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Rules for creating a dictionary: Every key must be unique (otherwise it will be overridden) Every key must be hashable (can use the hash function to hash it; otherwise TypeError will be thrown) There is no particular order for the keys. # Creating and populating it with values stock = {'egg...

def foobar(foo=None, bar=None): return "{}{}".format(foo, bar) values = {"foo": "foo", "bar": "bar"} foobar(**values) # "foobar"

One way to mock a function is to use the create_autospec function, which will mock out an object according to its specs. With functions, we can use this to ensure that they are called appropriately. With a function multiply in custom_math.py: def multiply(a, b): return a * b And a function...

A way to use confirm() is when some UI action does some destructive changes to the page and is better accompanied by a notification and a user confirmation - like i.e. before deleting a post message: <div id="post-102"> <p>I like Confirm modals.</p> <a data-dele...

A JSON Array is an ordered collection of values. It is surrounded by square braces i.e [], and values are comma-delimited: { "colors" : [ "red", "green", "blue" ] } JSON Arrays can also contain any valid JSON element, including objects, as in this example ...

Matrix multiplication can be done in two equivalent ways with the dot function. One way is to use the dot member function of numpy.ndarray. >>> import numpy as np >>> A = np.ones((4,4)) >>> A array([[ 1., 1., 1., 1.], [ 1., 1., 1., 1.], [ 1., 1.,...

Since functions are ordinary values, there is a convenient syntax for creating functions without names: List.map (fun x -> x * x) [1; 2; 3; 4] (* - : int list = [1; 4; 9; 16] *) This is handy, as we would otherwise have to name the function first (see let) to be able to use it: let square x...

const int a = 0; /* This variable is "unmodifiable", the compiler should throw an error when this variable is changed */ int b = 0; /* This variable is modifiable */ b += 10; /* Changes the value of 'b' */ a += 10; /* Throws a compiler error */ The const qualif...

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...

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

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

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 spec collections in a number of ways. coll-of allows you to spec collections and provide some additional constraints. Here's a simple example: (clojure.spec/valid? (clojure.spec/coll-of int?) [1 2 3]) ;; => true (clojure.spec/valid? (clojure.spec/coll-of int?) '(1 2 3)) ;; => tru...

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...

A package.json file, usually present in the project root, contains metadata about your app or module as well as the list of dependencies to install from npm when running npm install. To initialize a package.json type npm init in your command prompt. To create a package.json with default values use...

Any time you instantiate a class that Implements IDisposable, you should call .Dispose1 on that class when you have finished using it. This allows the class to clean up any managed or unmanaged dependencies that it may be using. Not doing this could cause a memory leak. The Using keyword ensures th...

Sometimes, you have to create two Disposable objects in a row. There is an easy way to avoid nesting Using blocks. This code Using File As New FileStream("MyFile", FileMode.Append) Using Writer As New BinaryWriter(File) 'You code here Writer.Writer("Hello&quot...

The @Header and @Body annotations can be placed into the method signatures and Retrofit will automatically create them based on your models. public interface MyService { @POST("authentication/user") Call<AuthenticationResponse> authenticateUser(@Body AuthenticationReques...

Import in your gradle root file classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8' Import in your gradle app file apt 'com.google.auto.value:auto-value:1.2' apt 'com.ryanharter.auto.value:auto-value-gson:0.3.1' provided 'com.jakewharton.auto.value:auto-value-annotations:1.2-update...