Re: [R] renaming objects

From: hadley wickham <h.wickham_at_gmail.com>
Date: Mon, 03 Mar 2008 16:48:29 -0600

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

-- 
http://had.co.nz/

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Received on Mon 03 Mar 2008 - 22:58:24 GMT

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