获取numpy数组中项目的索引，其中value在列表中

import numpy as np

# 创建一个numpy数组
arr = np.array([1, 2, 3, 4, 5])

# 获取值为3的索引
index = np.where(arr == 3)

print(index)

(array([2]),)

import numpy as np

# 创建一个numpy数组
arr = np.array([1, 2, 3, 4, 5])

# 获取值为2和4的索引
index = np.where((arr == 2) | (arr == 4))

print(index)

(array([1, 3]),)

import numpy as np

# 创建一个二维numpy数组
arr = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])

# 获取值为5的索引
index = np.where(arr == 5)

print(index)

(array([1]), array([1]))