Uwe L. Korn created ARROW-2428: ---------------------------------- Summary: [Python] Support ExtensionArrays in to_pandas conversion Key: ARROW-2428 URL: https://issues.apache.org/jira/browse/ARROW-2428 Project: Apache Arrow Issue Type: Improvement Components: Python Reporter: Uwe L. Korn Fix For: 1.0.0
With the next release of Pandas, it will be possible to define custom column types that back a {{pandas.Series}}. Thus we will not be able to cover all possible column types in the {{to_pandas}} conversion by default as we won't be aware of all extension arrays. To enable users to create {{ExtensionArray}} instances from Arrow columns in the {{to_pandas}} conversion, we should provide a hook in the {{to_pandas}} call where they can overload the default conversion routines with the ones that produce their {{ExtensionArray}} instances. This should avoid additional copies in the case where we would nowadays first convert the Arrow column into a default Pandas column (probably of object type) and the user would afterwards convert it to a more efficient {{ExtensionArray}}. This hook here will be especially useful when you build {{ExtensionArrays}} where the storage is backed by Arrow. The meta-issue that tracks the implementation inside of Pandas is: https://github.com/pandas-dev/pandas/issues/19696 -- This message was sent by Atlassian JIRA (v7.6.3#76005)