如何在本地修改dict，以免在python中影响全局变量

Question

如何在python中创建一个传递给函数的字典，如下所示：

def foobar(dict):
    dict = tempdict # I want tempdict to not point to dict, but to be a different  dict
    #logic that modifies tempdict
    return tempdict

我该怎么做？

Answer 1

你需要将dict复制到tempdict。

def foobar(d):
    temp = d.copy()
    # your logic goes here
    return temp

copy制作dict的浅表副本（即复制其值，但不复制其值的值）。

% python
Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56) 
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> d = {'x': 17, 'y': 23}
>>> t = d.copy()
>>> t
{'y': 23, 'x': 17}
>>> t['x'] = 93
>>> t
{'y': 23, 'x': 93}
>>> d
{'y': 23, 'x': 17}
>>>