Adding text labels to lattice plots with multiple panels

Hi:

After a number of false starts, I finally consulted Deepayan's book and the
example on p. 73, suitably adapted, yielded a solution. Add a variable for
the labels and then...

df$lab <- rep(1:6, each = 3)
bwplot(dv ~ f1 | f2, data = df, ylim = c(0.5, 1),
?panel = function(x, y, ..., subscripts) {
?? lab <- df$lab[subscripts]
?? panel.bwplot(x, y,? ...)
?? panel.text(x, 0.55, labels = lab)
?}
)

If you look closely, you'll see that each label is overplotted three times.
A similar plot in ggplot2? would be

library(ggplot2)
ggplot(df, aes(x = f1, y = dv)) + geom_boxplot() +
??? geom_text(aes(x = as.numeric(f1), lab = lab), y = 0.55, alpha = 0.5) +
??? facet_wrap( ~ f2) + ylim(0.5, 1)

The alpha argument in geom_text() is designed to mitigate the overplotting
effect somewhat.

HTH,
Dennis


On Fri, Apr 8, 2011 at 5:32 AM, Jeff Stevens <stev0175 at googlemail.com>
wrote:

Hi,

I am trying to add text to the bottom of a lattice bwplot with
multiple panels. ?I would like to add a label below each boxplot, but
the labels do not come from the data. ?I've tried the following, code:

f1 <- c(rep(c(rep("a", 3), rep("b", 3), rep("c", 3)), 2))
f2 <- c(rep("A", 9), rep("B", 9))
dv <- c(0.9, 0.8, 0.85, 0.6, 0.65, 0.7, 0.8, 0.85, 0.8, 0.95, 0.85,
0.9, 0.65, 0.7, 0.75, 0.85, 0.9, 0.85)
df <- data.frame(f1, f2, dv)
lab <- c(1, 2, 3, 4, 5, 6)

bwplot(dv ~ f1 | f2, data = df, ylim = c(0.5, 1),
?panel = function(x, y, ...) {
? ?panel.bwplot(x, y, ...)
? ?panel.text(x, 0.55, labels = lab)
?}
)

I have two problems. ?First, the label values are writing over one
another. ?I wrote a horrible hack (below) that fixes that problem, but
I would like to know if there are better/more flexible ways to do
this.

bwplot(dv ~ f1 | f2, data = df, ylim = c(0.5, 1),
?panel = function(x, y, ...) {
? ?x2 <- as.factor(c("a", "b", "c"))
? ?panel.bwplot(x, y, ...)
? ?panel.text(x2, 0.55, labels = lab)
?}
)

Second, when using the horrible hack the first values are repeated in
the second panel. ?How do I display the correct values in the second
panel? ?The subscripts argument seems to do the trick when the labels
come from the data, but how do I get the proper values when the labels
come from outside of the data?


Many thanks,
Jeff