The Quicksort algorithm

Quicksort.py

def quicksort(a):
    if len(a) <= 1: return a
    pivot = a.pop(len(a)/2)
    less, greater = [], []
    for x in a:
        if x <= pivot:
            less.append(x)
        else:
            greater.append(x)
    return quicksort(less) + [pivot] + quicksort(greater)