[Rd] how to exclude terms preceded by - from model frame

[Prof Brian Ripley]

On Wed, 19 Mar 2008, Liaw, Andy wrote:

> [I believe few users manipulate formulae and model frames like this, so
> I'm posting here instead of R-help.]
>
> I just found out that model.frame() includes all terms, including those
> preceded by "-" in the formula, in its output (as mentioned on its help
> page).  Is there a recommended way of excluding "negative" terms?  My
> guess is that I can use info in the terms attribute to figure this out,
> but that doesn't seem very straightforward.  Any pointer would be much
> appreciated.

?terms.formula, argument 'simplify', if I understand you aright.


>
> Best,
> Andy
>
> Andy Liaw, PhD
> Biometrics Research    PO Box 2000 RY33-300
> Merck Research Labs        Rahway, NJ 07065
> andy_liaw(a)merck.com          732-594-0820


-- 
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)
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