python3中bytes与string的互相转换

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
 Type "help", "copyright", "credits" or "license" for more information.
 >>> 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/'
 >>>