我在尝试着:
- 在进程之间共享数据帧
- 根据对该数据帧执行的计算(但不更改)更新共享字典
我正在使用一个multiprocessing.Manager()
创建一个dict
在共享内存中(用于存储结果)和Namespace
存储/共享我想要读取的数据框。
import multiprocessing
import pandas as pd
import numpy as np
def add_empty_dfs_to_shared_dict(shared_dict, key):
shared_dict[key] = pd.DataFrame()
def edit_df_in_shared_dict(shared_dict, namespace, ind):
row_to_insert = namespace.df.loc[ind]
df = shared_dict[ind]
df[ind] = row_to_insert
shared_dict[ind] = df
if __name__ == '__main__':
manager = multiprocessing.Manager()
shared_dict = manager.dict()
namespace = manager.Namespace()
n = 100
dataframe_to_be_shared = pd.DataFrame({
'player_id': list(range(n)),
'data': np.random.random(n),
}).set_index('player_id')
namespace.df = dataframe_to_be_shared
for i in range(n):
add_empty_dfs_to_shared_dict(shared_dict, i)
jobs = []
for i in range(n):
p = multiprocessing.Process(
target=edit_df_in_shared_dict,
args=(shared_dict, namespace, i)
)
jobs.append(p)
p.start()
for p in jobs:
p.join()
print(shared_dict[1])
运行上面的代码时,它会写入shared_dict
当我的打印语句使用一些数据执行时正确。我还收到有关经理的错误:
Process Process-88:
Traceback (most recent call last):
File "/Users/henrysorsky/.pyenv/versions/3.7.3/lib/python3.7/multiprocessing/managers.py", line 788, in _callmethod
conn = self._tls.connection
AttributeError: 'ForkAwareLocal' object has no attribute 'connection'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Users/henrysorsky/.pyenv/versions/3.7.3/lib/python3.7/multiprocessing/process.py", line 297, in _bootstrap
self.run()
File "/Users/henrysorsky/.pyenv/versions/3.7.3/lib/python3.7/multiprocessing/process.py", line 99, in run
self._target(*self._args, **self._kwargs)
File "/Users/henrysorsky/Library/Preferences/PyCharm2019.2/scratches/scratch_13.py", line 34, in edit_df_in_shared_dict
row_to_insert = namespace.df.loc[ind]
File "/Users/henrysorsky/.pyenv/versions/3.7.3/lib/python3.7/multiprocessing/managers.py", line 1099, in __getattr__
return callmethod('__getattribute__', (key,))
File "/Users/henrysorsky/.pyenv/versions/3.7.3/lib/python3.7/multiprocessing/managers.py", line 792, in _callmethod
self._connect()
File "/Users/henrysorsky/.pyenv/versions/3.7.3/lib/python3.7/multiprocessing/managers.py", line 779, in _connect
conn = self._Client(self._token.address, authkey=self._authkey)
File "/Users/henrysorsky/.pyenv/versions/3.7.3/lib/python3.7/multiprocessing/connection.py", line 492, in Client
c = SocketClient(address)
File "/Users/henrysorsky/.pyenv/versions/3.7.3/lib/python3.7/multiprocessing/connection.py", line 619, in SocketClient
s.connect(address)
ConnectionRefusedError: [Errno 61] Connection refused
我知道这是来自经理的,似乎是因为它没有正确关闭。我在网上唯一能找到的类似问题:
python服务器中进程之间共享列表
建议加入所有子进程,我已经在这样做了。