Python实现的生产者、消费者问题完整实例

yipeiwu_com5年前Python基础

本文实例讲述了Python实现的生产者、消费者问题。分享给大家供大家参考,具体如下:

生产者、消费者问题,经典的线程同步问题:假设有一个缓冲池(列表),生产者往里面放东西,消费者从里面取,规则是:列表为空的时候,生产者才能放东西;列表不为空的时候,消费者才能取东西;为了简单起见,暂定缓冲池中最多只能有一个产品。这里生产者和消费者共同操作一个资源:缓冲池,因此每次操作的时候,需要给资源加锁,操作结束时,释放锁,这样才能做到资源同步。使用python实现,需要继承Thread类,获取锁对象,代码如下:

# -*- coding:utf-8 -*-
#! python2
from threading import Thread
from threading import Lock
import time,random
pro_list = []
lock = Lock()
class Producer(Thread):
  def run(self):
    global pro_list
    while True:
      i = random.randint(0, 100)
      lock.acquire()
      if len(pro_list) > 0:
        print "!--product still in list, wait consumer to get it.."
      else:
        pro_list.append(i)
        print ":::Producer put:", pro_list[0]
      lock.release()
      time.sleep(2)
class Consumer(Thread):
  def run(self):
    global pro_list
    while True:
      lock.acquire()
      if len(pro_list) == 0:
        print "!--No product now, wait producer put in..."
      else:
        print ":::Consumer fetch:", pro_list[0]
        pro_list.pop(0)
      lock.release()
      time.sleep(2)
Producer().start()
Producer().start()
Consumer().start()
Producer().start()
Producer().start()
Consumer().start()
Consumer().start()

这里使用多个生产者和消费者,共同操作缓冲池,部分执行结果如下:

:::Producer put: 78
!--product still in list, wait consumer to get it..
:::Consumer fetch: 78
:::Producer put: 99
!--product still in list, wait consumer to get it..
:::Consumer fetch: 99
!--No product now, wait producer put in...
:::Producer put: 12
:::Consumer fetch: 12
:::Producer put: 91
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::Consumer fetch: 91
!--No product now, wait producer put in...
:::Producer put: 63
:::Consumer fetch: 63
:::Producer put: 85
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::Consumer fetch: 85
!--No product now, wait producer put in...
:::Producer put: 1
:::Consumer fetch: 1
:::Producer put: 26
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::Consumer fetch: 26
!--No product now, wait producer put in...
:::Producer put: 8
:::Consumer fetch: 8
:::Producer put: 19
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::Consumer fetch: 19
!--No product now, wait producer put in...
:::Producer put: 74
!--product still in list, wait consumer to get it..
:::Consumer fetch: 74
:::Producer put: 50
!--product still in list, wait consumer to get it..
:::Consumer fetch: 50
!--No product now, wait producer put in...
:::Producer put: 97
:::Consumer fetch: 97
:::Producer put: 69
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::Consumer fetch: 69
!--No product now, wait producer put in...
:::Producer put: 41
!--product still in list, wait consumer to get it..
:::Consumer fetch: 41
:::Producer put: 6
!--product still in list, wait consumer to get it..
:::Consumer fetch: 6
!--No product now, wait producer put in...

更多关于Python相关内容感兴趣的读者可查看本站专题:《Python数据结构与算法教程》、《Python函数使用技巧总结》、《Python字符串操作技巧汇总》、《Python入门与进阶经典教程》及《Python数学运算技巧总结

希望本文所述对大家Python程序设计有所帮助。

相关文章

详解Django中类视图使用装饰器的方式

类视图使用装饰器 为类视图添加装饰器,可以使用两种方法。 为了理解方便,我们先来定义一个为函数视图准备的装饰器(在设计装饰器时基本都以函数视图作为考虑的被装饰对象),及一个要被装饰的类...

Django Celery异步任务队列的实现

背景 在开发中,我们常常会遇到一些耗时任务,举个例子: 上传并解析一个 1w 条数据的 Excel 文件,最后持久化至数据库。 在我的程序中,这个任务耗时大约 6s,对于用户来说,...

Python使用 Beanstalkd 做异步任务处理的方法

Python使用 Beanstalkd 做异步任务处理的方法

使用 Beanstalkd 作为消息队列服务,然后结合 Python 的装饰器语法实现一个简单的异步任务处理工具. 最终效果 定义任务: from xxxxx.job_queue i...

Python脚本判断 Linux 是否运行在虚拟机上

在 WebHostingTalk 论坛上有些国外奸商会把虚拟机当作独立服务器卖,去年7月份的时候就有一位中国同胞上当受骗,并在 WHT 上发帖声讨,证据确凿,甚至连服务商自己也承认,回帖...

pytorch查看torch.Tensor和model是否在CUDA上的实例

pytorch查看torch.Tensor和model是否在CUDA上的实例

今天训练faster R-CNN时,发现之前跑的很好的程序(是指在运行程序过程中,显卡利用率能够一直维持在70%以上),今天看的时候,显卡利用率很低,所以在想是不是我的训练数据torch...