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https://issues.apache.org/jira/browse/ARROW-6923?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wes McKinney updated ARROW-6923:
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Fix Version/s: 1.0.0
> [C++] Option for Filter kernel how to handle nulls in the selection vector
> --------------------------------------------------------------------------
>
> Key: ARROW-6923
> URL: https://issues.apache.org/jira/browse/ARROW-6923
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++
> Reporter: Joris Van den Bossche
> Priority: Major
> Fix For: 1.0.0
>
>
> How nulls are handled in the boolean mask (selection vector) in a filter
> kernel varies between languages / data analytics systems (e.g. base R
> propagates nulls, dplyr R skips (sees as False), SQL generally skips them as
> well I think, Julia raises an error).
> Currently, in Arrow C++ we "propagate" nulls (null in the selection vector
> gives a null in the output):
> {code}
> In [7]: arr = pa.array([1, 2, 3])
> In [8]: mask = pa.array([True, False, None])
> In [9]: arr.filter(mask)
> Out[9]:
> <pyarrow.lib.Int64Array object at 0x7fefe44b3048>
> [
> 1,
> null
> ]
> {code}
> Given the different ways this could be done (propagate, skip, error), should
> we provide an option to control this behaviour?
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