[Rd] pass-by-reference

[Henrik Bengtsson]

...and for tracing memory allocations/duplications, see tracemem().

/Henrik

On Thu, Jul 8, 2010 at 9:14 AM, Henrik Bengtsson <hb at stat.berkeley.edu> wrote:
> See packages R.oo and proto.
>
> If you wish to do it yourself, you want to utilize environments for this.
>
> /Henrik
>
> On Thu, Jul 8, 2010 at 6:52 AM, Paul Bailey <pdbailey at umd.edu> wrote:
>>
>> I'm working with a large object that I want to modify slightly in a function.
>> Pass-by-reference would make a lot of sense, but I don't know how to do it.
>>
>> I've searched this archive and thought that I can do something like
>>
>> f <- function(x) {
>>  v1 <- list(a=x,b=3)
>>  g(x)
>>  v1
>> }
>> g <- function(x) {
>>  frame <- parent.frame()
>>  assign("v1",list(a=x,b=x),frame)
>> }
>> f(4)
>> returns list(a=4,b=4)
>>
>> but what if I wanted to make v1[[1]] = v1[[1]] + v1[[2]] without creating a
>> copy of v1?
>>
>> f2 <- function(x) {
>>  v1 <- list(a=x,b=3)
>>  g2(x)
>>  v1
>> }
>> g2 <- function(x) {
>>  frame <- parent.frame()
>>  v1 <- get("v1",envir=frame)
>>  v1[[1]] <- v1[[1]] + v1[[2]]
>> }
>> f2(4)
>>
>> but this fails. (it returns list(a=4,b=3) because v1 was copied into g2, not
>> passed by reference) Is there a way to do this?
>> --
>> View this message in context: http://r.789695.n4.nabble.com/pass-by-reference-tp2281802p2281802.html
>> Sent from the R devel mailing list archive at Nabble.com.
>>
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>