[R] Matrix of dummy variables from a factor
roger koenker
rkoenker at uiuc.edu
Wed Dec 7 00:31:19 CET 2005
On Dec 6, 2005, at 3:27 PM, Berton Gunter wrote:
> But note: There are (almost?) no situations in R where the dummy
> variables
> coding is needed. The coding is (almost?) always handled properly
> by the
> modeling functions themselves.
>
> Question: Can someone provide a "straightforward" example where the
> dummy
> variable coding **is** explicitly needed?
>
Bert's question offers an opportunity for me to mention (again) my
long standing wish
for someone to write a version of model.matrix that directly produced
a matrix
in one of the common sparse matrix formats. This could be a good
project for one of
you who like using ";" ?
Roger
url: www.econ.uiuc.edu/~roger Roger Koenker
email rkoenker at uiuc.edu Department of Economics
vox: 217-333-4558 University of Illinois
fax: 217-244-6678 Champaign, IL 61820
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