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Learning paths
Each path is an ordered route through existing lessons and graded exercises in one track. Browse freely; nothing is locked to the order.
Beginner: clean data visually
Learn the core moves (trim, missing values, mappings, duplicates, joins) by building pipelines step by step, with a ledger of what each step changed.
12 steps · New to data cleaning, no code.
SQL analyst: cleaning in DuckDB
Validate before you cast, build ordered exception reports, deduplicate with window functions and join without fan-out.
11 steps · Comfortable with SELECT; wants reliable cleaning queries.
pandas practitioner: cleaning with Python
Override the pandas defaults that change results: null-key merges, whitespace, NA strings, float money and unstable sorts.
10 steps · Writes pandas; wants to stop defaults from changing data.
Interview ready: explain every decision
Solve take-home style exercises, then practise explaining the trade-offs with the interview question bank.
9 steps · Preparing for analyst or analytics-engineer interviews.