What Are Python Inheritance and Polymorphism? See Examples

Inheritance and polymorphism are key concepts in object-oriented programming (OOP) in Python.

• Inheritance allows a class (child) to inherit attributes and methods from another class (parent), promoting code reuse.
• Polymorphism allows objects of different classes to be used interchangeably, enabling flexible and scalable code.

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Why Inheritance and Polymorphism Are Important

• Reduces code duplication
• Promotes modular design
• Makes programs easier to maintain
• Enables real-world modeling of objects

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1. Python Inheritance

Inheritance allows a child class to inherit from a parent class using ParentClass in parentheses.

# Parent class
class Animal:
    def speak(self):
        print("Some sound")

# Child class
class Dog(Animal):
    def speak(self):
        print("Bark")

# Create objects
animal = Animal()
dog = Dog()

animal.speak()  # Output: Some sound
dog.speak()     # Output: Bark

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Types of Inheritance

1. Single Inheritance – One parent, one child
2. Multiple Inheritance – Multiple parents
3. Multilevel Inheritance – Grandparent → Parent → Child
4. Hierarchical Inheritance – One parent, multiple children

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2. Python Polymorphism

Polymorphism allows different objects to respond to the same method in different ways.

Example with Method Overriding

class Cat(Animal):
    def speak(self):
        print("Meow")

def make_sound(animal):
    animal.speak()

make_sound(Dog())  # Bark
make_sound(Cat())  # Meow

Here, the same make_sound() function works for multiple types of objects.

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Example with Operator Overloading

a = 5
b = 3
print(a + b)  # 8 (int addition)

x = "Hello"
y = "World"
print(x + y)  # HelloWorld (string concatenation)

Python uses polymorphism to handle different data types with the same operator.

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Best Practices

✔ Use inheritance only when there is a clear “is-a” relationship
✔ Avoid deep inheritance hierarchies
✔ Use polymorphism for flexible and reusable code
✔ Keep method overriding consistent with parent method signature

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Conclusion

Inheritance and polymorphism are powerful OOP concepts in Python. They help in creating reusable, modular, and scalable programs that model real-world problems efficiently.

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References

• Internal Reference: https://savanka.com/category/learn/python/
• External Reference: https://www.w3schools.com/python/