What is the Pythonic Way of Differentiating Between a String and a List?

Question

For my program I have a lot of places where an object can be either a string or a list containing strings and other similar lists. These are generally read from a JSON file. They both need to be treated differently. Right now, I am just using isinstance, but that does not feel like the most pythonic way of doing it, so does anyone have a better way of doing it?

Answer 1

No need to import modules, isinstance(), str and unicode (versions before 3 -- there's no unicode in 3!) will do the job for you.

Python 2.x:

Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29)  [GCC 4.2.1 (Apple Inc. build 5646)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> isinstance(u'', (str, unicode)) True >>> isinstance('', (str, unicode)) True >>> isinstance([], (str, unicode)) False  >>> for value in ('snowman', u'☃ ', ['snowman', u'☃ ']): ...     print type(value) ...  <type 'str'> <type 'unicode'> <type 'list'> 

Python 3.x:

Python 3.2 (r32:88445, May 29 2011, 08:00:24)  [GCC 4.2.1 (Apple Inc. build 5664)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> isinstance('☃ ', str) True >>> isinstance([], str) False  >>> for value in ('snowman', '☃ ', ['snowman', '☃ ']): ...     print(type(value)) ...  <class 'str'> <class 'str'> <class 'list'> 

From PEP008:

Object type comparisons should always use isinstance() instead of comparing types directly.