From brahm@alum.mit.edu  Wed May 29 14:58:55 2002
From: brahm@alum.mit.edu (David Brahm)
Date: Wed, 29 May 2002 09:58:55 -0400
Subject: (PR#1608) merge.data.frame can coerce character vectors to factor in some circumstances (PR#1608)
In-Reply-To: <15604.52739.590128.620397@gargle.gargle.HOWL>
References: <200205291110.NAA06480@pubhealth.ku.dk>
 <Pine.GSO.4.44.0205291229250.23715-100000@auk.stats>
 <15604.52739.590128.620397@gargle.gargle.HOWL>
Message-ID: <15604.56991.282396.570441@gargle.gargle.HOWL>

Brian D. Ripley <ripley@stats.ox.ac.uk> wrote:
> As I said before, [characters converted to factors] is a consequence of the
> general rules.  Data frames are not designed to have character columns, and
> those who insist on using them must make themselves aware of the
> consequences.

I think this is as true in S-Plus as it is in R, because S is fundamentally a
language designed for statistics, where everything is a real number or a
conditioning variable.  As a result, I (and my former group) abandoned the use
of dataframes years ago.  We created our own pseudo-class of "dataobjects"
(lists of equal-length vectors), and built our own versions of many standard
functions (read.table -> g.dataobj, merge -> g.join, "[" -> g.subset, etc.) for
them.

Dave Kane has made a strong push to use existing R classes and built-in
functions, but I'm convinced now I can bring him over to the Dark Side.
-- 
                              -- David Brahm (brahm@alum.mit.edu)
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(PR#1608) merge.data.frame can coerce character vectors to factor in some circumstances (PR#1608)
David Brahm