library(reshape) ## the easy way xx <- melt(x) head(xx) densityplot(~ value | cat1 * cat2, xx, groups = paste(variable, which), plot.points=FALSE, auto.key=list(columns=2), par.settings = simpleTheme(col = c("red","blue"), lty=c(1,1,2,2)))
Hint: using multiple terms in the formula as you did actually maps into the "groups" argument. It is generally not a good a idea to do that when you also specify "groups" directly. 2009/12/3 Joel Thomas <joel...@gmail.com>: > Hi, > I have two data sets; one is a population and the other a sample of > that population. I am trying to plot both on the same trellis display. > > # Example data set with two numerical attributes and two categorical > pop <- data.frame(var1=rnorm(2000, 2000, 500), var2=rnorm(2000, 2000, 500)) > > cat<-(runif(2000)<=.5)+0 > for(i in 1:length(cat)){ > if(cat[i] == 0){ > pop[i,"cat1"] = "this" > } > else{ > pop[i,"cat1"] = "that" > } > } > cat<-(runif(2000)<=.5)+0 > for(i in 1:length(cat)){ > if(cat[i] == 0){ > pop[i,"cat2"] = "here" > } > else{ > pop[i,"cat2"] = "there" > } > } > > #Extract sample > sam <- pop[sample(1:2000,50),] > > #Combine data sets > x <- make.groups(pop, sam) > > #Create trellis display > densityplot(~var1 + var2 | cat1 * cat2, data=x, groups=which, > plot.points=FALSE, auto.key=list(columns=2)) > > > This does not produce what I want. I would like four density plots in > each panel; var1 and var2 from the sample data as solid lines and var1 > and var2 from the population data as dotted lines with matching > colours. > > densityplot(~ var1 + var2 | cat1 * cat2, data=x, groups=which, > panel=panel.superpose, > panel.groups = function(x, y,...){ > panel.densityplot(x, ...) > }) > > ... gives the same result. > > I've read "The panel function demystified" section of the book many > times and still find the panel function mystifying. Could someone > please explain how to do this and also how it works. Thankyou > > ______________________________________________ > 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. > -- Felix Andrews / 安福立 Postdoctoral Fellow Integrated Catchment Assessment and Management (iCAM) Centre Fenner School of Environment and Society [Bldg 48a] The Australian National University Canberra ACT 0200 Australia M: +61 410 400 963 T: + 61 2 6125 4670 E: felix.andr...@anu.edu.au CRICOS Provider No. 00120C -- http://www.neurofractal.org/felix/ ______________________________________________ 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.