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https://issues.apache.org/jira/browse/ARROW-17096?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17567865#comment-17567865
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Yibo Cai commented on ARROW-17096:
----------------------------------
cc [~jorisvandenbossche] , [~apitrou] for comments.
In below test, the printed result *[false, false]* is wrong, but the underlying
buffer is correct *[false, true]* (00, 01).
Fiddling the buffer directly, looks pyarrow is treating the buffer as bitmap
(one bit per value), not one byte per value like C++ compute kernel.
{code:python}
In [1]: import pyarrow.compute as pc
In [2]: import pyarrow as pa
In [3]: m = pc.mode(pa.array([True, False]), 2)
In [4]: m.field(0)
Out[4:
<pyarrow.lib.BooleanArray object at 0x7fc50da06460>
[
false,
false
]
In [5]: m.field(0).buffers()[1].to_pybytes()
Out[5]: b'\x00\x01'
{code}
> pyarrow.compute.mode for boolean arrays does not return true when mixed with
> false
> ----------------------------------------------------------------------------------
>
> Key: ARROW-17096
> URL: https://issues.apache.org/jira/browse/ARROW-17096
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++, Python
> Affects Versions: 8.0.0
> Reporter: Matthew Roeschke
> Assignee: Yibo Cai
> Priority: Major
>
> {code:java}
> In [1]: import pyarrow.compute as pc
> In [2]: import pyarrow as pa
> In [3]: pa.__version__
> Out[3]: '8.0.0'
> In [4]: pc.mode(pa.array([True, True]))
> # Correct
> Out[4]:
> <pyarrow.lib.StructArray object at 0x1266d5c60>
> -- is_valid: all not null
> -- child 0 type: bool
> [
> true
> ]
> -- child 1 type: int64
> [
> 2
> ]
> # Incorrect
> In [5]: pc.mode(pa.array([True, False]), 2)
> Out[5]:
> <pyarrow.lib.StructArray object at 0x1262110c0>
> -- is_valid: all not null
> -- child 0 type: bool
> [
> false, # should be true
> false
> ]
> -- child 1 type: int64
> [
> 1,
> 1
> ] {code}
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