I often find custom-built lattice-based plot methods inscrutable and
end up falling back to figuring out how to get what I want directly with
lattice.
I haven't figured out how to get the label 'Diet' on the legend, but
otherwise this works pretty well ...
library(lattice)
library(nlme)
labs <- paste(attr(BodyWeight, "labels"),
attr(BodyWeight, "units"))
xyplot(weight ~ Time | Rat, type = c("p", "r"),
data = BodyWeight,
layout = c(NA, 1), ## enforce 1 row
groups = Diet,
auto.key = TRUE,
pch = 19,
xlab = labs[1],
ylab = labs[2],
par.settings = list(superpose.line = list(col = "black")))
On 12/2/25 06:06, Duncan Murdoch wrote:
On 2025-12-02 3:39 a.m., Leo Mada via R-help wrote:
Dear R-Users,
Is there a quick solution to plot colours based on a variable?
I tried something like this:
library(nlme)
plot(BodyWeight)
# Does NOT work!
colDiet = c(2:4)[BodyWeight$Diet]
plot(BodyWeight, col = colDiet)
# Wastes space
rat.fit = lme(weight ~ Time + Diet, data = BodyWeight, random = ~
Time|Rat)
plot(rat.fit, weight ~ Time | Rat + Diet)
Is there a quick way to base the colour on the Diet variable?
plot(BodyWeight, ...)
dispatches to plot.nfnGroupedData(), which uses lattice::xyplot()
graphics rather than base graphics. I don't know lattice well enough to
answer your question, but maybe this will give you a hint...
Duncan Murdoch
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