From kw.statr at gmail.com  Tue Jul 17 17:14:47 2007
From: kw.statr at gmail.com (Kevin Wright)
Date: Tue, 17 Jul 2007 10:14:47 -0500
Subject: [Rd] formula(CO2)
In-Reply-To: <971536df0707160628g37e301e1wf81eaee0b7feb841@mail.gmail.com>
References: <971536df0707160628g37e301e1wf81eaee0b7feb841@mail.gmail.com>
Message-ID: <c968588d0707170814k1351a429qa23b858b7e4abd2f@mail.gmail.com>

About a month ago I had a similar issue related to 'formula':
http://tolstoy.newcastle.edu.au/R/e2/devel/07/05/3329.html

In summary:

In S-Plus, the help for formula.data.frame says:
This is a method for the function formula() for objects inheriting
from class data.frame. If object is a model frame, the formula for the
model frame is returned, otherwise a formula is deduced from the names
of object. The first name is taken to be the response, and all the
remaining names are pasted together additively.

In R, the help for formula.data.frame is aliased to the help for
formula, but does not clearly document the usage with data.frames.

Kevin

On 7/16/07, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> The formula attribute of the builtin CO2 dataset seems a bit strange:
>
> > formula(CO2)
> Plant ~ Type + Treatment + conc + uptake
>
> What is one supposed to do with that?  Certainly its not suitable for
> input to lm and none of the examples in ?CO2 use the above.
>
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>



[Rd] formula(CO2)
Kevin Wright