如何修改本地的字典，以不影响全局变量在python

Question

如何创建一个Python字典传递给一个函数，以便它看起来像这样：

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 

我如何做这个？

Answer 1

你需要复制字典到tempdict。

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

copy使得字典的浅表副本（即复制其值，但不是其值值）。

% 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} 
>>>