[R] bwplot: how not to draw outliers

[Frank E Harrell Jr]

Sundar Dorai-Raj wrote:
> 
> 
> RenE J.V. Bertin wrote:
> 
>> Hello, and (somewhat belated) best wishes for 2005.
>>
>> Can one order not to draw outliers in bwplot, or at least exclude them 
>> from the vertical axis scaling? If so, how (or what doc do I need to 
>> consult)?
>> The options that have this effect in boxplot() do not appear to have 
>> any effect with bwplot (although outline=FALSE in boxplot does *not* 
>> change the scaling).
>>
>> Thanks,
>> RenE Bertin
>>
> 
> 
> RenE,
> 
> There may be other solutions but you can do this using the prepanel 
> option to set the ylim:
> 
> library(lattice)
> set.seed(1)
> z <- data.frame(x = rt(100, 1), g = rep(letters[1:4], each = 25))
> bwplot(x ~ g, z,
>        prepanel = function(x, y) {
>          bp <- boxplot(split(y, x), plot = FALSE)
>          ylim <- range(bp$stats)
>          list(ylim = ylim)
>        })
> 
> If you actually want to exclude the points (rather than just prevent 
> outliers from affecting the scale), you will have to modify the 
> panel.bwplot function in addition to using the above.
> 
> --sundar

You may also want to try

library(Hmisc)
library(lattice)
bwplot(..., panel=panel.bpplot)
?panel.bpplot


-- 
Frank E Harrell Jr   Professor and Chair           School of Medicine
                      Department of Biostatistics   Vanderbilt University