split
Split an array into multiple sub-arrays as views into the original array.
numpy.split(ary, indices_or_sections, axis=0)
Array to be divided into sub-arrays.
If an integer, N, the array will be divided into N equal arrays along axis. If such a split is not possible, an error is raised.If a 1-D array of sorted integers, the entries indicate where along axis the array is split. For example, [2, 3] would result in: The axis along which to split, default is 0.
list of ndarrays - A list of sub-arrays as views into ary.
Examples
import numpy as np
# Split into 3 equal parts
x = np.arange(9.0)
print(np.split(x, 3))
# [array([0., 1., 2.]), array([3., 4., 5.]), array([6., 7., 8.])]
# Split at specific indices
x = np.arange(8.0)
print(np.split(x, [3, 5, 6, 10]))
# [array([0., 1., 2.]),
# array([3., 4.]),
# array([5.]),
# array([6., 7.]),
# array([], dtype=float64)]
# Split 2-D array along axis 1
x = np.arange(12).reshape(3, 4)
print(np.split(x, 2, axis=1))
# [array([[0, 1],
# [4, 5],
# [8, 9]]),
# array([[ 2, 3],
# [ 6, 7],
# [10, 11]])]
See Also
array_split - Split array into multiple sub-arrays of equal or near-equal sizehsplit - Split array horizontallyvsplit - Split array verticallydsplit - Split array along the 3rd axis
array_split
Split an array into multiple sub-arrays.
numpy.array_split(ary, indices_or_sections, axis=0)
Array to be divided into sub-arrays.
If an integer that does not equally divide the axis, the first l % n sub-arrays will have size l//n + 1, and the rest will have size l//n.
The axis along which to split, default is 0.
list of ndarrays - A list of sub-arrays as views into ary.
Examples
import numpy as np
# Split into 3 parts (not evenly divisible)
x = np.arange(8.0)
print(np.array_split(x, 3))
# [array([0., 1., 2.]), array([3., 4., 5.]), array([6., 7.])]
# Split into 4 parts
x = np.arange(9)
print(np.array_split(x, 4))
# [array([0, 1, 2]), array([3, 4]), array([5, 6]), array([7, 8])]
See Also
split - Split array into multiple sub-arrays of equal size
hsplit
Split an array into multiple sub-arrays horizontally (column-wise).
numpy.hsplit(ary, indices_or_sections)
Array to be divided into sub-arrays.
If an integer, N, the array will be divided into N equal arrays along axis 1 (or axis 0 for 1-D arrays). If a 1-D array of sorted integers, the entries indicate where to split the array.
list of ndarrays - A list of sub-arrays as views into ary.
Examples
import numpy as np
# Split 2-D array horizontally
x = np.arange(16.0).reshape(4, 4)
print(x)
# array([[ 0., 1., 2., 3.],
# [ 4., 5., 6., 7.],
# [ 8., 9., 10., 11.],
# [12., 13., 14., 15.]])
print(np.hsplit(x, 2))
# [array([[ 0., 1.],
# [ 4., 5.],
# [ 8., 9.],
# [12., 13.]]),
# array([[ 2., 3.],
# [ 6., 7.],
# [10., 11.],
# [14., 15.]])]
# Split at specific columns
print(np.hsplit(x, np.array([3, 6])))
# [array([[ 0., 1., 2.],
# [ 4., 5., 6.],
# [ 8., 9., 10.],
# [12., 13., 14.]]),
# array([[ 3.],
# [ 7.],
# [11.],
# [15.]]),
# array([], shape=(4, 0), dtype=float64)]
# 1-D arrays split along axis 0
x = np.array([0, 1, 2, 3, 4, 5])
print(np.hsplit(x, 2))
# [array([0, 1, 2]), array([3, 4, 5])]
See Also
split - Split array into multiple sub-arrays of equal size
vsplit
Split an array into multiple sub-arrays vertically (row-wise).
numpy.vsplit(ary, indices_or_sections)
Array to be divided into sub-arrays. Must be at least 2-D.
If an integer, N, the array will be divided into N equal arrays along axis 0. If a 1-D array of sorted integers, the entries indicate where to split the array.
list of ndarrays - A list of sub-arrays as views into ary.
Examples
import numpy as np
# Split 2-D array vertically
x = np.arange(16.0).reshape(4, 4)
print(x)
# array([[ 0., 1., 2., 3.],
# [ 4., 5., 6., 7.],
# [ 8., 9., 10., 11.],
# [12., 13., 14., 15.]])
print(np.vsplit(x, 2))
# [array([[0., 1., 2., 3.],
# [4., 5., 6., 7.]]),
# array([[ 8., 9., 10., 11.],
# [12., 13., 14., 15.]])]
# Split at specific rows
print(np.vsplit(x, np.array([3, 6])))
# [array([[ 0., 1., 2., 3.],
# [ 4., 5., 6., 7.],
# [ 8., 9., 10., 11.]]),
# array([[12., 13., 14., 15.]]),
# array([], shape=(0, 4), dtype=float64)]
# 3-D arrays split along first axis
x = np.arange(8.0).reshape(2, 2, 2)
print(np.vsplit(x, 2))
# [array([[[0., 1.],
# [2., 3.]]]),
# array([[[4., 5.],
# [6., 7.]]])]
See Also
split - Split array into multiple sub-arrays of equal size
dsplit
Split array into multiple sub-arrays along the 3rd axis (depth).
numpy.dsplit(ary, indices_or_sections)
Array to be divided into sub-arrays. Must be at least 3-D.
If an integer, N, the array will be divided into N equal arrays along axis 2. If a 1-D array of sorted integers, the entries indicate where to split the array.
list of ndarrays - A list of sub-arrays as views into ary.
Examples
import numpy as np
# Split 3-D array along depth
x = np.arange(16.0).reshape(2, 2, 4)
print(x)
# array([[[ 0., 1., 2., 3.],
# [ 4., 5., 6., 7.]],
# [[ 8., 9., 10., 11.],
# [12., 13., 14., 15.]]])
print(np.dsplit(x, 2))
# [array([[[ 0., 1.],
# [ 4., 5.]],
# [[ 8., 9.],
# [12., 13.]]]),
# array([[[ 2., 3.],
# [ 6., 7.]],
# [[10., 11.],
# [14., 15.]]])]
# Split at specific indices
print(np.dsplit(x, np.array([1, 3])))
# [array([[[ 0.],
# [ 4.]],
# [[ 8.],
# [12.]]]),
# array([[[ 1., 2.],
# [ 5., 6.]],
# [[ 9., 10.],
# [13., 14.]]]),
# array([[[ 3.],
# [ 7.]],
# [[11.],
# [15.]]])]
See Also
split - Split array into multiple sub-arrays of equal sizehsplit - Split array horizontallyvsplit - Split array vertically
