functional_bubble_sort.py

def bubble_sort(ar):
    if len(ar)<=1:
        return ar
    if len(ar)==2:
        return ar if ar[0]<ar[1] else [ar[1],ar[0]]


    a,b,bs=ar[0],ar[1],ar[2:]
    res = []
    if a<b:
        res = [a] + bubble_sort([b]+bs)
    else:
        res = [b] + bubble_sort([a]+bs)
    return bubble_sort(res[:-1]) + res[-1:]