[Rd] Feature request: Allow comma after last element in a list

[Tomek Gieorgijewski]

Thank you for the link - definitely worth trying!

T.

czw., 30 kwi 2026 o 21:24 Duncan Murdoch <murdoch.duncan using gmail.com>
napisał(a):

>
> This is a great suggestion.  BTW, I think it would be possible to do
> this in RStudio as well.  See their Addins page here:
> https://rstudio.github.io/rstudioaddins/ .
>
> Duncan Murdoch
>
> On 2026-04-30 1:44 p.m., Tomek Gieorgijewski wrote:
> > Hi Manfred!
> >
> > As I can see that you already maintain the habit to have one element per
> > line,
> > I would like to propose that you incorporate some editing scripts in your
> > editor
> > to help ease your frustration.
> > I believe trying to change R parser will only add more of that feeling :)
> > I don't know your editor but if it's vim, I can propose this edit to
> .vimrc
> > file:
> > " ----
> > function! ListCommas() range
> >         if a:firstline < a:lastline
> >             " Add commas at the end from first to second to last line if
> > there's no comma yet
> >             execute a:firstline . "," . (a:lastline - 1) . 's/[^,]$/&,/e'
> >         endif
> >          " Delete comma from last line (if matched)
> >         execute a:lastline . 's/,$//e'
> >     endfunction
> >
> >     vnoremap <leader>, :call ListCommas()<CR>
> > " ---
> >
> > So, now if you rerun vim on your file you can swap, add, delete lines
> from
> > the list as you wish,
> > and at the end you can highlight all elements lines of your list in
> visual
> > mode and execute ListCommas
> > function on those lines with <leader>, shortcut.
> >
> > Of course only if you maintain your structure of element per line and
> > trailing parenthesis at a seperate line.
> >
> > I'm sure VS Code, Emacs and some other editors have similar abilities to
> > help you.
> > Unfortunately I don't know of any such possibility in RStudio.
> >
> > regards,
> > Tomek.
> >
> > pt., 24 kwi 2026 o 13:35 Manfred Kooistra <manfred.kooistra using gmail.com>
> > napisał(a):
> >
> >> I've always been irritated that R doesn't allow a comma after the last
> >> element in a "list":
> >>
> >>> a <- c(
> >> +     1,
> >> +     2,
> >> +     3
> >> + )
> >>> a
> >> [1] 1 2 3
> >>> b <- c(
> >> +     1,
> >> +     2,
> >> +     3,
> >> + )
> >> Error in c(1, 2, 3, ) : argument 4 is empty
> >>
> >> This makes updating lists unnecessarily cumbersome, which I find I
> >> frequently do, either when I test code and want to run it with lists of
> >> varying elements or varying orders of elements or when I maintain lists
> >> manually over time and have to add or delete elements from them.
> >>
> >> Is there a reason for this behavior in R and might it not be a good idea
> >> to change it?
> >> ______________________________________________
> >> R-devel using r-project.org mailing list
> >> https://stat.ethz.ch/mailman/listinfo/r-devel
> >>
> >
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> >
> > ______________________________________________
> > R-devel using r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
>
>

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