使用多处理将函数的返回值分配给变量?关于 IDLE 的问题?

2022-01-12 00:00:00 python multiprocessing return-value

问题描述

我正在尝试理解 python 中的多处理.

I'm trying to understand multiprocessing in python.

from multiprocessing import Process

def multiply(a,b):
    print(a*b)
    return a*b

if __name__ == '__main__':
    p = Process(target= multiply, args= (5,4))
    p.start()
    p.join()
    print("ok.")

在这个代码块中，例如，如果有一个名为结果"的变量.如何将乘法函数的返回值赋给结果"?

In this codeblock, for example, if there was an variable that called "result". How can we assign return value of multiply function to "result"?

还有一个关于 IDLE 的小问题:当我尝试使用 Python Shell 运行此示例时，它无法正常工作?如果我双击 .py 文件，输出是这样的:

And a little problem about IDLE: when i'm tried to run this sample with Python Shell, it doesn't work properly? If i double click .py file, output is like that:

20
ok.

但如果我尝试在 IDLE 中运行它:

But if i try to run this in IDLE:

ok.

谢谢...

解决方案

好的，我设法做到了.我查看了 python 文档，我了解到:使用 Queue 类，我们可以从函数中获取返回值.我的代码的最终版本是这样的:

Ok, i somehow managed this. I looked to python documentation, and i learnt that: with using Queue class, we can get return values from a function. And final version of my code is like this:

from multiprocessing import Process, Queue

def multiply(a,b,que): #add a argument to function for assigning a queue
    que.put(a*b) #we're putting return value into queue

if __name__ == '__main__':
    queue1 = Queue() #create a queue object
    p = Process(target= multiply, args= (5,4,queue1)) #we're setting 3rd argument to queue1
    p.start()
    print(queue1.get()) #and we're getting return value: 20
    p.join()
    print("ok.")

还有一个 pipe() 函数，我想我们也可以使用 pipe() 函数.但是 Queue 现在对我有用了.

And there is also a pipe() function, i think we can use pipe() function,too. But Queue worked for me, now.

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