[Python知识库][python专题笔记]学习/工作遇到的坑记录

python 进程

python 进程通信字典更新深度问题

直接在进程字典中修改多级的键值失败

• 问题现象，修改process_dict["key1"]["key2"] = "222" 失败

In [1]: import multiprocessing as MP

In [2]: process_dict = MP.Manager().dict()

In [3]: type(process_dict)
Out[3]: multiprocessing.managers.DictProxy

In [4]: process_dict["key1"]= {}

In [5]: type(process_dict)
Out[5]: multiprocessing.managers.DictProxy

In [6]: print(process_dict)
{'key1': {}}

In [7]: process_dict["key1"]["key2"] = {}

In [8]: print(process_dict)
{'key1': {}}

In [9]: type(process_dict)
Out[9]: multiprocessing.managers.DictProxy

In [10]: process_dict["key1"]["key2"] = "222"

In [11]: type(process_dict)
Out[11]: multiprocessing.managers.DictProxy

In [12]: print(process_dict)
{'key1': {}}

• 解决方法： 不能根据键值索引修改，需要整体修改方式来修改
  可以先拷贝一份字典内容，创建临时普通字典，再在普通字典上操作，最后赋值给进程字典，做到整体同时修改，例子如下

In [1]: import multiprocessing as MP

In [2]: process_dict = MP.Manager().dict()

In [3]: type(process_dict)
Out[3]: multiprocessing.managers.DictProxy

In [4]: process_dict["key1"]= {}

In [5]: print((process_dict))
{'key1': {}}
In [6]: process_dict["key1"]["key2"] = "222"

In [7]: print((process_dict))
{'key1': {}}

In [8]: temporary_dict = process_dict.copy() #拷贝一份修改前的字典内容

In [9]: #上述拷贝的普通字典完成

In [10]:

In [11]: temporary_dict["key1"]["key2"] = "222"

In [12]: process_dict.update(temporary_dict)

In [13]: print((process_dict))
{'key1': {'key2': '222'}}

In [14]: type(process_dict)
Out[14]: multiprocessing.managers.DictProxy