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name: python-patterns description: This skill should be used for Python idioms, type hints, async/await, pytest, Django, Flask, FastAPI, Python web frameworks, pandas, data processing whenToUse: Python code, type hints, async, pytest, .py files, Django, Flask, FastAPI, Python web, Python backend, pandas, data scripts whenNotToUse: Non-Python code, Jupyter-specific (use nbformat docs) seeAlso:

• skill: testing-strategies when: pytest architecture
• skill: api-design when: FastAPI/Flask endpoints
• skill: database-patterns when: SQLAlchemy models

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Python Patterns

Idiomatic Python patterns for Python 3.10+.

Type Hints

Copydef process(data: list[str]) -> dict[str, int]:
    return {item: len(item) for item in data}

Dataclasses

Copyfrom dataclasses import dataclass

@dataclass
class User:
    name: str
    email: str
    active: bool = True

Context Managers

Copywith open("file.txt") as f:
    content = f.read()

Pytest

Copyimport pytest

def test_add():
    assert add(2, 3) == 5

@pytest.fixture
def user():
    return User(name="test")

Async/Await

Copyasync def fetch_data(url: str) -> dict:
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as response:
            return await response.json()

Error Handling

Copytry:
    result = risky_operation()
except ValueError as e:
    logger.error(f"Invalid value: {e}")
    raise