python-ruleslisted

# Python Development ## Virtual Environment Runner Wrong -- bare python3 has no project dependencies: ```bash python3 scripts/run_analysis.py # ModuleNotFoundError: No module named 'pandas' ``` Right -- use the project's venv runner: ```bash uv run python scripts/run_analysis.py # Or: poetry run python scripts/run_analysis.py # Or: pipenv run python scripts/run_analysis.py ``` ## Package-Relative Imports Wrong -- direct execution breaks relative imports: ```bash python scripts/etl/transform.py # ModuleNotFoundError: No module named 'scripts.etl.utils' ``` Right -- use -m for scripts with package imports: ```bash python -m scripts.etl.transform ``` ## Python Version for uv Wrong -- uv auto-selects newest Python, packages lack wheels: ```bash uv sync # error: No wheel found for numpy on Python 3.14 ``` Right -- specify a stable Python version: ```bash # Check project requirements: cat .python-version # Pin the version: uv sync --python 3.13 ``` ## pip on macOS Wrong -- system pip blocked by PEP 668 on macOS: ```bash pip3 install httpie # error: externally-managed-environment ``` Right -- use brew for CLI tools, pipx for Python apps: ```bash brew install httpie # Or for Python-specific apps: pipx install httpie ```