Python 多线程顺序打印的一种解决方法

Cool_Breeze

[Python] 纯文本查看 复制代码

import threading
import typing

class TPrint(object):

    def pa(self) -> None:

        print("--->>> A <<<---")

    def pb(self) -> None:

        print("--->>> B <<<---")

    def pc(self) -> None:

        print("--->>> C <<<---")


def truna(tp:TPrint, locks:typing.Sequence[threading.Lock], current:int, then:int) -> None:

    with locks[current]:
        tp.pa()
        try:
            locks[then].release()
        except RuntimeError:
            pass
def trunb(tp:TPrint, locks:typing.Sequence[threading.Lock], current:int, then:int) -> None:

    with locks[current]:
        tp.pb()
        try:
            locks[then].release()
        except RuntimeError:
            pass
def trunc(tp:TPrint, locks:typing.Sequence[threading.Lock], current:int, then:int) -> None:

    with locks[current]:
        tp.pc()
        try:
            locks[then].release()
        except RuntimeError:
            pass


if __name__ == "__main__":

    wait_list = []
    locks = [ threading.Lock() for _ in range(3) ]
    for n in locks: n.acquire()
    pp = TPrint()
    ta = threading.Thread(target=truna,args=(pp,locks, 0, 1))
    tb = threading.Thread(target=trunb,args=(pp,locks, 1, 2))
    tc = threading.Thread(target=trunc,args=(pp,locks, 2, 0))
    wait_list.extend([ta,tb,tc])
    tc.start()
    tb.start()
    ta.start()

    locks[0].release()

    ta.join()
    tb.join()
    tc.join()

输出日志：

• --->>> A <<<---
• --->>> B <<<---
• --->>> C <<<---
  

xu2006

谢谢分享

Vvvvvoid

可以用 join 方法把

wuaikirin

上了锁不如直接用单线程

yllen

wuaikirin 发表于 2022-12-8 14:19
上了锁不如直接用单线程

是的，多线程加锁就没啥意义了