首先来设置一个原始的字符串，
Python 3.2.3 (default, Apr 11 2012, 07:15:24) [MSC v.1500 32 bit (Intel)] on win32
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>>> website = 'http://www.cnblogs.com/txw1958/'
>>> type(website)
<class 'str'>
>>> website
'http://www.cnblogs.com/txw1958/'
>>>
按utf-8的方式编码，转成bytes
>>> website_bytes_utf8 = website.encode(encoding="utf-8")
>>> type(website_bytes_utf8)
<class 'bytes'>
>>> website_bytes_utf8
b'http://www.cnblogs.com/txw1958/'
>>>
按gb2312的方式编码，转成bytes
>>> website_bytes_gb2312 = website.encode(encoding="gb2312")
>>> type(website_bytes_gb2312)
<class 'bytes'>
>>> website_bytes_gb2312
b'http://www.cnblogs.com/txw1958/'
>>>
解码成string，默认不填
>>> website_string = website_bytes_utf8.decode()
>>> type(website_string)
<class 'str'>
>>> website_string
'http://www.cnblogs.com/txw1958/'
>>>
>>>
解码成string，使用gb2312的方式
>>> website_string_gb2312 = website_bytes_gb2312.decode("gb2312")
>>> type(website_string_gb2312)
<class 'str'>
>>> website_string_gb2312
'http://www.cnblogs.com/txw1958/'
>>>
