Tutorial by Examples: io

//Swift let fooViewController = UIViewController() navigationController?.pushViewController(fooViewController, animated: true) //Objective-C UIViewController *fooViewController = [[UIViewController alloc] init]; [navigationController pushViewController:fooViewController animated:YES];

Typically, when using UIControl or UIButton, we add a selector as a callback action for when an event occurs on a button or control, such as the user pressing the button or touching the control. For example, we would do the following: import UIKit class ViewController: UIViewController { @...

Go to editor (from tool window) Esc Switching focus to corresponding tool window Windows: Alt + <tool window number> OS X / macOS: Cmd + <tool window number> For example switching focus to the project window Windows: Alt + 1 OS X / macOS: Cmd + 1 Recent files popup Windows: Ctrl...

It is common within applications to need to have code like this : a = a + 1 or a = a * 2 There is an effective shortcut for these in place operations : a += 1 # and a *= 2 Any mathematic operator can be used before the '=' character to make an inplace operation : -= decrement the va...

All of the Bitwise operators (except ~) have their own in place versions a = 0b001 a &= 0b010 # a = 0b000 a = 0b001 a |= 0b010 # a = 0b011 a = 0b001 a <<= 2 # a = 0b100 a = 0b100 a >>= 2 # a = 0b001 a = 0b101 a ^= 0b011 # a = 0b110

If you have both Python 3 and Python 2 installed, you can specify which version of Python you would like pip to use. This is useful when packages only support Python 2 or 3 or when you wish to test with both. If you want to install packages for Python 2, run either: pip install [package] or: p...

#;(define (commented-out-function x) (print (string-append "This entire " "s-expression is commented out!")))

Detailed instructions on getting unicode set up or installed.

(defun fn (x) (cond (test-condition1 the-value1) (test-condition2 the-value2) ... ... ... (t (fn reduced-argument-x)))) CL-USER 2788 > (defun my-fib (n) (cond ((= n 1) 1) ((= n...

(defun fn (x) (cond (test-condition the-value) (t (fn reduced-argument-x))))

Ruby has an or-equals operator that allows a value to be assigned to a variable if and only if that variable evaluates to either nil or false. ||= # this is the operator that achieves this. this operator with the double pipes representing or and the equals sign representing assigning of a valu...

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...

To play audio using the Web Audio API, we need to get an ArrayBuffer of audio data and pass it to a BufferSource for playback. To get an audio buffer of the sound to play, you need to use the AudioContext.decodeAudioData method like so: const audioCtx = new (window.AudioContext || window.webkitAud...

This example shows how to use two audio sources, and alter one of them based on the other. In this case we create an audio Ducker, that will lower the volume of the primary track if the secondary track produces sound. The ScriptProcessorNode will send regular events to its audioprocess handler. In ...

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...

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. ...