It can handle one more simplification step
# Rich Heiberger, removing intercept, including haireye data
haireye.df <- cbind(
as.data.frame(haireye),
model.matrix(Freq ~ Hair + Eye, data=haireye,
contrasts.arg=list(Hair=diag(4), Eye=diag(4)))[,-1]
)
haireye.df
On Tue, Dec 30, 2014 at 9:15 PM, Michael Friendly <frien...@yorku.ca> wrote:
> On 12/30/14 7:16 PM, Richard M. Heiberger wrote:
>>
>> I like this very simple version. Note that you don't need
>> as.data.frame().
>>
>> model.matrix(Freq ~ Hair + Eye, data=haireye,
>> contrasts.arg=list(Hair=diag(4), Eye=diag(4)))
>
> Thanks to all who replied to this question. model.matrix() was what I had
> missed, but to
> get the result in the form I wanted, required a bit more work. These
> solutions give me
> what I asked for.
>
> haireye <- margin.table(HairEyeColor, 1:2)
>
> # Jeff Newmiller, solution 2, corrected
>
> haireye.df <- as.data.frame(haireye)
> dummykeys <- data.frame( h = factor( as.integer( haireye.df$Hair ) )
> , e = factor( as.integer( haireye.df$Eye ) ) )
> dummy.hair <- as.data.frame( model.matrix( ~ h - 1, data=dummykeys ))
> dummy.eye <- as.data.frame( model.matrix( ~ e - 1, data=dummykeys ))
> haireye.df <- data.frame( haireye.df, dummy.hair, dummy.eye )
>
>
> # Rich Heiberger, removing intercept, including haireye data
> haireye.df <- as.data.frame(haireye)
> haireye.df <- cbind(
> haireye.df,
> model.matrix(Freq ~ Hair + Eye, data=haireye,
> contrasts.arg=list(Hair=diag(4), Eye=diag(4)))[,-1]
> )
> haireye.df
>
>
>
>
> --
> Michael Friendly Email: friendly AT yorku DOT ca
> Professor, Psychology Dept. & Chair, Quantitative Methods
> York University Voice: 416 736-2100 x66249 Fax: 416 736-5814
> 4700 Keele Street Web: http://www.datavis.ca
> Toronto, ONT M3J 1P3 CANADA
>
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