numpy学习笔记（二）

array的多维数组分割

1、按照行或者列分割：

import numpy as np
A = np.arange(12).reshape((3, 4))
print(A)
"""
array([[ 0,  1,  2,  3],
    [ 4,  5,  6,  7],
    [ 8,  9, 10, 11]])
"""
print(np.split(A, 2, axis=1) #  axis=1 为众向分割，axis=0为横向分割
"""
[array([[0, 1],  
        [4, 5],
        [8, 9]]), array([[ 2,  3],
        [ 6,  7],
        [10, 11]])]
"""

2、实现不等量的分割：np.array_split()

print(np.array_split(A, 3, axis=1))
"""
[array([[0, 1],
        [4, 5],
        [8, 9]]), array([[ 2],
        [ 6],
        [10]]), array([[ 3],
        [ 7],
        [11]])]
"""

3、在Numpy里还有列np.vsplit()与横np.hsplit()方式可用。

print(np.vsplit(A, 3)) #等于 print(np.split(A, 3, axis=0))
# [array([[0, 1, 2, 3]]), array([[4, 5, 6, 7]]), array([[ 8,  9, 10, 11]])]
print(np.hsplit(A, 2)) #等于 print(np.split(A, 2, axis=1))
"""
[array([[0, 1],
       [4, 5],
       [8, 9]]), array([[ 2,  3],
        [ 6,  7],
        [10, 11]])]
"""