如何在NumPy中附加到数组而不使数组变平?

如何在NumPy中附加两个数组而不进行扁平化? 我试着改变轴。

>>> h = np.array([])
>>> g = np.array([2,4])
>>> i = np.array([6,9])
>>> np.append(h,g)
array([2., 4.])
>>> h = np.append(h,g)
>>> h
array([2., 4.])
>>> np.append(h,i)
array([2., 4., 6., 9.])
>>> np.append(h,i, axis=0)
array([2., 4., 6., 9.])
>>> np.append(h,i, axis=1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/homebrew/lib/python3.11/site-packages/numpy/lib/function_base.py", line 5617, in append
    return concatenate((arr, values), axis=axis)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
numpy.exceptions.AxisError: axis 1 is out of bounds for array of dimension 1
>>> 

应为-

h = [[2,4],[6,9]]