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.
That being said, I'm pretty sure that the answer to the original
question ``Is there a way ... ?'' is ``No.'' The R-Core people
will be able to provide a definitive answer, but it appears to me
that the way a name is associated with an object is buried deep
in the innards of R and is not accessible to the user.
At this stage, I'd like to enquire ***why*** is it desired to
be able to do this? The one rationale that I can think of is the
situation that x is so huge that it is impossible to make a copy
of it (via ``y <- x'') without exceeding R's memory capacity.
If x is not that huge, one can simply do ``y <- x'' and then
``rm(x)'' and presto one has changed the object's name from ``x''
to ``y''.
I have written my own little utility function ``mv()'', imitating
the Unix command ``mv'' to facilitate this:
mv <- function (a, b) {
anm <- deparse(substitute(a))
bnm <- deparse(substitute(b))
if (!exists(anm,where=1,inherits=FALSE))
stop(paste(anm, "does not exist.\n"))
if (exists(bnm,where=1,inherits=FALSE)) {
ans <- readline(paste("Overwrite ", bnm, "? (y/n) ",
sep =
""))
if (ans != "y")
return(invisible())
}
assign(bnm, a, pos = 1)
rm(list = anm, pos = 1)
invisible()
}
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