Hi > > Hi, > A simple question I hope. I wish to add a single vertical line to a plot > with several density plots. > Here is a simplified example. > > ############ > thedata <- data.frame(x1=rnorm(100,1,1),x2=rnorm(100,3,1)) #create data > thedata.m<-melt(thedata) > densityplot(~value, thedata.m, groups=variable,auto.key=list(columns=2)) > #this gives the two density plots > ######### > > what I wish now is to add a vertical line, for example v=2.
If you mean densityplot from lattice here is a function (addapted from Gabor Grothendieck's code] which adds arbitrary line(s) into panels. Is options are similar to abline and once=TRUE means you want different lines to different panels. > addLine function (a = NULL, b = NULL, v = NULL, h = NULL, ..., once = FALSE) { tcL <- trellis.currentLayout() k <- 0 for (i in 1:nrow(tcL)) for (j in 1:ncol(tcL)) if (tcL[i, j] > 0) { k <- k + 1 trellis.focus("panel", j, i, highlight = FALSE) if (once) panel.abline(a = a[k], b = b[k], v = v[k], h = h[k], ...) else panel.abline(a = a, b = b, v = v, h = h, ...) trellis.unfocus() } } Regards Petr > > Many thanks, > Josh. > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.