R devel - Nov 2018 - Subsetting row in single column matrix drops names in resulting vector

Hello here. I'm struggling to understand R's subsetting behavior in
couple
of edge cases - subsetting row in a single column matrix and subsetting
column in a single row matrix. I've read R's docs several times and
haven't
found answer.

Consider following example:

a = matrix(1:2, nrow = 2, dimnames = list(c("row1", "row2"),
c("col1")))
a[1, ]
# 1

It returns *unnamed* vector `1` where I would expect named vector. In fact
it returns named vector when number of columns is > 1.
Same issue applicable to single row matrix. Is it a bug? looks very
counterintuitive.


-- 
Regards
Dmitriy Selivanov

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Hello,

Use drop = FALSE.

a[1, , drop = FALSE]
#     col1
#row1    1


Hope this helps,

Rui Barradas

?s 16:51 de 21/11/2018, Dmitriy Selivanov escreveu:
> Hello here. I'm struggling to understand R's subsetting behavior in
couple
> of edge cases - subsetting row in a single column matrix and subsetting
> column in a single row matrix. I've read R's docs several times and
haven't
> found answer.
> 
> Consider following example:
> 
> a = matrix(1:2, nrow = 2, dimnames = list(c("row1",
"row2"), c("col1")))
> a[1, ]
> # 1
> 
> It returns *unnamed* vector `1` where I would expect named vector. In fact
> it returns named vector when number of columns is > 1.
> Same issue applicable to single row matrix. Is it a bug? looks very
> counterintuitive.
> 
>

Hi Rui. Thanks for answer, I'm aware of drop = FALSE option. Unfortunately
it doesn't resolve the issue - I'm expecting to get a vector, not a
matrix .

??, 21 ????. 2018 ?. ? 20:54, Rui Barradas <ruipbarradas at sapo.pt>:
> Hello,
>
> Use drop = FALSE.
>
> a[1, , drop = FALSE]
> #     col1
> #row1    1
>
>
> Hope this helps,
>
> Rui Barradas
>
> ?s 16:51 de 21/11/2018, Dmitriy Selivanov escreveu:
> > Hello here. I'm struggling to understand R's subsetting
behavior in
> couple
> > of edge cases - subsetting row in a single column matrix and
subsetting
> > column in a single row matrix. I've read R's docs several
times and
> haven't
> > found answer.
> >
> > Consider following example:
> >
> > a = matrix(1:2, nrow = 2, dimnames = list(c("row1",
"row2"), c("col1")))
> > a[1, ]
> > # 1
> >
> > It returns *unnamed* vector `1` where I would expect named vector. In
> fact
> > it returns named vector when number of columns is > 1.
> > Same issue applicable to single row matrix. Is it a bug? looks very
> > counterintuitive.
> >
> >
>

-- 
Regards
Dmitriy Selivanov

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