Swift語言特性及基本數據類型

Today ，蘋果剛剛發布了Swift語言，我們來看下Swift的幾個主要特性：

        1         Safe

• • func configureLabels(labels: UILabel[]) {

  •    let labelTextColor = UIColor.greenColor()

  •    for label in labels {

  •        // label inferred to be UILabel

  •        label.textColor = labelTextColor

  •    }

  • }

  • 2        Modern

  • let cities = ["London", "San Francisco", "Tokyo", "Barcelona", "Sydney"]

  • let sortedCities = sort(cities) { $0 < $1 }

  • if let indexOfLondon = find(sortedCities, "London") {

       println("London is city number \(indexOfLondon + 1) in the list")

    }

    3        Powerful:

• let size = (20, 40)

• switch size {

• case let (width, height) where width == height:

•    println("square with sides \(width)")

• case (1..10, 1..10):

•    println("small rectangle")

• case let (width, height):

•    println("rectangle with width \(width) and height \(height)")

• }

                  4            Interactive 

                  5              Fast。

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基本數據類型：

 1 簡單屬性：

                  let：  恒定常量

                  var：可變常量

                        1.1 定義常量不用指定其固定類型，編譯器會處理，如需更多識別，請添加前綴：

                        let implicitInteger = 70

                        let implicitDouble = 70.0

                        let explicitDouble: Double = 70

                        println("int:\(implicitInteger)  double:\(implicitDouble) explicitDoubledss:\(explicitDouble)");

2  類型之間的轉化,必須是顯示的：

                        let label = "width is :";

                        let width = 54;

                        let widthLabel = label + String(width)

                        println("LabelWidth:\(widthLabel)");

 3    使用反斜杠在String中插入內容，代碼參考2 

 4   使用中括號創建數組和字典：

        var shoppingList = ["catfish", "water", "tulips", "blue paint"]

        shoppingList[1] = "bottle of water"

        var occupations = [

            "Malcolm": "Captain",

            "Kaylee": "Mechanic",

        ]

        occupations["Jayne"] = "Public Relations"

        println("array is \(shoppingList)")

        println("dictionary is :\(occupations)")

        //create Empty 

        let emptyArray = String[]()

        let emptyDictionary = Dictionary<String, Float>()

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