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Here we make a simple echo websocket using asyncio. We define coroutines for connecting to a server and sending/receiving messages. The communcations of the websocket are run in a main coroutine, which is run by an event loop. This example is modified from a prior post. import asyncio import ai...

PHP only allows single inheritance. In other words, a class can only extend one other class. But what if you need to include something that doesn't belong in the parent class? Prior to PHP 5.4 you would have to get creative, but in 5.4 Traits were introduced. Traits allow you to basically "copy...

A singleton is a pattern that restricts the instantiation of a class to one instance/object. Using a decorator, we can define a class as a singleton by forcing the class to either return an existing instance of the class or create a new instance (if it doesn't exist). def singleton(cls): i...

Using vanilla mathematics: var from:Point = new Point(100, 50); var to:Point = new Point(80, 95); var angle:Number = Math.atan2(to.y - from.y, to.x - from.x); Using a new vector representing the difference between the first two: var difference:Point = to.subtract(from); var angle:Number ...

Using vanilla mathematics: var from:Point = new Point(300, 10); var to:Point = new Point(75, 40); var a:Number = to.x - from.x; var b:Number = to.y - from.y; var distance:Number = Math.sqrt(a * a + b * b); Using inbuilt functionality of Point: var distance:Number = to.subtract(from).len...

var degrees:Number = radians * 180 / Math.PI;

var radians:Number = degrees / 180 * Math.PI;

A whole circle is 360 degrees or Math.PI * 2 radians. Half of those values follows to be 180 degrees or Math.PI radians. A quarter is then 90 degrees or Math.PI / 2 radians. To get a segment as a percentage of a whole circle in radians: function getSegment(percent:Number):Number { retur...

Assuming you have the angle you'd like to move in and an object with x and y values you want to move: var position:Point = new Point(10, 10); var angle:Number = 1.25; You can move along the x axis with Math.cos: position.x += Math.cos(angle); And the y axis with Math.sin: position.y += Mat...

You can test whether a point is inside a rectangle using Rectangle.containsPoint(): var point:Point = new Point(5, 5); var rectangle:Rectangle = new Rectangle(0, 0, 10, 10); var contains:Boolean = rectangle.containsPoint(point); // true

Prerequesites Grunt requires Node.js and npm to be installed. If you don’t have Node.js and/or npm installed on your machine, go to https://nodejs.org and download the installer or package for your operating system. First-time install If you're installing Grunt for the first time, you'll first ha...

A string can reversed using the built-in reversed() function, which takes a string and returns an iterator in reverse order. >>> reversed('hello') <reversed object at 0x0000000000000000> >>> [char for char in reversed('hello')] ['o', 'l', 'l', 'e', 'h'] reversed() can ...

In addition to predicates functioning as specs, you can register a spec globally using clojure.spec/def. def requires that a spec being registered is named by a namespace-qualified keyword: (clojure.spec/def ::odd-nums odd?) ;;=> :user/odd-nums (clojure.spec/valid? ::odd-nums 1) ;;=> tru...

clojure.spec/and & clojure.spec/or can be used to create more complex specs, using multiple specs or predicates: (clojure.spec/def ::pos-odd (clojure.spec/and odd? pos?)) (clojure.spec/valid? ::pos-odd 1) ;;=> true (clojure.spec/valid? ::pos-odd -3) ;;=> false or works similarl...

You can spec a map by specifying which keys should be present in the map: (clojure.spec/def ::name string?) (clojure.spec/def ::age pos-int?) (clojure.spec/def ::occupation string?) (clojure.spec/def ::person (clojure.spec/keys :req [::name ::age ::occupation])) (clojure.spec/valid? ::perso...

Sometimes you may only need to simulate an event with two outcomes, maybe with different probabilities, but you may find yourself in a situation that calls for many possible outcomes with different probabilities. Let's imagine you want to simulate an event that has six equally probable outcomes. T...

Consider a production table called questions_mysql and a table iwtQuestions (imported worktable) representing the last batch of imported CSV data from a LOAD DATA INFILE. The worktable is truncated before the import, the data is imported, and that process is not shown here. Update our production da...

9 Patches are stretchable images in which the areas which can be stretched are defined by black markers on a transparent border. There is a great tutorial here. Despite being so old, it's still so valuable and it helped many of us to deeply understand the 9 patch gear. Unfortunately, recently tha...

This example demonstrates creating a basic application in ExtJS using Sencha Cmd to bootstrap the process - this method will automatically generate some code and a skeleton structure for the project. Open a console window and change the working directory to an appropriate space in which to work. ...

A While loop starts by evaluating a condition. If it is true, the body of the loop is executed. After the body of the loop is executed, the While condition is evaluated again to determine whether to re-execute the body. Dim iteration As Integer = 1 While iteration <= 10 Console.Writeline(ite...