[R] Design matrix not identity

[John Fox]

Dear Patrick,

Try model.matrix(~ factor - 1).

I hope this helps,
 John

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Patrik Waldmann
> Sent: Wednesday, May 12, 2004 11:34 AM
> To: 'r-help at stat.math.ethz.ch'
> Subject: [R] Design matrix not identity
> 
> Hello again,
> 
> I was too quick before. What I was looking for was a function 
> that constructs the design (or incidence) matrix (X in a 
> linear model) from a factor. Uwe Ligges suggested using 
> model.matrix and this does almost what I want, but it is 
> first necessary to construct a data variable. It also asigns 
> ones to all rows of the first column (because this is set to 
> be the contrast, not really what I want - see below). Maybe 
> time for a function that just converts a factor into a design matrix?
> 
> I have a factor
> factor<-as.factor(c(1,1,2,2,3,3,3))
> 
> and I want a matrix
> 1 0 0
> 1 0 0
> 0 1 0
> 0 1 0
> 0 0 1
> 0 0 1
> 0 0 1
> 
> 
> Patrik Waldmann###########################################
>