python的_thread模块来实现多线程(<python核心编程例子>)

#例子一:自己手动在主线程中设置等待时间
import _thread
from time import ctime, sleep

def loop0():
    print("loop0 starts at:{}".format(ctime()))
    sleep(4)
    print("loop0 ends at:{}".format(ctime()))

def loop1():
    print("loop1 starts at:{}".format(ctime()))
    sleep(2)
    print("loop1 ends at:{}".format(ctime()))

if __name__ == "__main__":
    print("start_time:{}".format(ctime()))
    _thread.start_new_thread(loop0, ())
    _thread.start_new_thread(loop1, ())
    #此处设置sleep(6)是因为_thread主线程结束后,会马上杀死其他线程
    sleep(6)
    print("end_time:{}".format(ctime()))

#例子二:通过锁可以实现所有线程全部运行后立即退出
import _thread
from time import ctime, sleep

#每个loop等待的时间
wait_time_list = [4, 2]


def loop(i, wait_time, lock):
    """
    根据传入参数创建多个loop函数
    :param i:
    :param wait_time:
    :param lock:
    :return:
    """
    print("loop{} starts at:{}".format(i, ctime()))
    sleep(wait_time)
    print("loop{} ends at:{}".format(i, ctime()))
    #释放锁
    lock.release()


def main():
    print("start_time:", ctime())
    nloops = range(len(wait_time_list))
    locks = []

    #创建锁,上锁
    for i in nloops:
        lock = _thread.allocate_lock()
        lock.acquire()
        locks.append(lock)

    #之所以另起一个循环,是为了尽量保证所有线程能够同时启动,因为上面的循环中锁的操作也要花费一些时间
    for i in nloops:
        _thread.start_new_thread(loop, (i, wait_time_list[i], locks[i]))#loop函数中的参数放到元组里

    #等待所有的子线程释放锁后,结束主线程.(等待时间取决于执行时间最长的子线程,假如第一个子线程执行时间最长,等它执行完毕,下面的循环就不会再进入了.)
    for i in nloops:
        #注意这里locked()要带括号
        while locks[i].locked():
            pass
    print("all done! end_time:", ctime())


if __name__ == ‘__main__‘:
    main()