How to draw a rect() behind a hist() ?

On 2010-11-30 17:27, Jason Edgecombe wrote:

Hi,

I have the following code:

hist(gps$heartpercent, breaks=5)
rect(90, par("usr")[3], 100, par("usr")[4], col = "red")

How do I get the rectangle to appear behind the histogram. Barring that,
how can I make certain bars of the histogram to be a certain color?

Here are a couple of ways:
1. using hist(); just plot the histogram twice.

 x <- rnorm(1000, 100, 5)
 hist(x)
 rect(90, 0, 98, par('usr')[4], col = 'red')
 hist(x, add = TRUE)

For coloured bars, use a colour vector:

 hist(x, breaks = 5, col = c(3,3,4,4,2))

2. using lattice;

 histogram(x,
  panel=function(...){
    panel.rect(90,0,98,1000,col='bisque',border=NA)
    panel.histogram(...,col='transparent',lwd=2)
  }
 )

Again, you can define bar colours with a colour vector.
Lattice is more customizable albeit a little harder
to learn.

Peter Ehlers

Thanks,
Jason