Thanks a lot! That's exactly what I need.

On 1/26/07, ken knoblauch <knoblauch@lyon.inserm.fr> wrote:
>
> does expand.grid do what you want?
>
> expand.grid(c(0, 1), c(0, 1), c(0, 1))
>    Var1 Var2 Var3
> 1    0    0    0
> 2    1    0    0
> 3    0    1    0
> 4    1    1    0
> 5    0    0    1
> 6    1    0    1
> 7    0    1    1
> 8    1    1    1
>
>
> > Hi all R users,
> > I want to create a matrix having n columns and 2^n rows, and all its
> > entries
> > are only 0 or 1. In each row, column i is 0 means dimension i is
> > chosen, 0
> > means not.  The matrix will contains all the possible combination of
> > those n
> > dimensions.
> >
> > Here is an example, if n = 3, the matrix will look like:
> > 0 0 0
> > 0 0 1
> > 0 1 0
> > 1 0 0
> > 0 1 1
> > 1 0 1
> > 1 1 1
> >
> >
> > I know I can use n "for" loops to do this, but is there a better way?
> > Thanks,
> > -zm
> >
> >       [[alternative HTML version deleted]]
> >
> >
>
>
>
>

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