python 協程
阿新 • • 發佈:2018-07-03
接口 news import pytho 生產者 () pre code producer
‘‘‘協成、對於非搶占式的調度程序
1.與生成器 yleid()、保存狀態
2.用戶態的切換、切換由用戶決定
3.協程本身是一種微線程
4.協成也是面向IO操作
5.沒有切換的消耗
6.沒有鎖的概念
‘‘‘
(1)生成器函數
def f(): print("ok") s= yield 5 print(s) print("ok2") yield gen=f() x=gen.__next__() print(x) gen.send(0)
(2)生產者消費者模型用yeild實現
import queue import time q=queue.Queue() def Cousumer(name): print("準備開始吃包子>>>>>>>>") while True: new_baozi = yield print("cousumer %s has eat %s baozi" %(name,new_baozi)) def Producer(name): r = con1.__next__() r = con2.__next__() n = 0 while 1: time.sleep(1) print("Producer %s is making baozi %s and %s" %(name,n,n+1)) con1.send(n) con2.send(n+1) n +=2 if __name__ == ‘__main__‘: con1 =Cousumer("c1") con2 = Cousumer("c2") p = Producer("1號廚師")
(3)-------------greenlet 函數間的切換更加方便--------------------------
#通過 switch() 隨時切換 from greenlet import greenlet def too2(): print(898) gr1.switch() print(34) def too1(): print(89) gr2.switch() print("7897978") gr2.switch() gr1=greenlet(too1) gr2=greenlet(too2) # gr1.switch() # 動作的發起端 too1()
(4)-----------------gevent接口遇到IO等待操作實現自動切換---------------------
import requests,time,gevent t1=time.time() def f(url): print("GET: %s" % url) resp =requests.get(url) data=resp.text f= open("new.html","w",encoding="utf8") f.write(data) print("%d bytes recevied from %s" %(len(data),url)) gevent.joinall([ gevent.spawn(f,"https://www.bilibili.com/video/av21663728/?p=325"), gevent.spawn(f,"http://news.baidu.com/"), gevent.spawn(f,"http://www.okoook.com/"), gevent.spawn(f,"https://www.imooc.com/"), gevent.spawn(f,"http://www.xiaohuar.com/"), gevent.spawn(f,"http://www.xiaohuar.com/hua/"), ]) # print(time.time()-t1) #比較串行 # f("https://www.bilibili.com/video/av21663728/?p=325") # f("http://news.baidu.com/") #f("http://www.okoook.com/") # f("https://www.imooc.com/") # f("http://www.xiaohuar.com/") # f("http://www.xiaohuar.com/hua/") print(time.time()-t1)
python 協程