What Is Happening Here In Python With Oops While Trying Diamond Shape Problem

I am learning OOPs with python. created below code to replicate the diamond shape problem in multiple inheritence. I am running the below code in jupyter notebook and output is gen

Solution 1:

You may find the __mro__ attribute of a class informative. Here, MRO stands for Method Resolution Order.

Consider this modification to your code:

classParent:
    def__init__(self):
        self.a = 2
        self.b = 4defprint_name(self):
        print("parent")

    defform1(self):
        print("calling parent form1")
        print('p', self.a + self.b)


classChild1(Parent):
    def__init__(self):
        self.a = 50
        self.b = 4defprint_name(self):
        print("child1")

    defprint_super_name(self):
        super().print_name()

    defform1(self):
        print('bye', self.a - self.b)

    defcallchildform1(self):
        print("calling parent from child1")
        super().form1()


classChild2(Parent):
    def__init__(self):
        self.a = 3
        self.b = 4defprint_name(self):
        print("child2")

    defform1(self):
        print('hi', self.a * self.b)

    defcallchildform1(self):
        print("calling parent from child2")
        super().form1()


classGrandchild(Child1, Child2):
    def__init__(self):
        self.a = 10
        self.b = 4defprint_name(self):
        print("grandchild")

    defprint_super_name(self):
        super().print_name()

    defprint_super_super_name(self):
        super().print_super_name()

    defcallingparent(self):
        super().form1()


g = Grandchild()
print("When I print the name of my class it is:")
g.print_name()
print("When I print my superclass name, it is:")
g.print_super_name()
print("When I print the name of the superclass of my superclass, it is:")
g.print_super_super_name()
print("When you call methods on me, they will be executed from my class and my parent classes in the following order:")
print(Grandchild.__mro__)
g.form1()
g.callchildform1()
g.callingparent()

The output is:

When I print the name of my classitis:
grandchild
When I print my superclassname, it is:
child1
When I print the name of the superclassof my superclass, it is:
child2
When you call methods on me, they will be executed from my classand my parent classes in the following order:
(<class'__main__.Grandchild'>, <class'__main__.Child1'>, <class'__main__.Child2'>, <class'__main__.Parent'>, <class'object'>)
bye 6
calling parent from child1
hi 40
bye 6

When you run g.callchildform1() Python looks for the definition of callchildform1 in Grandchild. It isn't there, so the next place it looks is Child1. You can see from the example and from the method resolution order that when an instance of Grandchild calls a method defined in Child1 which calls super(), the search for the called method will begin in Child2.