装饰器篇：

1.编写装饰器，为多个函数加上认证的功能（用户的账号密码来源于文件），要求登录成功一次，后续的函数都无需再输入用户名和密码。

def login(func):

    def inner(*args, **kwargs):

        """登录程序

        """

        username = input('username:')

        password = input('password:')

        if username == 'boss_gold' and password == '':

            ret = func(*args, **kwargs)  # func是被装饰的函数

            return ret

        else:

            print('登录失败')

    return inner

@login

def shoplist_add():

    print('增加一件物品')

@login

def shoplist_del():

    print('删除一件物品')

shoplist_add()

shoplist_del()

# 但是这样有一样不好，就是运行了shoplist_add()之后再运行shoplist_del()还是要输入 用户名和密码。

FLAG = False

def login(func):

    def inner(*args, **kwargs):

        global FLAG

        """登录程序

        """

        if FLAG:

            ret = func(*args, **kwargs)  # func是被装饰的函数

            return ret

        else:

            username = input('username:')

            password = input('password:')

            if username == 'boss_gold' and password == '':

                FLAG = True

                ret = func(*args, **kwargs)  # func是被装饰的函数

                return ret

            else:

                print('登录失败')

    return inner

@login

def shoplist_add():

    print('增加一件物品')

@login

def shoplist_del():

    print('删除一件物品')

shoplist_add()

shoplist_del()

# 2.编写装饰器，为多个函数加上记录调用功能，要求每次调用函数都将被调用的函数名称写入文件。

def log(func):

    def inner(*args, **kwargs):

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

            f.write(func.__name__ + '\n')

        ret = func(*args, **kwargs)

        return ret

    return inner

@log

def shoplist_add():

    print('增加一件物品')

@log

def shoplist_del():

    print('删除一件物品')

shoplist_add()

1 li = ['qwer','asdf','zxcv','ty','gh','bn','uIo','UIj','plm']

2 lis = [i.upper() for i in li if len(i) >= 3]

3 print(lis)

lis = [(x,y) for x in range(0,6,2) for y in range(1,6,2)]

print(lis)

M = [[1,2,3],[4,5,6],[7,8,9]]

lis = [i[2] for i in M]

print(lis)

3.处理文件，用户指定要查找的文件和内容，将文件中包含要查找内容的每一行都输出到屏幕

def check_file(filename,aim):

    with open(filename,encoding='utf-8') as f:   #句柄 : handler,文件操作符，文件句柄

        for i in f:

            if aim in i:

                yield i

g = check_file('1.复习.py','生成器')

for i in g:

    print(i.strip())

4.写生成器，从文件中读取内容，在每一次读取到的内容之前加上‘***’之后再返回给用户。

def check_file(filename):

    with open(filename,encoding='utf-8') as f:   #句柄 : handler,文件操作符，文件句柄

        for i in f:

            yield '***'+i

for i in check_file('1.复习.py'):

    print(i.strip())

def init(func):

    def inner(*args,**kwargs):

        ret = func(*args,**kwargs)

        ret.__next__()

        return ret

    return inner

@init

def average():

    average = 0

    count = 0

    sum = 0

    while 1:

        num = yield average

        sum += num

        count += 1

        average = sum/count

ret = average()

print(ret.send(10))

print(ret.send(20))