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 <[email protected]> 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 > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: [email protected] Priv: [email protected] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
