What's the difference between super().method() and self.method()

Question

What\'s the difference between using super().method() and self.method(), when we inherit something from a parent class and why use one instead of anoth

Answer 1

super().method() will call the parent classes implementation of method, even if the child has defined their own. You can read the documentation for super for a more in-depth explanation.

class Parent:
    def foo(self):
        print("Parent implementation")

class Child(Parent):
    def foo(self):
        print("Child implementation")
    def parent(self):
        super().foo()
    def child(self):
        self.foo()

c = Child()
c.parent()
# Parent implementation
c.child()
# Child implementation

For singular-inheritance classes like Child, super().foo() is the same as the more explicit Parent.foo(self). In cases of multiple inheritance, super will determine which foo definition to use based on the Method Resolution Order, or MRO.

A further motivating example: which method gets called if we subclass Child and write another implementation of foo?

class Grandchild(Child):
    def foo(self):
        print("Grandchild implementation")

g = Grandchild()
g.parent()
# Parent implementation
g.child()
# Grandchild implementation

Answer 2

self

self, which is mostly used as the first parameter of instance methods of classes, always represents the calling object/instance of the class.

super()

super() refers to object of parent class. It is useful in case of method overriding and this is in case of numerous programming languages including C++, Java etc. In Java, super() is used to call the constructor of parent class.

Please have a look at the below little example.

class TopClass(object):
    def __init__(self, name, age):
        self.name = name;
        self.age = age;

    def print_details(self):
        print("Details:-")
        print("Name: ", self.name)
        print("Age: ", self.age)
        self.method()

    def method(self):
        print("Inside method of TopClass")

class BottomClass(TopClass):
    def method(self):
        print("Inside method of BottomClass")    

    def self_caller(self):
         self.method()

    def super_caller(self):
         parent = super()
         print(parent)
         parent.method()

child = BottomClass ("Ryan Holding", 26)
child.print_details()

"""
Details:-
Name:  Ryan Holding
Age:  26
Inside method of BottomClass
"""

parent = TopClass("Rishikesh Agrawani", 26)
parent.print_details()

"""
Details:-
Name:  Rishikesh Agrawani
Age:  26
Inside method of TopClass
"""

child.self_caller()
child.super_caller()

"""
Inside method of BottomClass
<super: <class 'BottomClass'>, <BottomClass object>>
Inside method of TopClass
"""