shuffled.playground

import Foundation

extension Array {
    func shuffled() -> [Element] {
        var array = self
        (0..<count).reversed().forEach { i in
            let j = Int(arc4random_uniform(UInt32(i + 1)))
            let tmp = array[i]
            array[i] = array[j]
            array[j] = tmp
        }
        return array
    }
}

let friends = ["serval", "wolf", "python", "cheetah", "brown bear"]
friends.shuffled()[0..<2]