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我第一次在 python3 中使用多处理。这是我要实现的：

import concurrent
t = concurrent.futures.ProcessPoolExecutor(4)
g = t.map(lambda x:10*x, range(10))

它抛出错误：

File "/usr/local/Cellar/python3/3.4.3/Frameworks/Python.framework/Versions/3.4/lib/python3.4/multiprocessing/queues.py", line 242, in _feed
    obj = ForkingPickler.dumps(obj)
  File "/usr/local/Cellar/python3/3.4.3/Frameworks/Python.framework/Versions/3.4/lib/python3.4/multiprocessing/reduction.py", line 50, in dumps
    cls(buf, protocol).dump(obj)
_pickle.PicklingError: Can't pickle <function <lambda> at 0x102f03730>: attribute lookup <lambda> on __main__ failed

并且每次都出去玩。

4

1 回答 1

3

传递给的函数t.map 必须是 picklable。匿名函数（即 lambda 函数）是不可挑选的——至少默认情况下是不可取的。要修复，请在全局命名空间中定义函数：

import concurrent.futures as CF
def func(x):
    return 10*x

if __name__ == '__main__':
    with CF.ProcessPoolExecutor(4) as t:
        g = t.map(func, range(10))
        print(list(g))
        # [0, 10, 20, 30, 40, 50, 60, 70, 80, 90]
于 2015-07-16T18:13:15.887 回答