Introduction 🌟
**Polymorphism** is a core concept in Object-Oriented Programming (OOP). It means **one action → many forms**, allowing different classes to use the same method name but implement their own behavior.
Note
Makes code flexible, reusable, and extendable.
1. Simple Example of Polymorphism 🧱
simple_polymorphism.py
class Dog:
def sound(self):
return "Bark"
class Cat:
def sound(self):
return "Meow"
for animal in [Dog(), Cat()]:
print(animal.sound())✔ Both classes have sound()
✔ Python chooses the correct method at runtime
2. Polymorphism with Functions 🔄
function_polymorphism.py
class Circle:
def draw(self):
print("Drawing Circle")
class Square:
def draw(self):
print("Drawing Square")
def render(shape):
shape.draw() # polymorphic call
render(Circle())
render(Square())✔ The same function behaves differently for different objects.
3. Polymorphism with Inheritance 🧬
inheritance_polymorphism.py
class Animal:
def sound(self):
return "Some sound"
class Dog(Animal):
def sound(self):
return "Bark"
class Cat(Animal):
def sound(self):
return "Meow"
animals = [Animal(), Dog(), Cat()]
for a in animals:
print(a.sound())✔ Child classes override parent class methods
✔ Python calls the correct version during runtime
4. Method Overriding (Runtime Polymorphism) ⚔️
method_overriding.py
class Parent:
def show(self):
print("Parent class")
class Child(Parent):
def show(self):
print("Child class")
c = Child()
c.show()✔ Child class method overrides parent method
✔ Known as *runtime polymorphism*
5. Polymorphism with Abstract Methods 🎭
abstract_polymorphism.py
from abc import ABC, abstractmethod
class Shape(ABC):
@abstractmethod
def area(self): pass
class Circle(Shape):
def area(self):
return 3.14 * 5 * 5
class Square(Shape):
def area(self):
return 4 * 4
for s in [Circle(), Square()]:
print(s.area())✔ Abstract classes enforce polymorphism
✔ All child classes must implement the abstract method
6. Operator Overloading (Polymorphism in Python Magic Methods) ⚡
Python allows polymorphism through special methods like __add__, __len__, etc.
operator_overloading.py
class Book:
def __init__(self, pages):
self.pages = pages
def __add__(self, other):
return self.pages + other.pages
b1 = Book(100)
b2 = Book(150)
print(b1 + b2) # 250✔ Polymorphism applied to operators
✔ + behaves differently depending on object type
7. Built-in Polymorphism in Python 📌
built_in_polymorphism.py
print(len("Hello")) # 5
print(len([1, 2, 3])) # 3✔ len() works for strings, lists, tuples, etc.
✔ Same function, different behavior → polymorphism!
8. Polymorphism in Real Projects 🌍
- ✔ UI frameworks: draw() for buttons, text fields, sliders
- ✔ Game engines: attack() for different characters
- ✔ APIs: process_request() for different request types
- ✔ Billing systems: calculate_bill() for different customers
9. Best Practices 💡
- ✔ Use method names consistently across related classes
- ✔ Use abstraction to enforce polymorphism
- ✔ Keep overridden methods simple and clear
- ✔ Avoid unnecessary overriding
10. Final Example — Payment System 💳
payment_polymorphism.py
class Payment:
def pay(self, amount):
print("Processing payment")
class CardPayment(Payment):
def pay(self, amount):
print(f"Paid {amount} using Card")
class UpiPayment(Payment):
def pay(self, amount):
print(f"Paid {amount} using UPI")
for method in [CardPayment(), UpiPayment()]:
method.pay(500)✔ A single method name pay() performs differently based on the object type.
Conclusion 🎉
You now fully understand Polymorphism in Python! Want the next topic? Try Inheritance, Magic Methods, Method Resolution Order (MRO), or OOP Project Examples. Just tell me! 😊