You can avoid the problem in Martin's example by only giving scalars to stopifnot(). E.g., using stopifnot(all(x>0)) or stopifnot(length(x)==1, x>0) instead of stopifnot(x>0). I think having stopifnot call all(predicate) if length(predicate)!=1 was probably a mistake.
Bill Dunlap TIBCO Software wdunlap tibco.com On Mon, Apr 13, 2020 at 9:28 AM Hervé Pagès <hpa...@fredhutch.org> wrote: > > > On 4/13/20 05:30, Martin Maechler wrote: > >>>>>> peter dalgaard > >>>>>> on Mon, 13 Apr 2020 12:00:38 +0200 writes: > > > > > Inline... > > >> On 13 Apr 2020, at 11:15 , Martin Maechler < > maech...@stat.math.ethz.ch> wrote: > > >> > > >>>>>>> Bert Gunter > > >>>>>>> on Sun, 12 Apr 2020 16:30:09 -0700 writes: > > >> > > >>> Don't know if this has come up before, but ... > > >>>> x <- c(0,0) > > >>>> length(x) > > >>> [1] 2 > > >>> ## but > > >>>> stopifnot(length(x)) > > >>> Error: length(x) is not TRUE > > >>> Called from: top level > > >>> ## but > > >>>> stopifnot(length(x) > 0) ## not an error; nor is > > >>>> stopifnot(as.logical(length(x))) > > >>> ## Ouch! > > >> > > >>> Maybe the man page should say something about not assuming > automatic > > >>> coercion to logical, which is the usual expectation. Or fix > this. > > >> > > >>> Bert Gunter > > >> > > >> Well, what about the top most paragraph of the help page is not > clear here ? > > >> > > >>> Description: > > >> > > >>> If any of the expressions (in '...' or 'exprs') are not 'all' > > >>> 'TRUE', 'stop' is called, producing an error message indicating > > >>> the _first_ expression which was not ('all') true. > > >> > > > > > This, however, is somewhat less clear: > > > > > ..., exprs: any number of (typically but not necessarily > ‘logical’) R > > > expressions, which should each evaluate to (a logical vector > > > of all) ‘TRUE’. Use _either_ ‘...’ _or_ ‘exprs’, the latter > > > > > What does it mean, "typically but not necessarily ‘logical’"? > > > > That's a good question: The '(....)' must have been put there a while > ago. > > I agree that it's not at all helpful. Strictly, we are really > > dealing with unevaluated expressions anyway ("promises"), but > > definitely all of them must evaluate to logical (vector or > > array..) of all TRUE values. In the very beginning of > > stopifnot(), I had thought that it should also work in other > > cases, e.g., for Matrix(TRUE, 4,5) {from the Matrix package} etc, > > but several use cases had convinced us / me that stopifnot > > should be stricter... > > > > > The code actually tests explicitly with is.logical, as far as I > can tell. > > > > > This creates a discrepancy between if(!...)stop(...) and > stopifnot(), > > > > yes indeed, on purpose now, for a very long time ... > > > > There's another discrepancy, more dangerous I think, > > as shown in the following > > {Note this discrepancy has been noted for a long time .. also on > > this R-devel list} : > > > > m <- matrix(1:12, 3,4) > > i <- (1:4) %% 2 == 1 & (0:3) %% 5 == 0 > > > > stopifnot(dim(m[,i]) == c(3,1)) # seems fine > > > > if(dim(m[,i]) != c(3,1)) stop("wrong dim") # gives an error (but not > ..) > > mmh... that is not good. I was under the impression that we could at > least expect 'stopifnot(x)' to be equivalent to 'if (!isTRUE(x)) > stop(...)'. I'll have to revisit my use of stopifnot() in many many > places... again :-/ Or may be just stop using it and use 'if > (!isTRUE(...))' instead. > > H. > > > > > > > Martin > > > > >> as in > > >> f <- function (x) if (!x) stop(paste(deparse(substitute(x)), "is > not TRUE")) > > >> f(0) > > > Error in f(0) : 0 is not TRUE > > >> f(1) > > >> stopifnot(0) > > > Error: 0 is not TRUE > > >> stopifnot(1) > > > Error: 1 is not TRUE > > > > > -pd > > > > > > >> If useR's expectations alone would guide the behavior of a > > >> computer language, the language would have to behave > > >> "personalized" and give different results depending on the user, > > >> which may be desirable in medicine or psychotherapy but not with > R. > > >> > > >> Martin > > >> > > >> ______________________________________________ > > >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, > see > > >> > https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Dhelp&d=DwIDaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=2kAPk_-c9XEQGS0BB1rf03oPxqQtflyqhqi-0BT8bWE&s=W8I5sRKBBKZgSjXrQC_PQw6XXUApw5h2DI5EUoDdl9w&e= > > >> PLEASE do read the posting guide > https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.org_posting-2Dguide.html&d=DwIDaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=2kAPk_-c9XEQGS0BB1rf03oPxqQtflyqhqi-0BT8bWE&s=ADWOmjdAMLWT3rJRMz411RnDjrc6Vyj4NNmZMoM3Sck&e= > > >> and provide commented, minimal, self-contained, reproducible > code. > > > > > -- > > > Peter Dalgaard, Professor, > > > Center for Statistics, Copenhagen Business School > > > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > > > Phone: (+45)38153501 > > > Office: A 4.23 > > > Email: pd....@cbs.dk Priv: pda...@gmail.com > > > > ______________________________________________ > > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Dhelp&d=DwIDaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=2kAPk_-c9XEQGS0BB1rf03oPxqQtflyqhqi-0BT8bWE&s=W8I5sRKBBKZgSjXrQC_PQw6XXUApw5h2DI5EUoDdl9w&e= > > PLEASE do read the posting guide > https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.org_posting-2Dguide.html&d=DwIDaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=2kAPk_-c9XEQGS0BB1rf03oPxqQtflyqhqi-0BT8bWE&s=ADWOmjdAMLWT3rJRMz411RnDjrc6Vyj4NNmZMoM3Sck&e= > > and provide commented, minimal, self-contained, reproducible code. > > > > -- > 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-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.