在矩阵中添加索引列

Question

I have an m by n two-dimensional matrix. I would like to add a new auto-incremented index column (1, 2, 3, 4, ..., m) .

Is there a quick and easy way to do so?

Answer 1

octave:1> m = 3; n = 4;
octave:2> M = randn(m,n);
octave:3> A = [ [1:m].', M ]
A =
   1.00000   0.68684   0.42748   0.75679  -1.31721
   2.00000   0.49668   1.67280   0.14784  -1.13983
   3.00000  -0.17439   0.42140  -1.85646  -1.31556