Hi , To my knowledge, there're two functions that can do principal component analysis, princomp and prcomp.
I don't really know the difference; the only thing I know is that when the sample size < number of variable, only prcomp will work. Could someone tell me the difference or where I can find easy-to-read reference? To access the first PC using princomp: Mpca<-princomp(M, cor=T) Mpca$scores[,1] How can I access the first PC using prcomp? Mpca<-prcomp(M) Is there an option for "cor=T"? In case where both functions work, will the results be the same? Thanks, Miao [[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.