如何将值追加到Python字典中的列表

my_dict = {'key': [1, 2, 3]}
my_dict['key'].append(4)
print(my_dict)  # 输出: {'key': [1, 2, 3, 4]}

my_dict = {}
my_dict.setdefault('key', []).append(1)
print(my_dict)  # 输出: {'key': [1]}

from collections import defaultdict

my_dict = defaultdict(list)
my_dict['key'].append(1)
print(my_dict)  # 输出: {'key': [1]}