Tutorial by Examples: a

ReactJS is an open-source, component based front end library responsible only for the view layer of the application. It is maintained by Facebook. ReactJS uses virtual DOM based mechanism to fill in data (views) in HTML DOM. The virtual DOM works fast owning to the fact that it only changes individ...

Post::find()->all(); // SELECT * FROM post or the shorthand (Returns an active record model instance by a primary key or an array of column values.) Post::findAll(condition); returns an array of ActiveRecord instances. Find All with where Condition $model = User::find() ->w...

OPERATORS $postsGreaterThan = Post::find()->where(['>', 'created_at', '2016-01-25'])->all(); // SELECT * FROM post WHERE created_at > '2016-01-25' $postsLessThan = Post::find()->where(['<', 'created_at', '2016-01-25'])->all(); // SELECT * FROM post WHERE created_at < '2...

<?php namespace models; use yii\db\ActiveRecord; use yii\behaviors\TimestampBehavior; class Post extends ActiveRecord { public static function tableName() { return 'post'; } public function rules() { ...

Twig is a templating language that compiles to optimized PHP code. It is primarily used for outputting HTML, but can also be used to output any other text-based format. It is a standalone component that can be easily integrated into any PHP project. It provides many excellent features: Autoescap...

To get your most recent stash after running git stash, use git stash apply To see a list of your stashes, use git stash list You will get a list that looks something like this stash@{0}: WIP on master: 67a4e01 Merge tests into develop stash@{1}: WIP on master: 70f0d95 Add user role to lo...

You have to keep the operator precedence in mind when using await keyword. Imagine that we have an asynchronous function which calls another asynchronous function, getUnicorn() which returns a Promise that resolves to an instance of class Unicorn. Now we want to get the size of the unicorn using th...

async functions do not replace the Promise type; they add language keywords that make promises easier to call. They are interchangeable: async function doAsyncThing() { ... } function doPromiseThing(input) { return new Promise((r, x) => ...); } // Call with promise syntax doAsyncThing() ...

When accessing arrays with pointers, there are no bounds check and therefore no IndexOutOfRangeException will be thrown. This makes the code faster. Assigning values to an array with a pointer: class Program { static void Main(string[] args) { unsafe { int...

The Oracle SQL and PL/SQL || operator allows you to concatenate 2 or more strings together. Example: Assuming the following customers table: id firstname lastname --- ----------- ---------- 1 Thomas Woody Query: SELECT firstname || ' ' || lastname || ' is in my database.' a...

The aggregate function AVG() returns the average of a given expression, usually numeric values in a column. Assume we have a table containing the yearly calculation of population in cities across the world. The records for New York City look similar to the ones below: EXAMPLE TABLE city_namepopula...

Prerequisites Installation

Prerequisites Installation

Prerequisites Installation

The second value in the curly braces dictates the length of the replacement string. By adjusting the second value to be positive or negative, the alignment of the string can be changed. string.Format("LEFT: string: ->{0,-5}<- int: ->{1,-5}<-", "abc", 123); string....

// Integral types as hex string.Format("Hexadecimal: byte2: {0:x2}; byte4: {0:X4}; char: {1:x2}", 123, (int)'A'); // Integers with thousand separators string.Format("Integer, thousand sep.: {0:#,#}; fixed length: >{0,10:#,#}<", 1234567); // Integer with leading zero...

Use existing .NET classes instantly with PowerShell by using [class]::Method(args): PS C:\> [guid]::NewGuid() Guid ---- 8874a185-64be-43ed-a64c-d2fe4b6e31bc Similarly, in PowerShell 5+ you may use the New-Guid cmdlet: PS C:\> New-Guid Guid ---- 8874a185-64be-43ed-a64c-d2fe4b6e31...

If value types are assigned to variables of type object they are boxed - the value is stored in an instance of a System.Object. This can lead to unintended consequences when comparing values with ==, e.g.: object left = (int)1; // int in an object box object right = (int)1; // int in an object bo...

Boxed value types can only be unboxed into their original Type, even if a conversion of the two Types is valid, e.g.: object boxedInt = (int)1; // int boxed in an object long unboxedInt1 = (long)boxedInt; // invalid cast This can be avoided by first unboxing into the original Type, e.g.: lon...

The Protractor API allows CSS element locators to use the jQuery-like shortcut notation $(). Normal CSS Element Locator: element(by.css('h1.documentation-text[ng-bind="title"]')); element(by.css('[ng-click="submit"])); Shortcut $() CSS Element Locator: $('h1.documentatio...