在中文字符串前面加u. 

Make sure your code is in UTF-8 (NOT Latin-1) and/or use a coding line as so:

#! /usr/bin/python
# -*- coding: utf-8 -*-
a = {"a": u"??"}
b = "??"
assert b == a[‘a‘]
assert b.decode(‘utf-8‘) == a[‘a‘].decode(‘utf-8‘)

If you‘re using unicode across the board, you can import unicode_literals from the future and cut back on encoding heartaches:

#! /usr/bin/python
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
a = {"a": u"??"}
b = "??"
assert b == a[‘a‘]
assert b == a[‘a‘]
assert b.encode(‘utf-8‘) != a[‘a‘]
assert b.encode(‘utf-8‘) == a[‘a‘].encode(‘utf-8‘)

If a file uses unicode_literals, all "strings" are now u"unicode" objects (per the coding of the file) if they‘re not b"prepended" with a b (to emulate the string/bytes split in Python 3.X).

关于在2.7中出现 "UnicodeWarning: Unicode equal comparison failed to convert both arguments to Unicode - interpreting them as being unequal"