a *= b not equivalent to a = a*b

[mlz]

I've been playing with the binomial function, and found that in the below code, rs *= x does not behave the same way as rs = rs * x. When I set FAIL to True, I get a different result.  Both results are below.

I had read that the two were equivalent. What am I missing?

thanks,
  -= miles =-


#!/usr/bin/python2

import sys
FAIL= True if len(sys.argv)>1 else False

def bin(n,k):
    rs=1
    k=min(k,n-k)
    
    for i in range(1,k+1):
        if FAIL: rs *= (n-(i-1))/i  # these should be the same, 
        else: rs = rs * (n-(i-1))/i  #  but apparently are not
    return rs
        
        
for n in range(10):
    for k in range(n+1):
        print bin(n,k),
    print''
       
------------------- output -------------------------


$ pascal2
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1
1 6 15 20 15 6 1
1 7 21 35 35 21 7 1
1 8 28 56 70 56 28 8 1
1 9 36 84 126 126 84 36 9 1

$ pascal2 fail
1
1 1
1 2 1
1 3 3 1
1 4 4 4 1
1 5 10 10 5 1
1 6 12 12 12 6 1
1 7 21 21 21 21 7 1
1 8 24 48 48 48 24 8 1
1 9 36 72 72 72 72 36 9 1