Encapsulation and abstract classes in Python: an in-depth guide

• Definition: Encapsulation is to hide data and methods in a class and expose only the necessary interfaces to control access to data.
• benefit:
  • ImproveSecurity: Data can only be accessed through class methods, and external code cannot modify it directly.
  • Improve maintainability: When modifying data inside the class, there is no need to worry about external code calls.
  • Improved flexibility: Internal storage can be changed as needed without affecting external code.

Achieve encapsulation:

• Use access modifiers (public, protected, private) to control access permissions.
• Use the self variable inside the class to reference the instance.
• Avoid direct access to instance properties outside the class.

Abstract class

• Definition: An abstract class is a special class that limits class behavior. It contains abstract methods that cannot be instantiated.
• Purpose:
  • Define an interface to force subclasses to implement these methods.
  • Prevent the creation of instances that do not implement all abstract methods.

Implement abstract class:

• Use @abstractmethod decorator to mark abstract methods.
• Implement all abstract methods in subclasses.
• Abstract classes cannot be instantiated directly, only subclass instances can be created.

The difference between abstract methods and ordinary methods:

• Abstract methods are not implemented and must be implemented in subclasses.
• Common methods have been implemented in the parent class and can be inherited and overridden by subclasses.

Advantages of abstract classes:

• Ensure that all subclasses implement the required behavior.
• Improve code maintainability: avoid incomplete or inconsistent implementations by enforcing abstract methods.
• Promote interface consistency: Using the same abstract class in multiple modules can ensure interface consistency.

Disadvantages of abstract classes:

• Increased implementation complexity: all abstract methods must be implemented in subclasses.
• Possible lack of flexibility: subclasses cannot freely modify abstract methods.

The difference between encapsulation and abstract class

Application scenarios

Package:

• Sensitive data protection.
• Management of complex data.
• Improve code maintainability.

Abstract class:

• Define common interface.
• Ensure consistent behavior for inherited classes.
• Achieve polymorphism.

Best Practices

• Use encapsulation moderately and hide only necessary data.
• When using abstract classes, consider the implementation complexity and flexibility of subclasses.
• Use the abstractmethod suffix in abstract method names to improve code readability.
• When implementing an abstract method in a subclass, use super() to call the parent class implementation to take advantage of reuse.

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