Atelier

Lesson 30 — Skills de l'agent Sheets

Cleaning without losing anything

2 min read

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This agent cannot delete or clear. That is a strength: the original data stays intact and every step is auditable and reversible. Principle: raw data stays, the clean version lives next to it.

When the user asks to "delete"

Say in one sentence that you don't delete, then offer the best alternative:

  • Unwanted rows → a "To delete" column (TRUE) + a filter or filter view that hides them; the user can then delete them in two clicks (filter TRUE, select, delete rows). Offer to set this up.
  • Unused columns / tabs → hide them (hiddenByUser / hidden).
  • Duplicates → a "Deduplicated" tab with =UNIQUE(Data!A1:F) (or =SORTN(Data!A2:F,9^9,2,1,TRUE) to dedupe on key column 1), + conditional formatting that highlights duplicates in the source.
  • Wrong value → write the correct value (sheets_ecrire, with confirmation), never an emptied cell.

New tab "Clean data", one array formula per column:

  • Spaces / invisible chars: =ARRAYFORMULA(IF(A2:A="",,TRIM(CLEAN(A2:A)))); case: PROPER / UPPER.
  • Numbers stored as text: =ARRAYFORMULA(IF(B2:B="",,VALUE(SUBSTITUTE(SUBSTITUTE(B2:B," ",""),",",".")))).
  • Text dates "12/10/2026": =ARRAYFORMULA(IF(C2:C="",,DATE(RIGHT(C2:C,4),MID(C2:C,4,2),LEFT(C2:C,2)))).
  • Postcodes / IDs losing leading zeros: TEXT(A2,"00000"); phone/email extraction: REGEXEXTRACT.
  • Inconsistent labels ("Lille", "LILLE", "lille ") → a mapping table + XLOOKUP, or PROPER(TRIM()).
  • Filtered and sorted in one go: =SORT(FILTER(Data!A2:F,Data!F2:F<>"Cancelled"),2,TRUE). Then run sheets_profil on the clean tab to PROVE the result (blanks, duplicates, types).

Merging tabs or files

={January!A2:F;February!A2:F;March!A2:F} stacks tabs with the same column layout; drop blank rows with =QUERY({January!A2:F;February!A2:F},"select * where Col1 is not null",0). Add a source column if needed: ={ARRAYFORMULA(IF(January!A2:A="",,"January")),January!A2:F}. Other spreadsheet: IMPORTRANGE (the user clicks "Allow access" once).

Sort, filter, reorganize

  • sortRange (row order only, nothing lost); setBasicFilter; addFilterView (named personal view, doesn't disturb others).
  • Reorder columns: moveDimension. Add a column in the middle: insertDimension.

Data-quality report (offer it)

Per column: % filled, invalid values, duplicates, outliers — from sheets_profil — as a short table, plus the fix applied for each issue.

Always

State before/after in numbers ("1,240 rows, 37 duplicates, 12 unreadable dates → fixed in tab Clean data") and give the link.

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