How to check if an object is an instance of a namedtuple?

Question

How do I check if an object is an instance of a Named tuple?

Answer 1

Calling the function collections.namedtuple gives you a new type that's a subclass of tuple (and no other classes) with a member named _fields that's a tuple whose items are all strings. So you could check for each and every one of these things:

def isnamedtupleinstance(x):     t = type(x)     b = t.__bases__     if len(b) != 1 or b[0] != tuple: return False     f = getattr(t, '_fields', None)     if not isinstance(f, tuple): return False     return all(type(n)==str for n in f) 

it IS possible to get a false positive from this, but only if somebody's going out of their way to make a type that looks a lot like a named tuple but isn't one;-).

Answer 2

If you want to determine whether an object is an instance of a specific namedtuple, you can do this:

from collections import namedtuple  SomeThing = namedtuple('SomeThing', 'prop another_prop') SomeOtherThing = namedtuple('SomeOtherThing', 'prop still_another_prop')  a = SomeThing(1, 2)  isinstance(a, SomeThing) # True isinstance(a, SomeOtherThing) # False