Day9：yield的表达式形式、面向过程编程（grep -rl 'root' /etc）

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)