On Wed, 17 Oct 2012, David Winsemius wrote:
What exactly is being requested? Do you just need to learn how to use the subset parameter? I would not think that the conditioning syntax would be used when there were only one level desired.
David, When I try xyplot(quant ~ sampdate | era, data = sb.d, main = 'Antimony Concentrations by Time', ylab = 'Concentration (mg/L)', xlab = 'Time', subset=era('Pre-Mining')) this error is returned: Error in eval(expr, envir, enclos) : could not find function "era" But, 'era' is a factor in the data frame. The syntax above works with bwplot() and I would like to understand why it's not working with xyplot(). Thanks, Rich ______________________________________________ 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.