R help - Mar 2013 - help with PCA

Dear all,

If I do a PCA like this:

dat<-matrix(rnorm(30),ncol=3)
res<-prcomp(dat)

Now, imagine that I got new data that I want to project onto the
original PC axes. How do I do that?

Thanks!

John

On Mar 16, 2013, at 8:49 AM, john d wrote:
> Dear all,
> 
> If I do a PCA like this:
> 
> dat<-matrix(rnorm(30),ncol=3)
> res<-prcomp(dat)
> 
> Now, imagine that I got new data that I want to project onto the
> original PC axes. How do I do that?
You can either read the help page or for worked examples do a search on
markmail:

list:org.r-project.r-help prcomp project new data onto components


-- 
David Winsemius
Alameda, CA, USA

?predict.prcomp

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of David Winsemius
> Sent: Saturday, March 16, 2013 1:33 PM
> To: john d
> Cc: r-help at r-project.org
> Subject: Re: [R] help with PCA
> 
> 
> On Mar 16, 2013, at 8:49 AM, john d wrote:
> 
> > Dear all,
> >
> > If I do a PCA like this:
> >
> > dat<-matrix(rnorm(30),ncol=3)
> > res<-prcomp(dat)
> >
> > Now, imagine that I got new data that I want to project onto the
> > original PC axes. How do I do that?
> 
> You can either read the help page or for worked examples do a search on
> markmail:
> 
> list:org.r-project.r-help prcomp project new data onto components
> 
> 
> --
> David Winsemius
> Alameda, CA, USA
> 
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