Basic Inheritance

Part of the Object Oriented Programming section of Coddy's Python journey — lesson 17 of 64.

Inheritance allows a class to inherit attributes and methods from another class, creating a parent-child relationship.

Here is an example of a parent class:

class Animal:
    def __init__(self, name):
        self.name = name
    
    def info(self):
        print(f"I am {self.name}, an animal")

Create a child class that inherits from the parent:

class Dog(Animal):
    pass  # Inherits everything from Animal

The syntax class Dog(Animal): means Dog inherits from Animal. Put the parent class name in parentheses.

Create objects from both classes:

generic_animal = Animal("Creature")
buddy = Dog("Buddy")

Use the inherited methods:

generic_animal.info()
buddy.info()

Output:

I am Creature, an animal
I am Buddy, an animal

Even though Dog doesn't define __init__ or info, it automatically gets them from Animal.

You can add new methods to the child class:

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

buddy = Dog("Buddy")
buddy.info()  # Inherited method
buddy.bark()  # New method

Output:

I am Buddy, an animal
Buddy says Woof!

Key Point: Child classes inherit all attributes and methods from their parent class. Use class Child(Parent): syntax to create inheritance. This helps you reuse code and create logical class hierarchies.

Challenge

Medium

vehicle.py: Contains the parent Vehicle class
car.py: Contains the Car class that inherits from Vehicle
driver.py: Main file to test your implementation

Each file contains detailed TODO comments to guide you through the implementation. You'll need to:

Complete the Vehicle class with make and model attributes
Implement proper class inheritance in the Car class
Set up the correct import statements between files
Create and test objects in the driver file

Follow the TODO comments carefully as they provide step-by-step guidance to the solution.

Cheat sheet

Inheritance allows a class to inherit attributes and methods from another class using class Child(Parent): syntax:

class Animal:
    def __init__(self, name):
        self.name = name
    
    def info(self):
        print(f"I am {self.name}, an animal")

class Dog(Animal):
    pass  # Inherits everything from Animal

Child classes automatically inherit all parent methods and attributes:

buddy = Dog("Buddy")
buddy.info()  # Uses inherited method
# Output: I am Buddy, an animal

Add new methods to child classes while keeping inherited functionality:

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

buddy = Dog("Buddy")
buddy.info()  # Inherited method
buddy.bark()  # New method

Try it yourself

# TODO: Import the Vehicle class from vehicle.py
# TODO: Import the Car class from car.py

# TODO: Create a Vehicle object with make "Toyota" and model "Corolla"
vehicle = None

# TODO: Create a Car object with make "Honda" and model "Civic"
car = None

# TODO: Call display_info() method on the vehicle object
# Expected output: "Vehicle: Toyota Corolla"

# TODO: Call display_info() method on the car object
# Expected output: "Vehicle: Honda Civic"
# Note: Car inherits display_info from Vehicle without modification