R help - Dec 1999 - ... and parameter checking

Hi,

when writing a wrapper function, I would like to be able to pass additional
arguments to more than one function inside, e.g.

  density.panel <- function(x, na.rm=TRUE, ...){
     usr <- par("usr")
     on.exit(par(usr))
     par(usr = c(usr[1:2], 0, 1) )
     lines( density(x, na.rm=na.rm, ...), ... )
  }

and then call it like

  density.panel(x, col="red",  kernel="rectangular")


However, doing so generates an error from density (col=), which does not
allow ... and a warnings from plot.default(), which does not know about
kernel= .

Obviously I could patch density() to have a ... parameter and ignore
warnings from plot(), but, well ...

Can someone teach me how to solve this properly?

I cannot remember to have had such problems with S+, is this a difference
between R and S+ ?

Regards


--
Dr. Jens Oehlschl?gel-Akiyoshi
MD FACTORY GmbH
Bayerstrasse 21

80335 M?nchen

Tel.: 089 545 28-27
Fax.: 089 545 28-10
http://www.mdfactory.de

Standard Disclaimers: Opinions expressed here are personal
and are not otherwise represented.


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>when writing a wrapper function, I would like to be able to pass additional
>arguments to more than one function inside, e.g.
The only way I know how to do this is something like

  density.panel <- function(x, na.rm=TRUE, density.args=NULL, ...){
     usr <- par("usr")
     on.exit(par(usr))
     par(usr = c(usr[1:2], 0, 1) )
     arglist <- append(list(x, na.rm=na.rm, ), density.args)
     lines( do.call("density", arglist),  ... )
  }

and then call it like

  density.panel(x, col="red", 
density.args=list(kernel="rectangular"))

Please note, I haven't tested this example so there may be small errors, but
this approach works generally. If someone know a more elegant approach I would
like to hear about it.

Paul Gilbert


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