How to find out if a Python object is a string?

Question

How can I check if a Python object is a string (either regular or Unicode)?

Answer 1

Python 2

To check if an object o is a string type of a subclass of a string type:

isinstance(o, basestring)

because both str and unicode are subclasses of basestring.

To check if the type of o is exactly str:

type(o) is str

To check if o is an instance of str or any subclass of str:

isinstance(o, str)

The above also work for Unicode strings if you replace str with unicode.

However, you may not need to do explicit type checking at all. "Duck typing" may fit your needs. See http://docs.python.org/glossary.html#term-duck-typing.

See also What’s the canonical way to check for type in python?