Question

I start with a 2×4 matrix A

import numpy as np
A = np.matrix([[1, 2, 3, 4], [5, 6, 7, 8]])

I also have another 1×4 matrix B

B = np.matrix([9, 10, 11, 12])

How do I concatenate A and B so that I get a 3×4 matrix C

C = [[9 10 11 12]
     [1 2 3 4]
     [5 6 7 8]]

Note that B is prepended before row 0 of matrix A.

Answer 1

From: http://docs.scipy.org/doc/numpy/reference/routines.array-manipulation.html

C = np.concatenate((B, A))