python基础一 day40 条件定时器队列线程池

青旅半醒 2024-04-20 10:59 74阅读 0赞

\# 条件  
\# 锁  
\# acquire release  
\# 一个条件被创建之初 默认有一个False状态  
\# False状态 会影响wait一直处于等待状态  
\# notify(int数据类型) 造钥匙

notify和wait需要在acquire release之间

wait（）是在等钥匙，写在acquire和wait之间的代码不受钥匙限制，要锁的代码必须放在wait后面

造出来的钥匙是不会还的，只能用一次

from threading import Thread,Condition
    def func(con,i):
        con.acquire()
        con.wait() # 等钥匙
        print('在第%s个循环里'%i)
        con.release()
    con = Condition()
    for i in range(10):
        Thread(target=func,args = (con,i)).start()
    while True:
        num = int(input('>>>'))
        con.acquire()
        con.notify(num)  # 造钥匙
        con.release()

定时器

import time
    from threading import Timer
    def func():
        print('时间同步')   #1-3
    
    while True:
        t = Timer(5,func).start()   # 非阻塞的
        time.sleep(5)

队列：

# queue
    import queue
    
    q = queue.Queue()  # 队列 先进先出
    # q.put()
    # q.get()
    # q.put_nowait()
    # q.get_nowait()
    
    # q = queue.LifoQueue()  # 栈 先进后出
    # q.put(1)
    # q.put(2)
    # q.put(3)
    # print(q.get())
    # print(q.get())
    
        q = queue.PriorityQueue()  # 优先级队列
        q.put((20,'a'))
        q.put((10,'b'))
        q.put((30,'c'))
        q.put((-5,'d'))
        q.put((1,'?'))
        print(q.get())

线程池：

import time
    from concurrent.futures import ThreadPoolExecutor
    def func(n):
        time.sleep(2)
        print(n)
        return n*n
    
    def call_back(m):
        print('结果是 %s'%m.result())
    
    tpool = ThreadPoolExecutor(max_workers=5)   #  默认 不要超过cpu个数*5
    for i in  range(20):
        tpool.submit(func,i).add_done_callback(call_back)
    
    
    # tpool.map(func,range(20))  # 拿不到返回值
    # t_lst = []
    # for i in  range(20):
    #     t = tpool.submit(func,i)
    #     t_lst.append(t)
    # tpool.shutdown()  # close+join    #
    # print('主线程')
    # for t in t_lst:print('***',t.result())
    
    # ftp
    # 并发编程

转载于:https://www.cnblogs.com/wang-tan/p/11449230.html