文档 https://itunes.apple.com/us/book/the-swift-programming-language/id881256329?mt=11 http://download.csdn.net/detail/surfsky/7440835 helloWorld println("Hello, world") ------------------------------------------------------------- 基础 ------------------------------------------------------------- 注释 // /**/ 分号 单行无需加分号 多个语句放在一行,需要加分号 变量 var myVariable = 42 常量 let myConstant = 42 let explicitDouble: Double = 70 ------------------------------------------------------------- 数据类型 ------------------------------------------------------------- 数字类型 类型 Int: Int32, Int64 UInt: UInt32, Uint64 Double Float 各种表示方法 let decimalInteger = 17 let binaryInteger = 0b10001 // 17 in binary notation let octalInteger = 0o21 // 17 in octal notation let hexadecimalInteger = 0x11 // 17 in hexadecimal notation let decimalDouble = 12.1875 let exponentDouble = 1.21875e1 let hexadecimalDouble = 0xC.3p0 let paddedDouble = 000123.456 let oneMillion = 1_000_000 布尔(boolean) let orangesAreOrange = true let turnipsAreDelicious = false 向量 let (statusCode, statusMessage) = (404, "Not Found") let (x, y) = (1, 2) let http200Status = (statusCode: 200, description: "OK") println("The status code is \(http200Status.statusCode)") 字符串 let label = "The width is " let width = 94 let widthLabel = label + String(width) 字符串相加 let apples = 3 let oranges = 5 let appleSummary = "I have \(apples) apples." let fruitSummary = "I have \(apples + oranges) pieces of fruit." 数组 var shoppingList = ["catfish", "water", "tulips", "blue paint"] shoppingList[1] = "bottle of water" var occupations = ["Malcolm": "Captain", "Kaylee": "Mechanic",] occupations["Jayne"] = "Public Relations" let emptyArray = String[]() shoppingList = [] 字典 let emptyDictionary = Dictionary<String, Float>() emptyDictionary = [:] 空(nil)和可为空对象 var serverResponseCode: Int? = 404 serverResponseCode = nil ---------------------------------------------- let possibleString: String? = "An optional string." println(possibleString!) let assumedString: String! = "An implicitly unwrapped optional string." println(assumedString) ------------------------------------------------------------- 数据流 ------------------------------------------------------------- if if i == 1 { // this example will compile successfully } switch let vegetable = "red pepper" switch vegetable { case "celery": let vegetableComment = "Add some raisins and make ants on a log." case "cucumber", "watercress": let vegetableComment = "That would make a good tea sandwich." case let x where x.hasSuffix("pepper"): let vegetableComment = "Is it a spicy \(x)?" default: let vegetableComment = "Everything tastes good in soup." } for var firstForLoop = 0 for var i = 0; i < 3; ++i { firstForLoop += 1 } for i in 0..3 { firstForLoop += i } for(遍历数组) let individualScores = [75, 43, 103, 87, 12] var teamScore = 0 for score in individualScores { if score > 50 { teamScore += 3 } else { teamScore += 1 } } for(遍历字典) let interestingNumbers = [ "Prime": [2, 3, 5, 7, 11, 13], "Fibonacci": [1, 1, 2, 3, 5, 8], "Square": [1, 4, 9, 16, 25], ] var largest = 0 for (kind, numbers) in interestingNumbers { for number in numbers { if number > largest { largest = number } } } while var n = 2 while n < 100 { n = n * 2 } do...while var m = 2 do { m = m * 2 } while m < 100 断言(assert) let age = -3 assert(age >= 0, "A person‘s age cannot be less than zero") ------------------------------------------------------------- 函数 ------------------------------------------------------------- 函数定义和调用 func greet(name: String, day: String) -> String { return "Hello \(name), today is \(day)." } greet("Bob", "Tuesday") 返回多个数据 func getGasPrices() -> (Double, Double, Double) { return (3.59, 3.69, 3.79) } getGasPrices() 不限个数参数 func sumOf(numbers: Int...) -> Int { var sum = 0 for number in numbers { sum += number } return sum } sumOf() sumOf(42, 597, 12) 嵌套函数 func returnFifteen() -> Int { var y = 10 func add() { y += 5 } add() return y } returnFifteen() 返回函数变量 func makeIncrementer() -> (Int -> Int) { func addOne(number: Int) -> Int { return 1 + number } return addOne } var increment = makeIncrementer() increment(7) 函数作为输入参数(类似lambda表达式) func hasAnyMatches(list: Int[], condition: Int -> Bool) -> Bool { for item in list { if condition(item) { return true } } return false } func lessThanTen(number: Int) -> Bool { return number < 10 } var numbers = [20, 19, 7, 12] hasAnyMatches(numbers, lessThanTen) 闭包 numbers.map({ (number: Int) -> Int in let result = 3 * number return result }) 用编号替代名字 sort([1, 5, 3, 12, 2]) { $0 > $1 } ------------------------------------------------------------- 对象和类 ------------------------------------------------------------- 类定义 class Shape { var numberOfSides: Int = 0 var name: String init(name: String) { self.name = name } func simpleDescription() -> String { return "A shape with \(numberOfSides) sides." } } 使用 var shape = Shape() shape.numberOfSides = 7 var shapeDescription = shape.simpleDescription() self/super self -> this super -> parent 继承 class Square: NamedShape { var sideLength: Double init(sideLength: Double, name: String) { self.sideLength = sideLength super.init(name: name) numberOfSides = 4 } func area() -> Double { return sideLength * sideLength } override func simpleDescription() -> String { return "A square with sides of length \(sideLength)." } } let test = Square(sideLength: 5.2, name: "my test square") test.area() test.simpleDescription() 属性 var perimeter: Double { get {return 3.0 * sideLength} set {sideLength = newValue / 3.0} } 方法重载 override func simpleDescription() -> String { return "An equilateral triagle with sides of length \(sideLength)." } willSet和didSet(属性的值设置前后处理) var triangle: EquilateralTriangle { willSet { square.sideLength = newValue.sideLength } } 可为空对象方法调用 let optionalSquare: Square? = Square(sideLength: 2.5, name: "optional square") let sideLength = optionalSquare?.sideLength 泛型
struct Pair<T: Equatable> { let a: T! let b: T! init(a: T, b: T) { self.a = a self.b = b } func equal() -> Bool { return a == b } } let pair = Pair(a: 5, b: 10) pair.a // 5 pair.b // 10 pair.equal() // false let floatPair = Pair(a: 3.14159, b: 2.0) floatPair.a // 3.14159 floatPair.b // 2.0 floatPair.equal() // false
------------------------------------------------------------- 枚举和结构体 ------------------------------------------------------------- 枚举 enum Rank: Int { case Ace = 1 case Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten case Jack, Queen, King func simpleDescription() -> String { switch self { case .Ace: return "ace" case .Jack: return "jack" case .Queen: return "queen" case .King: return "king" default: return String(self.toRaw()) } } } let ace = Rank.Ace let aceRawValue = ace.toRaw() if let convertedRank = Rank.fromRaw(3) { let threeDescription = convertedRank.simpleDescription() } 看得有点晕 enum ServerResponse { case Result(String, String) case Error(String) } let success = ServerResponse.Result("6:00 am", "8:09 pm") let failure = ServerResponse.Error("Out of cheese.") switch success { case let .Result(sunrise, sunset): let serverResponse = "Sunrise is at \(sunrise) and sunset is at \(sunset)." case let .Error(error): } 结构体 struct Card { var rank: Rank var suit: Suit func simpleDescription() -> String { return "The \(rank.simpleDescription()) of \(suit.simpleDescription())" } } let threeOfSpades = Card(rank: .Three, suit: .Spades) let threeOfSpadesDescription = threeOfSpades.simpleDescription()
时间: 2024-11-08 22:26:01