All, I'm trying to adapt some code provided by Deepayan Sarkar from a previous thread (https://stat.ethz.ch/pipermail/r-help/2005-October/081571.html) on this topic. ## This code produces a graph w/o error bars: xyplot(Y ~ Hr, data, groups=DRUG, panel=function(x,y,...){ panel.xyplot(x,y,..., type=c("g", "l") ) panel.points(x,y,..., pch=16, type='p', col='black', cex=1) }, auto.key = list(space = "top", text = c( "D","P"), points = FALSE, lines = TRUE, columns=2), par.settings = list(superpose.line = list(lty = c(1,5), col=c('black', 'black') ) ) ) ## this code uses the functions provided by Deepayan Sarkar to include the ## error bars for the same data: xyplot(Y ~ Hr, groups=DRUG, data=data, ly = data$lower, uy = data$upper, prepanel = prepanel.ci, panel = panel.superpose, panel.groups = panel.ci, type="b", auto.key = list(space = "top", text = c( "D","P"), points = FALSE, lines = TRUE, columns=2), par.settings = list(superpose.line = list(lty = c(1,5), col=c('black', 'black') ) ) ) Is it possible to write the second version in the format of the first, i.e., using panel = function(x,y, ...){ } ? Thanks, David ############################################################################ ### load the following: Hr = c(0,1,2,3,4,5,0,1,2,3,4,5) DRUG = rep(c("D", "P"), each=6) Y = c(1,2,2,2,2,1,3, 4, 4,4, 4, 3) data = data.frame(Hr, DRUG, Y) data$lower = data$Y - .5 data$upper = data$Y + .5 prepanel.ci <- function(x, y, ly, uy, subscripts, ...) { x <- as.numeric(x) ly <- as.numeric(ly[subscripts]) uy <- as.numeric(uy[subscripts]) list(ylim = range(y, uy, ly, finite = TRUE)) } panel.ci <- function(x, y, ly, uy, subscripts, pch = 16, ...) { x <- as.numeric(x) y <- as.numeric(y) ly <- as.numeric(ly[subscripts]) uy <- as.numeric(uy[subscripts]) panel.arrows(x, ly, x, uy, col = "black", length = 0.25, unit = "native", angle = 90, code = 3) panel.xyplot(x, y, pch = 16, ...)} ______________________________________________ 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.