On Mon, Jul 26, 2010 at 9:11 PM, Prasenjit Kapat <kap...@gmail.com> wrote: > Hi, > > (please Cc me) > > In xyplot (), type = "l" (or one that includes "l", *el*) is > (generally) meaningful only when the 'x' variable is sorted. In > practice, one either sorts the data frame before hand or writes a tiny > panel function which sorts the supplied x and then calls the default > panel.xyplot(). Trouble arises when there is a conditional variable as > well as a groups argument. > > Of course, sorting the data frame before hand is the simplest > solution. But, when one wishes to plot against multiple 'x' variables > the data has to be sorted each time, which, to me, doesn't seem the > "right" way (of course, a personal opinion). Hence a feature request > to add a sort option when type = "l". > > Before giving a reproducible example, is there anything even simpler > that I have missed? > > Example: > > Everything included: > >> source ('http://www.stat.osu.edu/~pkapat/miscl/Code4xyplot_sort_type_l.R') > > OR, step by step: > >> library (lattice) >> >> # toy data >> D <- read.csv >> ('http://www.stat.osu.edu/~pkapat/miscl/Data4xyplot_sort_type_l.csv') >> >> # default behavior: obviously wrong >> xyp1 <- xyplot (y ~ x/1000 | C, groups = G, data = D, type = "o", main = >> 'Wrong behavior, obviously') >>
Here are two simple enough solutions: ## uses panel.average xyplot(y ~ x/1000 | C, groups = G, data = D, type = c("p", "a")) ## more efficient, as no tapply involved panel.xyplot.sorted <- function(x, y, ...) { o <- order(x) panel.xyplot(x[o], y[o], ...) } xyplot(y ~ x/1000 | C, groups = G, data = D, type = "o", panel = panel.superpose, panel.groups = panel.xyplot.sorted) -Deepayan ______________________________________________ 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.