Python 3 Deep Dive

Notes from the Python 3 Deep Dive series (Udemy). Course

Mental Model

Everything is an object — functions and classes included; names are references bound to objects.
Mutable vs immutable — list/dict/set mutable; int/str/tuple immutable. Drives copying, default-arg, and hashing gotchas.
Truthiness — empty containers, 0, None, "" are falsy.
is vs == — identity vs equality; is only for None / singletons.
PEP 8 (style), PEP 20 (import this).

Tooling

uv venv && source .venv/bin/activate   # venv + installs (uv)
uvx ruff check . && uvx ruff format .  # lint + format, no install
python -m pytest                       # tests