Hervé Pagès
2020-May-15 20:44 UTC
[Rd] paste(character(0), collapse="", recycle0=FALSE) should be ""
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. H. 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 > > On Fri, May 15, 2020 at 11:05 AM Herv? Pag?s <hpages at fredhutch.org > <mailto:hpages at 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 at r-project.org <mailto:r-devel at 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 at r-project.org <mailto:R-devel at 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 at r-project.org <mailto:R-devel at 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> > > > -- > Herv? Pag?s > > 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: hpages at fredhutch.org <mailto:hpages at fredhutch.org> > Phone:? (206) 667-5791 > Fax:? ? (206) 667-1319 > > ______________________________________________ > R-devel at r-project.org <mailto:R-devel at 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=> >-- Herv? Pag?s 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: hpages at fredhutch.org Phone: (206) 667-5791 Fax: (206) 667-1319
Martin Maechler
2020-May-21 16:42 UTC
[Rd] paste(character(0), collapse="", recycle0=FALSE) should be ""
>>>>> Herv? Pag?s >>>>> 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 Herv? (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 Herv? Pag?s <hpages at fredhutch.org >> <mailto:hpages at 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 at r-project.org <mailto:r-devel at 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 at r-project.org <mailto:R-devel at 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 at r-project.org <mailto:R-devel at 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 >> > >> >> -- >> Herv? Pag?s >> >> 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: hpages at fredhutch.org <mailto:hpages at fredhutch.org> >> Phone:? (206) 667-5791 >> Fax:? ? (206) 667-1319 >> >> ______________________________________________ >> R-devel at r-project.org <mailto:R-devel at 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=> >> > -- > Herv? Pag?s > 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: hpages at fredhutch.org > Phone: (206) 667-5791 > Fax: (206) 667-1319 > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel
William Dunlap
2020-May-21 17:22 UTC
[Rd] paste(character(0), collapse="", recycle0=FALSE) should be ""
> 1) Bill and Herv? (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 <maechler at stat.math.ethz.ch> wrote:> >>>>> Herv? Pag?s > >>>>> 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 Herv? (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 Herv? Pag?s <hpages at fredhutch.org > >> <mailto:hpages at 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 at r-project.org <mailto:r-devel at 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 at r-project.org <mailto:R-devel at 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 at r-project.org <mailto:R-devel at 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> >> > > >> > >> -- > >> Herv? Pag?s > >> > >> 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: hpages at fredhutch.org <mailto:hpages at fredhutch.org> > >> Phone: (206) 667-5791 > >> Fax: (206) 667-1319 > >> > >> ______________________________________________ > >> R-devel at r-project.org <mailto:R-devel at 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> > > >> > > > -- > > Herv? Pag?s > > > 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: hpages at fredhutch.org > > Phone: (206) 667-5791 > > Fax: (206) 667-1319 > > > ______________________________________________ > > R-devel at r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel >[[alternative HTML version deleted]]
Gabriel Becker
2020-May-22 10:00 UTC
[Rd] paste(character(0), collapse="", recycle0=FALSE) should be ""
Hi Martin et al, On Thu, May 21, 2020 at 9:42 AM Martin Maechler <maechler at stat.math.ethz.ch> wrote:> >>>>> Herv? Pag?s > >>>>> 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 Herv? (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). >Herve makes a good point about when sep and collapse are both set. That said, if the user explicitly sets recycle0, Personally, I don't think it should be silently ignored under any configuration of other arguments. If all of the arguments are to go into effect, the question then becomes one of ordering, I think. Consider paste(c("a", "b"), NULL, c("c", "d"), sep = " ", collapse = ",", recycle0=TRUE) Currently that returns character(0), becuase the logic is essenttially (in pseudo-code) collapse(paste(c("a", "b"), NULL, c("c", "d"), sep = " ", recycle0=TRUE), collapse = ", ", recycle0=TRUE) -> collapse(character(0), collapse = ", " recycle0=TRUE) -> character(0) Now Bill Dunlap argued, fairly convincingly I think, that paste(..., collapse=<string>) should *always* return a character vector of length exactly one. With recycle0, though, it will return "" via the progression paste(c("a", "b"), NULL, c("c", "d"), sep = " ", collapse = ",", recycle0=TRUE) -> collapse(character(0), collapse = ", ") -> "" because recycle0 is still applied to the sep-based operation which occurs before collapse, thus leaving a vector of length 0 to collapse. That is consistent but seems unlikely to be what the user wanted, imho. I think if it does this there should be at least a warning when paste collapses to "" this way, if it is allowed at all (ie if mixing collapse=<string> and recycle0=TRUE is not simply made an error). I would like to hear others' thoughts as well though. @Pages, Herve <hpages at fredhutch.org> @William Dunlap <wdunlap at tibco.com> is "" what you envision as thee desired and useful behavior there? Best, ~G> 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 Herv? Pag?s <hpages at fredhutch.org > >> <mailto:hpages at 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 at r-project.org <mailto:r-devel at 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 at r-project.org <mailto:R-devel at 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 at r-project.org <mailto:R-devel at 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> >> > > >> > >> -- > >> Herv? Pag?s > >> > >> 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: hpages at fredhutch.org <mailto:hpages at fredhutch.org> > >> Phone: (206) 667-5791 > >> Fax: (206) 667-1319 > >> > >> ______________________________________________ > >> R-devel at r-project.org <mailto:R-devel at 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> > > >> > > > -- > > Herv? Pag?s > > > 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: hpages at fredhutch.org > > Phone: (206) 667-5791 > > Fax: (206) 667-1319 > > > ______________________________________________ > > R-devel at r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel >[[alternative HTML version deleted]]
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