On Fri, Jun 22, 2012 at 5:53 PM, Rui Barradas <ruipbarra...@sapo.pt> wrote: > Hello, > > 2L is an integer, 2 might be or not. In the case of apply(), there is no > difference. > > All possible values for margin? Any possible(*) combination of the > dimensions of 'x' in > > apply(x, margin, function) > > (*) non-null. If, say, x <- array(0, dim=c(2,3,4)) (3dim) then you can call > any of > > apply(x, 1, fun) or apply(x, 2, fun) or apply(x, 3, fun) but not margin=4; > apply(x, 1:2, fun) or apply(x, c(1, 3), fun) or ... > apply(x, 1:3, fun)
You can also get away with negative indexing in apply(): x <- array(1:24, dim = c(2,3,4)) apply(x, -1, sum) apply(x, -c(1,3), sum) but you seem to loose the array structure. As usual, you can't mix apply(x, c(-1, 2), sum) # ERROR It also seems zero doesn't work here: apply(x, 0, sum) # ERROR Best, Michael > > Hope this helps, > > Rui Barradas > > Em 22-06-2012 23:23, Luba G escreveu: > >> What is the difference of using 2L versus 2 as the margin argument in the >> apply() function? Where can I find detailed information on all of the >> possible margin arguments? >> >>> x >> >> [,1] [,2] >> [1,] 1 2 >> [2,] 3 4 >> [3,] 5 6 >> [4,] 7 8 >> [5,] 9 10 >>> >>> sqrt(apply(x, *2L*, function(r.st) var(r.st[!is.na(r.st)]))) >> >> [1] 3.162278 3.162278 >>> >>> sqrt(apply(x,* 2*, function(r.st) var(r.st[!is.na(r.st)]))) >> >> [1] 3.162278 3.162278 >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> 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. ______________________________________________ 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.
