[ARROW-11259] [Python] Allow to create field reference to nested field

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 8.0.0
• Component/s: Python
• Labels: dataset pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/27160
• Assignee: Alenka Frim
• Reporter: Joris Van den Bossche
• Created: 15/Jan/21 08:36
• Updated: 11/Jan/23 08:18
• Resolved: 18/Apr/22 10:46

Description

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.

Issue Links

• blocks: ARROW-13798 [Python] Selective projection of struct fields errors with use_legacy_dataset = False
• blocks: ARROW-14596 [Python] parquet.read_table nested fields in columns does not work for use_legacy_dataset=False
• is blocked by: ARROW-13987 [C++] Support nested FieldRefs
• links to: GitHub Pull Request #9799
• links to: GitHub Pull Request #12863