multiprocessing.Pool: What's the difference between map_async and imap?

问题：

I'm trying to learn how to use Python's multiprocessing package, but I don't understand the difference between map_async and imap .我正在尝试学习如何使用 Python 的multiprocessing包，但我不明白map_async和imap之间的区别。 I noticed that both map_async and imap are executed asynchronously.我注意到map_async和imap都是异步执行的。 So when should I use one over the other?那么我什么时候应该使用一个？ And how should I retrieve the result returned by map_async ?我应该如何检索map_async返回的结果？

Should I use something like this?我应该使用这样的东西吗？

def test():
    result = pool.map_async()
    pool.close()
    pool.join()
    return result.get()

result=test()
for i in result:
    print i

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解决方案：

参考一： https://en.stackoom.com/question/1nHGX
参考二： https://stackoom.com/question/1nHGX