From Kurt.Hornik@ci.tuwien.ac.at  Mon Feb 12 15:47:45 2001
From: Kurt.Hornik@ci.tuwien.ac.at (Kurt Hornik)
Date: Mon, 12 Feb 2001 16:47:45 +0100
Subject: [Rd] Re: tabular data (was RE: [R] Removing "row.names")
In-Reply-To: <200102091824.NAA03028@jessie.research.bell-labs.com>
References: <200102091824.NAA03028@jessie.research.bell-labs.com>
Message-ID: <14984.1441.181293.426501@mithrandir.hornik.net>

>>>>> David James writes:

> Hi,

> For instance, interfaces to XML, spreadsheets, DBMS, etc., will
> further expose some of the limitations of these existing objects.
> Tables holding data from relational DBMS are an easy case: this class
> should preserve the original data as much as possible, i.e., no
> coercing into factors, no changing column names, no row names, but
> otherwise very similar to data.frames.  (Timothy Keitt has a more
> interesting concept of "proxyTables" that presents some very
> interesting issues: should proxyTables, which "point" to remote
> relations in dbms, allow integer indexing? --- the relational database
> model does not support it)

> Is there something common to all these objects?  Obviously they all
> support indexing x[i,j, ...] plus the methods dim() and (possibly
> NULL) dimnames().  S4 defines vectors as a (virtual) class in terms of
> the indexing operation in exactly this way -- thus in S4 lists are
> vectors, and so are logicals, characters, etc.  We may be able to
> group the various "tabular data" classes under such virtual class, and
> provide simple coercion facilities so that users can easily fit, say,
> a linear model to data coming as an XML document or in a table stored
> in a dbms.

Maybe this is something to be kicked off at the official part of DSC and
discussed in the `r-core' part.

-k
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[Rd] Re: tabular data (was RE: [R] Removing "row.names")
Kurt Hornik