[R] How do I query "..." in a function call?

Søren Højsgaard Soren.Hojsgaard at agrsci.dk
Mon Nov 21 23:27:47 CET 2011


You can do something like this:

test <- function(x,...){
     print(x)
     args = list(...)
     if('y' %in% names(args))print(args$y)
     if('z' %in% names(args))print(args$z) 
}

Regards
Søren

________________________________________
Fra: r-help-bounces at r-project.org [r-help-bounces at r-project.org] På vegne af Jonathan Greenberg [jgrn at illinois.edu]
Sendt: 21. november 2011 23:18
Til: r-help
Emne: [R] How do I query "..." in a function call?

This is probably a very noobish question, but if I want to create a
function that allows an undetermined number of, say, numeric vectors to be
fed to it, I would use:

myfunction = function(...)
{
# Do something

}

Right?  If so, how do I a) count the number of vectors "fed" to the
function, and b) how do I treat those vectors as variables, e.g. for the
call:

myfunction(c(1:10),c(2:11),c(3:13))

Thanks!

--j

--
Jonathan A. Greenberg, PhD
Assistant Professor
Department of Geography
University of Illinois at Urbana-Champaign
607 South Mathews Avenue, MC 150
Urbana, IL 61801
Phone: 415-763-5476
AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307, Skype: jgrn3007
http://www.geog.illinois.edu/people/JonathanGreenberg.html

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