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Abstraction in Python

#abstraction #python #oop In this lecture, we'll explore the concept of abstraction in Python. We'll talk about what abstraction is in Object-Oriented Programming, why it's useful, and how it helps us simplify code by focusing on essential functionality while hiding implementation details. Then, we'll use a real-world analogy to explain the idea further. We'll move on to abstract classes and methods, learning how they define blueprints for subclasses. After that, we'll explore Python's abc module to implement abstract classes, followed by a real-world example of a payment system to see how abstraction works in practice. We'll also introduce abstract properties and how they enforce structure across subclasses. Finally, we'll wrap up by discussing best practices for using abstraction effectively. By the end of this lecture, you'll have a solid understanding of how to use abstraction to create structured and maintainable code. Abstraction is one of the key principles of Object-Oriented Programming. It allows us to hide the implementation details of our code and only expose the essential functionality. Think of it as focusing on what an object can do, rather than how it does it. Abstraction is essential because it enables us to create reusable components that can be used in different parts of the program without needing to know their inner workings. It helps keep the code base simple, easy to maintain, and free from unnecessary complexity. Let's take a moment to consider an everyday example: driving a car. When we drive, we don't need to know how the engine works or how the transmission engages. We only care about pressing the gas pedal to move forward or the brake pedal to stop the car. This is an example of abstraction in action. We only interact with the essential features while the details are hidden. In Python, abstraction is achieved through abstract classes and methods. An abstract class is a class that cannot be instantiated and usually contains one or more abstract methods. These methods don't have an implementation in the abstract class; instead, subclasses must provide the implementation. We create an abstract class when we want to define a common interface that different subclasses must follow. Abstract methods serve as blueprints that guide subclasses. Python provides the abc module to create Abstract Base Classes (or ABCs). The ABC class and the 'abstractmethod' decorator help us define abstract classes and methods. Let's see how we can create an abstract class in Python. I'll create a new file for this practice, and name it 'payment_system.py'. First, we import the necessary modules. From the abc module, we import the ABC class as well as the 'abstractmethod' decorator. Now, let's create a simple abstract class for a Payment system. The ABC class is used to define abstract base classes, and the 'abstractmethod' decorator is used to declare methods that must be implemented by any subclass. So, Payment is an abstract class, and process_payment is an abstract method. Notice that the method doesn't have any implementation. Subclasses must provide their own version of this method. Let's check and verify that we can't instantiate an abstract class like the Payment class. If we run the script, We'll get a TypeError saying that we can't instantiate abstract class Payment without an implementation for abstract method 'process_payment'. To make things more concrete, let's build a real-world example around a payment system. We'll create different payment methods by subclassing the abstract Payment class. Here, both PayPal and CreditCard are subclasses of Payment. Each provides its own implementation of the 'process_payment' method, which was defined as an abstract method in the parent class. In the PayPal class, the process_payment method prints a message that indicates a PayPal payment is being processed for the given amount. Similarly, the CreditCard class overrides the same method but prints a message indicating a payment through a Credit Card for the specified amount. These concrete implementations of the abstract method allow the subclasses to handle payments in their own specific ways while maintaining a consistent interface defined by the Payment class. After defining the PayPal and CreditCard classes, we can now create instances of them. Let's create an instance of the PayPal class and invoke its 'process_payment' method to process a payment of 100 dollars. If we comment out this problematic line and then run the code, We'll see the message: 'Processing PayPal payment of 100 dollars', which shows that the method from the PayPal class has been called. If we replace PayPal with CreditCard, we're now creating an instance of the CreditCard class instead. If we run again, This time, the method in the CreditCard class will be called, and the output will be: 'Processing Credit Card payment of 100 dollars'. This demonstrates how we can use the same method across different subclasses, but the...