[R] Optional variables in function?

From: Jonathan Greenberg <jgreenberg_at_arc.nasa.gov>
Date: Sun 02 Jul 2006 - 15:34:25 EST


I'm a bit new to writing R functions and I was wondering what the "best practice" for having optional variables in a function is, and how to test for optional and non-optional variables? e.g. if I have the following function:

helpme <- function(a,b,c) {

}

In this example, I want c to be an optional variable, but a and b to be required. How do I:
1) test to see if the user has inputted c 2) break out of the function of the user has NOT inputted a or b.

Thanks!

--j

--

Jonathan A. Greenberg, PhD
NRC Research Associate
NASA Ames Research Center
MS 242-4
Moffett Field, CA 94035-1000
Phone: 415-794-5043
AIM: jgrn3007
MSN: jgrn3007@hotmail.com



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