Python base 36 encoding

Question

How can I encode an integer with base 36 in Python and then decode it again?

Answer 1

This works if you only care about positive integers.

def int_to_base36(num):
    """Converts a positive integer into a base36 string."""
    assert num >= 0
    digits = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'

    res = ''
    while not res or num > 0:
        num, i = divmod(num, 36)
        res = digits[i] + res
    return res

To convert back to int, just use int(num, 36). For a conversion of arbitrary bases see https://gist.github.com/mbarkhau/1b918cb3b4a2bdaf841c