[R] enumerate subsets

[Gabor Grothendieck]

Try this replacing letters[1:4] with your set:

> do.call(expand.grid, as.data.frame(rbind(letters[1:4], NA)))
     V1   V2   V3   V4
1     a    b    c    d
2  <NA>    b    c    d
3     a <NA>    c    d
4  <NA> <NA>    c    d
5     a    b <NA>    d
6  <NA>    b <NA>    d
7     a <NA> <NA>    d
8  <NA> <NA> <NA>    d
9     a    b    c <NA>
10 <NA>    b    c <NA>
11    a <NA>    c <NA>
12 <NA> <NA>    c <NA>
13    a    b <NA> <NA>
14 <NA>    b <NA> <NA>
15    a <NA> <NA> <NA>
16 <NA> <NA> <NA> <NA>


On Sun, Jul 20, 2008 at 4:33 PM, lamack lamack <lamac_k at hotmail.com> wrote:
>
> Dear all, is there a R function that enumerate a partition of a vector of size n? (of course for n not very large).
> I would like enumerate all the (2 power n)-1 sub-sets. (2 power n)-1 since (2 power n) includes de empty subset.
>
> Best Regards.
>
> ps. It is not a homework. I never posted homework in this list.
>
> LL
>
>
>
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