多任务进程线程协程

import time
import threading


def sing():
    """唱歌5秒"""
    for i in range(5):
        print("--正在唱---")
        time.sleep(1)


def dance():    子线程
    for i in range(5):
        print("--正在跳舞---")
        time.sleep(1)


def main():
    t1 = threading.Thread(target=sing)
    t2 = threading.Thread(target=dance)    创建对象
    t1.start()
    t2.start()   主线程     创建子线程
　　 print(threading.enumerate())  #运行时查看有几个线程   如果没有延时不确定包含几个线程

if __name__ == '__main__': 
　　　　main()

调用start()的时候子线程开启 函数代买执行完子线程结束

并行：真的多任务并发：假的多任务

线程：程序运行起来执行代码的东西

主线程子线程：https://www.bilibili.com/video/av73705797?p=2

通过集成thread来创建线程

import threading
import time


class MyThread(thrading.Thread):
    def run(self):     #必须写run
        for i in range(3):
            time.sleep(1)
            msg = "I'm"+self.name+@+str(i)
            print(msg)


if __name__='__main__':
    t = MyThread()
    t.start   自动调用 run 方法

多个线程之间共享全局变量

num= 100
num=[11,22]

def test():
    global num   
       num += 100


def  test1():
    nums.append(33)
　　 #nums+=[100,200]#需要加global

print(num,nums)
test()
test1()
print(num,nums)
#改变其本身（内存地址）时需要加global   当改变其里面内容（不改变id）b不用加global

import time
import threading
g_num = 100
def test1():
    global  g_num
    g_num +=1
    print("---->%d"%g_num)

def test2():
    print("---->%d"%g_num)

def main():
    t1 = threading.Thread(target=test1)
    t2 = threading.Thread(target=test2)
    t1.start()
    time.sleep(1)
    t2.start()


if __name__ == '__main__':
    main()

-->101
--->101

多线程共享全局变量--args参数需要元组类型 join()

import time
import threading
g_num = 100
def test1(num):
    global  g_num
 　　for i in num:
    　　g_num +=1
    　　print("---->%d"%g_num)

def test2():
    print("---->%d"%g_num)

def main():
    t1 = threading.Thread(target=test1，args=(100，))
    t2 = threading.Thread(target=test2)
    t1.start()
    time.sleep(1)
    t2.start()


if __name__ == '__main__':
    main()

import time
import random
from threading import Thread,currentThread
dic = {}
def func(i):
    t = currentThread()
    time.sleep(random.random())
    dic[t.ident] = i**2
t_lst = []
for i in range(1,11):
    t = Thread(target=func,args=(i,))
    t.start()
    t_lst.append(t)
for t in t_lst:
    t.join()
    print(dic[t.ident])

多线程可以有多个锁

死锁可以添加超时时间解决

import json
import time
from multiprocessing import Process,Lock
def search_ticket(name):
    with open('ticket',encoding='utf-8') as f:
        dic = json.load(f)
        print('%s查询余票为%s'%(name,dic['count']))

def buy_ticket(name):
    with open('ticket',encoding='utf-8') as f:
        dic = json.load(f)
    time.sleep(2)
    if dic['count'] >= 1:
        print('%s买到票了'%name)
        dic['count'] -= 1
        time.sleep(2)
        with open('ticket', mode='w',encoding='utf-8') as f:
            json.dump(dic,f)
    else:
        print('余票为0,%s没买到票' % name)

def use(name,lock):
    search_ticket(name)
    print('%s在等待'%name)
    # lock.acquire()
    # print('%s开始执行了'%name)
    # buy_ticket(name)
    # lock.release()
    with lock:
        print('%s开始执行了'%name)
        buy_ticket(name)



if __name__ == '__main__':
    lock = Lock()
    l = ['alex','wusir','baoyuan','taibai']
    for name in l:
        Process(target=use,args=(name,lock)).start()

from threading import Lock,Thread

noodle_lock = Lock()
fork_lock = Lock()

def eat1(name):
    noodle_lock.acquire()   # 阻塞 宝元等面
    print('%s拿到面了'%name)
    fork_lock.acquire()
    print('%s拿到叉子了' % name)
    print('%s吃面'%name)
    fork_lock.release()
    print('%s放下叉子了' % name)
    noodle_lock.release()
    print('%s放下面了' % name)

def eat2(name):
    fork_lock.acquire()    # 阻塞 wu‘sir等叉子
    print('%s拿到叉子了' % name)
    noodle_lock.acquire()
    print('%s拿到面了'%name)
    print('%s吃面'%name)
    noodle_lock.release()
    print('%s放下面了' % name)
    fork_lock.release()
    print('%s放下叉子了' % name)

Thread(target=eat1,args = ('alex',)).start()
Thread(target=eat2,args = ('wusir',)).start()
Thread(target=eat1,args = ('baoyuan',)).start()

多线程版聊天 udp:

https://www.bilibili.com/video/av73705797?p=10

多任务 进程 线程 协程

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