bytes([1,2,3,4,5,6,7,8,9])
bytes("python", 'ascii') # 字符串，编码

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.1sucai.cn/'
>>> type(website)
<class 'str'>
>>> website
'http://www.1sucai.cn/'
>>>

>>> website_bytes_utf8 = website.encode(encoding="utf-8")
>>> type(website_bytes_utf8)
<class 'bytes'>
>>> website_bytes_utf8
b'http://www.1sucai.cn/'
>>>

>>> website_bytes_gb2312 = website.encode(encoding="gb2312")
>>> type(website_bytes_gb2312)
<class 'bytes'>
>>> website_bytes_gb2312
b'http://www.1sucai.cn/'
>>>

>>> website_string = website_bytes_utf8.decode()
>>> type(website_string)
<class 'str'>
>>> website_string
'http://www.1sucai.cn/'
>>>
>>>

>>> website_string_gb2312 = website_bytes_gb2312.decode("gb2312")
>>> type(website_string_gb2312)
<class 'str'>
>>> website_string_gb2312
'http://www.1sucai.cn/'
>>>