Python3.5多進程原理與用法實例分析

更新時間：2019年04月05日 09:20:35 作者：loveliuzz

這篇文章主要介紹了Python3.5多進程原理與用法,結(jié)合實例形式分析了多進程的原理、單進程、多進程、進程類及進程隊列等相關(guān)定義與使用技巧,需要的朋友可以參考下

本文實例講述了Python3.5多進程原理與用法。分享給大家供大家參考，具體如下：

進程類：Process

示例及代碼：

（1）創(chuàng)建函數(shù)作為單進程

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
import multiprocessing
import time
#創(chuàng)建函數(shù)并將其作為單個進程
def worker(interval):
  n = 5    #進程數(shù)
  while n>0:
    print("The time is ：{0}".format(time.ctime()))   #初始化時間
    time.sleep(interval)    #睡眠時間
    n-=1
if __name__ == "__main__":
  # 創(chuàng)建進程，target：調(diào)用對象，args：傳參數(shù)到對象
  p = multiprocessing.Process(target=worker,args=(2,))
  p.start()    #開啟進程
  print("進程號:",p.pid)
  print("進程別名:",p.name)
  print("進程存活狀態(tài):",p.is_alive())

運行結(jié)果：

進程號: 6784
進程別名: Process-1
進程存活狀態(tài): 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）創(chuàng)建函數(shù)作為多進程

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
import multiprocessing
import time
#創(chuàng)建函數(shù)作為多進程
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核數(shù)
  for p in multiprocessing.active_children():     #循環(huán)打印子進程的名稱和pid
    print("子進程名稱：%s，子進程pid：%d" %(p.name,p.pid))
  print("ending....")

運行結(jié)果：

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

注：先運行主進程的內(nèi)容，再運行子進程

（3）將進程定義成一個類

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
import multiprocessing
import time
#將進程定義為一個類
class ClockProcess(multiprocessing.Process):
  def __init__(self,interval):
    multiprocessing.Process.__init__(self)   #重構(gòu)了Process類里面的構(gòu)造函數(shù)
    self.interval = interval
  def run(self):     #固定用run方法，啟動進程自動調(diào)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()

運行結(jié)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（隊列）實現(xiàn)多進程數(shù)據(jù)傳輸

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
import multiprocessing
#Queue是多進程安全的隊列，可以使用實現(xiàn)多進程之間的數(shù)據(jù)傳遞
def writer_proc(q):
  try:
    q.put(1,block=False)    #put方法插入數(shù)據(jù)到隊列中
  except:
    pass
def reader_proc(q):
  try:
    print(q.get(block=False))    #get方法從隊列中讀取并刪除一個元素
  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()

運行結(jié)果：