python - 创建嵌套字典的副本而不是引用

Question

这个问题已经有答案了:

Deep copy of a dict in python (4 个回答)

已关闭 8 年前。

为什么使用dict()函数不会像标准键:值对字典那样创建带有嵌套字典的副本？

字典

A = {'key' : 'value'}
B = dict(A)
A['key'] = 10
print A, B

输出:

{'key': 10} {'key': 'value'}

嵌套字典:

A = {'key' : {'subkey' : 'value'}}
B = dict(A)
A['key']['subkey'] = 10
print A, B

输出:

{'key': {'subkey': 10}} {'key': {'subkey': 10}}

Answer 1

您需要创建一个 deepcopy :

from copy import deepcopy
A = {'key' : {'subkey' : 'value'}}
B = deepcopy(A)
A['key']['subkey'] = 10
print(A, B)
# {'key': {'subkey': 10}} {'key': {'subkey': 'value'}}