Re: Using apply for functions with more than one argument

[Sarah Goslee <sarah.goslee@gmail.com>]

On 6/7/05, Luis Apiolaza <luis.apiolaza@forestrytas.com.au> wrote:

> All examples that I have seen for 'apply' use functions with only a
> single argument. Is there a more general way of using apply for more
> complex functions? I just want to avoid using an explicit loop.

Did you look at the help for apply? 

It gives an example for what you are trying to do.
     x <- cbind(x1 = 3, x2 = c(4:1, 2:5))
     ##- function with extra args:
     cave <- function(x, c1,c2) c(mean(x[c1]),mean(x[c2]))
     apply(x,1, cave,  c1="x1", c2=c("x1","x2"))

You do need to provide an argument x to your function even if you
don't use it, because of the way apply functions. I think.

Sarah
-- 
Sarah Goslee 
http://www.stringpage.com