Guide · updated 2026-11-04
Mapping categories with an approved dictionary
How to turn free-typed categories into a controlled vocabulary without guessing.
Normalize, then map
Trim and fold case first, then look values up in a reviewed mapping table. Normalize the table's keys the same way.
Unmapped means exception
A value not in the dictionary goes to the exception report as unmapped. Nearest-match guessing turns typos into silent decisions.
Keep the mapping as data
Store the mapping in a table with the raw value, the approved value and who approved it. Version it and reuse it in SQL, pandas and visual pipelines.