Tutorial by Examples: r

A Stopwatch instance can measure elapsed time over several intervals with the total elapsed time being all individual intervals added together. This gives a reliable method of measuring elapsed time between two or more events. Stopwatch stopWatch = new Stopwatch(); stopWatch.Start(); double d =...

Redux is very functional, so unit testing is very straightforward. Action creator: export function showSidebar () { return { type: 'SHOW_SIDEBAR' } } Action creators unit test: import expect from 'expect' import actions from './actions' import * as type from './constants' desc...

We're defining a robust version of a function that reads the HTML code from a given URL. Robust in the sense that we want it to handle situations where something either goes wrong (error) or not quite the way we planned it to (warning). The umbrella term for errors and warnings is condition Functio...

Strict mode does not allow you to use duplicate function parameter names. function foo(bar, bar) {} // No error. bar is set to the final argument when called "use strict"; function foo(bar, bar) {}; // SyntaxError: duplicate formal argument bar

The simple answer, when asking how to use threads in Python is: "Don't. Use processes, instead." The multiprocessing module lets you create processes with similar syntax to creating threads, but I prefer using their convenient Pool object. Using the code that David Beazley first used to...

;Sends the keystroke for the letter "a" every 3 seconds. #Persistent SetTimer, SendLetterA, 3000 return SendLetterA() { Send, a }

This is an example of something that would have been straight up impossible with labels. If you execute the same label multiple times at the same time and they rely on variables that are being defined within them, they very likely interfere and cause unexpected behavior. Here is how to do it with f...

Consider the following example: type Company struct { Name string Location string } Hide/Skip Certain Fields To export Revenue and Sales, but hide them from encoding/decoding, use json:"-" or rename the variable to begin with a lowercase letter. Note that this prevents ...

Pipe operators are used to pass parameters to a function in a simple and elegant way. It allows to eliminate intermediate values and make function calls easier to read. In F#, there are two pipe operators: Forward (|>): Passing parameters from left to right let print message = print...

When you are programming in OpenGL or any other graphics api you will hit a brick wall when you are not that good in math. Here I will explain with example code how you can achieve movement/scaling and many other cool stuff with your 3d object. Let's take a real life case... You've made a awesome (...

If we have this dictionary: set alpha {alice {items {}} bob {items {}} claudia {items {}} derek {items {}}} And want to add "fork" and "peanut" to Alice's items, this code won't work: dict lappend alpha alice items fork peanut dict get $alpha alice # => items {} items f...

There are two ways to register a background page in the extension manifest. The scripts property In the common case, a background page doesn't require any HTML markup. We can register these kinds of background pages using the scripts property. In this case, a background page will be generated...

The sort algorithm sorts a sequence defined by two iterators. This is enough to sort a built-in (also known as c-style) array. C++11 int arr1[] = {36, 24, 42, 60, 59}; // sort numbers in ascending order sort(std::begin(arr1), std::end(arr1)); // sort numbers in descending order sort(std::b...

The ref keyword is used to pass an Argument as Reference. out will do the same as ref but it does not require an assigned value by the caller prior to calling the function. Ref Parameter :-If you want to pass a variable as ref parameter then you need to initialize it before you pass it as ref param...

In Swift, memory management is done for you automatically using Automatic Reference Counting. (See Memory Management) Allocation is the process of reserving a spot in memory for an object, and in Swift understanding the performance of such requires some understanding of the heap and the stack. The h...

Assume we want to create a data type Person, which has a first and last name, an age, a phone number, a street, a zip code and a town. We could write data Person = Person String String Int Int String String String If we want now to get the phone number, we need to make a function getPhone :: P...

thinky is a lightweight node.js ORM for RethinkDB. First you need to have RethinkDB running on your server. Then install the thinky.io npm package into your project. npm install --save thinky Now import thinky into your model file. const thinky = require('thinky)(); const type = thinky.type ...

defmodule ATest do use ExUnit.Case [{1, 2, 3}, {10, 20, 40}, {100, 200, 300}] |> Enum.each(fn {a, b, c} -> test "#{a} + #{b} = #{c}" do assert unquote(a) + unquote(b) = unquote(c) end end) end Output: . 1) test 10 + 20 = 40 (Test.Test) t...

With Resources class it's possible to dynamically load assets that are not part of the scene. It's very usefull when you have to use on demand assets, for example localize multi language audios, texts, etc.. Assets must be placed in a folder named Resources. It's possible to have multiple Resource...

With ASP.NET Core the Microsoft team also introduced the Options pattern, which allows to have strong typed options and once configured the ability to inject the options into your services. First we start with a strong typed class, which will hold our configuration. public class MySettings { ...