[jira] [Commented] (ARROW-11259) [Python] Allow to create field reference to nested field

["Ben Kietzman (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARROW-11259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17289159#comment-17289159 ] 

Ben Kietzman commented on ARROW-11259:
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Note that this will require some added functionality for FieldRef, since some functions assume only top level fields will be materialized. For example IpcReadOptions::included_fields is a set of indices of top level fields. So we'll need to add functionality to extract the top level field from a nested FieldRef

> [Python] Allow to create field reference to nested field
> --------------------------------------------------------
>
>                 Key: ARROW-11259
>                 URL: https://issues.apache.org/jira/browse/ARROW-11259
>             Project: Apache Arrow
>          Issue Type: Improvement
>          Components: Python
>            Reporter: Joris Van den Bossche
>            Priority: Major
>              Labels: dataset
>             Fix For: 4.0.0
>
>
> Currently in the Python layer we have {{ds.field(name)}} for referencing a field eg when creating a filter expression.
> On the C++ side, the {{FieldRef}} has the ability to reference nested fields (eg a child of a struct), for example constructed with {{FieldRef::FromDotPath}}.
> We should think about how to enable users to reference nested fields like this in the Python API.



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