swift學習－閉包

// Playground - noun: a place where people can playimport Cocoavar str = "Hello, playground"/*閉包*/let names = ["chris","Alex","Ewa","Barry","Daniella"]func backwards(s1:String,s2:String) -> Bool {    return s1>s2}//排序var reversed = sort(names)var reversed1 = sort(names,backwards)//閉包運算式文法var reversed2 = sort(names,{(s1:String,s2:String) -> Bool in        return s1 > s2    })//省去參數類型,var reversed3 = sort(names,{s1,s2 in return s1 > s2})//單運算式閉包隱式返回，省去returnvar reversed4 = sort(names,{s1,s2 in s1 > s2})//參數名縮寫var reversed5 = sort(names,{$0 > $1})//運算子函數var reversed6 = sort(names,>)//尾隨閉包var reversed7 = sort(names){$0>$1}reversed7[0]let digitNames = [    0: "Zero", 1: "One", 2: "Two",   3: "Three", 4: "Four",    5: "Five", 6: "Six", 7: "Seven", 8: "Eight", 9: "Nine"]let numbers = [16, 58, 510]let strings = numbers.map {    (var number) -> String in    var output = ""    while number > 0 {        output = digitNames[number % 10]! + output        number /= 10    }    return output}strings[0]strings[1]//捕獲值func makeIncrementor(forIncrement amount: Int) -> () -> Int {    var runningTotal = 0    func incrementor() -> Int {        runningTotal += amount        return runningTotal    }    return incrementor}//函數有int類型的參數，外部命名forIncrement,內部命名amount