If your samples are in the specified order (i.e. first 100 from group A and remaining from group B) you can try the following in your plot call:
plot(..., col=c("red", "blue")[c(rep(100, 1), rep(15, 2))]) -Christos > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of SNN > Sent: Tuesday, February 26, 2008 4:11 PM > To: r-help@r-project.org > Subject: [R] Plot Principal component analysis > > > Hi, > > I have matrix of 300,000*115 (snps*individual). I ran the PCA > on the covariance matrix which has a dimention oof 115*115. I > have the first 100 individuals from group A and the rest of > 15 individuals from group B. I need to plot the data in two > and 3 dimentions with respect to PC1 and PC2 and (in 3D with > respect to PC1, PC2 and PC3). I do not know how to have the > plot ploting the first 100 points corresponding to group A in > red (for example) and the rest of the 15 points in Blue? i.e > I want the each group in a diffrent color in the same plot. I > appreciate if someone can help. > > Thanks, > -- > View this message in context: > http://www.nabble.com/Plot-Principal-component-analysis-tp1570 > 0123p15700123.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > > ______________________________________________ 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.