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

You can get the class of an object by calling object.__class__, so in order to check if object is the default string type:

    isinstance(object,"".__class__)

And You can place the following in the top of Your code so that strings enclosed by quotes are in unicode in python 2:

    from __future__ import unicode_literals

Answer 2

You can try this at the beginning of your code:

from __future__ import print_function
import sys
if sys.version[0] == "2":
    py3 = False
else:
    py3 = True
if py3: 
    basstring = str
else:
    basstring = basestring

and later in the code:

anystring = "test"
# anystring = 1
if isinstance(anystring, basstring):
    print("This is a string")
else:
    print("No string")

Answer 3

If you're writing 2.x-and-3.x-compatible code, you'll probably want to use six:

from six import string_types
isinstance(s, string_types)

Answer 4

The most terse approach I've found without relying on packages like six, is:

try:
  basestring
except NameError:
  basestring = str

then, assuming you've been checking for strings in Python 2 in the most generic manner,

isinstance(s, basestring)

will now also work for Python 3+.