Python by Example 🐍

A collection of small Python code snippets demonstrating important (and sometimes surprising) behaviors of the language and libraries I use.

🚀 Getting Started

Setting Up the Environment

• NixOS users (like me 😉): Simply run nix-shell, and you’re ready to explore Python’s intricacies.

• Other systems: Use uv to configure the project:

  uv sync

  After this, you should be good to go!

Running Examples

Browse the examples/ directory (organized by topic), read the commented code to understand what each script does, and run it with Python. For example:

python examples/threads/sql_alchemy_is_not_thread_safe.py

Happy coding! 🎉

📑 Index

builtins

• booleans_are_integers - Demonstrates how Python booleans are actually a subtype of integers
• round_is_not_math_round - Shows that Python's default rounding uses banker's rounding (round-to-even) rather than standard mathematical rounding

functions

• default_mutable_args_are_bad - Illustrates unexpected behavior when using mutable data structures as default function arguments

threads

• race_conditions.py - Demonstrates race condition prevention during deque insertion (using a practical example)
• sql_alchemy_session_is_not_thread_safe.py - Shows a race condition that can occur with SQLAlchemy sessions due to their thread-unsafe nature