python getattr multiple levels with values being passed as well

Question

so I've been reading up on getattr, and was wondering what the equivalent of

example = val1.val2.val3(item)

would be. So I get that you have to use nested getattr to implement multiple levels attributes

example = getattr(getattr(val1, "val2"), "val3")

but how do I represent the object being passed in?

Answer 1

Or you can use a neat function from the standard library operator.attrgetter. Here a little example on how to use it.

from operator import attrgetter

from collections import namedtuple

# Define some objects
Foo = namedtuple('Foo', 'attr')
Bar = namedtuple('Bar', 'subattr1')

instance = Foo(attr=Bar('this_is_my_value'))

retriever = attrgetter('attr.subattr1')
result = retriever(instance)
print(result)

This executed will give you

this_is_my_value

Answer 2

You're almost there:

val3 = getattr(getattr(val1, "val2"), "val3")
example = val3(item)

# Or simply:
example = getattr(getattr(val1, "val2"), "val3")(item)