Tue Oct 19 17:02:20 2021 HSTACK_TEST Python version: 3.6.9 np.hstack() horizontally stacks arrays of same column dimension. Matrix A: Col: 0 1 2 Row 0: 11 12 13 1: 21 22 23 2: 31 32 33 3: 41 42 43 Matrix B: Col: 0 1 Row 0: 104 105 1: 204 205 2: 304 305 3: 404 405 Matrix hstack(A,B) Col: 0 1 2 3 4 Row 0: 11 12 13 104 105 1: 21 22 23 204 205 2: 31 32 33 304 305 3: 41 42 43 404 405 Matrix hstack(A[:,0:1], B, A[:,1:3]) Col: 0 1 2 3 4 Row 0: 11 104 105 12 13 1: 21 204 205 22 23 2: 31 304 305 32 33 3: 41 404 405 42 43 HSTACK_TEST: Normal end of execution. Tue Oct 19 17:02:20 2021