python系统编程（五）

多线程-threading

python的thread模块是比较底层的模块，python的threading模块是对thread做了一些包装的，可以更加方便的被使用

1. 使用threading模块

单线程执行

#coding=utf-8

import time

def saySorry():

    print("亲爱的，我错了，我能吃饭了吗？")

    time.sleep(1)

if __name__ == "__main__":

    for i in range(5):

        saySorry()

多线程执行

#coding=utf-8

import threading

import time

def saySorry():

    print("亲爱的，我错了，我能吃饭了吗？")

    time.sleep(1)

if __name__ == "__main__":

    for i in range(5):

        t = threading.Thread(target=saySorry)

        t.start() #启动线程，即让线程开始执行

2. 主线程会等待所有的子线程结束后才结束

#coding=utf-8

import threading

from time import sleep,ctime

def sing():

    for i in range(3):

        print("正在唱歌...%d"%i)

        sleep(1)

def dance():

    for i in range(3):

        print("正在跳舞...%d"%i)

        sleep(1)

if __name__ == '__main__':

    print('---开始---:%s'%ctime())

    t1 = threading.Thread(target=sing)

    t2 = threading.Thread(target=dance)

    t1.start()

    t2.start()

    #sleep(5) # 屏蔽此行代码，试试看，程序是否会立马结束？

    print('---结束---:%s'%ctime())

3. 查看线程数量

#coding=utf-8

import threading

from time import sleep,ctime

def sing():

    for i in range(3):

        print("正在唱歌...%d"%i)

        sleep(1)

def dance():

    for i in range(3):

        print("正在跳舞...%d"%i)

        sleep(1)

if __name__ == '__main__':

    print('---开始---:%s'%ctime())

    t1 = threading.Thread(target=sing)

    t2 = threading.Thread(target=dance)

    t1.start()

    t2.start()

    while True:

        length = len(threading.enumerate())

        print('当前运行的线程数为：%d'%length)

        if length<=1:

            break

        sleep(0.5)