Bert, I think this is what is needed for the data frame
ix <- cbind(1:2,2:3) ixm <- matrix(FALSE,4,3) ixm[ix] <- TRUE zdf[ixm] <- NA Hope this is helpful, Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of Bert Gunter > Sent: Tuesday, May 01, 2012 11:46 AM > To: Duncan Murdoch > Cc: r-help@r-project.org > Subject: Re: [R] Data frame vs matrix quirk: Hinky error message? > > Duncan: > > Maybe there **is** a bug, then. > > > zmat <- matrix(1:12,nr=4) > > zdf <- data.frame(zmat) > > ix <- cbind(c(FALSE,TRUE),c(TRUE,TRUE)) > > zmat[ix] > [1] 2 3 4 6 7 8 10 11 12 > > zdf[ix] > [1] 2 3 4 6 7 8 10 11 12 > > zmat[ix] <- NA > > zmat > [,1] [,2] [,3] > [1,] 1 5 9 > [2,] NA NA NA > [3,] NA NA NA > [4,] NA NA NA > > ## ?? > > > zdf[ix] <- NA > Error in `[<-.data.frame`(`*tmp*`, ix, value = NA) : > only logical matrix subscripts are allowed in replacement > > That matrix replacement should not work with (in general mixed type) > data frames seems reasonable, actually. Trying to "fix things" may not > be. But I leave this to you and your fellow expeRts, > > Cheers, > Bert > > > On Tue, May 1, 2012 at 11:30 AM, Duncan Murdoch > <murdoch.dun...@gmail.com> wrote: > > On 01/05/2012 2:12 PM, Bert Gunter wrote: > >> > >> Many thanks, Ista: > >> > >> I only looked in "].default" so the answer is: Alternative 4: dumb > >> Bert. Rap knuckles with ruler. > >> > >> Actually, indexing by a logical matrix doesn't make much sense to > me > >> in either case, as it does not have the effect of selecting > individual > >> elements, which is what numeric matrix indices do. But that's a > matter > >> of usage, neither bug nor feature. > >> > >> If I had gotten something like the error message: "Matrix indices > not > >> allowed for replacement in data frames," I would not have been > >> surprised. But as you said, the behavior **IS** documented. > > > > > > Your version is not correct: matrix indices *are* allowed for > replacement, > > but only logical matrix indices, not two column numerical ones. The > > message might be clearer if instead of saying "only logical matrix > > subscripts are allowed in replacement" > > it said "matrix subscripts must be logical matrices in replacement", > but I > > think the basic problem is the limitation. I'll fix that. > > > > Duncan Murdoch > > > >> > >> Best, > >> Bert > >> > >> > >> > >> On Tue, May 1, 2012 at 10:49 AM, Ista Zahn<istaz...@gmail.com> > wrote: > >> > Hi Bert, > >> > > >> > The failure itself is the documented behavior: ?'[.data.frame' > says > >> > > >> > "Matrix indexing ('x[i]' with a logical or a 2-column integer > >> > matrix 'i') using '[' is not recommended, and barely > supported. > >> > For extraction, 'x' is first coerced to a matrix. For > >> > replacement, a logical matrix (only) can be used to select > the > >> > elements to be replaced in the same way as for a matrix." > >> > > >> > The error message may be a bit hinky, as obviously data.frames > can be > >> > indexed by things other than logical matricies. Or is there > another > >> > reason this strikes you as odd? > >> > > >> > Best, > >> > Ista > >> > > >> > On Tue, May 1, 2012 at 1:33 PM, Bert > Gunter<gunter.ber...@gene.com> > >> > wrote: > >> >> AdvisoRs: > >> >> > >> >> Is the following a bug, feature, hinky error message, or dumb > Bert? > >> >> > >> >>> mtest<- matrix(1:12,nr=4) > >> >>> dftest<- data.frame(mtest) > >> >>> ix<- cbind(1:2,2:3) > >> >>> mtest[ix]<- NA > >> >>> mtest > >> >> [,1] [,2] [,3] > >> >> [1,] 1 NA 9 > >> >> [2,] 2 6 NA > >> >> [3,] 3 7 11 > >> >> [4,] 4 8 12 > >> >> > >> >> ## But ... > >> >>> dftest[ix]<- NA > >> >> Error in `[<-.data.frame`(`*tmp*`, ix, value = NA) : > >> >> only logical matrix subscripts are allowed in replacement > >> >> > >> >> Obviously, I was expecting matrix indexing for replacement to > work > >> >> similarly in both cases; however, I can see why it would be > >> >> problematic for data frames (mixed types), but was a bit > nonplussed by > >> >> the error message, which seems hinky to me. > >> >> > >> >> Cheers, > >> >> Bert > >> >> > >> >> -- > >> >> > >> >> Bert Gunter > >> >> Genentech Nonclinical Biostatistics > >> >> > >> >> Internal Contact Info: > >> >> Phone: 467-7374 > >> >> Website: > >> >> > >> >> http://pharmadevelopment.roche.com/index/pdb/pdb-functional- > groups/pdb-biostatistics/pdb-ncb-home.htm > >> >> > >> >> ______________________________________________ > >> >> R-help@r-project.org mailing list > >> >> 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. > >> > >> > >> > > > > > > -- > > Bert Gunter > Genentech Nonclinical Biostatistics > > Internal Contact Info: > Phone: 467-7374 > Website: > http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb- > biostatistics/pdb-ncb-home.htm > > ______________________________________________ > R-help@r-project.org mailing list > 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. ______________________________________________ R-help@r-project.org mailing list 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.
