[ARROW-5859] [Python] Support ExtentionType on conversion to numpy/pandas

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.16.0
• Component/s: Python
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/22276
• Assignee: Joris Van den Bossche
• Reporter: Joris Van den Bossche
• Created: 04/Jul/19 21:51
• Updated: 11/Jan/23 07:43
• Resolved: 19/Nov/19 10:43

Description

Currently converting a Table of RecordBatch with an ExtensionType array to pandas gives:

ArrowNotImplementedError: No known equivalent Pandas block for Arrow data of type extension<arrow.py_extension_type> is known.

And similarly converting the array itself to a python object (to_pandas or to_pylist) gives an ArrowNotImplementedError or a "KeyError: 28"

Initial support could be to fall back to the storage type.

Issue Links

• links to: GitHub Pull Request #5826