[Rd] paste(character(0), collapse="", recycle0=FALSE) should be ""

[Gabriel Becker]

Hi all,

This makes sense to me, but I would think that recycle0 and collapse should
actually be incompatible and paste should throw an error if recycle0 were
TRUE and collapse were declared in the same call. I don't think the value
of recycle0 should be silently ignored if it is actively specified.

~G

On Fri, May 15, 2020 at 11:05 AM Hervé Pagès <hpages using fredhutch.org> wrote:

> Totally agree with that.
>
> H.
>
> On 5/15/20 10:34, William Dunlap via R-devel wrote:
> > I agree: paste(collapse="something", ...) should always return a single
> > character string, regardless of the value of recycle0.  This would be
> > similar to when there are no non-NULL arguments to paste; collapse="."
> > gives a single empty string and collapse=NULL gives a zero long character
> > vector.
> >> paste()
> > character(0)
> >> paste(collapse=", ")
> > [1] ""
> >
> > Bill Dunlap
> > TIBCO Software
> > wdunlap tibco.com
> >
> >
> > On Thu, Apr 30, 2020 at 9:56 PM suharto_anggono--- via R-devel <
> > r-devel using r-project.org> wrote:
> >
> >> Without 'collapse', 'paste' pastes (concatenates) its arguments
> >> elementwise (separated by 'sep', " " by default). New in R devel and R
> >> patched, specifying recycle0 = FALSE makes mixing zero-length and
> >> nonzero-length arguments results in length zero. The result of paste(n,
> >> "th", sep = "", recycle0 = FALSE) always have the same length as 'n'.
> >> Previously, the result is still as long as the longest argument, with
> the
> >> zero-length argument like "". If all og the arguments have length zero,
> >> 'recycle0' doesn't matter.
> >>
> >> As far as I understand, 'paste' with 'collapse' as a character string is
> >> supposed to put together elements of a vector into a single character
> >> string. I think 'recycle0' shouldn't change it.
> >>
> >> In current R devel and R patched, paste(character(0), collapse = "",
> >> recycle0 = FALSE) is character(0). I think it should be "", like
> >> paste(character(0), collapse="").
> >>
> >> paste(c("4", "5"), "th", sep = "", collapse = ", ", recycle0 = FALSE)
> >> is
> >> "4th, 5th".
> >> paste(c("4"     ), "th", sep = "", collapse = ", ", recycle0 = FALSE)
> >> is
> >> "4th".
> >> I think
> >> paste(c(        ), "th", sep = "", collapse = ", ", recycle0 = FALSE)
> >> should be
> >> "",
> >> not character(0).
> >>
> >> ______________________________________________
> >> R-devel using r-project.org mailing list
> >>
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> >>
> >
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> >
>
> --
> Hervé Pagès
>
> Program in Computational Biology
> Division of Public Health Sciences
> Fred Hutchinson Cancer Research Center
> 1100 Fairview Ave. N, M1-B514
> P.O. Box 19024
> Seattle, WA 98109-1024
>
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