Data & control flow. The shapes data takes and the loops that walk through them.

Python's workhorse data structure. Creating, reading, slicing, mutability, and the three mistakes every beginner makes.

append, extend, insert, remove, pop, sort. sorted vs sort. Slicing with step, slice assignment, and the reference-vs-copy trap.

Lists aren't the only shape data takes. Dicts for key/value lookups, sets for uniqueness and fast membership, tuples for fixed groupings.

Indefinite iteration: retry loops, polling, input validation. When to choose while over for, and how to avoid infinite loops.

The workhorse loop. range(), enumerate(), zip(), looping over dicts, and an intro to list comprehensions for one-liners.

Exit early with break, skip iterations with continue, work with nested loops without writing spaghetti. Plus the rare loop-else clause.

Deeper on functions: positional vs keyword, defaults, *args, **kwargs, returning multiple values, and the design rules for signatures that don't suck.