Python Inheritance

Inheritance is a fundamental concept in object-oriented programming (OOP) that allows classes to inherit attributes and methods from other classes. It promotes code reuse and establishes a hierarchical relationship between classes.

Basic Syntax

In Python, inheritance is implemented using the following syntax:

class ChildClass(ParentClass):
    # Child class definition

The child class inherits all attributes and methods from the parent class, also known as the base class or superclass.

Types of Inheritance

• Single Inheritance: A child class inherits from one parent class
• Multiple Inheritance: A child class inherits from multiple parent classes
• Multilevel Inheritance: A child class inherits from a parent class, which in turn inherits from another class

Example: Single Inheritance

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

    def speak(self):
        pass

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

dog = Dog("Buddy")
print(dog.speak())  # Output: Buddy says Woof!

In this example, the Dog class inherits from the Animal class and overrides the speak method.

The super() Function

The super() function allows you to call methods from the parent class. It's particularly useful when you want to extend the functionality of a parent class method:

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

    def speak(self):
        return f"{self.name} chirps!"

parrot = Bird("Polly", 20)
print(parrot.speak())  # Output: Polly chirps!

Method Resolution Order (MRO)

In cases of multiple inheritance, Python uses the C3 linearization algorithm to determine the method resolution order. You can view the MRO using the __mro__ attribute or the mro() method:

print(Bird.__mro__)
# Output: (<class '__main__.Bird'>, <class '__main__.Animal'>, <class 'object'>)

Best Practices

• Use inheritance to model "is-a" relationships
• Favor composition over inheritance for "has-a" relationships
• Keep inheritance hierarchies shallow to maintain code readability
• Use abstract base classes to define interfaces (Python Abstract Classes)

Related Concepts

To fully understand inheritance in Python, it's helpful to explore these related topics:

• Python Classes and Objects
• Python Encapsulation
• Python Polymorphism
• Python Method Overriding

By mastering inheritance, you'll be able to create more efficient, organized, and reusable code in your Python projects.