Lesson 13: Classes, Objects, and Inheritance

Recap: Classes and Objects

Classes define the structure and behavior of objects. Objects are instances created from those classes. Inheritance allows one class to extend another, reusing and customizing behavior.

Creating a Base Class

A base (or parent) class defines common attributes and methods:

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

    def speak(self):
        return "Some sound"

Creating a Child Class (Inheritance)

A child class inherits from a parent class and can override or extend its behavior:

class Dog(Animal):
    def speak(self):
        return "Woof!"

Using the Child Class

d = Dog("Buddy")
print(d.name)        # Buddy
print(d.speak())     # Woof!

Using super()

The super() function allows a child class to call methods from its parent class:

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

Method Overriding

Child classes can replace parent methods with their own versions:

class Bird(Animal):
    def speak(self):
        return "Tweet!"

Multiple Inheritance

Python allows a class to inherit from multiple parents:

class Flyer:
    def fly(self):
        return "Flying!"

class Eagle(Animal, Flyer):
    pass

e = Eagle("Sky")
print(e.fly())   # Flying!

isinstance() and issubclass()

Check relationships between objects and classes:

isinstance(d, Dog)        # True
isinstance(d, Animal)     # True
issubclass(Dog, Animal)   # True

Why Inheritance Matters

• Reduces code duplication
• Encourages modular, reusable design
• Allows specialization of behavior
• Supports scalable, maintainable applications

Next Steps

Now that you understand inheritance, you're ready to learn how to manage Python environments and dependencies in Lesson 14: Virtual Environments and Dependency Management.

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