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- add more examples; update examples
- now runs in the Xcode 6 b6 playground - add MARK sections
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C. Bess
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@ -2,6 +2,7 @@
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language: swift
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contributors:
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- ["Grant Timmerman", "http://github.com/grant"]
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- ["Christopher Bess", "http://github.com/cbess"]
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filename: learnswift.swift
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---
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@ -11,21 +12,34 @@ See also Apple's [getting started guide](https://developer.apple.com/library/pre
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```js
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//
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// Basics
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// MARK: Basics
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//
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println("Hello, world")
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var myVariable = 42
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//let fƒ∆ = "value" // unicode in variable names
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let myConstant = 3.1415926
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let convenience = "keyword" // contextual variable name
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let weak = "keyword"; let override = "another keyword" // statements can be separated by a semi-colon
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let `class` = "keyword" // backticks allow keywords to be used as variable names
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let explicitDouble: Double = 70
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let intValue = 0007 // 7
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let largeIntValue = 77_000 // 77000
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let label = "some text " + String(myVariable) // Casting
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let piText = "Pi = \(myConstant)" // String interpolation
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var optionalString: String? = "optional" // Can be nil
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optionalString = nil
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/*
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Comment here
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/*
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Nested comment here
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*/
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*/
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//
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// Arrays and Dictionaries
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// MARK: Collections
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//
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// Array
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@ -35,65 +49,66 @@ let emptyArray = [String]()
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// Dictionary
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var occupations = [
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"Malcolm": "Captain",
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"kaylee": "Mechanic"
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"Malcolm": "Captain",
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"kaylee": "Mechanic"
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]
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occupations["Jayne"] = "Public Relations"
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let emptyDictionary = Dictionary<String, Float>()
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//
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// Control Flow
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// MARK: Control Flow
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//
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// for loop (array)
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let myArray = [1, 1, 2, 3, 5]
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for value in myArray {
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if value == 1 {
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println("One!")
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} else {
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println("Not one!")
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}
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if value == 1 {
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println("One!")
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} else {
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println("Not one!")
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}
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}
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// for loop (dictionary)
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var dict = ["one": 1, "two": 2]
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for (key, value) in dict {
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println("\(key): \(value)")
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println("\(key): \(value)")
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}
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// for loop (range)
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for i in -1...1 { // [-1, 0, 1]
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println(i)
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println(i)
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}
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// use ..< to exclude the last number
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// while loop
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var i = 1
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while i < 1000 {
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i *= 2
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i *= 2
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}
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// do-while loop
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do {
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println("hello")
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println("hello")
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} while 1 == 2
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// Switch
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let vegetable = "red pepper"
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switch vegetable {
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case "celery":
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let vegetableComment = "Add some raisins and make ants on a log."
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let vegetableComment = "Add some raisins and make ants on a log."
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case "cucumber", "watercress":
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let vegetableComment = "That would make a good tea sandwich."
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let vegetableComment = "That would make a good tea sandwich."
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case let x where x.hasSuffix("pepper"):
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let vegetableComment = "Is it a spicy \(x)?"
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let vegetableComment = "Is it a spicy \(x)?"
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default: // required (in order to cover all possible input)
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let vegetableComment = "Everything tastes good in soup."
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let vegetableComment = "Everything tastes good in soup."
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}
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//
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// Functions
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// MARK: Functions
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//
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// Functions are a first-class type, meaning they can be nested
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@ -101,31 +116,31 @@ default: // required (in order to cover all possible input)
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// Function
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func greet(name: String, day: String) -> String {
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return "Hello \(name), today is \(day)."
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return "Hello \(name), today is \(day)."
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}
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greet("Bob", "Tuesday")
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// Function that returns multiple items in a tuple
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func getGasPrices() -> (Double, Double, Double) {
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return (3.59, 3.69, 3.79)
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return (3.59, 3.69, 3.79)
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}
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// Args
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// Variadic Args
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func setup(numbers: Int...) {}
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// Passing and returning functions
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func makeIncrementer() -> (Int -> Int) {
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func addOne(number: Int) -> Int {
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return 1 + number
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}
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return addOne
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func addOne(number: Int) -> Int {
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return 1 + number
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}
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return addOne
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}
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var increment = makeIncrementer()
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increment(7)
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//
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// Closures
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// MARK: Closures
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//
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var numbers = [1, 2, 6]
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@ -135,93 +150,142 @@ var numbers = [1, 2, 6]
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// `->` separates the arguments and return type
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// `in` separates the closure header from the closure body
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numbers.map({
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(number: Int) -> Int in
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let result = 3 * number
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return result
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})
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(number: Int) -> Int in
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let result = 3 * number
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return result
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})
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// When the type is known, like above, we can do this
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numbers = numbers.map({ number in 3 * number })
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//Or even this
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// Or even this
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//numbers = numbers.map({ $0 * 3 })
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print(numbers) // [3, 6, 18]
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// Trailing closure
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numbers = sorted(numbers) { $0 > $1 }
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print(numbers) // [18, 6, 3]
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// Super shorthand, since the < operator infers the types
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numbers = sorted(numbers, < )
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print(numbers) // [3, 6, 18]
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//
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// Classes
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// MARK: Classes
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//
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class Shape {
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func getArea() -> Int {
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return 0;
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}
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}
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// All methods and properties of a class are public.
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// If you just need to store data in a
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// structured object, you should use a `struct`
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// A simple class `Square` extends `Shape`
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class Rect: Shape {
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var sideLength: Int = 1
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// Custom getter and setter property
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var perimeter: Int {
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get {
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return 4 * sideLength
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var sideLength: Int = 1
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// Custom getter and setter property
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var perimeter: Int {
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get {
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return 4 * sideLength
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}
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set {
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sideLength = newValue / 4
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}
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}
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set {
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sideLength = newValue / 4
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// If you don't need a custom getter and setter,
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// but still want to run code before and after getting or setting
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// a property, you can use `willSet` and `didSet`
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var identifier: String = "defaultID" {
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willSet(someIdentifier) {
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print(someIdentifier)
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}
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}
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}
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init(sideLength: Int) {
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super.init()
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self.sideLength = sideLength
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}
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func shrink() {
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if sideLength > 0 {
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--sideLength
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init(sideLength: Int) {
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super.init()
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self.sideLength = sideLength
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}
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func shrink() {
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if sideLength > 0 {
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--sideLength
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}
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}
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override func getArea() -> Int {
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return sideLength * sideLength
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}
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}
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override func getArea() -> Int {
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return sideLength * sideLength
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}
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}
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var mySquare = new Square(sideLength: 5)
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class Square: Rect {
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convenience init() {
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self.init(sideLength: 5)
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}
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}
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var mySquare = Square()
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print(mySquare.getArea()) // 25
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mySquare.shrink()
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print(mySquare.sideLength) // 4
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// If you don't need a custom getter and setter,
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// but still want to run code before and after getting or setting
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// a property, you can use `willSet` and `didSet`
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//
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// Enums
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// MARK: Enums
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//
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// Enums can optionally be of a specific type or on their own.
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// They can contain methods like classes.
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enum Suit {
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case Spades, Hearts, Diamonds, Clubs
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func getIcon() -> String {
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switch self {
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case .Spades: return "♤"
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case .Hearts: return "♡"
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case .Diamonds: return "♢"
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case .Clubs: return "♧"
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case Spades, Hearts, Diamonds, Clubs
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func getIcon() -> String {
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switch self {
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case .Spades: return "♤"
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case .Hearts: return "♡"
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case .Diamonds: return "♢"
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case .Clubs: return "♧"
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}
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}
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}
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}
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//
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// Other
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// MARK: Other
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//
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// `protocol`: Similar to Java interfaces.
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// `extension`s: Add extra functionality to an already created type
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protocol ShapeGenerator {
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func buildShape() -> Shape
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}
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// `extension`s: Add extra functionality to an already existing type
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extension Square: Printable {
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var description: String {
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return "Area: \(self.getArea()) - ID: \(self.identifier)"
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}
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}
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println("Square: \(mySquare)")
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// Generics: Similar to Java. Use the `where` keyword to specify the
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// requirements of the generics.
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func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? {
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for (index, value) in enumerate(array) {
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if value == valueToFind {
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return index
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}
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}
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return nil
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}
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```
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