I'm not sure I understand your question. It is always better to use an example:
> set.seed(42) > dataN <- array(sapply(1:5, function(i) assign(paste0("data",i), + matrix(rnorm(6), 2, 3))), c(2, 3, 5)) > meanmtrx <- apply(dataN,1:2,mean) > meanmtrx [,1] [,2] [,3] [1,] 0.189669255 0.3368646 0.34261301 [2,] -0.009700353 -0.4676745 0.01974906 The result is a matrix, not a data frame, and certainly not "resulting data frames." What are you trying to cbind? ---------------------------------------------- David L Carlson Associate Professor of Anthropology Texas A&M University College Station, TX 77843-4352 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of ya > Sent: Saturday, January 19, 2013 8:50 AM > To: r-help > Subject: [R] calculating mean matrix > > Hi list, > > Thank you vey much for reading this post. > > I have a data frame, I am trying to split it into a couple of data > frame using one of the columns, say, x. After I get the data frames, I > am planning to treat them as matrices and trying to calculate an > element by element mean matrix. Could anyone give me some advice how to > do it? > > So far, I know that if I have a couple of matrices, say > data1,data2,data3,data4...dataN, I can do it like this: > > data=array(cbind(data1,data2,data3,data4,....dataN), c(2, 3, N)) > #2 refers to row number of matrix, 3 refers to column number of matrix, > N refers to number of matrices to be averaged. > meanmtrx=apply(data,1:2,mean) > > but I do not know how to use the resulting data frames with cbind(). > Maybe there are other better ways. Any advice is appreciated. > > Thank you very much. > > Have a nice day. > > ya > [[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.