Course › Week 2

Week 2. Clean and trust the data

Profiling, contracts, Polars/DuckDB, Claude Code, quality gates. QSR chain.

Raw data is evidence; it is not yet information. This week you turn messy daily drops into typed, validated, explainable tables, and you learn where an AI assistant like Claude Code speeds this up and where it must be fenced in.

Sector: quick-service restaurants (three burger, taco and wing brands, 18 locations, a business day that runs past midnight).

Proof project 2: qsr-clean: a cleaning pipeline with data contracts, a quarantine for bad rows, a data-quality report, and tests, built in Polars and DuckDB.

Days

1. Day 8 Profiling and data contracts 4h · learn 70m · lab 130m · ship 25m · review 15m
2. Day 9 Transforming with Polars and DuckDB 4h · learn 60m · lab 140m · ship 25m · review 15m
3. Day 10 The messy-data field guide 4h · learn 75m · lab 125m · ship 25m · review 15m
4. Day 11 Cleaning with Claude Code and open models 4h · learn 70m · lab 130m · ship 25m · review 15m
5. Day 12 Duplicates, keys and entity resolution 4h · learn 65m · lab 135m · ship 25m · review 15m
6. Day 13 Quality gates, quarantine and the DQ report 4h · learn 60m · lab 140m · ship 25m · review 15m
7. Day 14 Proof 2: qsr-clean, a trustworthy cleaning pipeline 4h · build 150m · README 60m · review 30m