Bubble Sort

number_list = [64,23,122,334,631,233,142,144,233,563,253,127,436,139,064,375,175,137,127]
MAX_ROUND = len(number_list)

def swap(pos1,pos2):
    global number_list
    tmp1,tmp2 = number_list[pos1],number_list[pos2]
    number_list[pos1],number_list[pos2] = tmp2,tmp1

for time in range(1,MAX_ROUND):
    for pos in range(MAX_ROUND-time):
        if number_list[pos] > number_list[pos+1]:
            swap(pos,pos+1)
print number_list