68 

    69 # Base 36 functions: useful for generating compact URLs

    70 

    71 def base36_to_int(s):

    72     """

    73     Convertd a base 36 string to an integer

    74     """

    75     return int(s, 36)

    76 

    77 def int_to_base36(i):

    78     """

    79     Converts an integer to a base36 string

    80     """

    81     digits = "0123456789abcdefghijklmnopqrstuvwxyz"

    82     factor = 0

    83     # Find starting factor

    84     while True:

    85         factor += 1

    86         if i < 36 ** factor:

    87             factor -= 1

    88             break

    89     base36 = []

    90     # Construct base36 representation

    91     while factor >= 0:

    92         j = 36 ** factor

    93         base36.append(digits[i / j])

    94         i = i % j

    95         factor -= 1

    96     return ''.join(base36)