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name: python description: Best practices for Python development including PEP 8, modern Python 3.10+ features, and package management. globs: ["/*.py", "/Pipfile", "/pyproject.toml", "/setup.py", "**/requirements.txt"] priority: 100 tags: ["language"]

Python Best Practices

Code Style

• Follow PEP 8 style guide
• Use snake_case for functions/variables
• Use PascalCase for classes
• Maximum line length: 88 (Black) or 79 (PEP 8)
• Use meaningful variable names

Modern Python (3.10+)

• Use f-strings for formatting: f"Hello {name}"
• Use pathlib for file paths instead of os.path
• Use dataclasses or Pydantic for data models
• Type hints for function signatures
• Use walrus operator := for assignment expressions
• Use match-case for pattern matching
• Use | for union types instead of Union

Error Handling

• Be specific with exception types
• Use context managers (with) for resources
• Log exceptions with traceback
• Never use bare except:
• Use finally for cleanup

Package Management

• Always use virtual environments (venv, conda, poetry)
• Pin dependency versions in requirements.txt
• Use pyproject.toml for modern projects
• Separate dev dependencies from production

Testing

• Use pytest over unittest
• Use fixtures for test setup
• Use parametrize for multiple test cases
• Aim for high test coverage