Tutorial by Examples: def

Functions in Racket can be created with the lambda form. The form takes a list of arguments and a body. (lambda (x y) (* x y)) In the example above, the function takes in two arguments and returns the result of multiplying them. > ((lambda (x y) (* x y)) 4 4) 16 > ((lambda (x y) (* x y)...

To get a value in NSUserDefaults you can use the following functions: Swift arrayForKey(_:) boolForKey(_:) dataForKey(_:) dictionaryForKey(_:) floatForKey(_:) integerForKey(_:) objectForKey(_:) stringArrayForKey(_:) stringForKey(_:) doubleForKey(_:) URLForKey(_:) Objective-C -(nullab...

There are use cases when you might want to rename your app directory to something else. In Laravel4 you could just change a config entry, here's one way to do it in Laravel5. In this example we'll be renaming the app directory to src. Override Application class The directories name app is hardcod...

var A var is a reference variable, similar to variables in languages like Java. Different objects can be freely assigned to a var, so long as the given object has the same type that the var was declared with: scala> var x = 1 x: Int = 1 scala> x = 2 x: Int = 2 scala> x = "foo...

Visual Studio Code is an open-source and feature-rich code editor from Microsoft. To set it up it for NativeScript development, open the Command Palette (F1 or ⌘+Shift+P) and type ext install NativeScript. Once the NativeScript extension is installed, the debugger should allow you to set breakpoint...

You can pass default parameters to any named function using the syntax: param \\ value: defmodule Example do def func(p1, p2 \\ 2) do IO.inspect [p1, p2] end end Example.func("a") # => ["a", 2] Example.func("b", 4) # => ["b", ...

An Option is a discriminated union with two cases, None or Some. type Option<'T> = Some of 'T | None

docker-compose.yml version: '2' services: php: image: phpmyadmin/phpmyadmin links: - mysql:db depends_on: - mysql mysql: image: k0st/alpine-mariadb volumes: - ./data/mysql:/var/lib/mysql environment: - MYSQL_DATABASE=mydb ...

An Akka MessageDispatcher is what makes Akka Actors "tick", it is the engine of the machine so to speak. All MessageDispatcher implementations are also an ExecutionContext, which means that they can be used to execute arbitrary code, for instance Futures. Every ActorSystem will have a def...

To read default configuration properties: package com.example; public class ExampleApplication { private Properties getDefaults() throws IOException { Properties defaults = new Properties(); try (InputStream defaultsStream = ExampleApplication.class.getResou...

When working with multiple open Workbooks, each of which may have multiple Sheets, it’s safest to define and set reference to all Workbooks and Sheets. Don't rely on ActiveWorkbook or ActiveSheet as they might be changed by the user. The following code example demonstrates how to copy a range from...

Declared variable without a value will have the value undefined var a; console.log(a); // logs: undefined Trying to retrieve the value of undeclared variables results in a ReferenceError. However, both the type of undeclared and unitialized variables is "undefined": var a; console...

C of all versions, will effectively treat any integer value other than 0 as true for comparison operators and the integer value 0 as false. If you don't have _Bool or bool as of C99 available, you could simulate a Boolean data type in C using #define macros, and you might still find such things in...

The Firebase Realtime Database allows ordering and querying data. For small data sizes, the database supports ad hoc querying, so indexes are generally not required during development. Before launching your app though, it is important to specify indexes for any queries you have to ensure they contin...

The default rules require Authentication. They allow full read and write access to authenticated users of your app. They are useful if you want data open to all users of your app but don't want it open to the world. // These rules require authentication { "rules": { ".read&...

using the vibrate(long[] pattern, int repeat) Vibrator vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE); // Start time delay // Vibrate for 500 milliseconds // Sleep for 1000 milliseconds long[] pattern = {0, 500, 1000}; // 0 meaning is repeat indefinitely vibrator.vib...

By default, GHCI's prompt shows all the modules you have loaded into your interactive session. If you have many modules loaded this can get long: Prelude Data.List Control.Monad> -- etc The :set prompt command changes the prompt for this interactive session. Prelude Data.List Control.Monad&g...

To define a new middleware we have to create the middleware class: class AuthenticationMiddleware { //this method will execute when the middleware will be triggered public function handle ( $request, Closure $next ) { if ( ! Auth::user() ) { return red...

In ui-router a state can hold multiple views, each with his own controller and a template .state('dashboard', { name: 'dashboard', url: '/dashboard', views: { "view1": { templateUrl: "path/to/view1.html", controller: "...

The scope outside of any function or class is the global scope. When a PHP script includes another (using include or require) the scope remains the same. If a script is included outside of any function or class, it's global variables are included in the same global scope, but if a script is include...