How do I tell dict() in Python 2 to use unicode instead of byte string?

问题

Here is an example:

d = dict(a = 2)
print d
{'a': 2}

How can I tell dict() constructor to use Unicode instead without writing the string literal expliclity like u'a'? I am loading a dictionary from a json module which defaults to use unicode. I want to make use of unicode from now on.

回答1:

To get a dict with Unicode keys, use Unicode strings when constructing the dict:

>>> d = {u'a': 2}
>>> d
{u'a': 2}

Dicts created from keyword arguments always have string keys. If you want those to be Unicode (as well as all other strings), switch to Python 3.

回答2:

Keyword arguments in 2.x can only use ASCII characters, which means bytestrings. Either use a dict literal, or use one of the constructors that allows specifying the full type.

>>> dict(((u'a', 2),))
{u'a': 2}

来源：https://stackoverflow.com/questions/20357210/how-do-i-tell-dict-in-python-2-to-use-unicode-instead-of-byte-string