from math import log
 
def getDigit(n, b, k):
    return (n // b ** k) % b  # pulls the selected digit
 
def mkBlanks(k):
    return [ [] for i in range(k) ]  # create a list of empty lists to hold the split by digit
 
def split(l, b, k):
    x = mkBlanks(b)
    for i in l:
        x[getDigit(i, b, k)].append(i)  # append the number to the list selected by the digit
    return x
 
def merge(x): # concatenate the lists back in order for the next step
    l = []
    for sublist in x:
       for item in sublist:
           l.append(item)
    return l
 
def maxAbs(l):
    return max(abs(x) for x in l)  # largest abs value element of a list
 
def radixSort(l, b):
    passes = int(log(maxAbs(l), b) + 1)  # there are as many passes as there are digits in the longest number
    t = list(l)
    for i in range(passes):
        t = merge(split(t, b, i))
    return t

print radixSort([170, 45, 75, -90, 2, 24, -802, 66], 10) ;

[2, 24, 45, 66, 75, 170, -802, -90]