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Merge pull request #3129 from shuliang/master
[Swift/zh-cn] update to swift 4.1
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commit
73a5e522f4
@ -110,7 +110,7 @@ anyObjectVar = "Changed value to a string, not good practice, but possible."
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//
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// Mark: 数组与字典(关联数组)
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// MARK: 数组与字典(关联数组)
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//
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/*
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@ -214,9 +214,9 @@ func greet(name: String, day: String) -> String {
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}
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greet("Bob", day: "Tuesday")
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// 第一个参数表示外部参数名和内部参数名使用同一个名称。
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// 第一个参数`_`表示不使用外部参数名,忽略`_`表示外部参数名和内部参数名使用同一个名称。
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// 第二个参数表示外部参数名使用 `externalParamName` ,内部参数名使用 `localParamName`
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func greet2(requiredName requiredName: String, externalParamName localParamName: String) -> String {
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func greet2(_ requiredName: String, externalParamName localParamName: String) -> String {
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return "Hello \(requiredName), the day is \(localParamName)"
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}
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greet2(requiredName:"John", externalParamName: "Sunday") // 调用时,使用命名参数来指定参数的值
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@ -250,7 +250,7 @@ var increment = makeIncrementer()
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increment(7)
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// 强制进行指针传递 (引用传递),使用 `inout` 关键字修饰函数参数
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func swapTwoInts(inout a: Int, inout b: Int) {
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func swapTwoInts(a: inout Int, b: inout Int) {
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let tempA = a
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a = b
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b = tempA
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@ -521,7 +521,7 @@ class MyShape: Rect {
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// 在 optional 属性,方法或下标运算符后面加一个问号,可以优雅地忽略 nil 值,返回 nil。
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// 这样就不会引起运行时错误 (runtime error)
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if let reshape = self.delegate?.canReshape?() where reshape {
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if let reshape = self.delegate?.canReshape?() {
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// 注意语句中的问号
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self.delegate?.reshape?()
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}
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@ -575,10 +575,10 @@ print(foundAtIndex == 2) // true
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// 自定义运算符可以以下面的字符打头:
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// / = - + * % < > ! & | ^ . ~
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// 甚至是 Unicode 的数学运算符等
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prefix operator !!! {}
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prefix operator !!!
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// 定义一个前缀运算符,使矩形的边长放大三倍
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prefix func !!! (inout shape: Square) -> Square {
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prefix func !!! (shape: inout Square) -> Square {
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shape.sideLength *= 3
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return shape
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}
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@ -591,8 +591,8 @@ print(mySquare.sideLength) // 4
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print(mySquare.sideLength) // 12
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// 运算符也可以是泛型
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infix operator <-> {}
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func <-><T: Equatable> (inout a: T, inout b: T) {
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infix operator <->
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func <-><T: Equatable> (a: inout T, b: inout T) {
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let c = a
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a = b
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b = c
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