swift 粗略文法

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文檔      https://itunes.apple.com/us/book/the-swift-programming-language/id881256329?mt=11      http://download.csdn.net/detail/surfsky/7440835helloWorld    println("Hello, world")-------------------------------------------------------------基礎-------------------------------------------------------------注釋    //    /**/分號    單行無需加分號    多個語句放在一行,需要加分號變數    var myVariable = 42常量    let myConstant = 42    let explicitDouble: Double = 70-------------------------------------------------------------資料類型-------------------------------------------------------------數字類型    類型          Int: Int32, Int64          UInt: UInt32, Uint64          Double          Float    各種表示方法      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布爾(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)")字串    let label = "The width is "    let width = 94    let widthLabel = label + String(width)    字串相加        let apples = 3        let oranges = 5        let appleSummary = "I have \(apples) apples."        let fruitSummary = "I have \(apples + oranges) pieces of fruit."數組    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)和可為空白對象    var serverResponseCode: Int? = 404    serverResponseCode = nil    ----------------------------------------------        let possibleString: String? = "An optional string."    println(possibleString!)    let assumedString: String! = "An implicitly unwrapped optional string."    println(assumedString)        -------------------------------------------------------------資料流-------------------------------------------------------------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(遍曆數組)    let individualScores = [75, 43, 103, 87, 12]    var teamScore = 0    for score in individualScores {        if score > 50 {            teamScore += 3        } else {            teamScore += 1        }    }    for(遍曆字典)    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        斷言(assert)    let age = -3    assert(age >= 0, "A person‘s age cannot be less than zero")    -------------------------------------------------------------函數-------------------------------------------------------------函數定義和調用    func greet(name: String, day: String) -> String {        return "Hello \(name), today is \(day)."    }    greet("Bob", "Tuesday")返回多個資料    func getGasPrices() -> (Double, Double, Double) {        return (3.59, 3.69, 3.79)    }    getGasPrices()不限個數參數    func sumOf(numbers: Int...) -> Int {        var sum = 0        for number in numbers {            sum += number        }        return sum    }    sumOf()    sumOf(42, 597, 12)嵌套函數    func returnFifteen() -> Int {        var y = 10        func add() {            y += 5        }        add()        return y    }    returnFifteen()返回函數變數    func makeIncrementer() -> (Int -> Int) {        func addOne(number: Int) -> Int {            return 1 + number        }        return addOne    }    var increment = makeIncrementer()    increment(7)函數作為輸入參數(類似lambda運算式)    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)閉包    numbers.map({        (number: Int) -> Int in        let result = 3 * number        return result    })用編號替代名字    sort([1, 5, 3, 12, 2]) { $0 > $1 }-------------------------------------------------------------對象和類-------------------------------------------------------------類定義    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    繼承    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()屬性    var perimeter: Double {        get {return 3.0 * sideLength}        set {sideLength = newValue / 3.0}    }方法重載    override func simpleDescription() -> String {        return "An equilateral triagle with sides of length \(sideLength)."    }willSet和didSet(屬性的值設定前後處理)    var triangle: EquilateralTriangle {        willSet {            square.sideLength = newValue.sideLength        }    }可為空白對象方法調用    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 // 5pair.b // 10pair.equal() // false let floatPair = Pair(a: 3.14159, b: 2.0)floatPair.a // 3.14159floatPair.b // 2.0floatPair.equal() // false

 

-------------------------------------------------------------枚舉和結構體-------------------------------------------------------------枚舉    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()    }看得有點暈    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):    }結構體    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()

swift 粗略文法

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