Dear List, I am creating a boxplot with two subsets, very similar to the example by Roger Bivand at ?boxplot (reproduced below). I am trying to change the labels on the x-axis to have one number to cover both subsets. I can do this in other plots by using axis=FALSE followed by a separate axis() command. I have also tried variations in the names= argument but can't get it to work. Ideally I would like tickmarks on either side of each factor with the number for the level centered between the two tick marks. Any suggestions? Thanks, Tim
Example: boxplot(len ~ dose, data = ToothGrowth, boxwex = 0.25, at = 1:3 - 0.2, subset = supp == "VC", col = "yellow", main = "Guinea Pigs' Tooth Growth", xlab = "Vitamin C dose mg", ylab = "tooth length", xlim = c(0.5, 3.5), ylim = c(0, 35), yaxs = "i") boxplot(len ~ dose, data = ToothGrowth, add = TRUE, boxwex = 0.25, at = 1:3 + 0.2, subset = supp == "OJ", col = "orange") legend(2, 9, c("Ascorbic acid", "Orange juice"), fill = c("yellow", "orange")) Tim Clark Marine Ecologist National Park of American Samoa ______________________________________________ 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.