[SPARK-24444] Improve pandas_udf GROUPED_MAP docs to explain column assignment

• Type: Documentation
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.0
• Fix Version/s: 2.3.1, 2.4.0
• Component/s: PySpark
• Target Version/s: 2.3.1, 2.4.0
• Assignee: Bryan Cutler
• Reporter: Bryan Cutler
• Created: 31/May/18 18:48
• Updated: 12/Dec/22 18:11
• Resolved: 01/Jun/18 17:54

Description

There have been several bugs regarding this and a clean solution still changes some behavior.  Until this can be resolved, improve docs to explain that columns are assigned by position.

Issue Links

• is related to: SPARK-24324 Pandas Grouped Map UserDefinedFunction mixes column labels
• links to: [Github] Pull Request #21471 (BryanCutler)
• links to: [Github] Pull Request #21478 (BryanCutler)