[R] renaming objects

[hadley wickham]

On Mon, Mar 3, 2008 at 4:37 PM, Rolf Turner <r.turner at auckland.ac.nz> wrote:
>
>  On 4/03/2008, at 10:38 AM, Ericka Lundström wrote:
>
>  > On 03/03/2008, at 22.20, Giles.Crane at doh.state.nj.us wrote:
>  >> Is there a way to rename R objects?
>  >> I am looking for a way to rename objects
>  >> without making new objects.
>  >>
>  >> #For example:
>  >> x = c(1:40)
>  >> # I wish to use a function to rename x, already created, to y,
>  >> perhaps by
>  >> obj.rename(x,y)
>  >> # or
>  >> obj.rename("x","y")
>  > y <- x # changes x to y with same values.
>
>         That makes a new object --- which is precisely what the enquirer
>         wanted ***NOT*** to do.

It doesn't though!

> gc()
         used (Mb) gc trigger (Mb) max used (Mb)
Ncells 133095  3.6     350000  9.4   350000  9.4
Vcells  87049  0.7     786432  6.0   478831  3.7
> a <- runif(1e7)
> gc()
           used (Mb) gc trigger (Mb) max used (Mb)
Ncells   133112  3.6     350000  9.4   350000  9.4
Vcells 10087364 77.0   11458389 87.5 10087374 77.0
> b <- a
> gc()
           used (Mb) gc trigger (Mb) max used (Mb)
Ncells   133117  3.6     350000  9.4   350000  9.4
Vcells 10087365 77.0   12111308 92.5 10087476 77.0

R will only create a copy if either of a or b is modified.

Hadley



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