Hi David, Here is a suggestion:
matrix(colMeans(do.call(rbind, lapply(ll, function(x) as.vector(x)))), nrow = length(ll)) HTH, Jorge On Tue, Apr 27, 2010 at 11:05 AM, David Freedman <3.14da...@gmail.com>wrote: > > I've got a list of 5 matrices that are each 5 x 6. I'd like to end up with > a > 5 x 6 matrix that contains the mean value of the 5 original matrices. I > can > do this by brute force, but there must be a better way than making each > matrix into a vector and then remaking a matrix > > thanks very much for any help > david freedman > > ll=list(structure(c(9.7, 17.6, 20.8, 24.1, 33.8, 14.5, 25.7, 29.8, > 33.6, 44.8, 21.8, 32.6, 37.5, 40.9, 53.3, 16.7, 26.1, 29.5, 32.7, > 42.6, 26.2, 34.3, 37, 39.8, 47.1, 31.9, 40.3, 43.3, 46.2, 54.1 > ), .Dim = 5:6), structure(c(9.4, 17.7, 20.7, 24.1, 33.7, 14.5, > 25.7, 29.8, 33.6, 44.8, 21.8, 32.7, 37.5, 40.9, 53.1, 16, 26, > 29.5, 32.7, 42.7, 25.6, 34.1, 37, 39.8, 47.1, 31.9, 40.3, 43.3, > 46.1, 54.1), .Dim = 5:6), structure(c(9.6, 17.7, 20.8, 24.4, > 34.3, 14.5, 25.7, 29.8, 33.6, 44.8, 21.8, 32.6, 37.5, 40.9, 53.2, > 16.7, 26.1, 29.5, 32.8, 42.8, 26.2, 34.2, 36.8, 39.9, 47.1, 31.9, > 40.3, 43.3, 46.1, 54.8), .Dim = 5:6), structure(c(9.7, 17.6, > 20.7, 24.1, 33.8, 14.5, 25.7, 29.8, 33.6, 44.8, 21.8, 32.6, 37.5, > 41.1, 52.6, 16.7, 26.1, 29.5, 32.8, 42.8, 26.1, 34.3, 37, 40, > 47.1, 31.9, 40.3, 43.3, 46.2, 54.9), .Dim = 5:6), structure(c(8.6, > 17.6, 20.7, 24.1, 33.8, 14.5, 25.6, 29.8, 33.6, 44.8, 21.8, 32.6, > 37.5, 40.9, 52.5, 16, 26, 29.4, 32.8, 42.8, 25.6, 34.2, 37, 40.1, > 47.1, 31.9, 40.3, 43.1, 46.1, 54.1), .Dim = 5:6)) > > ll > > x=rbind(as.vector(ll[[1]]),as.vector(ll[[2]]),as.vector(ll[[3]]),as.vector(ll[[4]]),as.vector(ll[[5]])); > x > x2=apply(x,2,mean); matrix(x2,byrow=F,nrow=5); > > -- > View this message in context: > http://r.789695.n4.nabble.com/get-means-of-elements-of-5-matrices-in-a-list-tp2067722p2067722.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. > [[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.
