多线程

# 模拟多线程
import threading
num=0
lock=threading.Lock()
def change_it(n):
    global num
    if lock.acquire():
        try:
            for i in range(1000000):
                num = num + n
                num = num - n
        finally:
            lock.release()
            print('释放锁')
    print(num)

th=threading.Thread(target=change_it,args=(8,))
th.start()
threass=[
    threading.Thread(target=change_it,args=(8,)),  #
    # threading.Thread(target=change_it,args=(10,)),
]

# [ t.start() for t in threass   ]

# [ t.join() for t in threass   ]

print(num,'9999999999999')

　　

import time
from threading import Thread


def func(name):
    print(f"{name}开始")
    time.sleep(0.5)
    print(f"{name}结束")


if __name__ == '__main__':
    t1 = Thread(target=func, args=("线程1",))
    t2 = Thread(target=func, args=("线程2",))
    t1.start()
    t2.start()
    print("主线程结束")