Thank you, Rui! This is incredibly helpful -- anonymous functions are new to me, and I appreciate being shown how useful they are.
Best regards, David On Wed, Dec 12, 2012 at 10:12 AM, Rui Barradas <ruipbarra...@sapo.pt> wrote: > Hello, > > As for the first question try > > scoreset <- lapply(pcl, function(x) x$scores[, 1]) > do.call(cbind, scoreset) > > > As for the second question, you want to know which columns in 'datasets' > have NA's? > > colidx <- apply(datasets, 2, function(x) any(is.na(x))) > datasets[, colidx] # These have NA's > > > For the column numbers you can do > > colnums <- which(colidx) > > Hope this helps, > > Rui Barradas > > Em 12-12-2012 17:14, David Romano escreveu: >> >> Hi everyone, >> >> Suppose I have a 3D array of datasets, where say dimension 1 corresponds >> to >> cases, dimension 2 to datasets, and dimension 3 to observations within a >> dataset. As an example, suppose I do the following: >> >>> x <- sample(1:20, 48, replace=TRUE) >>> datasets <- array(x, dim=c(4,3,2)) >> >> Here, for each j=1,2,3, I'd like to think of datasets[,j,] as a single >> data >> matrix with four cases and two observations. Now, I'd like to be able to >> do the following: apply pca to each dataset, and create a matrix of the >> first principal component scores. >> >> In this example, I could do: >> >>> pcl<-apply(datasets,2,princomp) >> >> which yields a list of princomp output, one for each dataset, so that the >> vector of first principal component scores for dataset 1 is obtained by >> >>> score1set1 <- pcl[[1]]$scores[,1] >> >> and I could then obtain the desired matrix by >> >>> score1matrix <- cbind( score1set1, score1set2, score1set3) >> >> >> So my first question is: 1) how could I use *apply to do this? I'm having >> trouble because pcl is a list of lists, so I can't use, say, >> do.call(cbind, >> ...) without first having a list of the first component score vectors, >> which I'm not sure how to produce. >> >> My second question is: 2) Having answered question 1), now suppose there >> may be datasets containing NA value -- how could I select the subset of >> values from dimension 2 corresponding to the datasets for which this is >> true (again using *apply?)? >> >> Thanks in advance for any light you might be able to shed on these >> questions! >> >> David Romano >> >> [[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.
