Hi
The implementation answer is that grid::unit() calls as.numeric() on
'x', which drops names.
The design answer is that having names on units was (naively) not
considered in the original design.
The obstacle is that all functions that manipulate units would need to
be made "names-aware". That might be tricky for more complex units
like ...
max(unit(1:3, "in"))
... though I guess the behaviour of numeric vectors could provide a
role-model.
Paul
On 28/08/2025 2:08 am, David Firth via R-devel wrote:> I am asking here first, rather than filing a feature request directly. It
concerns a function in the grid package, maintained by R-core.
>
> Is there a reason why grid::unit(x, units) does not preserve the names (if
such exist) from vector x?
>
> I have a use-case where that would be helpful. But maybe there is some
obstacle that I have not thought of?
>
> Current behaviour seems to be:
>
>> x <- 7:9
>> names(x) <- letters[1:3]
>> x
> a b c
> 7 8 9
>> z <- grid::unit(x, "native")
>> z
> [1] 7native 8native 9native
>> str(z)
> 'simpleUnit' num [1:3] 7native 8native 9native
> - attr(*, "unit")= int 4
>> class(z)
> [1] "simpleUnit" "unit" "unit_v2"
>
> ## Now assign names
>> names(z) <- names(x)
>> z
> [1] 7native 8native 9native
>> names(z)
> [1] "a" "b" "c"
>> str(z)
> 'simpleUnit' Named num [1:3] 7native 8native 9native
> - attr(*, "unit")= int 4
> - attr(*, "names")= chr [1:3] "a" "b"
"c"
>
> I would welcome any comments or suggestions.
>
> Thanks -- David
>
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--
Dr Paul Murrell (he/him)
Te Kura Tatauranga | Department of Statistics
Waipapa Taumata Rau | The University of Auckland
Private Bag 92019, Auckland 1142, New Zealand
64 9 3737599 x85392
paul at stat.auckland.ac.nz
www.stat.auckland.ac.nz/~paul/