Can I swap variables inside a function using pointers in R? - r

Question

Here is a silly (maybe only in my mind) way to accomplish my goal:
A <- "This is a test."
B <- "This is the answer."
swap <- function(item1,item2) {
tmp <- item2
item2 <- item1
item1 <- tmp
return(list(item1,item2))
}
AB <- swap(A,B)
A <- AB[[1]]
B <- AB[[2]]
But I'm considering something similar to the C code following:
void swap(int *a, int *b)
{
int iTemp ;
iTemp = *a;
*a = *b;
*b = iTemp;
}
My motivations:
My real data is quite large, e.g. 5k*5k matrix, so the assignment of the existing variable in the iteration twice, inside the function and outside the function, must be time squandering.
The closest question on the SO is this one, but just like the OP in the question, my R session also has lots of objects: I'm working with Rmpi, and each slave will have a great number of variables.
In my humble opinion, R is written in C, so R may have pointers like C does, while I can't find much on the net surprisingly.

Answer 1

How about this; this just assigns to the parent environment.
A <- "This is a test."
B <- "This is the answer."
swap <- function(item1, item2) {
tmp <- item1
assign(deparse(substitute(item1)), item2, pos = 1)
assign(deparse(substitute(item2)), tmp, pos = 1)
}
swap(A, B)
A
#[1] "This is the answer."
B
#[1] "This is a test.