Python: Are instance methods first-class objects?

Question

In python, is there a way of doing the following?

for method in list_of_methods:
   class_instance.method(data)

I would think this to be possible in python, since many things are 1st class objects.

Edit: Using some comments below, I tried this:

class Class_Test:
    def __init__(self):
        pass
    
    def method1(self, data):
        print(f"Method 1: {data}")
    def method2(self,data):
        print(f"Method 1: {data}")
        
list_of_methods = ["method1","method2"]
for method in list_of_methods:
    getattr(Class_Test(),method)("inside for loop")

Does this answer your question? Calling a function of a module by using its name (a string) — Kris
– Kris, Commented Sep 28, 2022 at 13:39

AKX · Accepted Answer · 2022-09-28 13:39:04Z

2

If list_of_methods is a list of strings of method names, use getattr to get the bound instance method by name, then call it.

for method in list_of_methods:
    getattr(class_instance, method)(data)

If, instead, list_of_methods is a list of unbound methods from the same class,

for method in list_of_methods:
    method(class_instance, data)

I.e.,

class Animal:
    def __init__(self, name):
        self.name = name

    def make_sound(self, volume):
        print(f"{self.name} makes a sound at volume {volume}")


list_of_animals = [Animal("Puppo"), Animal("Catto")]
list_of_method_names = ["make_sound"]
list_of_methods = [Animal.make_sound]

for animal in list_of_animals:
    for method_name in list_of_method_names:
        getattr(animal, method_name)(15)
    for method in list_of_methods:
        method(animal, 24)

prints out

Puppo makes a sound at volume 15
Puppo makes a sound at volume 24
Catto makes a sound at volume 15
Catto makes a sound at volume 24

answered Sep 28, 2022 at 13:39

AKX

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1 Comment

An old man in the sea. Over a year ago

I really enjoyed the unbounded methods list way of doing it. ;)

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