Usually you can just use cor() and it will do all the possibilities directly:
x <- matrix(rnorm(100), ncol = 10) cor(x) But that works on the columns, so you'll need to transpose things if you want all possible row combinations: cor(t(x)) Hope this helps, Michael On Fri, Apr 6, 2012 at 9:57 AM, Cserháti Mátyás <cs_ma...@yahoo.com> wrote: > Hello everyone, > > My name is Matthew and I'm new to this list. greetings to everyone. > Sorry if I'm asking an old question, but I have an m x n matrix where the > rows are value profiles and the columns are conditions. > What I want to do is calculate the correlation between all possible pairs of > rows. > > That is, if there are 10 rows in my matrix, then I want to calculate 10 x 10 > = 100 correlation values (all against all). > Now R is slow when I use two for loops. > What kind of other function or tool can I use to get the job done more > speedily? > I've heard of tapply, lapply, etc. and by and aggregate. > > Any kind of help is gladly appreciated. > > Thanks, > > > Matthew > [Deleted the unnecessary digest] ______________________________________________ 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.
