[R] Argument validation within functions

[Berwin A Turlach]

G'day Johannes,

On Tue, 06 Dec 2011 16:15:21 +0100
"Johannes Radinger" <JRadinger at gmx.at> wrote:

> Thank you, i didn't know that the !operator is
> also working for is.numeric etc.
> 
> Anyway I want to test if an argument is set in the
> function call and if not a code is executed... So 
> far I tried:
> 
> f <-function(a,b){
> 	if(!exists("b")) print("exists: b is not set")
> 	if(is.null("b")) print("is.null : b is not set")
> }
> 
> f(a=1,b=2)
> f(a=1)
> f(b=2)
> 
> I don't really know how to do it...e.g: for f(a=1) b is not set
> so it also can't be NULL (thats why is.null is not working). I
> just want to "test" if it is set with the function call not outside
> the function or before etc.

?missing

Cheers,
	
	Berwin

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