python的thread模块作用

import threading
import time

def hello_for():
    print("你好 世界, 你好  中国")
    time.sleep(1)

if __name__ == "__main__":
    for i in range(5):
        t = threading.Thread(target=hello_for)
        t.start() #启动线程，即让线程开始执行

import threading
import time

def hello_for():
    print("你好 世界, 你好  中国")
    time.sleep(1)

if __name__ == "__main__":
    for i in range(5):
        t = threading.Thread(target=hello_for)
        t.start() #启动线程，即让线程开始执行

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()

    print(‘---结束---:%s‘%ctime())

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)