On Thu, Jun 28, 2012 at 9:27 PM, startend <startend...@gmail.com> wrote: > Hi, > > Now i am dealing with longitudinal data set and I want to see the rough > marginal plot for 2 variables separately. > I found the code from one example here, > > reading <- > read.table("http://www.ats.ucla.edu/stat/R/examples/alda/data/reading_pp.txt", > header=T, sep=",") > reading[reading$id %in% c(4, 27, 31, 33, 41, 49, 69, 77, 87), ] > > xyplot(piat~age | id > , data=reading[reading$id %in% c(4, 27, 31, 33, 41, 49, 69, 77, 87), > ],panel=function(x,y,*subscripts*){ > panel.xyplot(x, y, pch=16) > panel.lmline(x,y, lty=4) > panel.xyplot(reading$agegrp*[subscripts]*, y, pch=3) > panel.lmline(reading$agegrp*[subscripts]*,y) > } > , ylim=c(0, 80), as.table=T, *subscripts*=T) > > I just don't know what the subscripts for and the meaning of that. > Can someone kindly let me know how it works.
See ?xyplot, particularly the entry for 'panel'. If a lattice plot has one or more conditioning variables ('id' here), then the data used in each panel is a subset of the full data. 'subscripts' is an optional argument passed to the panel function that allows you to obtain the association between the original rows of the data and the data used in the panels. For example, if your data is x y id 1 1 1 2 2 2 3 3 1 4 4 2 5 5 1 6 6 2 7 7 1 8 8 2 9 9 1 10 10 2 and the formula is y ~ x | id, then the first panel (corresponding to id = 1) will have subscripts=c(1, 3, 5, 7, 9), and the second will have c(2, 4, 6, 8, 10). For a more realistic example, see http://lattice.r-forge.r-project.org/Vignettes/src/lattice-tricks/regression-lines.pdf (page 12). -Deepayan ______________________________________________ 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.