Python: .encode方法

官方教程: http://docs.python.org/2/howto/unicode.html
方法.encode([encoding],
[errors='strict']), 返回一个 8-bit string version of the Unicode string, encoded in the requested encoding.

The errors parameter is the same as the parameter of the unicode() constructor, with one additional possibility; as well as ‘strict’,‘ignore’,
and ‘replace’, you can also pass ‘xmlcharrefreplace’ which uses XML’s character references. 以下的例子说明了其不同的结果:

>>> u = unichr(40960) + u'abcd' + unichr(1972)
>>> u.encode('utf-8')
'\xea\x80\x80abcd\xde\xb4'
>>> u.encode('ascii')
Traceback (most recent call last):
...
UnicodeEncodeError: 'ascii' codec can't encode character u'\ua000' in
position 0: ordinal not in range(128)
>>> u.encode('ascii', 'ignore')
'abcd'
>>> u.encode('ascii', 'replace')
'?abcd?'
>>> u.encode('ascii', 'xmlcharrefreplace')
'ꀀabcd޴'