R help - Feb 2008 - multiple functions with three dots

Dear all,

I am creating functions with the "three dot" strategy. I wold like to
have
suggestion when writing multiple functions that calls multiple functions
with "...".

I will give you a couple of example:
>a=1:5
>b=6:10
>d=3:7
>example=function(x,y, z, ...){
   plot(x,y, ...)
   points(x,z, ...)

}
>example(a,b,d)
how can I set different parameters for points and plot functions? for
example in plot I want to have bigger dots (lwd=3), while in the points I
want to have green dots.

any suggestion?


thank you.

	[[alternative HTML version deleted]]

You can try something like:
>a <- 1:5
>b <- 6:10
>d <- 3:7
>example <- function(x,y, z, ..., plot.dots, points.dots){
   plot.list <- list(x=x,y=y)
   plot.list <- c(plot.list,list(...), as.list(plot.dots))
   do.call(plot, plot.list)

   points.list <- list(x=x,y=z)
   points.list <- c(points.list, list(...), as.list(points.dots) )
   do.call(points, points.list)

}
>example(a,b,d, pch=0, plot.dots=list(cex=2),
points.dots=list(col='green'))

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
(801) 408-8111
 
 
> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of John Lande
> Sent: Friday, February 01, 2008 7:34 AM
> To: r-help at r-project.org
> Subject: [R] multiple functions with three dots
> 
> Dear all,
> 
> I am creating functions with the "three dot" strategy. I wold 
> like to have suggestion when writing multiple functions that 
> calls multiple functions with "...".
> 
> I will give you a couple of example:
> 
> >a=1:5
> >b=6:10
> >d=3:7
> 
> >example=function(x,y, z, ...){
>    plot(x,y, ...)
>    points(x,z, ...)
> 
> }
> 
> >example(a,b,d)
> 
> how can I set different parameters for points and plot 
> functions? for example in plot I want to have bigger dots 
> (lwd=3), while in the points I want to have green dots.
> 
> any suggestion?
> 
> 
> thank you.
> 
> 	[[alternative HTML version deleted]]
> 
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>

John Lande wrote:
> Dear all,
> 
> I am creating functions with the "three dot" strategy. I wold
like to have
> suggestion when writing multiple functions that calls multiple functions
> with "...".
> 
> I will give you a couple of example:
> 
> 
>>a=1:5
>>b=6:10
>>d=3:7
> 
> 
>>example=function(x,y, z, ...){
> 
>    plot(x,y, ...)
>    points(x,z, ...)
> 
> }
> 
> 
>>example(a,b,d)
> 
> 
> how can I set different parameters for points and plot functions? for
> example in plot I want to have bigger dots (lwd=3), while in the points I
> want to have green dots.
> 
> any suggestion?
> 
Hi John,
There are probably better solutions to this problem, but I usually add 
explicit arguments like this:

example<-function(x,y,z,y.lwd,z.col,...) {
  ...
  plot(x,y,lwd=y.lwd,...)
  points(x,z,col=z.col)
  ...
}

Jim