[Rd] built-in NAMED(obj) from within R
simon.urbanek at r-project.org
Sat Nov 10 04:01:49 CET 2012
On Nov 9, 2012, at 9:46 PM, Hadley Wickham wrote:
> On Friday, November 9, 2012, Simon Urbanek wrote:
> On Nov 9, 2012, at 8:00 AM, Hadley Wickham wrote:
> >>> The goal is to ascertain whether a copy of an object has been made.
> >> Then :
> >> ?tracemem
> >> One demonstration of using both together is here :
> >> http://stackoverflow.com/a/10312843/403310
> > Note that tracemem detects duplications (in a technical R sense), not
> > copies - i.e.
> > x <- 1:10
> > tracemem(x)
> > x <- 11L
> > although all the individual elements are copied,
> No elements are copied - this is a subassignment and it is done in place hence there is neither duplication nor copying - simply the value of the 11th element is changed.
> But there was no 11th element - it was only 10 long.
Ah, I see what you mean - the misleading part is rather that x is now a new object that is no longer traced - this is not about duplication or copying.
More information about the R-devel