Unicode literals causing invalid syntax

问题

The following code:

s = s.replace(u"&", u"&")

is causing an error in python:

SyntaxError: invalid syntax

removing the u's before the " fixes the problem, but this should work as is? I'm using Python 3.1

回答1:

The u is no longer used in Python 3. String literals are unicode by default. See What's New in Python 3.0.

You can no longer use u"..." literals for Unicode text. However, you must use b"..." literals for binary data.

回答2:

On Python 3, strings are unicode. There is no need to (and as you've discovered, you can't) put a u before the string literal to designate unicode.

Instead, you have to put a b before a byte literal to designate that it isn't unicode.

回答3:

In Python3.3+ unicode literal is valid again, see What’s New In Python 3.3:

New syntax features:

New yield from expression for generator delegation.
The u'unicode' syntax is accepted again for str objects.

来源：https://stackoverflow.com/questions/7569014/unicode-literals-causing-invalid-syntax