R help - Mar 2008 - R objects layout

Hi,

Can anyone point me to documentation of how R objects such as vectors, 
lists, matrices and data frames are laid out in memory? For example, which 
of these are laid out as a 1-d array, 2-d array and so forth?

The R Internals document seems like the natural place to look, but I don't 
see it there. If such things are only documented in source code, could you 
point me to the relevant place(s)?

(Please CC me; I'm not subscribed.)
                                                             Thanks, Faheem.

On 3/26/2008 12:20 PM, Faheem Mitha wrote:
> Hi,
> 
> Can anyone point me to documentation of how R objects such as vectors, 
> lists, matrices and data frames are laid out in memory? For example, which 
> of these are laid out as a 1-d array, 2-d array and so forth?
Vectors, lists and matrices are 1-d arrays.  Data frames are lists of 
vectors. This is in various places in the Intro and Language Reference 
manuals.  For example, from the latter:

"Matrices and arrays are simply vectors with the attribute dim and 
optionally dimnames attached to the vector."

Duncan Murdoch
> The R Internals document seems like the natural place to look, but I
don't
> see it there. If such things are only documented in source code, could you 
> point me to the relevant place(s)?
> 
> (Please CC me; I'm not subscribed.)
>                                                              Thanks,
Faheem.
> 
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