The first line was missing. It should be: mat <- do.call(rbind, a) sapply(apply(mat, 2, table), function(x) mean(as.numeric(names(x))[x == length(a)]))
On Jan 11, 2008 7:23 PM, Gabor Grothendieck <[EMAIL PROTECTED]> wrote: > Assume that no component matrix can have repeated values. > > First we apply table to mat yielding a list of named counts. > To each component of that we sapply the indicated function > which picks out those that occur length(a) times (so they are > in every column), converts the name to numeric and averages > them. > > sapply(apply(mat, 2, table), function(x) mean(as.numeric(names(x))[x > == length(a)])) > > By the way, note that the a you define is slightly different from the > a displayed in your post. > > > On Jan 11, 2008 6:09 PM, dxc13 <[EMAIL PROTECTED]> wrote: > > > > useR's, > > > > I want to match the real number elements of a list that has 3 matrices as > > its elements and then average those numbers. I think I am close, but I > > can't get it to quite work out. For example, > > > > > a <- list(matrix(c(10,NA,NA,12,11, > > > 10,13,NA,14,12),ncol=2),matrix(c(10,12,15,13,11, > > > 13,NA,NA,12,10),ncol=2),matrix(c(10,15,NA,13,NA, 13,12,NA,NA,10),ncol=2)) > > > a > > [[1]] > > [,1] [,2] > > [1,] 10 10 > > [2,] NA 13 > > [3,] NA NA > > [4,] 13 14 > > [5,] 11 12 > > > > [[2]] > > [,1] [,2] > > [1,] 10 13 > > [2,] 12 NA > > [3,] 15 NA > > [4,] 13 12 > > [5,] 11 10 > > > > [[3]] > > [,1] [,2] > > [1,] 10 13 > > [2,] 15 12 > > [3,] NA NA > > [4,] 13 NA > > [5,] NA 10 > > > > I want to average the non-NA numbers that simultaneously appear in each > > column of all 3 matrices. For the first column, 10 and 13 are the only > > numbers that appear in all 3 matrices. Thus, I want to take the average of > > 10 and 13. Then repeat the same process for the second column. The data > > here is only a sample, but with the data I work with, there are many more > > columns in each matrix in the list. Does anyone know a efficient way to do > > this? Maybe using lapply()? Thanks in advance. > > > > dxc13 > > -- > > View this message in context: > > http://www.nabble.com/matching-values-in-a-list-tp14767170p14767170.html > > Sent from the R help mailing list archive at Nabble.com. > > > > ______________________________________________ > > 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.
