Sarah and elisacarli21 principal in the psych package will do principal components of a correlation or covariance matrix.
ex: library(psych) principal(Thurstone,3,rotate="none") #First three principal components of the Thurstone correlation matrix #compare with eigen e <- eigen(Thurstone) #perform an eigen value decomposition e #show the resuls e$vectors %*% diag(sqrt(e$values)) #convert to "loadings" and compare with the output from principal Bill On Dec 28, 2011, at 9:09 AM, Sarah Goslee wrote: > Hi, > > On Wed, Dec 28, 2011 at 7:54 AM, elisacarli21 <elisacarl...@gmail.com> wrote: >> Dear all, >> >> I've a correlation matrix with rows and columns headings. >> I've two questions: >> >> 1) How can i import it in R, setting first row as row heading and first >> column as column heading? > > read.table, with the appropriate options. You can see what they are > by typing > ?read.table > at an R prompt. > >> 2) Which is the best principal component anlysis package in R? > > Best for what? > > I'd start with > ?princomp > and if that doesn't meet your needs go looking farther. > www.rseek.org is good for finding R functions for particular purposes. > > But if you're starting with the correlation matrix rather than the raw > data, you might need to do the eigenanalysis yourself rather than > relying on an existing function that assumes raw data. > > Sarah > > -- > Sarah Goslee > http://www.functionaldiversity.org > > ______________________________________________ > 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. > William Revelle http://personality-project.org/revelle.html Professor http://personality-project.org Department of Psychology http://www.wcas.northwestern.edu/psych/ Northwestern University http://www.northwestern.edu/ Use R for psychology http://personality-project.org/r It is 6 minutes to midnight http://www.thebulletin.org ______________________________________________ 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.
