Vetor para linha, para vetor coluna
>>> a[None].T
array([[1],
[2],
[3]])
>>> np.newaxis is None
True
>>> a.reshape(a.shape+(1,))
array([[1],
[2],
[3]])
>>> a[:,None]
array([[1],
[2],
[3]])
apenas algumas anotações...
>>> a[None].T
array([[1],
[2],
[3]])
>>> np.newaxis is None
True
>>> a.reshape(a.shape+(1,))
array([[1],
[2],
[3]])
>>> a[:,None]
array([[1],
[2],
[3]])