def generator():

    print(123)

    content = yield 1     #content接收的是send传的值

    print('=======',content)

    print(456)

    arg = yield 2

    print('nihao')

    ''''''

    yield

g = generator()

ret = g.__next__() #

print('***',ret) # *** 1

ret = g.send('hello')   #send的效果和next一样

# print('***',ret)

g.__next__()

'''

123
*** 1
======= hello
456
nihao

'''

def generator():

    print(123)

    yield 1

    print('=======')

    print(456)

    arg = yield 2

    print('nihao')

    ''''''

    yield

g = generator()

ret = g.__next__() #

print('***',ret) # *** 1

ret = g.send(None)   #send的效果和next一样

# print('***',ret)

g.__next__()

'''

123

*** 1

=======

456

nihao

'''

def generator():

    print(123)

    content = yield 1

    print('=======',content)

    print(456)

    arg = yield 2

    print('nihao')

    ''''''

    yield

g = generator()

ret = g.__next__() #

print('***',ret) # *** 1

ret = g.__next__()   #send的效果和next一样

print('***',ret)

g.__next__()

print('***',ret)

'''

*** 1
======= None
456
*** 2
nihao
*** 2

'''

# 获取移动平均值

# 10 20 30 10

# 10 15 20 17.5

#avg = sum/count

def average():

    sum = 0

    count = 0

    avg = 0

    while True:

        num = yield avg

        sum += num    #

        count += 1    #

        avg = sum/count

avg_g = average()

avg_g.__next__()

avg1 = avg_g.send(10)

avg1 = avg_g.send(20)

print(avg1)

#预激生成器的装饰器

def init(func):   #装饰器

    def inner(*args,**kwargs):

        g = func(*args,**kwargs)    #g = average()

        g.__next__()

        return g

    return inner

@init

def average():

    sum = 0

    count = 0

    avg = 0

    while True:

        num = yield avg

        sum += num    #

        count += 1    #

        avg = sum/count

avg_g = average()   #===> inner

ret = avg_g.send(10)

print(ret)

ret = avg_g.send(20)

print(ret)

import os

def init(func):

    def wrapper(*args,**kwargs):

        g=func(*args,**kwargs)

        next(g)

        return g

    return wrapper

@init

def list_files(target):

    while 1:

        dir_to_search=yield

        for top_dir,dir,files in os.walk(dir_to_search):

            for file in files:

                target.send(os.path.join(top_dir,file))

@init

def opener(target):

    while 1:

        file=yield

        fn=open(file)

        target.send((file,fn))

@init

def cat(target):

    while 1:

        file,fn=yield

        for line in fn:

            target.send((file,line))

@init

def grep(pattern,target):

    while 1:

        file,line=yield

        if pattern in line:

            target.send(file)

@init

def printer():

    while 1:

        file=yield

        if file:

            print(file)

g=list_files(opener(cat(grep('python',printer()))))

g.send('/test1')

协程应用：grep -rl /dir

tail&grep

#python 3

def generator():

    a = 'abcde'

    b = ''

    for i in a:

        yield i

    for i in b:

        yield i

def generator():

    a = 'abcde'

    b = ''

    yield from a

    yield from b

g = generator()

for i in g:

    print(i)

# send

    # send的作用范围和next一模一样

    # 第一次不能用send

    # 函数中的最后一个yield不能接受新的值

# 计算移动平均值的例子

# 预激生成器的装饰器的例子

# yield from