使用np.nan查找和替换列表中的字符串

import numpy as np

my_list = ['apple', 'banana', 'orange', 'apple', 'pear']

index = np.where(np.array(my_list) == 'apple')[0]

my_list[index] = np.nan

import numpy as np

my_list = ['apple', 'banana', 'orange', 'apple', 'pear']
index = np.where(np.array(my_list) == 'apple')[0]
my_list[index] = np.nan

print(my_list)

[nan, 'banana', 'orange', nan, 'pear']