> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Rolf Turner > Sent: Monday, March 03, 2008 4:37 PM > To: hadley wickham > Cc: r-help; [EMAIL PROTECTED] > Subject: Re: [R] renaming objects > > > On 4/03/2008, at 11:48 AM, hadley wickham wrote: > > > On Mon, Mar 3, 2008 at 4:37 PM, Rolf Turner > > <[EMAIL PROTECTED]> wrote: > >> > >> On 4/03/2008, at 10:38 AM, Ericka Lundström wrote: > >> > >>> On 03/03/2008, at 22.20, [EMAIL PROTECTED] 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. > > Well RMIHATMTTL!!! R is even cleverer than I thought!!! > > cheers, > > Rolf
But, the OP should know that in the above scenario, if a or b is changed the copy will be created, doubling the storage requirements. Of course, this can be prevented by removing vector a after the assignment. Hope this is helpful, Dan Daniel J. Nordlund Research and Data Analysis Washington State Department of Social and Health Services Olympia, WA 98504-5204 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
