Tutorial by Examples: ha

One of the easiest examples of using shared services is when we want to store some data from a given page of our application, and then get that data again but from another page. One option could be to send that data as a parameter (for instance, if one page calls the other one) but if we want to us...

jQuery datepicker has two options to allow displaying dropdowns for month and year selection. These options make navigation through large timeframes easier. <input type="text" id="datepicker"> <script> $("#datepicker").datepicker({ changeMont...

add_action( 'pre_get_posts', 'single_category_exclude' ); function single_category_exclude( $query ) { if( !$query->is_main_query() || is_admin() ) return; $query->set( 'cat', '-1' ); return; }

All we need to do is to use set() method of $query object. It takes two arguments, first what we want to set and second what value to set. add_action( 'pre_get_posts', 'change_posts_per_page' ); function change_posts_per_page( $query ) { if( !$query->is_main_query() || is_admin() ) retu...

Let's say we have type ENUM('fish','mammal','bird') An alternative is type VARCHAR(20) COMENT "fish, bird, etc" This is quite open-ended in that new types are trivially added. Comparison, and whether better or worse than ENUM: (same) INSERT: simply provide the string (worse?)...

Changing an auto-increment value is useful when you don't want a gap in an AUTO_INCREMENT column after a massive deletion. For example, you got a lot of unwanted (advertisement) rows posted in your table, you deleted them, and you want to fix the gap in auto-increment values. Assume the MAX value o...

using System; using System.Linq; using System.Security.Cryptography; namespace YourCryptoNamespace { /// <summary> /// Salted password hashing with PBKDF2-SHA1. /// Compatibility: .NET 3.0 and later. /// </summary> /// <remarks>See http://crackstation.net/h...

ALTER TABLE fish_data.fish DROP PRIMARY KEY; ALTER TABLE fish_data.fish MODIFY COLUMN fish_id DECIMAL(20,0) NOT NULL PRIMARY KEY; An attempt to modify the type of this column without first dropping the primary key would result in an error.

Sometimes it's useful to be able to extend a class with new functions. For example let's suppose that a string should be converted to a camel case string. So we need to tell TypeScript, that String contains a function called toCamelCase, which returns a string. interface String { toCamelCase()...

# list gem sources: gem sources -l # remove default gem source: gem sources -r https://rubygems.org/ # add other gem sources: gem sources -a https://ruby.taobao.org/

AppBundle/Entity/Person.php <?php namespace AppBundle\Entity; use DoctrineORM\Mapping as ORM; use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity; /** * @ORM\Entity * @ORM\Table(name="persons") * @ORM\Entity(repositoryClass="AppBundle\Entity\PersonRe...

Dedicated Workers A dedicated web worker is only accessible by the script that called it. Main application: var worker = new Worker('worker.js'); worker.addEventListener('message', function(msg) { console.log('Result from the worker:', msg.data); }); worker.postMessage([2,3]); worker.j...

XML <Goku> <child name="Gohan"/> <child name="Goten"/> </Goku> XPATH count(/Goku/child) OUTPUT 2.0

You can register for notifications of when the device text size is changed. Swift NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(updateFont), name: name:UIContentSizeCategoryDidChangeNotification, object: nil) Objective-C [[NSNotificationCenter defaultCenter] addObs...

The CharField is used for storing defined lengths of text. In the example below up to 128 characters of text can be stored in the field. Entering a string longer than this will result in a validation error being raised. from django.db import models class MyModel(models.Model): name = models...

You can use the following code for going back and forward. if (!function_exists('codepoint_encode')) { function codepoint_encode($str) { return substr(json_encode($str), 1, -1); } } if (!function_exists('codepoint_decode')) { function codepoint_decode($str) { re...

You can use the following code for going back and forward. if (!function_exists('mb_internal_encoding')) { function mb_internal_encoding($encoding = NULL) { return ($from_encoding === NULL) ? iconv_get_encoding() : iconv_set_encoding($encoding); } } if (!function_exists('mb_c...

Save the session variable as a variable. $session = Yii::$app->session; $sess = $session['keys']; Then create or update the array value you want $sess['first'] = 'abc'; And finally save to the session variable $session['keys'] = $sess

Use a mutex to synchronise access to a variable which is accessed from multiple threads: counter = 0 counter_mutex = Mutex.new # Start three parallel threads and increment counter 3.times.map do |index| Thread.new do counter_mutex.synchronize { counter += 1 } end end.each(&:joi...

Go to the project.json directory and publish: dotnet publish It will print the output directory of the operation, enter the directory and run the published project: dotnet <project output>.dll The default folder will be: <project root>/bin/<configuration>/<target framewo...