plot() - thicker points when pair exist more than 1 time?

Hi to all,
is it possible to show in anyway that point 1,1 is existing more  
than 1one time?
f.e.:
f<-  data.frame("x"=c(1,3,5,6,1),"y"=c(1,2,3,4,1))
plot(f)

Regards Knut

Several options:

   # See ?sunflowerplot
   sunflowerplot(f)


   # See ?xyTable referenced in the above
   coords <- xyTable(f)
   plot(coords$x, coords$y, cex = coords$number)

   or

   coords <- xyTable(f)
   plot(f, type = "n")
   text(coords$x, coords$y, labels = coords$number)


   # See ?jitter
   plot(jitter(f$x), jitter(f$y))


HTH,

Marc Schwartz