Inheritance

What is Python inheritance?

Python inheritance is a mechanism that allows you to create new classes based on existing classes. The new class is called a subclass, and the existing class is called the superclass. The subclass inherits all of the attributes and methods of the superclass.

Example:

Python

class Animal:
  """A class to represent an animal."""

  def __init__(self, name, age):
    self.name = name
    self.age = age

  def speak(self):
    print(f"{self.name} makes an animal sound.")

class Dog(Animal):
  """A class to represent a dog."""

  def __init__(self, name, age, breed):
    super().__init__(name, age)
    self.breed = breed

  def bark(self):
    print(f"{self.name} barks!")

# Create a dog object
my_dog = Dog("Fido", 5, "Golden Retriever")

# Call the dog's bark method
my_dog.bark()
 

Output:

Fido barks!
 

In this example, the Dog class inherits from the Animal class. This means that the Dog class has all of the attributes and methods of the Animal class, plus the additional breed attribute and the bark() method.

Benefits of using Python inheritance

There are several benefits to using Python inheritance:

• Code reuse: Inheritance allows you to reuse your code by creating new classes based on existing classes. This can save you time and effort.
• Modularity: Inheritance allows you to break down your code into smaller, more manageable pieces. This can make your code more readable and easier to maintain.
• Flexibility: Inheritance allows you to create custom classes that are tailored to your specific needs.

Example of using inheritance to create custom classes:

Python

class Vehicle:
  """A class to represent a vehicle."""

  def __init__(self, make, model, year):
    self.make = make
    self.model = model
    self.year = year

  def move(self):
    print(f"{self.make} {self.model} moves forward.")

class Car(Vehicle):
  """A class to represent a car."""

  def __init__(self, make, model, year, num_wheels):
    super().__init__(make, model, year)
    self.num_wheels = num_wheels

class Truck(Vehicle):
  """A class to represent a truck."""

  def __init__(self, make, model, year, bed_size):
    super().__init__(make, model, year)
    self.bed_size = bed_size

# Create a car object
my_car = Car("Toyota", "Camry", 2023, 4)

# Create a truck object
my_truck = Truck("Ford", "F-150", 2023, 8)

# Call the move method on each object
my_car.move()
my_truck.move()
 

Output:

Toyota Camry moves forward.
Ford F-150 moves forward.
 

In this example, the Car and Truck classes inherit from the Vehicle class. The Car and Truck classes have additional attributes and methods that are specific to cars and trucks, respectively.

Conclusion

Python inheritance is a powerful tool that can help you to write more efficient, reusable, and maintainable code. By understanding how to use Python inheritance, you can become a better Python programmer.