def foo():

    print('starting')

    while True:

        x=yield None#return 2

        print('value ：',x)

g=foo()

print(next(g))

print(g.send(2))

运行结果：

starting  #运行函数，打印starting后碰到yield停住

None　　　 #next()触发后 yield将None赋值给x，打印None后循环碰到yield停住

value ： 2　　#g.send(2)将2赋值给yield，yield将2赋值给x，继续循环打印出2碰到yield停住

None　　　　  #碰到yield停住并返回None,print的结果就是None

def init(func):

    def wrapper(*args,**kwargs):

        g=func(*args,**kwargs)

        next(g)

        return g

    return wrapper

@init #foo=init(foo)

def foo():

    print('starting')

    while True:

        x=yield

        print('value ：',x)

g=foo() #wrapper()

g.send(2)

运行结果：

starting

value ：2

# _*_ coding:utf-8 _*_

def init(func):

    def wrapper(*args,**kwargs):

        g=func(*args,**kwargs)

        next(g)

        return g

    return wrapper

@init

def eater(name):

    print('%s ready to eat'%name)

    food_list=[]

    while True:

        food=yield food_list

        food_list.append(food)

        print('%s start to eat %s'%(name,food))

e=eater('alex')

print(e.send('food1'))

print(e.send('food2'))

print(e.send('food3'))

运行结果：

alex ready to eat

alex start to eat food1

['food1']

alex start to eat food2

['food1', 'food2']

alex start to eat food3

['food1', 'food2', 'food3']

import os

#装饰器，自动next()

def init(func):

    def wrapper(*args,**kwargs):

        g = func(*args,**kwargs)

        next(g)

        return g

    return wrapper

#j阶段一:递归地找出目录下所有文件的绝对路径，把路径发给阶段二

@init

def search(target):

    'search file abspath'

    while True:

        start_path=yield

        g = os.walk(start_path)

        for par_dir,_,files in g:

            for file in files:

                file_path = r'%s\%s' %(par_dir,file)

                target.send(file_path)

#阶段二:收到文件路径，打开文件获取文件对象，把文件对象发给阶段三

@init

def opener(target):

    while True:

        file_path = yield

        with open(file_path,encoding = 'utf-8') as f:

            target.send((file_path,f))

#阶段三：收到文件对象，for循环读取文件的每一行内容，把每一行内容发给阶段四

@init

def cat(target):

    while True:

        file_path,f = yield

        for line in f:

            res=target.send((file_path,line))

            if res:

                break

#阶段四：收到一行内容，判断root是否在这一行中，如果在，则把文件名发给阶段五

@init

def grep(target,pattern):

    tag=False

    while True:

        filepath,line=yield tag

        tag=False

        if pattern in line:

            target.send(filepath)

            tag=True

#阶段五：收到文件名，打印结果

@init

def printer():

    while True:

        filename = yield

        print(filename)

start_path = r'E:\PycharmProjects\qz5\day9'

# search(opener(cat(grep(printer(),'Jack'))),start_path)

g=search(opener(cat(grep(printer(),'Jack'))))

g.send(start_path)