Python2的編解碼
python2中程序數據類型默認為ASCII，所以需要先將數據解碼（decode）成為Unicode類型，然后再編碼（encode）成為想要轉換的數據類型（gbk，utf-8，gb18030，gb2312），然后再解碼成為對應的數據類型顯示在屏幕上；
Python3的編解碼
python3中程序默認數據類型為Unicode，所以直接將數據編碼（encode）成為想要轉換的數據類型（gbk，utf-8，gb18030，gb2312），然后解碼成為對應的數據類型顯示在屏幕上。
base64
Base64編碼是一種“防君子不防小人”的編碼方式。廣泛應用於MIME協議，作為電子郵件的傳輸編碼，生成的編碼可逆，后一兩位可能有“=”，生成的編碼都是ascii字符。
因此對於python2來說，編解碼相對要容易一些。python3因為要從Unicode轉換一下，相對麻煩一些。一切見下例：
- Python2
1 def b64encode(s, altchars=None): 2 """Encode a string using Base64. 3 4 s is the string to encode. Optional altchars must be a string of at least 5 length 2 (additional characters are ignored) which specifies an 6 alternative alphabet for the '+' and '/' characters. This allows an 7 application to e.g. generate url or filesystem safe Base64 strings. 8 9 The encoded string is returned. 10 """ 11 # Strip off the trailing newline 12 encoded = binascii.b2a_base64(s)[:-1] 13 if altchars is not None: 14 return encoded.translate(string.maketrans(b'+/', altchars[:2])) 15 return encoded
1 def b64decode(s, altchars=None): 2 """Decode a Base64 encoded string. 3 4 s is the string to decode. Optional altchars must be a string of at least 5 length 2 (additional characters are ignored) which specifies the 6 alternative alphabet used instead of the '+' and '/' characters. 7 8 The decoded string is returned. A TypeError is raised if s is 9 incorrectly padded. Characters that are neither in the normal base-64 10 alphabet nor the alternative alphabet are discarded prior to the padding 11 check. 12 """ 13 if altchars is not None: 14 s = s.translate(string.maketrans(altchars[:2], '+/')) 15 try: 16 return binascii.a2b_base64(s) 17 except binascii.Error, msg: 18 # Transform this exception for consistency 19 raise TypeError(msg)
這里面的s是一個字符串類型的對象。
1 import base64 2 3 s = 'Hello, python' 4 b = base64.b64encode(s) 5 print 'b為：', b 6 7 c = base64.b64decode(b) 8 print 'c為：', c 9 10 11 # output 12 b為： SGVsbG8sIHB5dGhvbg== 13 c為： Hello, python
- Python3
1 def b64encode(s, altchars=None): 2 """Encode the bytes-like object s using Base64 and return a bytes object. 3 4 Optional altchars should be a byte string of length 2 which specifies an 5 alternative alphabet for the '+' and '/' characters. This allows an 6 application to e.g. generate url or filesystem safe Base64 strings. 7 """ 8 encoded = binascii.b2a_base64(s, newline=False) 9 if altchars is not None: 10 assert len(altchars) == 2, repr(altchars) 11 return encoded.translate(bytes.maketrans(b'+/', altchars)) 12 return encoded
1 def b64decode(s, altchars=None, validate=False): 2 """Decode the Base64 encoded bytes-like object or ASCII string s. 3 4 Optional altchars must be a bytes-like object or ASCII string of length 2 5 which specifies the alternative alphabet used instead of the '+' and '/' 6 characters. 7 8 The result is returned as a bytes object. A binascii.Error is raised if 9 s is incorrectly padded. 10 11 If validate is False (the default), characters that are neither in the 12 normal base-64 alphabet nor the alternative alphabet are discarded prior 13 to the padding check. If validate is True, these non-alphabet characters 14 in the input result in a binascii.Error. 15 """ 16 s = _bytes_from_decode_data(s) 17 if altchars is not None: 18 altchars = _bytes_from_decode_data(altchars) 19 assert len(altchars) == 2, repr(altchars) 20 s = s.translate(bytes.maketrans(altchars, b'+/')) 21 if validate and not re.match(b'^[A-Za-z0-9+/]*={0,2}$', s): 22 raise binascii.Error('Non-base64 digit found') 23 return binascii.a2b_base64(s)
這里面的s是一個bytes對象，則字符串首先要經過編碼encode()。經過b64encode/b64decode之后的返回結果也是bytes對象，所以我們要轉換為Unicode對象就要再使用decode()方法去解碼。
1 import base64 2 3 s = 'Hello, Python!' 4 b = base64.b64encode(s.encode('utf-8')).decode('utf-8') 5 print(b) 6 7 c = base64.b64decode(b.encode('utf-8')).decode('utf-8') 8 print(c) 9 10 # output 11 SGVsbG8sIFB5dGhvbiE= 12 Hello, Python!