> 1) Bill and Hervé (I think) propose that 'recycle0' should have > no effect whenever 'collapse = <string>'
I think that collapse=<string> should make paste() return a single string, regardless of the value of recycle0. E.g., I would like to see > paste0("X",seq_len(3),collapse=", ", recycle0=TRUE) [1] "X1, X2, X3" > paste0("X",seq_len(0),collapse=", ", recycle0=TRUE) [1] "" Currently the latter gives character(0). paste's collapse argument has traditionally acted after all the other arguments were dealt with, as in the following not extensively tested function. altPaste <- function (..., collapse = NULL) { tmp <- paste(...) if (!is.null(collapse)) { paste(tmp, collapse=collapse) } else { tmp } } E.g., in post-R-4.0.0 R-devel > altPaste("X", seq_len(3), sep="", collapse=", ") [1] "X1, X2, X3" > altPaste("X", seq_len(0), sep="", collapse=", ") [1] "X" > altPaste("X", seq_len(0), sep="", collapse=", ", recycle0=TRUE) [1] "" I think it would be good if the above function continued to act the same as paste itself. Bill Dunlap TIBCO Software wdunlap tibco.com On Thu, May 21, 2020 at 9:42 AM Martin Maechler <maech...@stat.math.ethz.ch> wrote: > >>>>> Hervé Pagès > >>>>> on Fri, 15 May 2020 13:44:28 -0700 writes: > > > There is still the situation where **both** 'sep' and 'collapse' are > > specified: > > >> paste(integer(0), "nth", sep="", collapse=",") > > [1] "nth" > > > In that case 'recycle0' should **not** be ignored i.e. > > > paste(integer(0), "nth", sep="", collapse=",", recycle0=TRUE) > > > should return the empty string (and not character(0) like it does at > the > > moment). > > > In other words, 'recycle0' should only control the first operation > (the > > operation controlled by 'sep'). Which makes plenty of sense: the 1st > > operation is binary (or n-ary) while the collapse operation is > unary. > > There is no concept of recycling in the context of unary operations. > > Interesting, ..., and sounding somewhat convincing. > > > On 5/15/20 11:25, Gabriel Becker wrote: > >> 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 > > Just to summarize what I think we should know and agree (or be > be "disproven") and where this comes from ... > > 1) recycle0 is a new R 4.0.0 option in paste() / paste0() which by default > (recycle0 = FALSE) should (and *does* AFAIK) not change anything, > hence paste() / paste0() behave completely back-compatible > if recycle0 is kept to FALSE. > > 2) recycle0 = TRUE is meant to give different behavior, notably > 0-length arguments (among '...') should result in 0-length results. > > The above does not specify what this means in detail, see 3) > > 3) The current R 4.0.0 implementation (for which I'm primarily responsible) > and help(paste) are in accordance. > Notably the help page (Arguments -> 'recycle0' ; Details 1st para ; > Examples) > says and shows how the 4.0.0 implementation has been meant to work. > > 4) Several provenly smart members of the R community argue that > both the implementation and the documentation of 'recycle0 = > TRUE' should be changed to be more logical / coherent / sensical .. > > Is the above all correct in your view? > > Assuming yes, I read basically two proposals, both agreeing > that recycle0 = TRUE should only ever apply to the action of 'sep' > but not the action of 'collapse'. > > 1) Bill and Hervé (I think) propose that 'recycle0' should have > no effect whenever 'collapse = <string>' > > 2) Gabe proposes that 'collapse = <string>' and 'recycle0 = TRUE' > should be declared incompatible and error. If going in that > direction, I could also see them to give a warning (and > continue as if recycle = FALSE). > > I have not yet my mind up but would tend to agree to "you guys", > but I think that other R Core members should chime in, too. > > Martin > > >> On Fri, May 15, 2020 at 11:05 AM Hervé Pagès <hpa...@fredhutch.org > >> <mailto:hpa...@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 > >> < > https://urldefense.proofpoint.com/v2/url?u=http-3A__tibco.com&d=DwMFaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=cC2qctlVXd0qHMPvCyYvuVMqR8GU3DjTTqKJ0zjIFj8&s=rXIwWqf4U4HZS_bjUT3KfA9ARaV5YTb_kEcXWHnkt-c&e= > > > >> > > >> > > >> > On Thu, Apr 30, 2020 at 9:56 PM suharto_anggono--- via R-devel < > >> > r-devel@r-project.org <mailto:r-devel@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@r-project.org <mailto:R-devel@r-project.org> mailing > list > >> >> > >> > https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Ddevel&d=DwICAg&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=776IovW06eUHr1EDrabHLY7F47rU9CCUEItSDI96zc0&s=xN84DhkZeoxzn6SG0QTMpOGg2w_ThmjZmZymGUuD0Uw&e= > >> >> > >> > > >> > [[alternative HTML version deleted]] > >> > > >> > ______________________________________________ > >> > R-devel@r-project.org <mailto:R-devel@r-project.org> mailing list > >> > > >> > https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Ddevel&d=DwICAg&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=776IovW06eUHr1EDrabHLY7F47rU9CCUEItSDI96zc0&s=xN84DhkZeoxzn6SG0QTMpOGg2w_ThmjZmZymGUuD0Uw&e= > >> > > >> > >> -- > >> 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 > >> > >> E-mail: hpa...@fredhutch.org <mailto:hpa...@fredhutch.org> > >> Phone: (206) 667-5791 > >> Fax: (206) 667-1319 > >> > >> ______________________________________________ > >> R-devel@r-project.org <mailto:R-devel@r-project.org> mailing list > >> https://stat.ethz.ch/mailman/listinfo/r-devel > >> < > https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Ddevel&d=DwMFaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=cC2qctlVXd0qHMPvCyYvuVMqR8GU3DjTTqKJ0zjIFj8&s=COnDeGgHNnHJlLLZOznMlhcaFU1nIRlkaSbssvlrMvw&e= > > > >> > > > -- > > 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 > > > E-mail: hpa...@fredhutch.org > > Phone: (206) 667-5791 > > Fax: (206) 667-1319 > > > ______________________________________________ > > R-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel