常见的实现，

要熟悉了解，

至于闭包逃逸，

自动闭包这些内容，

可以以后用到时再学吧。

let names = ["Chris", "Alex", "Eva", "Barry", "Daniella"]func backward(_ s1: String, _ s2: String) -> Bool {return s1 < s2
}
var rNames = names.sorted(by: backward)
rNames = names.sorted(by: {(s1: String, s2: String) -> Bool in return s1 > s2
})
rNames = names.sorted(by: {(s1: String, s2: String) -> Bool in return s1 > s2})
rNames = names.sorted(by: {s1, s2 in return s1 > s2})
rNames = names.sorted(by: {s1, s2 in s1 > s2})
rNames = names.sorted(by: {$0 > $1})
rNames = names.sorted(by: >)
rNames = names.sorted(){$0 > $1}
rNames = names.sorted{$0 > $1}print(rNames)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 {(number) -> String in var number = numbervar output = ""repeat {output = digitNames[number % 10]! + outputnumber /= 10} while number > 0return output
}print(strings)func makeIncrementer(forIncrement amount: Int) -> () -> Int {var runningTotal = 0func incrementer() -> Int {runningTotal += amountreturn runningTotal}return incrementer
}let incrementByTen = makeIncrementer(forIncrement: 10)
print(incrementByTen())
print(incrementByTen())
print(incrementByTen())
print(incrementByTen())