You said: "The elements of the first vector are irrelevant because they are only counted, so we should get the same result if it were a character vector, but we don't: "
You don't get to invent your own rules! ?ave -- always nice to read the Help docs **before posting** -- clearly states that the x argument must be __numeric__. So if you choose to ignore what you are told, you do so at your own risk. Who knows what you'll get? -- it's a user error, not a bug. And if (my understanding of) what you say is the case, this whole post is silly. See ?table to do exactly what you claim is wanted without trying to invent square wheels. Cheers, Bert Bert Gunter Genentech Nonclinical Biostatistics (650) 467-7374 "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." Clifford Stoll On Wed, Dec 24, 2014 at 11:30 AM, Mike Miller <mbmille...@gmail.com> wrote: > R 3.0.1 on Linux 64... > > I was working with someone else's code. They were using ave() in a way that > I guess is nonstandard: Isn't FUN always supposed to be a variant of > mean()? The idea was to count for every element of a factor vector how many > times the level of that element occurs in the factor vector. > > > gl() makes a factor: > >> gl(2,2,5) > > [1] 1 1 2 2 1 > Levels: 1 2 > > > ave() applies FUN to produce the desired count, and it works: > >> ave( 1:5, gl(2,2,5), FUN=length ) > > [1] 3 3 2 2 3 > > > The elements of the first vector are irrelevant because they are only > counted, so we should get the same result if it were a character vector, but > we don't: > >> ave( as.character(1:5), gl(2,2,5), FUN=length ) > > [1] "3" "3" "2" "2" "3" > > The output has character type, but it is supposed to be a collection of > vector lengths. > > > Two questions: > > (1) Is that a bug in ave()? It certainly is unexpected. > > (2) What is the best way to do this sort of thing? > > The truth is that we start with a character vector and we want to create an > integer vector that tells us for every element of the character vector how > many times that string occurs. Here are two vectors of length 6 that should > give the same result: > >> intvec <- c(4,5,6,5,6,6) >> charvec <- c("A","B","C","B","C","C") > > > The code was used like this with integer vectors and it seemed to work: > >> ave( intvec, intvec, FUN=length ) > > [1] 1 2 3 2 3 3 > > When a character vector came along, it would fail by producing a character > vector as output: > >> ave( charvec, charvec, FUN=length ) > > [1] "1" "2" "3" "2" "3" "3" > > This seems more appropriate, and it might always work, but is it OK?: > >> ave( rep(1, length(charvec)), as.factor(charvec), FUN=sum ) > > [1] 1 2 3 2 3 3 > > I suspect that ave() isn't the best choice, but what is the best way to do > this? > > > Thanks in advance. > > Mike > > ______________________________________________ > 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. ______________________________________________ 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.