Tutorial by Examples: w

Extensions are used to extend the functionality of existing types in Swift. Extensions can add subscripts, functions, initializers, and computed properties. They can also make types conform to protocols. Suppose you want to be able to compute the factorial of an Int. You can add a computed property...

Type the following code into your terminal, then press Enter: echo "Hello World" This will produce the following output: Hello World

Exponentiation can be used by using the builtin pow-function or the ** operator: 2 ** 3 # 8 pow(2, 3) # 8 For most (all in Python 2.x) arithmetic operations the result's type will be that of the wider operand. This is not true for **; the following cases are exceptions from this rule: B...

The math-module contains another math.pow() function. The difference to the builtin pow()-function or ** operator is that the result is always a float: import math math.pow(2, 2) # 4.0 math.pow(-2., 2) # 4.0 Which excludes computations with complex inputs: math.pow(2, 2+0j) TypeErro...

A basic Employees table, containing an ID, and the employee's first and last name along with their phone number can be created using CREATE TABLE Employees( Id int identity(1,1) primary key not null, FName varchar(20) not null, LName varchar(20) not null, PhoneNumber varchar(10)...

First, install a version of Microsoft Visual Studio, including the free Community edition. Then, create a Visual Basic Console Application project of type Console Application, and the following code will print the string 'Hello World' to the Console: Module Module1 Sub Main() Consol...

Using the Cars Table, we will calculate the total, max, min and average amount of money each costumer spent and haw many times (COUNT) she brought a car for repairing. Id CustomerId MechanicId Model Status Total Cost SELECT CustomerId, SUM(TotalCost) OVER(PARTITION BY Cust...

from itertools import imap from future_builtins import map as fmap # Different name to highlight differences image = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] list(map(None, *image)) # Out: [(1, 4, 7), (2, 5, 8), (3, 6, 9)] list(fmap(None, *image)) # Out: [(1, 4, 7), (2, 5, 8),...

A submodule is always checked out at a specific commit SHA1 (the "gitlink", special entry in the index of the parent repo) But one can request to update that submodule to the latest commit of a branch of the submodule remote repo. Rather than going in each submodule, doing a git checkout...

int i = 42; i = i++; /* Assignment changes variable, post-increment as well */ int a = i++ + i--; Code like this often leads to speculations about the "resulting value" of i. Rather than specifying an outcome, however, the C standards specify that evaluating such an expression produc...

single channel, single goroutine, one write, one read. package main import "fmt" import "time" func main() { // create new channel of type string ch := make(chan string) // start new anonymous goroutine go func() { time.Sleep(time.Second) ...

Python's str type also features a number of methods that can be used to evaluate the contents of a string. These are str.isalpha, str.isdigit, str.isalnum, str.isspace. Capitalization can be tested with str.isupper, str.islower and str.istitle. str.isalpha str.isalpha takes no arguments and retu...

// Animal.php class Animal { public function eats($food) { echo "Yum, $food!"; } } // zoo.php require 'Animal.php'; $animal = new Animal; $animal->eats('slop'); // aquarium.php require 'Animal.php'; $animal = new Animal; $animal->eats('shrimp'); H...

// autoload.php spl_autoload_register(function ($class) { require_once "$class.php"; }); // Animal.php class Animal { public function eats($food) { echo "Yum, $food!"; } } // Ruminant.php class Ruminant extends Animal { public function eat...

If it's not already done in php.ini, error reporting can be set dynamically and should be set to allow most errors to be shown: Syntax int error_reporting ([ int $level ] ) Examples // should always be used prior to 5.4 error_reporting(E_ALL); // -1 will show every possible error, even whe...

6 ES6's Object.assign() function can be used to copy all of the enumerable properties from an existing Object instance to a new one. const existing = { a: 1, b: 2, c: 3 }; const clone = Object.assign({}, existing); This includes Symbol properties in addition to String ones. Object rest/sp...

Perl tries to do what you mean: print "Hello World\n"; The two tricky bits are the semicolon at the end of the line and the \n, which adds a newline (line feed). If you have a relatively new version of perl, you can use say instead of print to have the carriage return added automatical...

Defines an <initially-hidden> custom element which hides its contents until a specified number of seconds have elapsed. const InitiallyHiddenElement = document.registerElement('initially-hidden', class extends HTMLElement { createdCallback() { this.revealTimeoutId = null; } at...

6 Exceptions are to synchronous code what rejections are to promise-based asynchronous code. If an exception is thrown in a promise handler, its error will be automatically caught and used to reject the promise instead. Promise.resolve(5) .then(result => { throw new Error("I ...

Assuming a single source file named main.cpp, the command to compile and link an non-optimized executable is as follows (Compiling without optimization is useful for initial development and debugging, although -Og is officially recommended for newer GCC versions). g++ -o app -Wall main.cpp -O0 T...