Try the reshape package This should do what you want. ================================================ library(reshape) df1 <- melt(mydata, id=c("ID"), measured=c("a1","a2","a3")) ; df1 stats <- cast(df1, ID ~ variable , mean) ; stats =================================================
--- affy snp <[EMAIL PROTECTED]> wrote: > > Dear list, > > I have a data frame like: > > > > > log2.ratios[1:3,1:4] > > ID a1 a2 > a3 > > 1 GS1-232B23 -0.0207500 0.17553833 > 0.21939333 > > 2 RP11-82D16 -0.1896667 0.02645167 > -0.03112333 > > 3 RP11-62M23 -0.1761700 0.08214500 > -0.04877000 > > 4 RP11-62M23 0.2761700 -0.15214500 > -0.05877000 > > > > the 3rd and 4th rows are of the same ID, I would > like to take the avarage of > these > two rows and get the data frame to: > > ID a1 a2 > a3 > 1 GS1-232B23 -0.0207500 0.17553833 0.21939333 > 2 RP11-82D16 -0.1896667 0.02645167 -0.03112333 > 3 RP11-62M23 -0.05 -0.035 > 0.094135 > > Can anyone suggest how to deal with this (to take > the ave of two rows of the > same ID ) more quickly? > > Thanks a bunch! > > Allen > > [[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. > ______________________________________________ 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.