[R] null plotting symbol ?

[Prof Brian Ripley]

NAs in pch cause the corresponding points to be omitted.

On Mon, 5 May 2003 tblackw at umich.edu wrote:

> I am calling  plot()  with argument pch as a vector of numeric 
> symbol codes, the same length as x and y.  Is there some code 
> which produces no symbol - a blank - so that I can come back 
> with a second call to  points()  and fill in these locations 
> using a different fill color and a different symbol size ?  
> 
> There's always a work-around, but both x and y are generated 
> on the fly by calls to  cumsum(),  so it's inconvenient to put 
> NAs into either x or y to suppress plotting that way.  Guess 
> I should *try* mixing numeric and character symbol codes, 
> although the example in  help("points")  explicitly uses a list 
> at that point.  

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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