Hi

I would like to superimpose group-specific densityplots on top of an overall
histogram using panel.histogram and panel.densityplot. Furthermore, I would
like to automatically adjust the range of the y-axis to take into account
the ranges of both histogram and densityplot. This last part is where I have
a problem. I believe using the prepanel argument of histogram is typically
the way to go, but I did not have very much success with my attempts. Is
this the way to go, or should I calculate the range outside the histogram
call using some stat function (density?) on each group and use it as a ylim
argument?

Any advise would be greatly appreciated.

Thank you

Sebastien

require(lattice)
set.seed(12345)

foo1 <- data.frame(x=rnorm(100,0,0.1),grp=1)
foo2 <- data.frame(x=rnorm(100,2,1),grp=2)

foo <- rbind(foo1,foo2)

#
# Some code to calculate ylim...
#

histogram(~x,data=foo,groups=grp,
  #prepanel=function(x,type,groups,...){???},
  panel=function(x,type,groups,...){
    panel.histogram(x,col='transparent',...)
    panel.densityplot(x,groups=groups,...)
  },
  #ylim=ylim,
  type='density')

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