[jira] [Commented] (ARROW-9594) [Python] DictionaryArray.to_numpy does not correctly convert null indexes to null values

["Steve M. Kim (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARROW-9594?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17261743#comment-17261743 ] 

Steve M. Kim commented on ARROW-9594:
-------------------------------------

i checked and confirmed that this is broken in pyarrow 2.0.0

> [Python] DictionaryArray.to_numpy does not correctly convert null indexes to null values
> ----------------------------------------------------------------------------------------
>
>                 Key: ARROW-9594
>                 URL: https://issues.apache.org/jira/browse/ARROW-9594
>             Project: Apache Arrow
>          Issue Type: Bug
>    Affects Versions: 1.0.0
>            Reporter: Steve M. Kim
>            Priority: Major
>
> Example
> {code:java}
> >>> a = pa.DictionaryArray.from_arrays(pa.array([0, 1, None, 0], type=pa.int32()), pa.array(['foo', 'bar']))
> >>> a
> <pyarrow.lib.DictionaryArray object at 0x7f12fc94ccf0>-- dictionary:
>   [
>     "foo",
>     "bar"
>   ]
> -- indices:
>   [
>     0,
>     1,
>     null,
>     0
>   ]
> >>> a.to_pandas()  # this works
> 0    foo
> 1    bar
> 2    NaN
> 3    foo
> dtype: category
> Categories (2, object): [foo, bar]
> >>> a.to_numpy(zero_copy_only=False)  # this is broken
> array(['foo', 'bar', 'bar', 'foo'], dtype=object)
> {code}
>  



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