From simon.urbanek at r-project.org  Sat Nov 10 02:59:46 2012
From: simon.urbanek at r-project.org (Simon Urbanek)
Date: Fri, 9 Nov 2012 20:59:46 -0500
Subject: [Rd] built-in NAMED(obj) from within R
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Message-ID: <BA1B8718-4D98-4C04-8D40-E409D1A774E0@r-project.org>


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.


> the vector is not duplicated.  This confused me at first, so I thought I'd point it out.
> 

I'm not quite sure what is your distinction you are trying to make there...

Cheers,
Simon


> Hadley
> 
> -- 
> RStudio / Rice University
> http://had.co.nz/
> 
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[Rd] built-in NAMED(obj) from within R
Simon Urbanek