ISBN, the International Standard Book Number, will migrate to 13-digits version from current 10-digits version on 2007-01-01. This recipe converts ISBN-10 to ISBN-13 by regenerating the check digit.
Python, 28 lines
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Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | def check_digit_10(isbn):
assert len(isbn) == 9
sum = 0
for i in range(len(isbn)):
c = int(isbn[i])
w = i + 1
sum += w * c
r = sum % 11
if r == 10: return 'X'
else: return str(r)
def check_digit_13(isbn):
assert len(isbn) == 12
sum = 0
for i in range(len(isbn)):
c = int(isbn[i])
if i % 2: w = 3
else: w = 1
sum += w * c
r = 10 - (sum % 10)
if r == 10: return '0'
else: return str(r)
def convert_10_to_13(isbn):
assert len(isbn) == 10
prefix = '978' + isbn[:-1]
check = check_digit_13(prefix)
return prefix + check
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Web Based Implementation. I put this recipe into an online calculator:
http://www.utilitymill.com/utility/ISBN_10_to_ISBN_13_Converter
I hope it's useful.
Small command line utility. Hi,
I've created a small utility based on this module and I've make some changes on the code too. Take a look at:
http://osantana-code.googlecode.com/svn/trunk/others/isbn.py
Thanks, Osvaldo
Thanks a lot! Save me a lot of time ...
Michael