R help - Aug 2004 - Lattice: how to index in a custom panel function?

Hi,

I have a lattice xyplot that contains panels according to FactorA, and 
curves for the 2 levels of Factor B within a panel.
I try to add text in the panels of a lattice graph. I suppose I have to 
write a custom function (panel.txt).
What I really would like is to adapt the text in the panel according to 
the levels of FactorA.
In the manuals, I find examples for the strips using which.given and 
which.panel. But this does not work for the panels...

Can Anybody give a hint? Thanks
Joris

I work with R 1.9.1 under Linux


panel.txt = function(sometxt,x,y,...){
    grid.text(sometxt,x,y)
}

xyplot(data = Pdata, P ~ DAS | FactorA,
   groups = FactorB,
   type ="s",
   col = c("red","blue"),
  panel = function(x,y,...){
        panel.abline(h = 100, lty = 5, lwd =0.5, col = "darkgrey")
        panel.txt(mytext, 0.2, 0.8)
}





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====================================================================== 
Joris De Wolf
CropDesign N.V. 
Plant Evaluation Group
Technologiepark 3 
B-9052 Zwijnaarde 
Belgium 
Tel. : +32 9 242 91 55
Fax  : +32 9 241 91 73
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On Friday 06 August 2004 04:16, Joris DeWolf wrote:
> Hi,
>
> I have a lattice xyplot that contains panels according to FactorA,
> and curves for the 2 levels of Factor B within a panel.
> I try to add text in the panels of a lattice graph. I suppose I have
> to write a custom function (panel.txt).
> What I really would like is to adapt the text in the panel according
> to the levels of FactorA.
> In the manuals, I find examples for the strips using which.given and
> which.panel. But this does not work for the panels...
>
> Can Anybody give a hint? Thanks
> Joris
>
> I work with R 1.9.1 under Linux
>
>
> panel.txt = function(sometxt,x,y,...){
>     grid.text(sometxt,x,y)
> }
>
> xyplot(data = Pdata, P ~ DAS | FactorA,
>    groups = FactorB,
>    type ="s",
>    col = c("red","blue"),
>   panel = function(x,y,...){
>         panel.abline(h = 100, lty = 5, lwd =0.5, col =
"darkgrey")
>         panel.txt(mytext, 0.2, 0.8)
> }
As described in ?xyplot under the entry for 'panel', your panel function
can have an argument called panel.number which would index the levels 
of the conditioning variable (or combinations thereof if there are more 
than one). e.g., 

  panel = function(x,y, panel.number, ...){
      cat(paste("In panel", panel.number, "\n"))
      panel.abline(h = 100, lty = 5, lwd =0.5, col = "darkgrey")
      panel.txt(mytext, 0.2, 0.8)
  }

Deepayan