cor() on sets of vectors
Use 1:n as an index. e.g. sapply(1:n, function(i) cor(x[,i],y[,i])) -- Bert
On Thu, Feb 23, 2012 at 2:10 PM, Sam Steingold <sds at gnu.org> wrote:
suppose I have two sets of vectors: x1,x2,...,xN and y1,y2,...,yN. I want N correlations: cor(x1,y1), cor(x2,y2), ..., cor(xN,yN). my sets of vectors are arranged as data frames x & y (vector=column): ?x <- data.frame(a=rnorm(10),b=rnorm(10),c=rnorm(10)) ?y <- data.frame(d=rnorm(10),e=rnorm(10),f=rnorm(10)) cor(x,y) returns a _matrix_ of all pairwise correlations: ?cor(x,y) ? ? ? ? ?d ? ? ? ? ?e ? ? ? ? ? ?f a 0.2763696 -0.3523757 -0.373518870 b 0.5892742 -0.1969161 -0.007159589 c 0.3094301 ?0.1111997 -0.094970748 which is _not_ what I want. I want diag(cor(x,y)) but without the N^2 calculations. thanks. -- Sam Steingold (http://sds.podval.org/) on Ubuntu 11.10 (oneiric) X 11.0.11004000 http://www.childpsy.net/ http://iris.org.il http://americancensorship.org http://dhimmi.com http://www.PetitionOnline.com/tap12009/ http://jihadwatch.org Never argue with an idiot: he has more experience with idiotic arguments.
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Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm