[R] Design matrix not identity

[Gabor Grothendieck]

f<-as.factor(c(1,1,2,2,3,3,3))
model.matrix(~f-1)

Patrik Waldmann <Patrik.Waldmann <at> genfys.slu.se> writes:

: 
: 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
: 
: 
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