將 3D numpy 陣列拆分為更小的 3D arrays

Question

我有一個 3D np.array

arr = np.array([ 
                [ [0, 205, 25], [210, 150, 30], [0, 0, 0], [1, 2, 3], [4, 5, 6], [7, 8, 9] ],
                [ [0, 255, 0], [255, 40, 0], [0, 0, 200], [7, 8, 9], [10, 11, 12], [120, 51, 58] ],
                [ [0, 0, 30], [0, 40, 0], [200, 100, 20], [12, 13, 14], [15, 16, 17], [13, 78, 84], ],
                [ [0, 205, 25], [210, 150, 30], [0, 0, 0], [1, 2, 3], [4, 5, 6], [7, 8, 9] ],
                [ [0, 255, 0], [255, 40, 0], [0, 0, 200], [7, 8, 9], [10, 11, 12], [120, 51, 58] ],
                [ [0, 0, 30], [0, 40, 0], [200, 100, 20], [12, 13, 14], [15, 16, 17], [13, 78, 84], ],
                [ [0, 205, 25], [210, 150, 30], [0, 0, 0], [1, 2, 3], [4, 5, 6], [7, 8, 9] ],
                [ [0, 255, 0], [255, 40, 0], [0, 0, 200], [7, 8, 9], [10, 11, 12], [120, 51, 58] ],
                [ [0, 0, 30], [0, 40, 0], [200, 100, 20], [12, 13, 14], [15, 16, 17], [13, 78, 84], ],
              ])

我需要將其拆分為 3x2x3 3D arrays

[ [0, 205, 25], [210, 150, 30],    [0, 0, 0], [1, 2, 3],             [4, 5, 6], [7, 8, 9] ],
[ [0, 255, 0],  [255, 40, 0],      [0, 0, 200], [7, 8, 9],           [10, 11, 12], [120, 51, 58] ],
[ [0, 0, 30],   [0, 40, 0],        [200, 100, 20], [12, 13, 14],     [15, 16, 17], [13, 78, 84], ],

[ [0, 205, 25], [210, 150, 30],    [0, 0, 0], [1, 2, 3],             [4, 5, 6], [7, 8, 9] ],
[ [0, 255, 0],  [255, 40, 0],      [0, 0, 200], [7, 8, 9],           [10, 11, 12], [120, 51, 58] ],
[ [0, 0, 30],   [0, 40, 0],        [200, 100, 20], [12, 13, 14],     [15, 16, 17], [13, 78, 84], ],

[ [0, 205, 25], [210, 150, 30],    [0, 0, 0], [1, 2, 3],             [4, 5, 6], [7, 8, 9] ],
[ [0, 255, 0],  [255, 40, 0],      [0, 0, 200], [7, 8, 9],           [10, 11, 12], [120, 51, 58] ],
[ [0, 0, 30],   [0, 40, 0],        [200, 100, 20], [12, 13, 14],     [15, 16, 17], [13, 78, 84], ],

使用我按空格選擇的這些 3D 塊獲得 4D 數組。 零元素必須是

[ 
    [[0, 205, 25], [210, 150, 30]],
    [[0, 255, 0], [255, 40, 0]],
    [[0, 0, 30], [0, 40, 0]] 
]

等等。

我已經閱讀了這個問題，但仍然不明白如何做到這一點（為什么我們需要重新整形、轉置和重新整形，以及transpose()中的神奇數字是什么）。 我可以嘗試編寫自己的 function 但我想知道如何以原生方式進行。

Answer 1

您可以對其進行整形和轉置

arr.reshape(3, 3, 3, 2, 3).transpose(2, 0, 1, 3, 4)
# array([[[[[  0, 205,  25],
#           [210, 150,  30]],
# 
#          [[  0, 255,   0],
#           [255,  40,   0]],
# 
#          [[  0,   0,  30],
#           [  0,  40,   0]]],
# 
# 
#         [[[  0, 205,  25],
#           [210, 150,  30]],
# 
#          [[  0, 255,   0],
#           [255,  40,   0]],
# 
#          [[  0,   0,  30],
#           [  0,  40,   0]]],
# 
# 
# ...