创建嵌套字典的副本而不是引用

Question

为什么使用dict()函数不能像标准那样创建带有嵌套字典的副本键：值对字典？在

字典

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

输出：

^{pr2}$

嵌套词典：

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

输出：

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

Answer 1

您需要生成一个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'}}