[Rd] data.frame weirdness

[Deepayan Sarkar]

They differ in whether the row names are "automatic":

> .row_names_info(a1)
[1] -3
> .row_names_info(a2)
[1] 3

Best,
-Deepayan

On Tue, 14 Nov 2023 at 08:23, Gabor Grothendieck
<ggrothendieck using gmail.com> wrote:
>
> What is going on here?  In the lines ending in #### the inputs and outputs
> are identical yet one gives a warning and the other does  not.
>
> a1 <- `rownames<-`(anscombe[1:3, ],  NULL)
> a2 <- anscombe[1:3, ]
>
> ix <- 5:8
>
> # input arguments to #### are identical in both cases
>
> identical(stack(a1[ix]), stack(a2[ix]))
> ## [1] TRUE
> identical(a1[-ix], a2[-ix])
> ## [1] TRUE
>
>
> res1 <- data.frame(stack(a1[ix]), a1[-ix]) ####
> res2 <- data.frame(stack(a2[ix]), a2[-ix]) ####
> ## Warning message:
> ## In data.frame(stack(a2[ix]), a2[-ix]) :
> ##   row names were found from a short variable and have been discarded
>
> # results are identical
> identical(res1, res2)
> ## [1] TRUE
>
>
> --
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