在 NumPy 中拆分数组

原文:https://www.geeksforgeeks.org/splitting-arrays-in-numpy/

数组拆分可以是垂直的、水平的或深度方向的。同样的，我们可以分别使用hsplit()、vsplit()和dsplit()功能。我们可以通过指示拆分应该发生的位置，将数组拆分成相同形状的数组。

• Horizontal splitting: The ‘hsplit()’ function splits an array along axis parameter = 1. ‘numpy.hsplit’ is equivalent to ‘split’ with axis parameter = 1, the array is always splitted along the second axis regardless of the array dimension. This function split an array into multiple sub-arrays horizontally (column-wise).

  语法:

  py numpy.hsplit(ary, indices_or_sections)

  示例:

  ```py

  Horizontal array splitting using np.hsplit()

  import numpy as np

  Making of  a 3x3 array

  a = np.arange(9).reshape(3, 3)

  Horizontal splitting of array

  'a' using np.hsplit().

  print("The array {} gets splitted \ horizontally to form {} ".format(a, np.hsplit(a, 3)))

  Horizontal splitting of array 'a'

  using 'split' with axis parameter = 1.

  print("The array {} gets splitted \ horizontally to form {} ".format(a, np.split(a, 3, 1))) ```

  输出:

  py The array [[0 1 2] [3 4 5] [6 7 8]] gets splitted horizontally to form [array([[0], [3], [6]]), array([[1], [4], [7]]), array([[2], [5], [8]])] The array [[0 1 2] [3 4 5] [6 7 8]] gets splitted horizontally to form [array([[0], [3], [6]]), array([[1], [4], [7]]), array([[2], [5], [8]])]

• Vertical splitting: The ‘vsplit()’ function splits an array along axis parameter = 0.‘numpy.vsplit’ is equivalent to ‘split’ with axis parameter = 0. This function split an array into multiple sub-arrays vertically (row-wise).

  py numpy.vsplit(ary, indices_or_sections)

  示例:

  ```py import numpy as np

  Making of  a 3x3 array

  a = np.arange(9).reshape(3, 3)

  Vertical splitting of array 'a'

  using np.vsplit().

  print("The array {} gets splitted \ vertically to form {} ".format(a, np.vsplit(a, 3)))

  Vertical splitting of array 'a'

  using 'split' with axis parameter = 0.

  print("The array {} gets splitted \ vertically to form {} ".format(a, np.split(a, 3, 0))) ```

  输出:

  数组[[0 1 2] [3 4 5] [6 7 8]]被垂直拆分成[数组([[0，1，2]])、数组([[3，4，5]])、数组([[6，7，8]])] 数组[[0 1 2] [3 4 5] [6 7 8]]被垂直拆分成[数组([[0，1，2]])、数组([[3，4，5]])]、数组([[3，4，5])

• Depth-wise splitting: It Split the array into multiple sub-arrays along the 3rd axis (depth).

  py numpy.dsplit(ary, indices_or_sections)

  示例:

  ```py import numpy as np

  Making of  a 3x3x3 array.

  b = np.arange(27).reshape(3, 3, 3)

  Depth-wise splitting of array

  'b' using np.dsplit().

  print("The array {} gets splitted \ depth-wise to form {}".format(b, np.dsplit(b, 3))) ```

  输出:

  数组[[[ 0 1 2] [ 3 4 5] [ 6 7 8]]

  [[9 10 11] [12 13 14] [15 16 17]]

  [[18 19 20] [21 22 23] [24 25 26]]]在深度方向上被分割以形成[数组([[ 0]， [ 3]， [ 6]]，

  [[ 9]， [12]， [15]]，

  [[18]， [21]， [24]]])，数组([[ 1]， [ 4]， [ 7]]，

  [[10]， [13]， [16]]，

  [[19]， [22]， [25]]])，数组([[ 2]， [ 5]， [ 8]]，

  [[11]， [14]， [17]]，

  [[20]， [23]， [26]]])]

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