Radix sort with nice helper functions

radix.py

#!/usr/bin/env python

from math import log, ceil

def get_longest(array):
    return int(ceil(log(max(array), 10)))

def get_digit(number,digit):
    return number / (10 ** digit) % 10

def get_bins():
    return [[] for i in range(10)]

def merge_bins(bins):
    return [i for sub in bins for i in sub]

def sort_on_digit(array,digit):
    bins = get_bins()
    for number in array:
        bins[get_digit(number, digit)].append(number)
    return merge_bins(bins)

def radix_sort(array):
    length = get_longest(array)
    for digit in range(length + 1):
        array = sort_on_digit(array, digit)
    return array

if __name__ == '__main__':
    import sys
    array = range(30, -1, -1)
    #array = [403, 25, 23, 1000, 800, 101, 16, 15, 2]
    print radix_sort(array)