python-patterns_skill

Overview

This skill documents Pythonic idioms, PEP 8 standards, type hints, and pragmatic best practices for building robust, efficient, and maintainable Python applications. It focuses on readable, explicit code, modern typing, error handling, concurrency patterns, and sensible project layout. Use it as a checklist during coding, reviews, and refactors to keep code consistent and production-ready.

How this skill works

The skill inspects common development patterns and recommends replacements for anti-patterns with concrete code examples. It highlights readability, explicit behavior, EAFP error handling, type annotations (including Protocols and TypeVar), context managers, generators, data classes, decorators, and concurrency choices. It also prescribes package layout, import conventions, and tooling commands to automate style and quality checks.

When to use it

• Writing new Python modules or services
• Performing code reviews or pair programming
• Refactoring legacy code to modern Python idioms
• Designing package structure and public API exports
• Choosing concurrency model for I/O vs CPU-bound work

Best practices

• Prefer clear, descriptive names and small functions; readability over clever one-liners
• Favor explicit configuration and avoid hidden side effects; follow PEP 8 import order
• Use modern type hints and Protocols to document intent and enable static checking
• Apply EAFP: catch specific exceptions and chain errors to preserve tracebacks
• Use context managers for resource safety and dataclasses for simple value objects
• Pick concurrency model by task type: threads for I/O, processes for CPU, async for many concurrent I/O tasks

Example use cases

• Add type hints and Protocols to a public API to improve editor tooling and mypy checks
• Refactor a memory-heavy class to use __slots__ and generators to reduce peak memory
• Replace complex list comprehensions with generator functions for clarity and performance
• Implement custom context managers for transactions or timing to centralize resource logic
• Set up black, isort, ruff, mypy and pytest in CI to enforce style, types, and tests