如何防止函数在Swift 4中生成相同的随机数集

Question

我开发了一些代码来生成五个数组，每个数组包含1到49之间的六个数字。我使用arc4random_uniform(49)函数来尝试这样做。但是，当appendArrays()为所有五个循环生成相同的数字集时。

 class six49: lottery {

    var price: Int
    var winner: [Int] = []

    override init(draws: Int, lines: Int){

        price = 3
        super.init(draws: draws, lines: lines)
        }

    func appendArrays(win: inout [Int], win2: inout [[Int]]) -> [[Int]] {

        while win2.count < lines {

            while win.count < 6 {

                let selection = arc4random_uniform(49)

                if win.contains(Int(selection)){
                    continue
                } else {
                    win.append(Int(selection))
                    win = win.sorted()

                }
            }

            win2.append(win)

        }

        return win2

    }

}


let result = six49(draws: 1, lines: 5)

var arr2: [[Int]] = []
var arr1: [Int] = []
var collection = result.appendArrays(win: &arr1,win2: &arr2)

print(collection)

这是输出：

  <[，[11,16,27,31,37,39]，[11,16,27,31,37,39]，[11,16,27,31,37,39]，[11,16] ，27,31,37,39]，[11,16,27,31,37,39]]

我一直在寻找每个循环尝试创建不同的数字集，但我似乎无法找到任何解决方案。