[R] Chapters

[Marshall Feldman]

Thanks.

Reading the discussion of differences between S and R, I had almost come to
this conclusion but wanted to be sure. Since R keeps its working data in
RAM, the use of chapters seemed unlikely, but I wanted to be sure.

I am, however, surprised this has not come up before. The online
documentation says R is an "implementation" of S, but since there are no
standards defining S versus variations on it, exactly what an
"implementation of S" means is not clear. Besides, other than the online
documentation on R, people using R must use the various books using S. I had
expected others to have asked for clarification on the differences between R
and S, including the various incarnations of the latter.

Thanks again.

	Marsh Feldman

Dr. Marshall Feldman
Acting Director of Research and Academic Affairs
Center for Urban Studies and Research 
The University of Rhode Island
80 Washington Street
Providence, RI 02903-1819
email: marsh @ uri.edu (remove spaces) 
telephone: (401) 277-5218
fax: (401) 277-5099


-----Original Message-----
From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk] 
Sent: Monday, June 12, 2006 2:07 AM
To: Marshall Feldman
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] Chapters

On Sun, 11 Jun 2006, Marshall Feldman wrote:

> I'm surprised this isn't a FAQ, but I searched all over and could not find
a
> reference to it.

I have never seen in mentioned before.  R is not an implementation of S4 
as described in Chambers (1998), so I do not know where you got the idea 
that was relevant.  (The methods package in R is an implementation of 
something close to the class system described in that book, but R can be 
used without the methods package.)

> Chambers (1998) makes repeated references to "Chapters" in S (e.g., p. 6),
> but I can find no reference to "Chapters" in R. Since Chapters were not
used
> in earlier versions of S, I'm wondering if R uses them or not. If it does,
> how does one get them to work? I've been unable to do so.

The closest analogues are

1) packages
2) using different working directories.

Since R does not store objects on file and chapters are directories with 
collections of stored objects (and other things, including DLLs), the 
analogues cannot be very close.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595