python - 词典使用问题

Question

这个问题已经有答案了:

How to copy a dictionary and only edit the copy (23 个回答)

已关闭 5 年前。

这是我的代码:

everyday = {'hello':[],'goodbye':{}}
i_want = everyday
i_want ['afternoon'] = 'sun'
i_want['hello'].append((1,2,3,4))
print(everyday)

我想获得这个:

i_want = {'afternoon': 'sun', 'hello': [(1, 2, 3, 4)], 'goodbye': {}}

everyday = {'hello':[],'goodbye':{}}

但我得到:

i_want = {'afternoon': 'sun', 'hello': [(1, 2, 3, 4)], 'goodbye': {}}

everyday = {'afternoon': 'sun', 'hello': [(1, 2, 3, 4)], 'goodbye': {}}

如何在不修改“日常”词典的情况下得到我想要的东西？

Answer 1

只需更改此:

everyday = {'hello':[],'goodbye':{}}
i_want = dict(everyday)
i_want ['afternoon'] = 'sun'
i_want['hello'] = []    # We're facing the same issue here and this is why we are initializing a new list and giving it to the hello key
i_want['hello'].append((1,2,3,4))

# to add to goodbye don't forget  the following:
# i_want['goodbye'] = {}
# i_want['goodbye'] = "Some value"

print(everyday)

发生的情况是，调用 (i_want = daily) 实际上是创建对 daily 的引用

要进行进一步测试，如果您想查看您的词典是否被引用，只需调用

print(i_want is everyday)