https://docs.scipy.org/doc/numpy/reference/generated/numpy.c_.html
Examples
>>> np.c_[np.array([1,2,3]), np.array([4,5,6])]
array([[1, 4], [2, 5], [3, 6]])
>>> np.c_[np.array([[1,2,3]]), 0, 0, np.array([[4,5,6]])]
array([[1, 2, 3, 0, 0, 4, 5, 6]])