Dear List members, i am seeking a multivariate version of aggregate. I want to compute, fro example the correlation between subsets of two vectors. In aggregate, i can only supply one vector with indices for subsets. Is there ready function for this or do i need to program my own? Cheers Jannis
You can pass a matrix to by()> set.seed(42) > dat <- data.frame(x=runif(50)*20, y=runif(50)*20,g=rep(LETTERS[1:2], each=25))> as.vector(by(dat[,1:2], dat$g, function(x) cor(x)[1,2]))[1] -0.05643063 0.16465040 ------------------------------------- David L Carlson Associate Professor of Anthropology Texas A&M University College Station, TX 77840-4352 -----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Jannis Sent: Thursday, June 27, 2013 12:27 PM To: r-help Subject: [R] multivariate version of aggregate Dear List members, i am seeking a multivariate version of aggregate. I want to compute, fro example the correlation between subsets of two vectors. In aggregate, i can only supply one vector with indices for subsets. Is there ready function for this or do i need to program my own? Cheers Jannis ______________________________________________ R-help at 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.
Look at the plyr package, probably the ddply function in that package. You can write your own function to do whatever you want on the pieces of the split apart object. Correlation between a specified pair of columns would be simple. On Thu, Jun 27, 2013 at 11:26 AM, Jannis <bt_jannis@yahoo.de> wrote:> Dear List members, > > > i am seeking a multivariate version of aggregate. I want to compute, fro > example the correlation between subsets of two vectors. In aggregate, i can > only supply one vector with indices for subsets. Is there ready function > for this or do i need to program my own? > > > Cheers > Jannis > > ______________________________**________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help> > PLEASE do read the posting guide http://www.R-project.org/** > posting-guide.html <http://www.R-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. >-- Gregory (Greg) L. Snow Ph.D. 538280@gmail.com [[alternative HTML version deleted]]