9 7 Abstraction Explained

Key Concepts

Abstraction in Python involves several key concepts:

• Abstract Classes
• Abstract Methods
• Concrete Methods
• Inheritance and Abstraction
• Practical Applications

1. Abstract Classes

An abstract class is a class that cannot be instantiated on its own and is meant to be subclassed. It serves as a blueprint for other classes.

Example:

from abc import ABC, abstractmethod

class Animal(ABC):
    @abstractmethod
    def speak(self):
        pass
    

2. Abstract Methods

Abstract methods are methods declared in an abstract class that have no implementation. Subclasses of the abstract class must provide an implementation for these methods.

Example:

class Animal(ABC):
    @abstractmethod
    def speak(self):
        pass
    

3. Concrete Methods

Concrete methods are methods in an abstract class that have a complete implementation. These methods can be inherited and used by subclasses without modification.

Example:

class Animal(ABC):
    @abstractmethod
    def speak(self):
        pass

    def sleep(self):
        return "Zzzz..."
    

4. Inheritance and Abstraction

Inheritance allows subclasses to inherit abstract methods from an abstract class. Subclasses must implement these abstract methods to be instantiated.

Example:

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

my_dog = Dog()
print(my_dog.speak())  # Output: Woof!
print(my_dog.sleep())  # Output: Zzzz...
    

5. Practical Applications

Abstraction is useful in scenarios where you want to define a common interface for a group of related classes without specifying the implementation details.

Example:

class Shape(ABC):
    @abstractmethod
    def area(self):
        pass

class Circle(Shape):
    def __init__(self, radius):
        self.radius = radius

    def area(self):
        return 3.14 * self.radius ** 2

class Rectangle(Shape):
    def __init__(self, width, height):
        self.width = width
        self.height = height

    def area(self):
        return self.width * self.height

circle = Circle(5)
rectangle = Rectangle(4, 6)

print(circle.area())  # Output: 78.5
print(rectangle.area())  # Output: 24