python 进程和队列 简单示例

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import time import random   from multiprocessing import Process, Queue, current_process, freeze_support     # # Function run by worker processes #   def worker(input, output):     for func, args in iter(input.get, 'STOP'):         result = calculate(func, args)         output.put(result) # # Function used to calculate result # def calculate(func, args):     result = func(*args)     return '%s says that %s%s = %s' % \            (current_process().name, func.__name__, args, result) # # Functions referenced by tasks # def mul(a, b):     time.sleep(0.5 * random.random())     return a * b   def plus(a, b):     time.sleep(0.5 * random.random())     return a + b   def test():     NUMBER_OF_PROCESSES = 4     TASKS1 = [(mul, (i, 7)) for i in range(20)]     TASKS2 = [(plus, (i, 8)) for i in range(10)]       # Create queues     task_queue = Queue()     done_queue = Queue()       # Submit tasks     for task in TASKS1:         task_queue.put(task)       # Start worker processes     for i in range(NUMBER_OF_PROCESSES):         Process(target=worker, args=(task_queue, done_queue)).start()       # Get and print results     print('Unordered results:')     for i in range(len(TASKS1)):         print('\t', done_queue.get())       # Add more tasks using `put()`     # for task in TASKS2:     #     task_queue.put(task)       # Get and print some more results     # for i in range(len(TASKS2)):     #     print('\t', done_queue.get())     #     # # Tell child processes to stop     for i in range(NUMBER_OF_PROCESSES):         task_queue.put('STOP')   if __name__ == '__main__':     freeze_support()     test()