How to check for a function type in Python?

Question

I\'ve got a list of things, of which some can also be functions. If it is a function I would like to execute it. For this I do a type-check. This normally works for other ty

Answer 1

Because function isn't a built-in type, a NameError is raised. If you want to check whether something is a function, use hasattr:

>>> hasattr(f, '__call__')
True

Or you can use isinstance():

>>> from collections import Callable
>>> isinstance(f, Callable)
True
>>> isinstance(map, Callable)
True

Answer 2

Don't check types, check actions. You don't actually care if it's a function (it might be a class instance with a __call__ method, for example) - you just care if it can be called. So use callable(f).

Answer 3

collections.Callable can be used:

import collections

print isinstance(f, collections.Callable)

Answer 4

import types

if type(f) == types.FunctionType: 
    print 'It is a function!!'