Example code for the book Fluent Python, Second Edition by Luciano Ramalho (O'Reilly, 2022).

This repository ships with a pyproject.toml and uv.lock so a single shared environment covers the example code across chapters. Python 3.12 is pinned via .python-version.

uv sync

That installs the runtime deps (click, fastapi, geolib, httpx, tqdm, uvicorn) plus the dev tools (pytest, mypy, ruff) into .venv/.

Use uv run — no need to activate the venv:

uv run python 19-concurrency/spinner_thread.py
uv run python 20-executors/demo_executor_map.py

pytest.ini is configured with --doctest-modules, so most chapter files double as doctests:

uv run pytest 11-pythonic-obj/vector2d_v0.py
uv run pytest 17-it-generator/sentence.py

uv run mypy 11-pythonic-obj/vector2d_v0.py
uv run ruff check 11-pythonic-obj/

• curio (used only in 21-async/domains/curio) is not in the shared env — its latest release is broken on Python 3.12. To run that example, create a separate environment with Python ≤3.11:

  cd 21-async/domains/curio && uv venv --python 3.11 && uv pip install curio

• A few chapters have their own requirements.txt from the upstream book repo. They overlap with the root environment and can generally be ignored.

All chapters are undergoing review and updates, including significant rewrites in the chapters about concurrency in Part V.

New chapters in Fluent Python 2e are marked with 🆕.

🚨  This table of contents is subject to change at any time until the book goes to the printer.
Latest change: Old Part I—Prologue merged into new Part I—Data Structures; parts renumbered accordingly; chapter numbers unchanged.