Difference in python between basestring and types.StringType?

Question

What's the difference between:

isinstance(foo, types.StringType)

and

isinstance(foo, basestring)

?

Answer 1

For Python2: basestring is the base class for both str and unicode, while types.StringType is str. If you want to check if something is a string, use basestring. If you want to check if something is a bytestring, use str and forget about types.

Answer 2

This stuff is completely different in Python3

types not longer has StringType
str is always unicode
basestring no longer exists

So try not to sprinkle that stuff through your code too much if you might ever need to port it

Answer 3

>>> import types
>>> isinstance(u'ciao', types.StringType)
False
>>> isinstance(u'ciao', basestring)
True
>>> 

Pretty important difference, it seems to me;-).

Answer 4

If you need to write code that works in both Python 2 and Python 3 you can use install future via pip install future and import from past.builtins import basestring.

from past.builtins import basestring

See https://python-future.org/compatible_idioms.html#strings-and-bytes

Answer 5

For Python 2.x:

try:
    basestring        # added in Python 2.3
except NameError:
    basestring = (str, unicode)
...
if isinstance(foo, basestring):
    ...

Of course this might not work for Python 3, but I'm quite sure the 2to3 converter will take care of the topic.