# grouped(by:) Creates a grouping of rows that the method selects by choosing unique values in a column. ``` func grouped(by columnID: ColumnID) -> RowGrouping where GroupingKey : Hashable ``` ## Parameters `columnID` A column identifier. ## Return Value A collection of groups. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)