CSV Desk practice pack — 2026-10-22

Extract all files into one folder. Requires Python 3.9 or newer; standard library only.
Run commands in this folder (Windows: replace python3 with py -3):

python3 csv_structure_check.py quotes-input.csv
python3 csv_map_headers.py combined.csv schema-a.csv schema-b.csv schema-c.csv
python3 test_csv_practice.py

The mapping command creates a NEW output and refuses an existing name. Inputs are never modified. No network access or uploads. Output logs can contain source values. The scripts limit each input to 5 MB and hold decoded records in memory. They validate a fixed UTF-8/comma/double-quote dialect, not business correctness or spreadsheet-formula safety.

All sample records are fictional. The expected mapping file predates this release and is compared byte for byte. See csv-structure-mapping-test-notes.txt for actual checks and limitations.

Guides:
https://csvfieldguide.com/guides/csv-quotes-and-line-breaks/
https://csvfieldguide.com/guides/combine-csv-column-order/
