Convert an upper to lower triangle matrix in r

Question

I looked inot several posts, but I still couldn't find a way to just transform an upper triangle matrix into a lower triangle matrix.

I just want this:

    1   2   3
a   10  11  12
b       13  14
c           15

To become this:

    a   b   c
1   10
2   11  13
3   12  14  15

Answer 1

We just need to transpose it

t(m1)