Python3.5多进程原理与用法实例分析

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：

1

希望本文所述对大家Python程序设计有所帮助。

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