协程

什么是协程？

协程就是单线程下实现并发。是由用户自己控制调度的，也就是说需要在应用程序里实现。

协程的实现

Greenlet模块

from greenlet import greenletimport timedef eat(name):print('%s eat 1'%name) g2.switch('rose')print('%s eat 2'%name) g2.switch()def play(name):print('%s play1'%name) g1.switch()print('%s play2'%name)g1 = greenlet(eat)g2 =greenlet(play)g1.switch('lucy')

 

lucy eat 1

rose play1

lucy eat 2

rose play2

 

Greenlet可以很方便地实现切换，但是他不会监测IO，不能实现IO阻塞就切换。

Gevent模块

import geventdef eat(name):print('%s eat 1' % name) gevent.sleep(2)print('%s eat 2' % name)def play(name):print('%s play' % name) gevent.sleep(2)print('%s play' % name)g1 = gevent.spawn(eat, 'lucy')g2 = gevent.spawn(play, 'lile')g1.join()g2.join()

 

lucy eat 1

lile play

lucy eat 2

lile play

 

Gevent模块提高了执行效率，实现了并发操作，但是gevent.sleep()就可以监测自身，如果把这个改成time.sleep()就不会切换任务了，但是gevent下有个宝贝：

from gevent import monkey;monkey.patch_all()import geventimport timedef eat(name):print('%s eat 1' % name) time.sleep(2)print('%s eat 2' % name)def play(name):print('%s play' % name) time.sleep(2)print('%s play' % name)g1 = gevent.spawn(eat, 'lucy')g2 = gevent.spawn(play, 'lile')# g1.join()# g2.join() # 等待执行完才结束进程gevent.joinall([g1,g2]) # 同上，等待所有

就把ＩＯ阻塞变成非阻塞，但是一定要在文件开头写上。

转载于:https://www.cnblogs.com/yuliangkaiyue/p/9759117.html