MeritKeep

Dicts and sets

Lookup by key and membership testing, and the reason both are fast — which is also the reason their keys have to be hashable.

core~2hWe mark it against a checklist you can read first
The barWhat counts as knowing this

Use a dict or set to replace a linear scan, and explain what it costs

That sentence is the bar. It only counts once your work shows you can do it. Reading about it does not.
Prove itA check for this one skill

Up to 3 questions on this skill alone, marked against the bar beside this. It stops as soon as the answer is clear. No account, and your answers are not kept.

01 · Prerequisites

You'll need these first

03 · What comes next

What it unlocks

Start on Python Fundamentals

Every skill above, ordered by what depends on what, with the projects above that as the evidence you actually did it. We work out where you already are first, so the path skips what you can do.

About three minutes to set up. Nothing is marked until you hand something in.Start this path
Part of Python Fundamentals.

One cookie, so we can see which subjects people finish and where the site loses them — plus a replay of where you click. Nothing you type is recorded, and once you’re signed in the words on screen are blanked out too. No advertising, nothing sold. The detail.