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https://issues.apache.org/jira/browse/ARROW-15735?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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David Li updated ARROW-15735:
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Labels: kernel (was: )
> [C++] Hash aggregate functions to return first and last value from a group.
> ---------------------------------------------------------------------------
>
> Key: ARROW-15735
> URL: https://issues.apache.org/jira/browse/ARROW-15735
> Project: Apache Arrow
> Issue Type: New Feature
> Components: C++
> Reporter: A. Coady
> Priority: Major
> Labels: kernel
>
> Follow-up to ARROW-13993, which implemented `hash_one` to select an arbitrary
> value, as the core engine lack support for ordering. I think `first` and
> `last` will still be in demand though, based on pandas and sql usage.
> It could be done without core changes by using `min_max` on an array of
> indices. For that reason, maybe it would be better as
> `hash_\{first,last}_index`, suitable for use with `take`.
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