快速洗牌()

如果你看 Array.shuffled () -> [T] :

Array.shuffled数组 可以写成

(([T]) -> (() -> [T]))

然后我们可以将其用作参数类型:

func testShuffle<T>(array: [T], function: (([T]) -> (() -> [T])) = Array.shuffled) {
    let shuffleFunction = function(array)
    let shuffledArray = shuffleFunction()
    // do stuff with shuffledArray...
}

// usage
extension Array {
    func myCustomShuffled() -> [Element] {
        // ...
    }
}

let arr = [1,2,3,4,5,6,7]
testShuffle(array: arr, function: Array.myCustomShuffled)

请注意,相同的方法不适用于 Array.shuffle

也可以将参数类型写入 ([T]) -> [T] ,则必须像这样传递默认参数:

func testShuffle<T>(array: [T], function: ([T]) -> [T] = { $0.shuffled() }) {
    let shuffledArray = function(array)
}