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  • Swift 语言概览 -自己在Xcode6 动手写1

    Swift是什么?

    Swift是苹果于WWDC 2014发布的编程语言,这里引用The Swift Programming Language的原话:

    Swift is a new programming language for iOS and OS X apps that builds on the best of C and Objective-C, without the constraints of C compatibility.

    Swift adopts safe programming patterns and adds modern features to make programming easier, more flexible and more fun.

    Swift’s clean slate, backed by the mature and much-loved Cocoa and Cocoa Touch frameworks, is an opportunity to imagine how software development works.

    Swift is the first industrial-quality systems programming language that is as expressive and enjoyable as a scripting language.

    简单的说:

    1. Swift用来写iOS和OS X程序。(估计也不会支持其它屌丝系统)
    2. Swift吸取了C和Objective-C的优点,且更加强大易用。
    3. Swift可以使用现有的Cocoa和Cocoa Touch框架。
    4. Swift兼具编译语言的高性能(Performance)和脚本语言的交互性(Interactive)。

    Swift语言概览

    // Playground - noun: a place where people can play
    
    import Cocoa
    
    var str = "Hello, playground"
    var str1 = "Hello Wrold!!!"
    var str2 = "O(∩_∩)O哈哈~"
    
    // Hello, world
    println("Hello, world")
    
    
    // 变量与常量
    // Swift 使用 var 声明 变量 , let 声明常量
    var myVariable = 42
    myVariable = 50
    let myConstant = 42
    
    // 类型推导
    let explicitDouble : Double = 70
    
    // Swift 不支持隐式 类型转换 (所以需要显式类型转换)
    let label = "The width is"
    let width = 94
    let width1 = label + String(width)
    
    // 使用 (item) 的形式进行 字符串格式化
    let apples = 3
    let orages = 5
    let sum = "I have (apples) apples."
    let sum1 = "I have (apples + orages) pieces of fruit."
    
    // 数组和字典
    // Swift 使用[] 操作符声明 数组(array)和字典 (dictionary)
    var listArr = ["fish","water","apple","rice"]
    listArr[1] = "bottle of water"
    
    var dict = [
        "name": "melody",
        "age" : "26",
    
    ]
    dict["sex"] = "female"
    
    // 一般使用初始化器(initializer)语法创建空数组和空字典
    
    let emptyArray = String[]()
    let emptyDict = Dictionary<String, Float>()

    Xcode贴图

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  • 原文地址:https://www.cnblogs.com/yaoji/p/3765789.html
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