Python_生成器函数进阶_39

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

'''

#send 获取下一个值的效果和next基本一致
#只是在获取下一个值的时候，给上一yield的位置传递一个数据
#使用send的注意事项
# 第一次使用生成器的时候 是用next获取下一个值
# 最后一个yield不能接受外部的值

# 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

Eva_J

https://www.cnblogs.com/Eva-J/p/7277026.html