SWIFT 4

func createShuffledSequenceOfNumbers(max:UInt)->[UInt] {

    var array:[UInt]! = []
    var myArray:[UInt]! = []
    for i in 1...max {
        myArray.append(i)
    }
    for i in 1...max {
        array.append(i)
    }
    var tempArray:[Int]! = []
    for index in 0...(myArray.count - 1) {

        var isNotFinded:Bool = true
        while(isNotFinded){

            let randomNumber = arc4random_uniform(UInt32(myArray.count))
            let randomIndex = Int(randomNumber)

            if(!tempArray.contains(randomIndex)){
                tempArray.append(randomIndex)

                array[randomIndex] = myArray[index]
                isNotFinded = false
            }
        }
    }

    return array
}

这是我所使用的:

import GameplayKit

extension Collection {
    func shuffled() -> [Iterator.Element] {
        let shuffledArray = (self as? NSArray)?.shuffled()
        let outputArray = shuffledArray as? [Iterator.Element]
        return outputArray ?? []
    }
    mutating func shuffle() {
        if let selfShuffled = self.shuffled() as? Self {
            self = selfShuffled
        }
    }
}

// Usage example:

var numbers = [1,2,3,4,5]
numbers.shuffle()

print(numbers) // output example: [2, 3, 5, 4, 1]

print([10, "hi", 9.0].shuffled()) // output example: [hi, 10, 9]

这是如何在Swift 3.0中洗牌一个种子数组。

extension MutableCollection where Indices.Iterator.Element == Index {
    mutating func shuffle() {
        let c = count
        guard c > 1 else { return }


        for (firstUnshuffled , unshuffledCount) in zip(indices, stride(from: c, to: 1, by: -1)) {
            srand48(seedNumber)
            let number:Int = numericCast(unshuffledCount)
            let r = floor(drand48() * Double(number))

            let d: IndexDistance = numericCast(Int(r))
            guard d != 0 else { continue }
            let i = index(firstUnshuffled, offsetBy: d)
            swap(&self[firstUnshuffled], &self[i])
        }
    }
}

以Nate的算法为例，我想看看Swift 2和协议扩展会是什么样子。

这是我想到的。

extension MutableCollectionType where Self.Index == Int {
    mutating func shuffleInPlace() {
        let c = self.count
        for i in 0..<(c - 1) {
            let j = Int(arc4random_uniform(UInt32(c - i))) + i
            swap(&self[i], &self[j])
        }
    }
}

extension MutableCollectionType where Self.Index == Int {
    func shuffle() -> Self {
        var r = self
        let c = self.count
        for i in 0..<(c - 1) {
            let j = Int(arc4random_uniform(UInt32(c - i))) + i
            swap(&r[i], &r[j])
        }
        return r
    }
}

现在，任何MutableCollectionType都可以使用这些方法，因为它使用Int作为索引

这里有一些可能更短的内容:

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

这是Nate为Swift 4实现的Fisher-Yates shuffle的一个版本 (Xcode 9)。

extension MutableCollection {
    /// Shuffle the elements of `self` in-place.
    mutating func shuffle() {
        for i in indices.dropLast() {
            let diff = distance(from: i, to: endIndex)
            let j = index(i, offsetBy: numericCast(arc4random_uniform(numericCast(diff))))
            swapAt(i, j)
        }
    }
}

extension Collection {
    /// Return a copy of `self` with its elements shuffled
    func shuffled() -> [Element] {
        var list = Array(self)
        list.shuffle()
        return list
    }
}

这些变化是:

约束indexes . iterator . element == Index现在是部分 的收集协议，并且不需要强加于 扩展了。 交换元素必须通过调用集合上的swapAt()来完成， 添加mutableccollection . swapat(_:_:)。 Element是Iterator.Element的别名。