In that case use a modification of Jim's solution: a <- array(cbind(mat1, mat2, mat3), c(3, 3, 3)) apply(a, 1:2, mean, na.rm = TRUE)
On Tue, May 19, 2009 at 8:49 AM, dxc13 <dx...@health.state.ny.us> wrote: > > Easy enough. What if some of the matrix elements contained missing values? > Then how could you still calculate the means? Example code below: > mat1 <- matrix(c(1,2,3,4,5,NA,7,8,9),3,3) > mat2 <- matrix(c(NA,6,1,9,0,5,8,2,7),3,3) > mat3 <- matrix(c(5,9,1,8,NA,3,7,2,4),3,3) > > > Gabor Grothendieck wrote: >> >> Try this: >> >> (mat1 + mat2 + mat3) / 3 >> >> On Mon, May 18, 2009 at 8:40 PM, dxc13 <dx...@health.state.ny.us> wrote: >>> >>> useR's, >>> I have several matrices of size 4x4 that I want to calculate means of >>> their >>> respective positions with. For example, consider I have 3 matrices given >>> by >>> the code: >>> mat1 <- matrix(sample(1:20,16,replace=T),4,4) >>> mat2 <- matrix(sample(-5:15,16,replace=T),4,4) >>> mat3 <- matrix(sample(5:25,16,replace=T),4,4) >>> >>> The result I want is one matrix of size 4x4 in which position [1,1] is >>> the >>> mean of position [1,1] of the given three matrices. The same goes for >>> all >>> other positions of the matrix. If these three matrices are given in >>> separate text files, how can I write code that will get this result I >>> need? >>> >>> Thanks in advance, >>> dxc13 >>> -- >>> View this message in context: >>> http://www.nabble.com/how-to-calculate-means-of-matrix-elements-tp23607694p23607694.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. >> >> > > -- > View this message in context: > http://www.nabble.com/how-to-calculate-means-of-matrix-elements-tp23607694p23615755.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.
