How to determine the datatype in Python?

Question

astring ('a','tuple')

How do I determine if "x" is a tuple or string?

Answer 1

if isinstance(x, basestring):
   # a string
else:
   try: it = iter(x)
   except TypeError:
       # not an iterable
   else:
       # iterable (tuple, list, etc)

@Alex Martelli's answer describes in detail why you should prefer the above style when you're working with types in Python (thanks to @Mike Hordecki for the link).

Answer 2

isinstance(x, str)
isinstance(x, tuple)

In general:

isinstance(variable, type)

Checks whether variable is an instance of type (or its subtype) (docs).

PS. Don't forget that strings can also be in unicode (isinstance(x, unicode) in this case) (or isinstance(x, basestring) (thanks, J.F. Sebastian!) which checks for both str and unicode).