Python多处理帮助按条件退出

我对Python中的多处理技术非常感兴趣，但我对这个问题没有任何兴趣。基本上，我有一个运行起来很耗时的过程。我需要在1到100的范围内运行它，但我希望在满足我要查找的条件后中止所有进程。返回值==90的条件

这是一段非多进程代码。有谁能给我一个例子，说明他们如何将其转换为多进程函数，一旦满足“90”的条件，代码将退出所有进程

def Addsomething(i):
    SumOfSomething = i + 1    
    return SumOfSomething

def RunMyProcess():
    for i in range(100):
        Something = Addsomething(i)
        print Something
    return

if __name__ == "__main__":
    RunMyProcess()

编辑：

我在测试第三个版本时遇到了这个错误。你知道这是什么原因吗

Exception in thread Thread-3:
Traceback (most recent call last):
  File "C:\Python27\lib\threading.py", line 554, in __bootstrap_inner
    self.run()
  File "C:\Python27\lib\threading.py", line 507, in run
    self.__target(*self.__args, **self.__kwargs)
  File "C:\Python27\lib\multiprocessing\pool.py", line 379, in _handle_results
    cache[job]._set(i, obj)
  File "C:\Python27\lib\multiprocessing\pool.py", line 527, in _set
    self._callback(self._value)
  File "N:\PV\_Proposals\2013\ESS - Clear Sky\01-CODE\MultiTest3.py", line 20, in check_result
    pool.terminate()
  File "C:\Python27\lib\multiprocessing\pool.py", line 423, in terminate
    self._terminate()
  File "C:\Python27\lib\multiprocessing\util.py", line 200, in __call__
    res = self._callback(*self._args, **self._kwargs)
  File "C:\Python27\lib\multiprocessing\pool.py", line 476, in _terminate_pool
    result_handler.join(1e100)
  File "C:\Python27\lib\threading.py", line 657, in join
    raise RuntimeError("cannot join current thread")
RuntimeError: cannot join current thread

---

也许这就是你要找的？请记住，我是为Python 3编写的。上面的print语句是Python2，在这种情况下，需要注意的是使用xrange而不是range

from argparse import ArgumentParser
from random import random
from subprocess import Popen
from sys import exit
from time import sleep

def add_something(i):

    # Sleep to simulate the long calculation
    sleep(random() * 30)
    return i + 1

def run_my_process():

    # Start up all of the processes, pass i as command line argument
    # since you have your function in the same file, we'll have to handle that
    # inside 'main' below
    processes = []
    for i in range(100):
        processes.append(Popen(['python', 'thisfile.py', str(i)]))

    # Wait for your desired process result
    # Might want to add a short sleep to the loop
    done = False
    while not done:
       for proc in processes:
            returncode = proc.poll()
            if returncode == 90:
                done = True
                break

    # Kill any process that are still running
    for proc in processes:

        if proc.returncode is None:

            # Might run into a race condition here,
            # so might want to wrap with try block
            proc.kill()

if __name__ == '__main__':

    # Look for optional i argument here
    parser = ArgumentParser()
    parser.add_argument('i', type=int, nargs='?')
    i = parser.parse_args().i

    # If there isn't an i, then run the whole thing
    if i is None:
        run_my_process()

    else:
        # Otherwise, run your expensive calculation and return the result
        returncode = add_something(i)
        print(returncode)
        exit(returncode)

编辑：

下面是一个更简洁的版本，它使用多处理模块而不是子流程：

from random import random
from multiprocessing import Process
from sys import exit
from time import sleep

def add_something(i):

    # Sleep to simulate the long calculation
    sleep(random() * 30)

    exitcode = i + 1
    print(exitcode)
    exit(exitcode)

def run_my_process():

    # Start up all of the processes
    processes = []
    for i in range(100):
        proc = Process(target=add_something, args=[i])
        processes.append(proc)
        proc.start()

    # Wait for the desired process result
    done = False
    while not done:
        for proc in processes:
            if proc.exitcode == 90:
                done = True
                break

    # Kill any processes that are still running
    for proc in processes:
        if proc.is_alive():
            proc.terminate()

if __name__ == '__main__':
    run_my_process()

编辑2:

这是最后一个版本，我认为比其他两个版本好得多：

from random import random
from multiprocessing import Pool
from time import sleep

def add_something(i):

    # Sleep to simulate the long calculation
    sleep(random() * 30)
    return i + 1

def run_my_process():

    # Create a process pool
    pool = Pool(100)

    # Callback function that checks results and kills the pool
    def check_result(result):
        print(result)
        if result == 90:
            pool.terminate()

    # Start up all of the processes
    for i in range(100):
        pool.apply_async(add_something, args=[i], callback=check_result)

    pool.close()
    pool.join()

if __name__ == '__main__':
    run_my_process()

---

为什么不在print Something行之后放一个空的return呢？是要运行单独的进程还是单独的线程？向Popen进程发送kill信号很容易，但对于线程，您需要手动创建和检查事件对象之类的内容。另外，您能否澄清一下，您是只想在后台执行RunMyProcess，还是想为i的每个值添加并行执行的内容？此外，请记住，线程的返回值与函数的返回值并不相同。返回值需要通过轮询或回调函数来访问。我希望运行单独的进程。我的实际代码每次迭代运行大约需要30秒。对于这个示例，“Addsomething”表示我的代码，它花费了很长时间，并且每次迭代都需要运行。我想并行运行每一个I，但一旦达到90，就终止所有进程。我安装了2.7，但运行时没有任何错误。它每次也会在90停止。我想我已经掌握了它是如何工作的。我需要花一些时间来处理它，使它与我的代码一起工作。如果遇到问题，我会通知您。是否必须使用：if name==“main”调用：运行我的\u进程（）如果遇到的错误是“RuntimeEror:cannotjoin current thread”，则这是在2.7和3.2中修复的Python错误。有关详细信息，请参阅。当我在mac电脑上运行内置的2.7时，就会出现这个错误。但它与我安装的3.3版本运行良好，看起来我使用的是2.7.2。最新版本是2.7.6。我尝试更新，看看是否有效。是的，更新到2.7.6解决了这个问题。谢谢