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https://issues.apache.org/jira/browse/ARROW-18265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17637388#comment-17637388
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Joris Van den Bossche commented on ARROW-18265:
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bq. I think you are referring to this:
Indeed. But so in your code example above, the {{pc.field(0)* 2}} is used to
refer to the flat list values (the first child field). While the proposal in
this issue is to have {{pc.field(0)}} mean to select the first element of each
list value (eg in projections).
That seems quite a different meaning, and so I am not sure we should use the
same API for both use cases.
> [C++] Allow FieldPath to work with ListElement
> ----------------------------------------------
>
> Key: ARROW-18265
> URL: https://issues.apache.org/jira/browse/ARROW-18265
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++
> Reporter: Miles Granger
> Assignee: Miles Granger
> Priority: Major
> Labels: pull-request-available
> Fix For: 11.0.0
>
> Time Spent: 1h 40m
> Remaining Estimate: 0h
>
> {{FieldRef::FromDotPath}} can parse a single list element field. ie.
> {{{}'path.to.list[0]`{}}}but does not work in practice. Failing with:
> _struct_field: cannot subscript field of type list<....>_
> Being able to add a slice or multiple list elements is not within the scope
> of this issue.
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