L14 Polymorphism

A pianist can play different types of pianos, and a driver can drive different types of vehicles. This is an example of polymorphism—the ability to perform the same action in different ways.

In Python, polymorphism allows different objects to share the same method names but behave differently based on their class.

💡 Analogy: A universal remote control works with different devices—a TV, an AC, and a sound system—all with the same buttons but different behaviors.

Learning Objectives

By the end of this lesson, you will be able to:

1. Understand the concept of polymorphism in Object-Oriented Programming.

2. Use method overriding to achieve polymorphism.

3. Implement polymorphism with different classes having methods with the same name.

Key Terms

• Polymorphism – The ability of different classes to implement the same method in different ways.

• Method overriding – A child class redefining a method from its parent class.

• Duck typing – The concept that an object's behavior is more important than its class.

• Abstract classes – Classes that provide a common interface but cannot be instantiated.

• Code flexibility – Writing code that can work with multiple data types or objects.

Example 1: Method Overriding for Polymorphism

class Animal:

    def make_sound(self):

        return "Some generic sound"

class Dog(Animal):

    def make_sound(self):

        return "Bark!"

class Cat(Animal):

    def make_sound(self):

        return "Meow!"

dog = Dog()

cat = Cat()

print(dog.make_sound())  # Output: Bark!

print(cat.make_sound())  # Output: Meow!

🛑 Common Mistakes

1. Not overriding methods properly—ensure method names match exactly.

2. Using the wrong class hierarchy, leading to unintended behavior.