[R] lattice code to plot columns over another variable

[Deepayan Sarkar]

On Tue, Apr 20, 2010 at 9:03 AM, Rajarshi Guha <rajarshi.guha at gmail.com> wrote:
> Hi, I've been struggling with a lattice visualiation. I have a
> data.frame with 4 columns. What I'd like to have is a set of 3 panels.
> Ecah panel will have the first column plotted against serial number
> and then will superimpose the relevant column. My non-lattice version
> is as follows:
>
> x <- data.frame( ... )
> par(mfrow=c(3,1))
> for (i in 2:4) {
>  plot(x[,1])
>  points(x[,i])
> }
>
> Any suggestions as to how I could convert this to a lattice version
> would be much appreciated

Easiest to think of this as a data reshaping problem.

x <- as.data.frame(matrix(rnorm(4 * 20), 20, 4))

n <- nrow(x)
y <- data.frame(i = seq_len(n), y1 = x[,1],
                y2 = unlist(x[-1]),
                g = gl(ncol(x) - 1, n))
xyplot(y2 + y1 ~ i | g, data = y, type = "l")

-Deepayan