多线程

import time, threading
from threading import Lock

def work(timer):
    # 如果在函数内部找不到变量，就会向上寻找，main 函数属于向上的领域
    with lock:
        print('操作文件')
        print('只要在with lock里，就是单线程')
    

    print(f'线程名称名:{threading.current_thread().name}')
    time.sleep(timer)

if __name__ == '__main__':
    print('主线程开始')
    lock = Lock()  # 声明锁对象
    lst = [threading.Thread(target=work, args=(2,)) for i in range(5)]
    for t in lst:
        # t 是一个线程对象
        t.start()
    for t in lst:
        t.join()
    print('主线程结束')