Modules, Libraries and the Python Ecosystem

Nobody writes every line of a real program from scratch. Python ships with a large standard library — modules for maths, randomness, statistics, dates and time zones, counting and grouping, file paths, JSON, CSV, regular expressions and exact decimal money — and hundreds of thousands of further packages are a single pip install away. This track teaches you to find, import and use that code confidently, and to organise your own programs the same way: as modules and packages that other files can import.

It is written for learners who already know functions, data structures, text, files and error handling. The first half works through the standard-library modules you will reach for every week, with seeded randomness and fixed dates so every result is reproducible. The second half moves to the ecosystem around your code: splitting a program into files, packages and the if __name__ == "__main__" guard, then PyPI, pip, semantic versioning, virtual environments, requirements files and pyproject.toml. Commands you would type in a terminal are shown as clearly labelled demonstrations — the browser cannot run pip — and you practise the ideas behind them with real code: comparing versions, parsing requirement lines and reading project metadata. The track ends by reading documentation well, judging third-party packages, and building a small utility package step by step.