[Rd] Parser bug? A comma too much.
peter dalgaard
pd@|gd @end|ng |rom gm@||@com
Fri Sep 16 17:00:06 CEST 2022
As a general matter, empty arguments are allowed and are used meaningfully in some contexts, notably A[i,], which is syntactic sugarcoating of "["(A,i,).
I.e., these are different:
> "["(Sigma,2,) # 2nd row
[1] 0.077 0.168
> "["(Sigma,2) # 2nd element
[1] 0.077
It is somewhat rare to have an empty last argument, intermediate ones are more common:
> seq(0,1,,5)
[1] 0.00 0.25 0.50 0.75 1.00
-pd
> On 16 Sep 2022, at 16:33 , Rui Barradas <ruipbarradas using sapo.pt> wrote:
>
> Hello,
>
> Why doesn't the comma throw an error?
>
>
> plot(1:5,) # works, no complaints
>
>
> Shouldn't this be considered a bug? I would expect the parser to at least give a warning.
>
>
> sessionInfo()
> R version 4.2.1 (2022-06-23 ucrt)
> Platform: x86_64-w64-mingw32/x64 (64-bit)
> Running under: Windows 10 x64 (build 22000)
>
> Matrix products: default
>
> locale:
> [1] LC_COLLATE=Portuguese_Portugal.utf8 LC_CTYPE=Portuguese_Portugal.utf8
> [3] LC_MONETARY=Portuguese_Portugal.utf8 LC_NUMERIC=C
> [5] LC_TIME=Portuguese_Portugal.utf8
>
> attached base packages:
> [1] stats graphics grDevices utils datasets methods base
>
> loaded via a namespace (and not attached):
> [1] compiler_4.2.1
>
>
> Rui Barradas
>
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--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes using cbs.dk Priv: PDalgd using gmail.com
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