[ARROW-9249] [C++] Implement "list_parent_indices" vector function

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0.0
• Component/s: C++
• External issue URL: https://github.com/apache/arrow/issues/25345
• Assignee: Wes McKinney
• Reporter: Wes McKinney
• Created: 27/Jun/20 16:02
• Updated: 11/Jan/23 08:05
• Resolved: 07/Jul/20 12:41

Description

The return value has the same size as the child array of a List type and contains values providing the "cell index" of each child value relative to the parent list array.

For example, the list array

[ [0, 1], null, [2], [3, 4]]

would output

[0, 0, 2, 3, 3]

Note that there is no null because the child array has no nulls. If the list has null values whose offsets point to non-empty child sections then these will have to be null in the output to preserve the contract that the output array has the same length as the child array

Issue Links

• is related to: ARROW-6775 [C++] [Python] Proposal for several Array utility functions