Python3.5多进程原理与用法实例分析

更新时间：2020-06-29 09:12:01 作者：startmvc

本文实例讲述了Python3.5多进程原理与用法。分享给大家供大家参考，具体如下：进程类：Pro

本文实例讲述了Python3.5多进程原理与用法。分享给大家供大家参考，具体如下：

进程类：Process

示例及代码：

（1）创建函数作为单进程


#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
import multiprocessing
import time
#创建函数并将其作为单个进程
def worker(interval):
 n = 5 #进程数
 while n>0:
 print("The time is ：{0}".format(time.ctime())) #初始化时间
 time.sleep(interval) #睡眠时间
 n-=1
if __name__ == "__main__":
 # 创建进程，target：调用对象，args：传参数到对象
 p = multiprocessing.Process(target=worker,args=(2,))
 p.start() #开启进程
 print("进程号:",p.pid)
 print("进程别名:",p.name)
 print("进程存活状态:",p.is_alive())

运行结果：

进程号: 6784 进程别名: Process-1 进程存活状态: True The time is ：Wed Nov 1 10:59:03 2017 The time is ：Wed Nov 1 10:59:05 2017 The time is ：Wed Nov 1 10:59:07 2017 The time is ：Wed Nov 1 10:59:09 2017 The time is ：Wed Nov 1 10:59:11 2017

（2）创建函数作为多进程


#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
import multiprocessing
import time
#创建函数作为多进程
def work1(interval):
 print("work1...")
 time.sleep(interval)
 print("end work1...")
def work2(interval):
 print("work2...")
 time.sleep(interval)
 print("end work2...")
def work3(interval):
 print("work3...")
 time.sleep(interval)
 print("end work3...")
if __name__ == "__main__":
 p1 = multiprocessing.Process(target=work1,args=(1,))
 p2 = multiprocessing.Process(target=work2,args=(2,))
 p3 = multiprocessing.Process(target=work3,args=(3,))
 p1.start()
 p2.start()
 p3.start()
 print("The number of CPU is %d:"%(multiprocessing.cpu_count())) #打印CPU核数
 for p in multiprocessing.active_children(): #循环打印子进程的名称和pid
 print("子进程名称：%s，子进程pid：%d" %(p.name,p.pid))
 print("ending....")

运行结果：

The number of CPU is 4: 子进程名称：Process-2，子进程pid：7108 子进程名称：Process-1，子进程pid：1896 子进程名称：Process-3，子进程pid：7952 ending.... work3... work1... work2... end work1... end work2... end work3...

注：先运行主进程的内容，再运行子进程

（3）将进程定义成一个类


#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
import multiprocessing
import time
#将进程定义为一个类
class ClockProcess(multiprocessing.Process):
 def __init__(self,interval):
 multiprocessing.Process.__init__(self) #重构了Process类里面的构造函数
 self.interval = interval
 def run(self): #固定用run方法，启动进程自动调用run方法
 n = 5
 while n>0:
 print("The time is {0}".format(time.ctime()))
 time.sleep(self.interval)
 n-=1
if __name__ == "__main__":
 p = ClockProcess(2)
 p.start()

运行结果：

The time is Wed Nov 1 11:31:28 2017 The time is Wed Nov 1 11:31:30 2017 The time is Wed Nov 1 11:31:32 2017 The time is Wed Nov 1 11:31:34 2017 The time is Wed Nov 1 11:31:36 2017

（4）Queue（队列）实现多进程数据传输


#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
import multiprocessing
#Queue是多进程安全的队列，可以使用实现多进程之间的数据传递
def writer_proc(q):
 try:
 q.put(1,block=False) #put方法插入数据到队列中
 except:
 pass
def reader_proc(q):
 try:
 print(q.get(block=False)) #get方法从队列中读取并删除一个元素
 except:
 pass
if __name__ == "__main__":
 q = multiprocessing.Queue()
 writer = multiprocessing.Process(target=writer_proc,args=(q,))
 writer.start()
 reader = multiprocessing.Process(target=reader_proc,args=(q,))
 reader.start()
 reader.join()
 writer.join()

运行结果：