Perhaps a much simpler method (just thought of it) would be to set
options(na.action="na.pass")
before you start. Or use na.action=na.pass() as an argument in
the call to model.frame(), since that's where the problem begins.
See help("na.omit"), help("model.frame").
- tom blackwell - u michigan medical school - ann arbor -
On Mon, 27 Oct 2003, J.R. Lockwood wrote:
> I have a factor (with "n" observations and "k" levels), with only
> "nobs" < n of the observations not missing. I would like to produce a
> (n x k) model matrix with treatment contrasts for this factor, with
> rows of NAs placeholding the missing observations. If I use
> model.matrix() I get back a (nobs x k) matrix. Is there an easy way
> to get the (n x k) without carrying along a row ID and merging?
> Thanks.
>
> J.R. Lockwood
> 412-683-2300 x4941
> [EMAIL PROTECTED]
> http://www.rand.org/methodology/stat/members/lockwood/
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