Tutorial by Examples: r

Multiple type parameters

Generics types can have more than one type parameters, eg. Result is defined like this: pub enum Result<T, E> { Ok(T), Err(E), }

Rust • Generics

// Only accept T and U generic types that also implement Debug fn print_objects<T: Debug, U: Debug>(a: T, b: U) { println!("A: {:?} B: {:?}", a, b); } print_objects(13, 44); // or annotated explicitly print_objects::<usize, u16>(13, 44); The bounds must cover a...

Rust • Generics

Generic functions

Generic functions allow some or all of their arguments to be parameterised. fn convert_values<T, U>(input_value: T) -> Result<U, String> { // Try and convert the value. // Actual code will require bounds on the types T, U to be able to do something with them. } If the compi...

Rust • Generics

Creating a new object

PowerShell, unlike some other scripting languages, sends objects through the pipeline. What this means is that when you send data from one command to another, it's essential to be able to create, modify, and collect objects. Creating an object is simple. Most objects you create will be custom obj...

PowerShell • Working with Objects

Using expression in string literals

You can use curly braces to interpolate expressions into string literals: def f(x: String) = x + x val a = "A" s"${a}" // "A" s"${f(a)}" // "AA" Without the braces, scala would only interpolate the identifier after the $ (in this case f...

Scala Language • String Interpolation

Identify Binary Files

Git is pretty good at identifying binary files, but you can explicitly specify which files are binary. Create a .gitattributes file in the project root containing: *.png binary binary is a built-in macro attribute equivalent to -diff -merge -text.

Git • Using a .gitattributes file

Configuring line endings

Description When working with a team who uses different operating systems (OS) across the project, sometimes you may run into trouble when dealing with line endings. Microsoft Windows When working on Microsoft Windows operating system (OS), the line endings are normally of form - carriage return ...

Git • Configuration

Basic WordPress loop structure

Each time WordPress loads the page, it will run main loop. The loop is the way to iterate over all elements related to the page you are currently on. Main loop will work on a global WP_Query object. The query has a globalized method have_posts(), that allows us to loop through all results. Finally...

WordPress • The Loop (main WordPress loop)

Alternative loop syntax

You can also use loop with curly brackets like this: if ( have_posts() ) { while ( have_posts() ) { the_post(); var_dump( $post ); } }

WordPress • The Loop (main WordPress loop)

Function Prototype Scope

#include <stdio.h> /* The parameter name, apple, has function prototype scope. These names are not significant outside the prototype itself. This is demonstrated below. */ int test_function(int apple); int main(void) { int orange = 5; orange = test_function(oran...

C Language • Identifier Scope

Plugins - Getting Started

The jQuery API may be extended by adding to its prototype. For example, the existing API already has many functions available such as .hide(), .fadeIn(), .hasClass(), etc. The jQuery prototype is exposed through $.fn, the source code contains the line jQuery.fn = jQuery.prototype Adding functio...

jQuery • Plugins

Calculate Content Bounds (for i.e. dynamic cell heights)

A common use case for wanting to calculate the frame a label will take up is for sizing table view cells appropriately. The recommended way of doing this is using the NSString method boundingRectWithSize:options:attributes:context:. options takes String drawing options: NSStringDrawingUsesLineFr...

iOS • UILabel

Show week of the year

The following code will show week of the year number on the left side of the datepicker. By default the week start on Monday, but it can be customized using firstDay option. The first week of the year contains the first Thursday of the year, following the ISO 8601 definition. <input type="t...

jQuery UI Library • Datepicker

Complex Example - jQuery UI Dynamicly Create Dialog

Generally, dialog relies on a div within the HTML. Sometimes you may want to create a dialog from scratch, programmatically. Here is an example of a complex modal dialog created dynamically with interactive functions. HTML <div id="users-contain" class="ui-widget"> &lt...

jQuery UI Library • Dialog

Overview

Redis is an in-memory remote database that offers high performance, replication, and a unique data model to produce a platform for solving problems. Redis is an open source (BSD licensed), in-memory data structure , used as database, cache and message broker. It is categorized as a NoSQL key-value s...

redis • Getting started with redis

Use requestAnimationFrame to fade in element

View jsFiddle: https://jsfiddle.net/HimmatChahal/jb5trg67/ Copy + Pasteable code below: <html> <body> <h1>This will fade in at 60 frames per second (or as close to possible as your hardware allows)</h1> <script> // Fad...

JavaScript • requestAnimationFrame

Member initialization

Each of the enum members may be initialized with a value. If a value is not specified for a member, by default it's initialized to 0 (if it's the first member in the member list) or to a value greater by 1 than the value of the preceding member. Module Module1 Enum Size Small ...

Visual Basic .NET Language • Enum

The Flags attribute

With the <Flags> attribute, the enum becomes a set of flags. This attribute enables assigning multiple values to an enum variable. The members of a flags enum should be initialized with powers of 2 (1, 2, 4, 8...). Module Module1 <Flags> Enum Material Wood = 1 ...

Visual Basic .NET Language • Enum

Builder Pattern / C# / Fluent Interrface

public class Email { public string To { get; set; } public string From { get; set; } public string Subject { get; set; } public string Body { get; set; } } public class EmailBuilder { private readonly Email _email; public EmailBuilder() { _email = ...

Design patterns • Builder Pattern

Devise Controller Filters & Helpers

To set up a controller with user authentication using devise, add this before_action: (assuming your devise model is 'User'): before_action :authenticate_user! To verify if a user is signed in, use the following helper: user_signed_in? For the current signed-in user, use this helper: current_us...

Ruby on Rails • User Authentication in Rails