🔹 What is Polymorphism?

The word Polymorphism means:

Poly = many, morph = form
So, Polymorphism = many forms

📌 In Python, the same function or method can work in different ways depending on the object.

🔹 Why Use Polymorphism?

✅ Makes code flexible
✅ Easy to understand and update
✅ Helps work with different objects in a similar way

🔹 Example: Polymorphism with Functions

def add(a, b):
    return a + b

print(add(3, 4))        # Numbers
print(add("Hi ", "Tom"))  # Strings

✅ Same function name add() works with numbers and strings — this is polymorphism.

🔹 Polymorphism with Classes

Let’s see two different classes using the same method name:

class Dog:
    def speak(self):
        print("Dog barks")

class Cat:
    def speak(self):
        print("Cat meows")

def animal_sound(animal):
    animal.speak()

d = Dog()
c = Cat()

animal_sound(d)
animal_sound(c)

✅ Different objects (Dog, Cat) use the same method speak() in different ways.

🔹 Polymorphism with Inheritance

class Vehicle:
    def move(self):
        print("Vehicle is moving")

class Car(Vehicle):
    def move(self):
        print("Car is driving")

class Boat(Vehicle):
    def move(self):
        print("Boat is sailing")

def start_trip(vehicle):
    vehicle.move()

v1 = Car()
v2 = Boat()

start_trip(v1)
start_trip(v2)

✅ move() method works differently for each object. This is runtime polymorphism.

🔹 Built-in Polymorphism Example

print(len("Python"))       # Output: 6
print(len([1, 2, 3, 4]))    # Output: 4
print(len((10, 20, 30)))    # Output: 3

✅ len() function works with string, list, tuple — same function name, many forms.

📝 Practice Questions with Answers

❓ Q1: Create a method called greet() in two classes: English and Spanish.

✅ Answer:

class English:
    def greet(self):
        print("Hello")

class Spanish:
    def greet(self):
        print("Hola")

def say_hello(obj):
    obj.greet()

e = English()
s = Spanish()
say_hello(e)
say_hello(s)

❓ Q2: Write a function that accepts any shape class and prints area using area() method.

✅ Answer:

class Circle:
    def area(self):
        print("Area of Circle: πr²")

class Square:
    def area(self):
        print("Area of Square: side²")

def print_area(shape):
    shape.area()

c = Circle()
s = Square()
print_area(c)
print_area(s)

🧾 Summary Table

🎯 Quick Recap

• Polymorphism helps the same method name work in different ways.
• It can be seen in:
  • Functions
  • Classes
  • Inheritance
  • Built-in functions