Python super() - Access Parent Methods

Introduction

The super() function in Python is a built-in function that allows you to call methods of a superclass from a subclass. This function plays a crucial role in facilitating cooperative multiple inheritance and is often used when extending the functionality of inherited methods. It enables a framework where subclasses can alter or extend the behavior of superclass methods without directly modifying the original method implementations.

In this article, you will learn how to effectively use the super() function in object-oriented programming with Python. Explore the use of super() in single inheritance and multiple inheritance scenarios, and discover how it helps in accessing overridden methods of parent classes.

Using super() in Single Inheritance

Access Parent Class Methods

1. Define a parent class with a method.

2. Create a subclass that inherits from this parent class.

3. Use super() in the subclass to access the parent class method.

   python Copy

   class Parent:
       def show(self):
           print("Inside Parent")
   
   class Child(Parent):
       def display(self):
           print("Inside Child")
           super().show()
   
   obj = Child()
   obj.display()
   

   This code defines two classes, Parent and Child, where Child inherits from Parent. The show() method in the Parent class is called from the display() method of the Child class using super(). The output will be "Inside Child" followed by "Inside Parent".

Override and Extend Parent Class Methods

1. Override a method in the subclass that already exists in the parent class.

2. Use super() to enhance, rather than replace, the parent class method functionality.

   python Copy

   class Parent:
       def show(self):
           print("Parent method")
   
   class Child(Parent):
       def show(self):
           print("Child method before calling super()")
           super().show()
           print("Child method after calling super()")
   
   obj = Child()
   obj.show()
   

   In this snippet, the show() method in the Child class first prints a message, then calls the same method from the Parent class using super(), and finally prints another message. This results in a sequence of prints that demonstrates extending the functionality of the parent method.

Using super() in Multiple Inheritance

Access Methods from Multiple Parents

1. Define two or more parent classes with unique methods.

2. Create a subclass that inherits from these multiple parent classes.

3. Use super() to access methods from multiple parent classes sequentially.

   python Copy

   class Father:
       def activity(self):
           print("Father's activity")
   
   class Mother:
       def activity(self):
           print("Mother's activity")
   
   class Child(Father, Mother):
       def activity(self):
           print("Child's activity")
           super().activity()
   
   obj = Child()
   obj.activity()
   

   In this example, both Father and Mother classes have a method called activity(). The Child class, which inherits from both, overrides the activity() method and uses super() to call the method from the first superclass listed in the inheritance tuple (Father in this case), thus demonstrating how super() resolves method calls in multiple inheritance.

Conclusion

The super() function in Python is essential for invoking superclass methods effectively, especially in complex class hierarchies involving multiple inheritance. It eliminates the need for explicitly referencing parent classes, making the code more maintainable and less prone to errors. By mastering super(), you ensure your code is robust, readable, and follows good object-oriented design principles. Whether in single or multiple inheritance scenarios, super() can simplify method calls and help manage method overriding systematically.