工作! !生物体是要洗牌的数组。

extension Array
{
    /** Randomizes the order of an array's elements. */
    mutating func shuffle()
    {
        for _ in 0..<10
        {
            sort { (_,_) in arc4random() < arc4random() }
        }
    }
}

var organisms = [
    "ant",  "bacteria", "cougar",
    "dog",  "elephant", "firefly",
    "goat", "hedgehog", "iguana"]

print("Original: \(organisms)")

organisms.shuffle()

print("Shuffled: \(organisms)")

在Swift 2.0中，GameplayKit可能会来拯救你!(iOS9或更高版本支持)

import GameplayKit

func shuffle() {
    array = GKRandomSource.sharedRandom().arrayByShufflingObjectsInArray(array)
}

swift 4.2有两个方便的功能:

// shuffles the array in place
myArray.shuffle()

and

// generates a new array with shuffled elements of the old array
let newArray = myArray.shuffled()

这里有一些可能更短的内容:

sorted(a) {_, _ in arc4random() % 2 == 0}

你也可以使用通用交换函数，实现前面提到的Fisher-Yates:

for idx in 0..<arr.count {
  let rnd = Int(arc4random_uniform(UInt32(idx)))
  if rnd != idx {
    swap(&arr[idx], &arr[rnd])
  }
}

或者更简洁:

for idx in 0..<steps.count {
  swap(&steps[idx], &steps[Int(arc4random_uniform(UInt32(idx)))])
}

斯威夫特4 在for循环中洗牌数组的元素，其中i是混合比例

var cards = [Int]() //Some Array
let i = 4 // is the mixing ratio
func shuffleCards() {
    for _ in 0 ..< cards.count * i {
        let card = cards.remove(at: Int(arc4random_uniform(UInt32(cards.count))))
        cards.insert(card, at: Int(arc4random_uniform(UInt32(cards.count))))
    }
}

或者扩展为Int

func shuffleCards() {
    for _ in 0 ..< cards.count * i {
        let card = cards.remove(at: cards.count.arc4random)
        cards.insert(card, at: cards.count.arc4random)
    }
}
extension Int {
    var arc4random: Int {
        if self > 0 {
            print("Arc for random positiv self \(Int(arc4random_uniform(UInt32(self))))")
        return Int(arc4random_uniform(UInt32(self)))
        } else if self < 0 {
            print("Arc for random negotiv self \(-Int(arc4random_uniform(UInt32(abs(self)))))")
            return -Int(arc4random_uniform(UInt32(abs(self))))
        } else {
            print("Arc for random equal 0")
            return 0
        }
    }
}