R help - Dec 2011 - making changes to global variables in functions

I'm trying to write a function that takes several objects with many
different attributes and then changes their attributes. So what I wanted to
happen in the simplified example below is for the function to change the
attributes of the objects state1 and state2 that are passed to it. But
because stateA and stateB are local, this isn't working. Are there any easy
solutions?

e.g., if I could combine the two objects stateA and stateB into a single
object, I could return it and then assign it back to objects state1 and
state2. Or if I could pass a pointer to the original object.. But I cannot
find an easy way of doing either.  Thanks in advance..

state1 <- list(n=100, won=0)
state2 <- list(n=100, won=0)

fight2 <- function(stateA, stateB){
   stateA$n <- 50
   stateB$n <-50
}

fight2(state1,state2)

state1$n
state2$n

	[[alternative HTML version deleted]]

No pointer functionality in R (that I know of), but if you want to
return two objects as one the standard way is to put them in a list
and to return that list.

Michael

On Tue, Dec 6, 2011 at 2:35 PM, Yev <kirpich at gmail.com>
wrote:
> I'm trying to write a function that takes several objects with many
> different attributes and then changes their attributes. So what I wanted to
> happen in the simplified example below is for the function to change the
> attributes of the objects state1 and state2 that are passed to it. But
> because stateA and stateB are local, this isn't working. Are there any
easy
> solutions?
>
> e.g., if I could combine the two objects stateA and stateB into a single
> object, I could return it and then assign it back to objects state1 and
> state2. Or if I could pass a pointer to the original object.. But I cannot
> find an easy way of doing either. ?Thanks in advance..
>
> state1 <- list(n=100, won=0)
> state2 <- list(n=100, won=0)
>
> fight2 <- function(stateA, stateB){
> ? stateA$n <- 50
> ? stateB$n <-50
> }
>
> fight2(state1,state2)
>
> state1$n
> state2$n
>
> ? ? ? ?[[alternative HTML version deleted]]
>
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