Inheritance in Python

In Python, inheritance is a fundamental concept in Object-Oriented Programming (OOP). It allows a class (called the child class) to inherit the attributes and methods of another class (called the parent class). This enables code reuse and helps to build a hierarchy of classes.

What is Inheritance?

Inheritance allows one class to inherit the properties and behaviors (methods) of another class. The new class is called the derived class or child class, and the class it inherits from is the base class or parent class. The child class can add new properties or methods, or it can modify the behavior of the parent class's methods.

Creating a Simple Inheritance Example

Here is a simple example of how inheritance works:

# Parent class (Animal)
class Animal:
    def __init__(self, name):
        self.name = name

    def speak(self):
        return f"{self.name} makes a sound."

# Child class (Dog) inheriting from Animal
class Dog(Animal):
    def speak(self):
        return f"{self.name} barks."

# Example Usage
dog = Dog("Buddy")
print(dog.speak())  # Output: Buddy barks.

Why Use Inheritance?

Inheritance helps in code reuse and allows us to create a modular structure. It is especially useful when multiple classes have similar behavior or attributes. Instead of rewriting code for each class, you can define common behavior in a parent class and have child classes inherit it.

Overriding Methods in the Child Class

A child class can override the methods of the parent class to provide its own implementation. For example: 

# Parent class (Animal)
class Animal:
    def __init__(self, name):
        self.name = name

    def speak(self):
        return f"{self.name} makes a sound."

# Child class (Cat) overriding the speak method
class Cat(Animal):
    def speak(self):
        return f"{self.name} meows."

cat = Cat("Whiskers")
print(cat.speak())  # Output: Whiskers meows.

Using super() to Access Parent Class Methods

Even if the child class overrides a method, you can call the parent class's version of the method using the super() function. This allows the child class to use the parent class's functionality along with its own. 

class Animal:
    def __init__(self, name):
        self.name = name

    def speak(self):
        return f"{self.name} makes a sound."

class Dog(Animal):
    def speak(self):
        return f"{self.name} barks."

    def parent_speak(self):
        return super().speak()

dog = Dog("Buddy")
print(dog.speak())          # Output: Buddy barks.
print(dog.parent_speak())   # Output: Buddy makes a sound.

Multiple Inheritance

Python supports multiple inheritance, which means a class can inherit from more than one parent class. For example: 

class Animal:
    def __init__(self, name):
        self.name = name

class Mammal:
    def is_mammal(self):
        return True

class Dog(Animal, Mammal):
    def speak(self):
        return f"{self.name} barks."

dog = Dog("Buddy")
print(dog.speak())        # Output: Buddy barks.
print(dog.is_mammal())    # Output: True

Summary of Inheritance