Single Responsibility Principle (SRP)
This principle states that each class should have a single responsibility. It emphasizes that a class should perform one specific function and not have too many reasons to change.
Example: Managing user information and sending email notifications.
class UserManager: def create_user(self, user_data): # Logic for creating a user pass class EmailService: def send_email(self, email_data): # Logic for sending an email pass
Open/Closed Principle (OCP)
This principle encourages extending functionality by adding new code rather than modifying existing code.
Example: Handling different payment methods in an e-commerce application.
from abc import ABC, abstractmethod class PaymentProcessor(ABC): @abstractmethod def process_payment(self): pass class CreditCardPaymentProcessor(PaymentProcessor): def process_payment(self): # Logic for processing credit card payment pass class PayPalPaymentProcessor(PaymentProcessor): def process_payment(self): # Logic for processing PayPal payment pass
Liskov Substitution Principle (LSP)
This principle asserts that objects of a derived class should be substitutable for objects of the base class without affecting the correctness of the program.
Example: Managing geometric shapes.
class Shape: def area(self): pass class Rectangle(Shape): def area(self): return self.width * self.height class Square(Shape): def area(self): return self.side * self.side
Interface Segregation Principle (ISP)
This principle advises breaking interfaces into smaller ones to avoid forcing classes to implement methods they don't need.
Example: Interfaces for updating and displaying data.
class UpdateableFeature: @abstractmethod def update_feature(self): pass class DisplayableFeature: @abstractmethod def display_feature(self): pass
Dependency Inversion Principle (DIP)
This principle suggests using dependency injection to manage dependencies.
Example: Using dependency injection to manage dependencies.
class OrderProcessor: def __init__(self, db_connection, email_service): self.db_connection = db_connection self.email_service = email_service
Remember that applying SOLID principles in Python should be done flexibly based on the specific purpose of your project and your understanding of SOLID and Python.