R:Binary matrix for all possible unique results

Question

How to generate a binary matrix for all possible permutations of \'i\' variables X, where \" i \" can be any number between 1 and infinite. Resultant matrix will have 2^ i u

Answer 1

The fonction combos of the package hier.part will do the job I think.

require(hier.part)
combos(2)$binary
     [,1] [,2]
[1,]    1    0
[2,]    0    1
[3,]    1    1

combos(3)$binary
     [,1] [,2] [,3]
[1,]    1    0    0
[2,]    0    1    0
[3,]    0    0    1
[4,]    1    1    0
[5,]    1    0    1
[6,]    0    1    1
[7,]    1    1    1

Except that you will have to add the "null" combination. HTH