Google Cloud Dataprep Documentation Documentation group Parameter Identifies the column by which the dataset is grouped for purposes of applying the transform. Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 3.0 License, and code samples are licensed under the Apache 2.0 License. For details, see our Site Policies. Java is a registered trademark of Oracle and/or its affiliates. Last updated January 23, 2018.