python库numpy使用技巧（二）——随机抽取二维矩阵中多行

使用库numpy

创建一个二维数组

import numpy as np

array = np.arange(24).reshape((4,6))

"""
array([[ 0,  1,  2,  3,  4,  5],
       [ 6,  7,  8,  9, 10, 11],
       [12, 13, 14, 15, 16, 17],
       [18, 19, 20, 21, 22, 23]])
"""

行与列随机抽取类似

行随机抽取

row_rand_array = np.arange(array.shape[0])

np.random.shuffle(row_rand_array)

row_rand = array[row_rand_array[0:2]]

"""
row_rand:
array([[12, 13, 14, 15, 16, 17],
       [ 0,  1,  2,  3,  4,  5]])
"""

列随机抽取

col_rand_array = np.arange(array.shape[1])

np.random.shuffle(col_rand_array)

col_rand = array[:,col_rand_array[0:2]]

"""
col_rand:
array([[ 1,  5],
       [ 7, 11],
       [13, 17],
       [19, 23]])
"""