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[11] <- 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.

Hadley


-- 
RStudio / Rice University
http://had.co.nz/

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