python--yield>>>协程

Python yield 使用浅析
廖雪峰Python教程–协程

def consumer():
    r = ''
    while True:
        n = yield r
        if not n:
            return
        print('[消费者]消费 %s...' % n)
        r = '200 OK'

def produce(c):
    c.send(None)
    #或写成，必须初始化，因为不能携带【r = c.send(n)】一个没有non-None值给刚开始的产生器
    #r = c.send(None)#TypeError: can't send non-None value to a just-started generator
    n = 0
    while n < 5:
        n = n+1
        print('[生产者]生产 %s...' % n)
        r = c.send(n)
        print('[生产者] 消费者返回r=%s' % r)
    c.close()

c = consumer()
produce(c)
# r = c.send(n) # r指的是 c携带n
# n = yeild r # r生产出来n