[R] plot question

[Marc Schwartz]

On Fri, 2006-08-25 at 09:08 -0400, Catherine Carter wrote:
> Hi everyone,
> 
> I have what may appear to be a newbie question, but I have looked 
> everywhere I can think to look and I cannot find an answer. On page 35 
> of "An Introduction to R" the following command appears: 
> plot(ecdf(eruptions), do.points=FALSE, verticals=TRUE). What is the 
> do.points argument? I know what it does (suppresses printing of the 
> points) but where can I find help on it? I want to be able to explain it 
> fully to my students.
> 
> Thanks for your help,
> Cathy

A couple of options:

1. If you are aware of how R uses "method dispatch", then you might know
that the plot() function is a generic method and that plot.ecdf() is the
specific method that is called when the initial argument is of class
"ecdf", as is the case above. 

Thus, using ?plot.ecdf will get you to the help page, where there is a
notation in the Arguments section that the '...' arguments are then
passed to plot.stepfun(). 'do.points' is passed in this fashion, so
using ?plot.stepfun will then get you to the help page where 'do.points'
is defined as:

  logical; if true, also draw points at the (xlim restricted)
  knot locations.


2. Using:

  RSiteSearch("do.points", restrict = "functions")

will search the online function documentation, bringing up a browser
window, where the first link gets you to ?plot.stepfun.

HTH,

Marc Schwartz