Maybe this?

group <- factor(c("A", "B","B","C","C","C"))
model.matrix(~0+group)

-tgs

On Sat, May 15, 2010 at 2:02 PM, Noah Silverman <noah@smartmediacorp.com>wrote:

> Hi,
>
> I'm looking for an easy way to discretize factors in R
>
> I've noticed that the lm function does this automatically with a nice
> result.
>
> If I have
>
> group <- c("A", "B","B","C","C","C")
>
> and run:
>
> lm(result ~ x1 + group)
>
> The lm function has split the group into separate binary variables {0,1}
> before performing the regression.  I now have:
> groupA
> groupB
> groupC
>
> Some of the other models that I want to try won't accept factors, so
> they need to be discretized this way.
>
> Is there a command in R for this, or some easy shortcut?  (I tried
> digging into the lm code, but couldn't find where this is being done.)
>
> Thanks!
>
> -N
>
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