How to check if variable is string with python 2 and 3 compatibility

Question

I\'m aware that I can use: isinstance(x, str) in python-3.x but I need to check if something is a string in python-2.x as well. Will isinstance(x, str)

Answer 1

This is @Lev Levitsky's answer, re-written a bit.

try:
    isinstance("", basestring)
    def isstr(s):
        return isinstance(s, basestring)
except NameError:
    def isstr(s):
        return isinstance(s, str)

The try/except test is done once, and then defines a function that always works and is as fast as possible.

EDIT: Actually, we don't even need to call isinstance(); we just need to evaluate basestring and see if we get a NameError:

try:
    basestring  # attempt to evaluate basestring
    def isstr(s):
        return isinstance(s, basestring)
except NameError:
    def isstr(s):
        return isinstance(s, str)

I think it is easier to follow with the call to isinstance(), though.