使用numpy将基于二维数组的列拆分为python中的两个二维数组

Question

我有一个由 19 行和 1280 列组成的二维数组。我想将它分成 2 个数组，由 19 行组成，70% 的列用于训练，30% 的列用于测试。这些列是随机选择的。我的代码在 python 中.请帮助我。谢谢

Answer 1

编辑为包括随机洗牌

您可以使用slicing将数组切片为所需的形状并numpy.random.shuffle()获得随机数组索引。

import numpy as np

from copy import deepcopy

# create example data

num_cols, num_rows = 10, 3

arr = np.array([[f'{row}_{col}' for col in range(num_cols)] for row in range(num_rows)])

# create a list of random indices

random_cols = list(range(arr.shape[1]))

np.random.shuffle(random_cols)

# calculate truncation index as 70% of total number of columns

truncation_index = int(arr.shape[1] * 0.7)

# use arrray slicing to extract two sub_arrays

train_array = arr[:, random_cols[:truncation_index]]

test_array = arr[:, random_cols[truncation_index:]]

print(f'arr: \n{arr} \n')

print(f'train array: \n{train_array} \n')

print(f'test array: \n{test_array} \n')

带输出

arr: 

[['0_0' '0_1' '0_2' '0_3' '0_4' '0_5' '0_6' '0_7' '0_8' '0_9']

 ['1_0' '1_1' '1_2' '1_3' '1_4' '1_5' '1_6' '1_7' '1_8' '1_9']

 ['2_0' '2_1' '2_2' '2_3' '2_4' '2_5' '2_6' '2_7' '2_8' '2_9']] 

train array: 

[['0_5' '0_8' '0_0' '0_7' '0_6' '0_1' '0_4']

 ['1_5' '1_8' '1_0' '1_7' '1_6' '1_1' '1_4']

 ['2_5' '2_8' '2_0' '2_7' '2_6' '2_1' '2_4']] 

test array: 

[['0_3' '0_9' '0_2']

 ['1_3' '1_9' '1_2']

 ['2_3' '2_9' '2_2']]