decimal to base conversion

gistfile1.py

#rem: int, int -> int
#print the remainder of (x/n)
def rem(x,n):
    #prevent division by zero
    assert(n != 0)    
    return x % n

def dec2b (xIn,b):
    """ Convert n from base 10 (decimal) to base b, printing steps and result. """
    assert(b > 1)
    result = []
    while(xIn > 0):
        print xIn, '/', b, ' R', rem(xIn,b)
        xIn,r = divmod(xIn,b)
        result.append(r)
    printResult = ''.join(map(str,result))[::-1]
    return printResult
#TODO: Implement hexadecimal lettering!!!

#example: prints conversions of 2^1, 2^2, 2^3 to their binary format.
#easy to verify - 2 ^ x in binary is 1 followed by x zeros
for x in range(1,4):
    print 2**x,':\n'
    print dec2b(2**x,2),'\n'

output:

2 :

2 / 2 R 0
1 / 2 R 1
10

4 :

4 / 2 R 0
2 / 2 R 0
1 / 2 R 1
100

8 :

8 / 2 R 0
4 / 2 R 0
2 / 2 R 0
1 / 2 R 1
1000