协程（四十八）

http://www.cnblogs.com/linhaifeng/articles/7429894.html

进程与线程都是抢占式的

协程对应的是协作，非抢占式的

　　优势：没有切换的消耗，没有锁的概念

　　协程本质上就是一个线程，不能用多核，多进程 + 协程 是一个很好的解决方案

　　协程主要解决的也是IO操作

　　yield(协程)

def f():
    print(1)
    yield 1 # 相当于return 只不过yield还可以返回函数继续调用
    print(2)
    s = yield # 接收send的值
    print(s)
    yield
    print(3)
    yield

g = f()
print(g) # <generator object f at 0x00000162B6CF7F10>
ret = next(g) # 1
print(ret) # 1
next(g) # 2
g.send(50)
g.__next__() # 3
#g.__next__() # StopIteration

yield用法

yeild实现简单的协程例子

import time

def constomer(name):
    print("%s ready to eat..." %name)
    while True:
        cake = yield
        print("[%s] is eating cake %s" %(name, cake))

def producer():
    r1 = con1.__next__()
    r2 = con2.__next__()
    n = 0
    while 1:
        time.sleep(1)
        print("\033[32;1mProduce\033[0m")
        con1.send(n)
        con2.send(n + 1)
        n += 2

if __name__ == "__main__":
    con1 = constomer("A君")
    con2 = constomer("B君")

    producer()
    
'''
A君 ready to eat...
B君 ready to eat...
Produce
[A君] is eating cake 0
[B君] is eating cake 1
Produce
[A君] is eating cake 2
[B君] is eating cake 3
Produce
[A君] is eating cake 4
[B君] is eating cake 5
'''

View Code

greenlet的switch