Feat add pivot transform to mo.UI.dataframe #7345

[heizerbalazs]

📝 Summary

Fixes #7345

🔍 Description of Changes

Backend

• Created handler and types for PivotTransform in marimo/_plugins/ui/_impl/dataframes/transforms
• Ibis backend doesn't support pivot. The handler implementation is using group_by.

Frontend

• Added icon to mo.ui.dataframe transform panel.
• Added PivotTransformSchema with column_ids, index_column_ids, value_column_ids, aggregation parameters in frontend/src/plugins/impl/data-frames/schema.ts.
• Added effect to collect unique column values so new column names can be generated on the frontend. frontend/src/plugins/impl/data-frames/panel.ts

📋 Checklist

• I have read the contributor guidelines.
• For large changes, or changes that affect the public API: this change was discussed or approved through an issue, on Discord, or the community discussions (Please provide a link if applicable).
• I have added tests for the changes made.
• I have run the code and verified that it works as expected.

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Project	Deployment	Review	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jan 5, 2026 6:21pm

[github-actions]

All contributors have signed the CLA ✍️ ✅
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[heizerbalazs]

I have read the CLA Document and I hereby sign the CLA

[Light2Dark]

tq!

[github-actions]

🚀 Development release published. You may be able to view the changes at https://marimo.app?v=0.18.5-dev179