线程间通信

#_author:来童星
#date:2019/12/17
from threading import Thread
import time

def plus():
    print('子线程1开始')
    global num
    num+=50
    print('num is %d'%num)
    print('子线程1结束')
def minus():
    print('子线程2开始')
    global num
    num-=50
    print('num is %d'%num)
    print('子线程2结束')
num=100
if __name__=='__main__':
        print('主线程开始')
        print('num is %d' % num)
        t1=Thread(target=plus)
        t2=Thread(target=minus)
        t1.start()
        t2.start()
        t1.join()
        t2.join()
        print('主线程结束')
运行结果：
主线程开始
num is 100
子线程1开始
num is 150
子线程1结束
子线程2开始
num is 100
子线程2结束