Multiple stacked barplots on the same graph?

St?phane CRUVEILLER <scruveil <at> genoscope.cns.fr> writes:

I would like to know whether it is possible to draw several
stacked barplots (i.e. side by side on the same sheet)...

my data look like :

                            Cond1  Cond1' Cond2   Cond2'
Compartment 1    11,81    2,05    12,49    0,70   
Compartment 2     10,51    1,98    13,56    0,85
Compartment 3     1,95    0,63    2,81    0,22  
Compartment 4     2,08    0,17    3,13    0,06   
Compartment 5     2,51    0,20    4,58    0,03

ps: Cond1' values should be stacked on Cond1, Cond2' on Cond 2 and so 
on... and series 1 and 2
should be side by side for each compartement....

Check the following example on xyplot/lattice:

barchart(yield ~ variety | site, data = barley,
         groups = year, layout = c(1,6), stack = TRUE, 
         auto.key = list(points = FALSE, rectangles = TRUE, space = "right"),
         ylab = "Barley Yield (bushels/acre)",
         scales = list(x = list(rot = 45)))

You have to reformat your data to the long format first for this, e.g. by using
reshape.

Comp  Cond  x
1     1     11.81
1     2      2.05

With allow.multiple=TRUE, it might be possible to avoid the reformatting, but I
never have used that form, because I the "long" had many advantages.

Dieter