On Fri, Nov 14, 2008 at 6:55 PM, Deepayan Sarkar <[EMAIL PROTECTED]> wrote: >> ...But how do I specify that I want to display all the Subjects on a... >> single graph, superimposing them all? > > Have you tried > xyplot ( conc ~ time , Indometh, groups = Subject ) ?
Thanks very much for your help! That works beautifully. Any particular reason this can't be specified in the formula? For a small number of levels, you can write xyplot( ifelse(Subject==1,conc,NA) + ifelse(Subject==2,conc,NA) ~ time, ...) but obviously that doesn't generalize. I'd have thought that something like conc*Subject or (conc | Subject) should mean the same thing, but these aren't allowed for some reason. But I don't know what the semantics of the formula operators are. Neither the 'formula' nor the 'logic' man page even defines `|`, and the 'xyplot' man page only gives examples, not a definition of the general case: "the formula is generally of the form... can also be supplied as ... a special case is ...". Thanks, -s ______________________________________________ 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.