Python数字38位,64位转换

10进制和38,64进制互转,URL的ID的转换成38或64位的，让地址看起来更短。可使的地方很多,如短链接生成.

38位转换

#!/usr/bin/env python
# -*- coding: utf-8 -*-
__author__ = 'Randy'

def encode_b38(n):
    table = '0123456789abcdefghijklmnopqrstuvwxyz-_'
    result = []
    temp = n
    if 0 == temp:
        result.append('0')
    else:
        while 0 < temp:
            result.append(table[temp % 38])
            temp /= 38
    return ''.join([x for x in reversed(result)])

def decode_b38(str):
    table = {"0": 0, "1": 1, "2": 2, "3": 3, "4": 4, "5": 5,
             "6": 6, "7": 7, "8": 8, "9": 9,
             "a": 10, "b": 11, "c": 12, "d": 13, "e": 14, "f": 15, "g": 16,
             "h": 17, "i": 18, "j": 19, "k": 20, "l": 21, "m": 22, "n": 23,
             "o": 24, "p": 25, "q": 26, "r": 27, "s": 28, "t": 29, "u": 30,
             "v": 31, "w": 32, "x": 33, "y": 34, "z": 35,
             "-": 36, "_": 37}
    result = 0
    for i in xrange(len(str)):
        result *= 38
        result += table[str[i]]
    return result

print encode_b38(123)
# 39
print encode_b38(8456789)
# 424j3
print decode_b38('1l7yex')
# 123456789

64位转换

#!/usr/bin/env python
# -*- coding: utf-8 -*-
__author__ = 'Randy'

def encode_b64(n):
    table = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_'
    result = []
    temp = n
    if 0 == temp:
        result.append('0')
    else:
        while 0 < temp:
            result.append(table[temp % 64])
            temp /= 64
    return ''.join([x for x in reversed(result)])

def decode_b64(str):
    table = {"0": 0, "1": 1, "2": 2, "3": 3, "4": 4, "5": 5,
             "6": 6, "7": 7, "8": 8, "9": 9,
             "a": 10, "b": 11, "c": 12, "d": 13, "e": 14, "f": 15, "g": 16,
             "h": 17, "i": 18, "j": 19, "k": 20, "l": 21, "m": 22, "n": 23,
             "o": 24, "p": 25, "q": 26, "r": 27, "s": 28, "t": 29, "u": 30,
             "v": 31, "w": 32, "x": 33, "y": 34, "z": 35,
             "A": 36, "B": 37, "C": 38, "D": 39, "E": 40, "F": 41, "G": 42,
             "H": 43, "I": 44, "J": 45, "K": 46, "L": 47, "M": 48, "N": 49,
             "O": 50, "P": 51, "Q": 52, "R": 53, "S": 54, "T": 55, "U": 56,
             "V": 57, "W": 58, "X": 59, "Y": 60, "Z": 61,
             "-": 62, "_": 63}
    result = 0
    for i in xrange(len(str)):
        result *= 64
        result += table[str[i]]
    return result

print encode_b64(123)
# 1X
print encode_b64(12345678789459)
# 2PFPPjJj
print decode_b64('7mYQl')
# 123456789