quickselect: function [a k][
    arr: new a
    while ø [
        indx: random 0 (size arr)-1
        pivot: arr\[indx]
        remove 'arr .index indx
        left: select arr 'item -> item<pivot
        right: select arr 'item -> item>pivot

        case [k]
            when? [= size left]-> return pivot
            when? [< size left]-> arr: new left
            else [
                k: (k - size left) - 1
                arr: new right
            ]
    ]
]

v: [9 8 7 6 5 0 1 2 3 4]

print map 0..(size v)-1 'i ->
    quickselect v i