python-进程池实例

from multiprocessing import Pool
import os, time, random


def worker(msg):
    t_start = time.time()
    print('{}开始执行，进程号为 {}'.format(msg, os.getpid()))
    # random.random() #随机生成0-1之间的浮点数
    time.sleep(random.random() * 2)
    t_stop = time.time()
    print('{} 执行完毕，耗时{}'.format(msg, t_stop - t_start))


def main():
    po = Pool(3)
    for i in range(10):
        # Pool.apply_async(强调要用的目标, (传递参数,))
        po.apply_async(worker, (i,))

    print('---开始---')
    po.close()  # 关闭进程池，关闭后po不再接受新的请求
    po.join()  # 等待po中所有进程执行完成，必须放在close语句之后
    print('---结束---')


if __name__ == '__main__':
    main()