Tutorial by Examples: w

Wikipedia currently defines a pure function as follows: The function always evaluates the same result value given the same argument value(s). The function result value cannot depend on any hidden information or state that may change while program execution proceeds or between different executions...

Suppose you have this type: data Person = Person { name :: String, age:: Int } deriving (Show, Eq) and two values: alex = Person { name = "Alex", age = 21 } jenny = Person { name = "Jenny", age = 36 } a new value of type Person can be created by copying from alex, specif...

The do...while statement will execute a block of code at least once - it then will repeat the loop as long as a condition is true. The following example will increment the value of $i at least once, and it will continue incrementing the variable $i as long as it has a value of less than 25; $i...

The while statement will execute a block of code if and as long as a test expression is true. If the test expression is true then the code block will be executed. After the code has executed the test expression will again be evaluated and the loop will continue until the test expression is foun...

Create function in MyComponent.php namespace app\components; use Yii; use yii\base\Component; use yii\base\InvalidConfigException; use yii\helpers\Url; use yii\helpers\ArrayHelper; use app\models\User; class MyComponent extends Component ...

Implementing the IEnumerable interface allows classes to be enumerated in the same way as BCL collections. This requires extending the Enumerator class which tracks the state of the enumeration. Other than iterating over a standard collection, examples include: Using ranges of numbers based on a...

Uploading Files Uploading files in Yii is usually done with the help of [[yii\web\UploadedFile]] which encapsulates each uploaded file as an UploadedFile object. Combined with [[yii\widgets\ActiveForm]] and models, you can easily implement a secure file uploading mechanism. Creating Models Lik...

So you've uploaded your files to a folder say /backend/web/uploads/ and you want these uploads to be visible on the frontend too. The easiest option is to create a symlink in the frontend that links to the backend: ln -s /path/to/backend/web/uploads/ /path/to/frontend/web/uploads In your views y...

Note: it's strongly advised to use Composer. The instruction below is basically what Composer does for you. Download archive extension file of needed version from Github Open composer.json Find PSR-4 autoload section and remember it for e.g. kmit/select2 Extract files to corresponding fold...

To create the classic "Hello, world" printing program, create a file called hello.d with a text editor containing the following code : import std.stdio; void main() { writeln("Hello, World!"); //writeln() automatically adds a newline (\n) to the output } Explanati...

Table Item The following class contains 2 properties a name (String) and the size (double). Both properties are wrapped in JavaFX properties to allow the TableView to observe changes. import javafx.beans.property.DoubleProperty; import javafx.beans.property.SimpleDoubleProperty; import javafx.be...

The below examples use the new form API introduced in RC3. pw-change.template.html <form class="container" [formGroup]="pwChangeForm"> <label for="current">Current Password</label> <input id="current" formControlName="curr...

If you need to add an attribute through razor that has a - (hyphen) in the name you cannot simply do @Html.DropDownListFor(m => m.Id, Model.Values, new { @data-placeholder = "whatever" }) it will not compile. data-* attributes are valid and common in html5 for adding extra values t...

composer update composer update will update our dependencies as they are specified in composer.json. For example, if our project uses this configuration: "require": { "laravelcollective/html": "2.0.*" } Supposing we have actually installed the 2.0.1 version ...

name:john* The * indicator allows you to do a wildcard search matching 0 or more characters after the search term john, will return documents containing john, johnson, john's, johnny and so on. name:do? The ? indicator allows you to do a wildcard search with a single character in the search term,...

PROGRAM zhello_world. START-OF-SELECTION. WRITE 'Hello, World!'. Instead of printing to the console, ABAP writes values to a list which will be displayed as soon as the main logic was executed.

Class implementation: CLASS lcl_abap_class DEFINITION. PRIVATE SECTION. METHODS method1 IMPORTING iv_string TYPE string CHANGING cv_string TYPE string EXPORTING ev_string TYPE string. ENDCLASS. CLASS lcl_abap_class IMPLEMENTATION. METHOD m...

Class implementation: CLASS lcl_abap_class DEFINITION. PRIVATE SECTION. METHODS method1 RETURNING VALUE(rv_string) TYPE string. ENDCLASS. CLASS lcl_abap_class IMPLEMENTATION. METHOD method1. rv_string = 'returned value'. ENDMETHOD. ENDCLASS. Method call example: ...

CMake knows several build types, which usually influence default compiler and linker parameters (such as debugging information being created) or alternative code paths. By default, CMake is able to handle the following build types: Debug: Usually a classic debug build including debugging informa...

You can add an interpreter directive (shebang) to your script. Create a file called hello_world.rb which contains: #!/usr/bin/env ruby puts 'Hello World!' Give the script executable permissions. Here's how to do that in Unix: $ chmod u+x hello_world.rb Now you do not need to call the Ru...