Question 1

How do I create a Python virtual environment?

Accepted Answer

Create virtual environment: python -m venv venv (or python3 -m venv venv). Activate Linux/Mac: source venv/bin/activate. Activate Windows: venv\Scripts\activate. Exit: deactivate. Virtual environment isolates project dependencies. Always use venv for Python projects to avoid conflicts. Delete venv folder to remove.

Question 2

How do I install Python packages?

Accepted Answer

Install package: pip install package-name. Install specific version: pip install package==1.2.3. Install from requirements file: pip install -r requirements.txt. Install development version: pip install git+https://github.com/user/repo.git. Save dependencies: pip freeze > requirements.txt. Always activate venv before installing.

Question 3

How do I run Python tests?

Accepted Answer

Run pytest: python -m pytest (or pytest). Run unittest: python -m unittest discover. Verbose output: pytest -v. Run specific test: pytest test_file.py::test_function. Coverage: pytest --cov=src. Parallel tests: pytest -n auto (pytest-xdist). Install pytest first: pip install pytest pytest-cov.

Question 4

How do I format Python code?

Accepted Answer

Format with Black: python -m black file.py (pip install black first). Format with autopep8: python -m autopep8 --in-place file.py. Check style: python -m flake8 file.py. Lint: python -m pylint file.py. Black is opinionated formatter, autopep8 follows PEP 8. Configure in pyproject.toml or .flake8.

Question 5

How do I build and publish a Python package?

Accepted Answer

Install build tools: pip install build twine. Build package: python -m build (creates dist/). Upload to PyPI: twine upload dist/*. Check package: twine check dist/*. Use pyproject.toml for modern packaging. Test PyPI: twine upload --repository testpypi dist/*. Register at pypi.org before publishing.

Python Command Cheat Sheet

Python Commands (31)

Virtual Environment Workflow

Pip vs Conda vs Poetry