Numpy append function

The function prototype

numpy.append(arr, values, axis=None)

Function interpretation

Add elements at the end of the array , According to the shape of the data, it can be added from different dimensions ; If not specified axis, Then the array is flattened into a one-dimensional array .

The usage function

>>> a = np.zeros((2, 2, 2))
>>> a
array([[[0., 0.],
        [0., 0.]],

       [[0., 0.],
        [0., 0.]]])
>>> b = np.zeros((1, 2, 2))
>>> b
array([[[0., 0.],
        [0., 0.]]])
#  Is not specified axis
>>> c = np.append(a, b)
>>> c
array([0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.])
#  stay axis=0 Add 
>>> d = np.append(a, b, axis=0)
>>> d
array([[[0., 0.],
        [0., 0.]],

       [[0., 0.],
        [0., 0.]],

       [[0., 0.],
        [0., 0.]]])
>>> e = np.zeros((2, 1, 2))
>>> e
array([[[0., 0.]],

       [[0., 0.]]])
>>> f = np.append(a, e, axis=1)
>>> f
array([[[0., 0.],
        [0., 0.],
        [0., 0.]],

       [[0., 0.],
        [0., 0.],
        [0., 0.]]])
>>> g = np.zeros((2, 2, 1))
>>> g
array([[[0.],
        [0.]],

       [[0.],
        [0.]]])
>>> h = np.append(a, g, axis=2)
>>> h
array([[[0., 0., 0.],
        [0., 0., 0.]],

       [[0., 0., 0.],
        [0., 0., 0.]]])