[R] panel.abline {lattice} help

[Deepayan Sarkar]

On Wed, Jun 9, 2010 at 6:49 PM, Xin Ge <xingemaillist at gmail.com> wrote:
> Hi All,
>
> I need a small help plotting median lines on lattice boxplots.
>
> # Data
> a <- rep(c("A","B"), each=10)
> b <- rep(c("a","a+b","b","b+a"), each=5)
> c <- c(1,9,5,2,7,7,8,8,8,5,4,5,3,2,5,6,7,8,9,1)
> x <- data.frame(a, b, c)
> med.A <- median(subset(x$c, x$a=="A"))
> med.B <- median(subset(x$c, x$a=="B"))
>
> median(group A) = 7
> median(group B) = 5
>
> I need help to plot two (horizontal) lines, one for each subgroup.
> - Line 1 coordinates should be (0, 7) to (2.5, 7)
> - Line 2 coordinates should be (2.5, 5) to (5, 5)
>
> I'm unable to control the length of these lines, can anyone please help me
> with this, I would highly appreciate any help. (I tried using panel.curve,
> but of no use)

You need panel.segments.

-Deepayan

> # Plotting code:
> library(lattice)
>
> bwplot(c ~ b, data = x,
>   panel = function(...)
>   {
>      panel.abline(v=2.5, col.line="gray")
>      panel.bwplot(...)
>   }
> )
>
> Thank in advance,
>
> --
> Xin Ge.
>
>        [[alternative HTML version deleted]]
>
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