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

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;-).

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

3.7+

def isinstance_namedtuple(obj) -> bool:
    return (
            isinstance(obj, tuple) and
            hasattr(obj, '_asdict') and
            hasattr(obj, '_fields')
    )

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

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