Beginner · every module free · 5 challenges
The Python that ML code is actually written in: types, generators, decorators, context managers and a test suite.
Broadcasting, striding, and deleting the loop — the skill every framework is built on top of.
pandas and Polars, joins, group-bys, time series, and finding the problem in the data before it becomes a problem in the model.
Window functions, CTEs, query plans and the schema design questions that appear in ML interviews.
Encoding, scaling, splits that do not leak, and pipelines that produce the same features in training and serving.