python - 与多处理错误的另一个混淆， 'module' 对象没有属性 'f'

Question

我知道这个问题之前已经回答过了，但似乎直接执行脚本“python filename.py”是行不通的。我在 SuSE Linux 上安装了 Python 2.6.2。

代码:

#!/usr/bin/python
# -*- coding: utf-8 -*-
from multiprocessing import Pool
p = Pool(1)
def f(x):
    return x*x
p.map(f, [1, 2, 3])

命令行:

> python example.py
Process PoolWorker-1:
Traceback (most recent call last):
File "/usr/lib/python2.6/multiprocessing/process.py", line 231, in _bootstrap
    self.run()
File "/usr/lib/python2.6/multiprocessing/process.py", line 88, in run
    self._target(*self._args, **self._kwargs)
File "/usr/lib/python2.6/multiprocessing/pool.py", line 57, in worker
    task = get()
File "/usr/lib/python2.6/multiprocessing/queues.py", line 339, in get
    return recv()
AttributeError: 'module' object has no attribute 'f'

Answer 1

重构您的代码，以便在创建 Pool 实例之前定义 f() 函数。否则worker看不到你的函数。

#!/usr/bin/python
# -*- coding: utf-8 -*-

from multiprocessing import Pool

def f(x):
    return x*x

p = Pool(1)
p.map(f, [1, 2, 3])