Martin Maechler
2018-Oct-17 14:14 UTC
[Rd] methods(class = class(<obj>)) - improve for |cl.| > 1 ?
With new "strict" settings in R-devel, the following glm() example> data(anorexia, package = "MASS") > fm <- glm(Postwt ~ Prewt + Treat + offset(Prewt), family = gaussian, data = anorexia) > methods(class = class(fm))Warning in grep(name, row.names(info)) : argument 'pattern' has length > 1 and only the first element will be used Warning in gsub(name, "", row.names(info)) : argument 'pattern' has length > 1 and only the first element will be used Warning in grep(pattern, all.names, value = TRUE) : argument 'pattern' has length > 1 and only the first element will be used Warning in grep(pattern, all.names, value = TRUE) : argument 'pattern' has length > 1 and only the first element will be used ........... ........... ........... [ca. 20 lines of warnings] and then shows the "glm" methods, but not "lm" ones. This is not a bug strictly, as ?methods says that class: a symbol or character string naming a class: only used if ?generic.function? is not supplied. and so the use of methods(class = class(<obj>)) is a user error when class(<obj>) is of length > 1. In the case of e.g. a randomForest() result, we also get 25 warnings, i.e. 50 lines, but then --->>> no methods found because > class(rf.fit) [1] "randomForest.formula" "randomForest" and no methods are defined for "randomForest.formula". --- Of course, all this works fine with S4 classes: There the full inheritance is used and all methods are found. Still, would it make sense to improve the underlying .S3methods() ? I assume it will break *some* overzealous package checks out there when .S3methods() and hence methods() would return *more* in such case. Comments? -- Martin Maechler ETH Zurich and R Core
Kevin Ushey
2018-Oct-19 17:55 UTC
[Rd] methods(class = class(<obj>)) - improve for |cl.| > 1 ?
I think this would be a good change. I think most users use the 'methods(class = <...>)' function to answer the question, "what methods can I call on objects with these classes?", and in that context I think it would be sensible for the function to accept more than one class. Kevin On Wed, Oct 17, 2018 at 7:15 AM Martin Maechler <maechler at stat.math.ethz.ch> wrote:> > With new "strict" settings in R-devel, the following glm() example > > > data(anorexia, package = "MASS") > > fm <- glm(Postwt ~ Prewt + Treat + offset(Prewt), family = gaussian, data = anorexia) > > methods(class = class(fm)) > Warning in grep(name, row.names(info)) : > argument 'pattern' has length > 1 and only the first element will be used > Warning in gsub(name, "", row.names(info)) : > argument 'pattern' has length > 1 and only the first element will be used > Warning in grep(pattern, all.names, value = TRUE) : > argument 'pattern' has length > 1 and only the first element will be used > Warning in grep(pattern, all.names, value = TRUE) : > argument 'pattern' has length > 1 and only the first element will be used > ........... > ........... > ........... > [ca. 20 lines of warnings] > > and then shows the "glm" methods, but not "lm" ones. > > This is not a bug strictly, as ?methods says that > > class: a symbol or character string naming a class: only used if > ?generic.function? is not supplied. > > and so the use of > > methods(class = class(<obj>)) > > is a user error when class(<obj>) is of length > 1. > > In the case of e.g. a randomForest() result, we also get 25 > warnings, i.e. 50 lines, but then > > --->>> no methods found > > because > > > class(rf.fit) > [1] "randomForest.formula" "randomForest" > > and no methods are defined for "randomForest.formula". > > --- > > Of course, all this works fine with S4 classes: There the full > inheritance is used and all methods are found. > > Still, would it make sense to improve the underlying .S3methods() ? > > I assume it will break *some* overzealous package checks out > there when .S3methods() and hence methods() would return *more* > in such case. > > Comments? > > -- > Martin Maechler > ETH Zurich and R Core > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel
Gabe Becker
2018-Oct-19 18:55 UTC
[Rd] methods(class = class(<obj>)) - improve for |cl.| > 1 ?
Martin and Kevin, Perhaps a variant of methods which more directly addresses the use-case Kevin mentions might be in order? I am happy to prepare a patch which implements a methodsForObj function (name very much negotiable), or a third obj argument to methods which takes the actual object and answers the question "what methods would I hit for an object just like this one?" directly. Is this something you (Martin, et al in R core), are interested in and would consider? I know people can always do methods(class = class(obj)) after the change being discussed (and contingent on that change what I described could be trivially implemented that way), but should they need to? Best, ~G On Fri, Oct 19, 2018 at 10:55 AM, Kevin Ushey <kevinushey at gmail.com> wrote:> I think this would be a good change. I think most users use the > 'methods(class = <...>)' function to answer the question, "what > methods can I call on objects with these classes?", and in that > context I think it would be sensible for the function to accept more > than one class. > > Kevin > > On Wed, Oct 17, 2018 at 7:15 AM Martin Maechler > <maechler at stat.math.ethz.ch> wrote: > > > > With new "strict" settings in R-devel, the following glm() example > > > > > data(anorexia, package = "MASS") > > > fm <- glm(Postwt ~ Prewt + Treat + offset(Prewt), family = gaussian, > data = anorexia) > > > methods(class = class(fm)) > > Warning in grep(name, row.names(info)) : > > argument 'pattern' has length > 1 and only the first element will be > used > > Warning in gsub(name, "", row.names(info)) : > > argument 'pattern' has length > 1 and only the first element will be > used > > Warning in grep(pattern, all.names, value = TRUE) : > > argument 'pattern' has length > 1 and only the first element will be > used > > Warning in grep(pattern, all.names, value = TRUE) : > > argument 'pattern' has length > 1 and only the first element will be > used > > ........... > > ........... > > ........... > > [ca. 20 lines of warnings] > > > > and then shows the "glm" methods, but not "lm" ones. > > > > This is not a bug strictly, as ?methods says that > > > > class: a symbol or character string naming a class: only used if > > ?generic.function? is not supplied. > > > > and so the use of > > > > methods(class = class(<obj>)) > > > > is a user error when class(<obj>) is of length > 1. > > > > In the case of e.g. a randomForest() result, we also get 25 > > warnings, i.e. 50 lines, but then > > > > --->>> no methods found > > > > because > > > > > class(rf.fit) > > [1] "randomForest.formula" "randomForest" > > > > and no methods are defined for "randomForest.formula". > > > > --- > > > > Of course, all this works fine with S4 classes: There the full > > inheritance is used and all methods are found. > > > > Still, would it make sense to improve the underlying .S3methods() ? > > > > I assume it will break *some* overzealous package checks out > > there when .S3methods() and hence methods() would return *more* > > in such case. > > > > Comments? > > > > -- > > Martin Maechler > > ETH Zurich and R Core > > > > ______________________________________________ > > 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 >-- Gabriel Becker, Ph.D Scientist Bioinformatics and Computational Biology Genentech Research [[alternative HTML version deleted]]