if tableView == table2 {
            return table2Data.count
        return Int()

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        if tableView == table1 {
            let cell = table1.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! UITableViewCell

            let row = indexPath.row
            cell.textLabel?.text = table1Data[row]

            return cell
        }else if tableView == table2 {

            let cell = table2.dequeueReusableCellWithIdentifier("Cell1", forIndexPath: indexPath) as! UITableViewCell

            let row = indexPath.row
            cell.textLabel?.text = table2Data[row]

            return cell

        return UITableViewCell()

And your result will be:

enter image description here

Creating a new database and new connection in Oracle SQL Developer

This tutorial should help you:

Getting Started with Oracle SQL Developer

See the prerequisites:

  1. Install Oracle SQL Developer. You already have it.
  2. Install the Oracle Database. Download available here.
  3. Unlock the HR user. Login to SQL*Plus as the SYS user and execute the following command:

    alter user hr identified by hr account unlock;

  4. Download and unzip the file that contains all the files you need to perform this tutorial.

Another version from May 2011: Getting Started with Oracle SQL Developer

For more info check this related question:

How to create a new database after initally installing oracle database 11g Express Edition?

Find out who is locking a file on a network share

PsFile does work on remote machines. If my login account already has access to the remote share, I can just enter:

psfile \\remote-share

(replace "remote-share" with the name of your file server) and it will list every opened document on that share, along with who has it open, and the file ID if I want to force the file closed. For me, this is a really long list, but it can be narrowed down by entering part of a path:

psfile \\remote-share I:\\Human_Resources

This is kind of tricky, since in my case this remote share is mounted as Z: on my local machine, but psfile identifies paths as they are defined on the remote file server, which in my case is I: (yours will be different). I just had to comb through the results of my first psfile run to see some of the paths it returned and then run it again with a partial path to narrow down the results.

Optionally, PsFile will let you specify credentials for the remote share if you need to supply them for access.

Lastly, a little known tip: if someone clicks on a file in Windows Explorer and cuts or copies the file with the intent to paste it somewhere else, that act also places a lock on the file.