rownames and colnames with specific value

Question

I have this matrix and i want to get a 2 column matrix, where one column has the rowname and the other column, the colname of cells with value 1

x

   X1 X2 X3
         


        

Answer 1

Here's one line answer

x
##    X1 X2 X3
## X1  1  0  1
## X2  0  1  0
## X3  0  1  1
## X4  1  0  0


cbind(rownames(x)[row(x) * x], colnames(x)[col(x) * x])
##      [,1] [,2]
## [1,] "X1" "X1"
## [2,] "X4" "X1"
## [3,] "X2" "X2"
## [4,] "X3" "X2"
## [5,] "X1" "X3"
## [6,] "X3" "X3"