从numpy数组中提取数据子集

a[a[:,1] > 6]

输出:

array([[3, 7], [4, 8]])

在哪里? a

使用 numpy.where :

import numpy as np

a = np.array([[1, 5], [2, 6], [3, 7], [4, 8]])
# all elements where the second item it greater than 6:
print(a[np.where(a[:, 1] > 6)])
# output: [[3 7], [4 8]]

使用列表理解:

array1 = [[1, 5], [2, 6], [3, 7], [4, 8]]

threshold = 6
print([elem for elem in array1 if elem[1] > threshold])
# [[3, 7], [4, 8]]

import numpy as np

array1 = np.array(array1)
print(array1[array1[:,1] > 6])
# array([[3, 7], [4, 8]])