How to multiply correctly in my situation

Question

def polmul(n1,n2):
      n1 = int (n1, 2)
      s = int ('0', 2)
      for c in n2 [:: -1]:
            if (c == '1'):
                 s = s ^ n1
            n1*=2
      Bin_out = bin(s)[2:].zfill(2)
      Mul = str(Bin_out)
      return Mul
n1 = '0000011'
n2 = '100010111'
x = polmul(n1,n2)

(result is 1100111001)

It is skipping zeros at the beginning. I need result 000001100111001 Please help

are you multiplying polynomials in GF(2)? would be nice if you mentioned that... — hiro protagonist, Feb 26 '18 at 09:35
Possible duplicate of [Convert to binary and keep leading zeros in Python](https://stackoverflow.com/questions/16926130/convert-to-binary-and-keep-leading-zeros-in-python) — gizzmole, Feb 26 '18 at 10:38

gizzmole · Accepted Answer · 2018-02-26T10:33:48.507

0

Bin_out = bin(s)[2:].zfill(15)

will do the trick, since *.zfill(fill_width) pads string on the left with zeros to fill_width (fill_width=15 in your case)

edited Feb 26 '18 at 10:33

answered Feb 26 '18 at 09:31

gizzmole

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While this code may answer the question, providing additional context regarding why and/or how this code answers the question improves its long-term value. – rollstuhlfahrer Feb 26 '18 at 09:52

How to multiply correctly in my situation

1 Answers1