Matrix concatenation with Numpy

[Addition] I wrote a memo like this when I was a student, but please calmly use `` `np.concatenate```: https://docs.scipy.org/doc/numpy/reference /generated/numpy.concatenate.html


Make a note because I often forget which one.

>>> import numpy as np
>>> a = np.array([[1,2,3], [4,5,6]])
>>> b = np.array([[7, 8, 9], [10, 11, 12]])
>>> c = np.array((1, 2, 3))
>>> d = np.array((4, 5, 6))

>>> a
array([[1, 2, 3],
       [4, 5, 6]])

>>> b
array([[ 7,  8,  9],
       [10, 11, 12]])

>>> c
array([1, 2, 3])

>>> d
array([4, 5, 6])

>>> np.r_[a, b]
array([[ 1,  2,  3],
       [ 4,  5,  6],
       [ 7,  8,  9],
       [10, 11, 12]])

>>> np.c_[a, b]
array([[ 1,  2,  3,  7,  8,  9],
       [ 4,  5,  6, 10, 11, 12]])

>>> np.r_[c, d]
array([1, 2, 3, 4, 5, 6])

>>> np.c_[c, d]
array([[1, 4],
       [2, 5],
       [3, 6]])

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