Array random take extension

RandomExtension.swift

import Foundation

extension Array {
    
    func random2(_ lower: Int, _ upper: Int) -> Int {
        return random() % (upper - lower) + lower
    }

    func randomTake<T>(_ n: Int) -> [T] {
    
        var take = [T]()
        
        var index = 0
        for x in self {
            if index < n {
                take.append(x as! T)
            }
            else {
                let pos = random2(0, index) 
                if  pos < n {
                    take[pos] = x as! T
                }
            }
            index += 1
        }
        return take
    }
    
    mutating func shuffle () {
        for i in 0 ..< self.endIndex - 2 {
            let x = random2(i, self.endIndex)
            //let x = random2(0, i+3)
            let temp = self[i]
            self[i] = self[x]
            self[x] = temp
        }
    }
    
    mutating func shuffle2 (){
        for _ in 0 ..< self.endIndex {
            let x = random2(0, self.endIndex)
            let y = random2(0, self.endIndex)
            
            let temp = self[x]
            self[x] = self[y]
            self[y] = temp
        }
    }
}
 
var list : [Int] = [0,1,2,3,4,5,6,7,8,9]

var count : [[Int]] = []
for x in 0 ..< 10 {
    count.append([0,0,0,0,0,0,0,0,0,0])
}

for x in 0..<50 {
    list.shuffle()
    for x in 0 ..< list.endIndex {
        count[x][list[x]] += 1
    }
}
for x in 0 ..< 10 {
    print(count[x])
}