[R] Passing additional arguments through '...'

[Charles C. Berry]

On Wed, 15 Jul 2009, escher2079 wrote:

>
> Hi,
>
> I know this is a simple question, but I've been having problems passing
> additional arguments through '...'. It is not matching the arguments
> correctly if the permanent argument of the function begins with the same
> letter as the additional argument. The following example will help show what
> I mean:
>
> fun.tester <- function(abc,...){
> + print(abc)
> + }
>
> But if I input:
> fun.tester(0,a=1)
>
> It returns the value '1' for abc. It does however, work properly if I input:
> fun.tester(abc=0,a=1)
>

I think you'll need to dig into sys.call() and match.call() and put 
together your own matching scheme to force a function to first match by 
position and then match all else by name.

If match.call() is unfamiliar to you, it is advised to read the first 10 
lines of lm().

HTH,

Chuck

p.s. every argument that comes AFTER '...' in the formals must match 
exactly. Perhaps this would help you.

> It seems like a simple problem, so I would assume I'm doing something
> stupid, but I haven't been able to find a solution anywhere. Thanks!
> -- 
> View this message in context: http://www.nabble.com/Passing-additional-arguments-through-%27...%27-tp24501159p24501159.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901