Try this:
f <- function(fo, data, groups) { g <- do.call("xyplot", list(as.formula(fo), groups = as.name(groups), data)) print(g) } f("yield ~ variety | site", data = barley, groups = "year") On Tue, Sep 22, 2009 at 3:03 PM, Erich Neuwirth <erich.neuwi...@univie.ac.at> wrote: > I need to play games with an expression similar to the following one: > > print(xyplot(DepVar ~ Group|Covar, groups=Othergroup, > data=mydf, pch = 18 ,main="Testcase",auto.key = TRUE)) > > > The problem is that the formula argument (the first argument) > an the groups argument are passed over from another program as strings. > > The formula argument does not pose problems, > I can do as.formula("DepVar ~ Group|Covar") > bit I could not find an equivalent technique for the groups parameter. > as.expression(... does not work and neither does > parse(text=... > > Is there a way of accomplishing what I need? > > ______________________________________________ > 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.