Python Development

Write clean, performant, idiomatic Python code.

When to Use

Writing Python code
Refactoring Python projects
Performance optimization
Setting up Python tooling
Code review for Python

Python Best Practices

Code Style

Follow PEP 8
Use type hints (Python 3.9+)
Prefer f-strings over .format()
Use pathlib over os.path

Modern Features

# Type hints
def process(data: list[dict]) -> dict[str, int]:
    ...

# Dataclasses
from dataclasses import dataclass

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

# Context managers
from contextlib import contextmanager

@contextmanager
def timer():
    start = time.time()
    yield
    print(f"Elapsed: {time.time() - start:.2f}s")

# Generators for memory efficiency
def read_large_file(path):
    with open(path) as f:
        yield from f

Error Handling

# Custom exceptions
class ValidationError(Exception):
    def __init__(self, field: str, message: str):
        self.field = field
        self.message = message
        super().__init__(f"{field}: {message}")

# Proper exception chaining
try:
    process()
except ValueError as e:
    raise ProcessingError("Failed to process") from e

Project Structure

project/
├── src/
│   └── package/
│       ├── __init__.py
│       └── module.py
├── tests/
│   └── test_module.py
├── pyproject.toml
└── README.md

Tooling Setup

# pyproject.toml
[tool.ruff]
line-length = 88
select = ["E", "F", "I", "UP"]

[tool.mypy]
strict = true

[tool.pytest.ini_options]
testpaths = ["tests"]

Testing Pattern

import pytest

@pytest.fixture
def sample_data():
    return {"key": "value"}

def test_process(sample_data):
    result = process(sample_data)
    assert result["status"] == "success"

Examples

Input: "Refactor this Python code" Action: Apply PEP 8, add type hints, simplify logic, improve error handling

Input: "Make this faster" Action: Profile, identify bottlenecks, use generators/caching, verify improvement

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