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https://issues.apache.org/jira/browse/ARROW-14457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17433765#comment-17433765
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Neal Richardson commented on ARROW-14457:
-----------------------------------------
{{Array$create(c(1, 2)) * Array$create(3)}} should error; you probably think it
should work (by recycling) because R treats length-1 vectors as scalars because
it has no proper scalar type. {{Array$create(c(1, 2)) * Scalar$create(3)}} does
recycle (and is what you get when you do {{Array$create(c(1, 2)) * 3}}).
{{Array$create(c(1,2)) * c(3, 4)}} could be made to work, and in fact there's a
TODO about it here:
https://github.com/apache/arrow/blob/master/r/R/arrow-datum.R#L127
> [R] Support multiplying Arrays by R vectors and scalar value recycling
> ----------------------------------------------------------------------
>
> Key: ARROW-14457
> URL: https://issues.apache.org/jira/browse/ARROW-14457
> Project: Apache Arrow
> Issue Type: Improvement
> Components: R
> Reporter: Nicola Crane
> Priority: Major
>
> Scalar value recycling doesn't work on Arrays:
> {code:r}
> > Array$create(c(1, 2)) * 3
> Array
> <double>
> [
> 3,
> 6
> ]
> > Array$create(c(1, 2)) * Array$create(c(3))
> Error: Invalid: Array arguments must all be the same length
> /home/nic2/arrow/cpp/src/arrow/compute/exec.cc:569
> ExecBatchIterator::Make(args, exec_context()->exec_chunksize())
> /home/nic2/arrow/cpp/src/arrow/compute/exec.cc:705
> this->SetupArgIteration(args)
> /home/nic2/arrow/cpp/src/arrow/compute/exec.cc:630 PrepareExecute(args)
> /home/nic2/arrow/cpp/src/arrow/compute/function.cc:239
> executor->Execute(implicitly_cast_args, &listener)
> {code}
> Neither does multiplying by vectors (as they are converted to Scalar lists)
> {code:r}
> > Array$create(c(1,2)) * c(3,4)
> Error: NotImplemented: Function multiply_checked has no kernel matching
> input types (array[double], scalar[list<item: double>])
> /home/nic2/arrow/cpp/src/arrow/compute/function.cc:215 DispatchBest(&inputs)
> > Array$create(c(1, 2)) * Array$create(c(3, 4))
> Array
> <double>
> [
> 3,
> 8
> ]
> {code}
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