Randomize two arrays the same way Swift

Question

I know there is a new shuffle method with iOS 9 but I am wondering if there is anyway to shuffle two arrays the same way?

For example

[1         


        

Answer 1

I'm unaware of any built-in shuffle mechanism in Swift 2.0. Assuming this doesn't exist, I borrowed some code from here.

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

extension MutableCollectionType where Index == Int {
    /// Shuffle the elements of `self` in-place.
    mutating func shuffleInPlace() {
        // empty and single-element collections don't shuffle
        if count < 2 { return }

        for i in 0..

This solves the problem in a really straight forward way. It creates an array, shuffleOrder, that just has an index for each possible index in the starting arrays. It then shuffles these indices to create a random sampling order. Finally, it constructs two new arrays, based off of the starting arrays, sampling them with the shuffled values. While this doesn't mutate the original 2 arrays in place, it would be simple to modify this to do so.