3.24迭代器生成器作业

编写课上讲解的有参装饰器

def auth(db_type):
    def wrapper(func):
        def inner(*args, **kwargs):
            name = input('name: ').strip()
            pwd = input('pwd: ').strip()

            if db_type == 'file':
                print('文件验证登录')
                if (name, pwd) == ('egon', '123'):
                    print('登录成功')
                    res = func(*args, **kwargs)
                    return res
                else:
                    print('用户名或密码错误')

            elif db_type == 'file':
                print('文件验证登录')
                if (name, pwd) == ('egon', '123'):
                    print('登录成功')
                    res = func(*args, **kwargs)
                    return res
                else:
                    print('用户名或密码错误')

        return inner
    return wrapper


@auth('file')
def index():
    print('123')


index()

　　

还记得我们用函数对象的概念，制作一个函数字典的操作吗

来来来，我们有更高大上的做法，在文件开头声明一个空字典

然后在每个函数前加上装饰器，完成自动添加到字典的操作

cmd_dict = {}

def append2dict(tips):
    def wrapper(func):
        def inner(*args, **kwargs):
            index = len(cmd_dict) + 1
            cmd_dict[str(index)] = (tips, func)
        return inner
    return wrapper


def auto_append():
    my_func = {k: v for k, v in globals().items() if callable(v) if k not in {'append2dict', 'auto_append'}}
    for func in my_func.values():
        func()


@append2dict(tips='登录')
def login():
    print('this is login')


@append2dict('注册')
def register():
    print('this is register')



auto_append()

while 1:
    for k, v in cmd_dict.items():
        print(f'{k}-{v[0]}'.center(20, '-'))

    cmd = input('请输出编号：').strip()
    if cmd not in cmd_dict:
        print('重新输入')
        continue
    func = cmd_dict.get(cmd)[1]
    func()

　　

编写日志装饰器，实现功能如：一旦函数f1执行，则将消息2017-07-21 11:12:11 f1 run写入到日志文件中，日志文件路径可以指定。注意：时间格式的获取

import time

def my_log(file_path):
    def wrapper(func):
        def inner(*args, **kwargs):
            now = time.strftime('%Y-%m-%d %H:%M:%S')
            msg = f'{now} {func.__name__} run\n'
            with open(file_path, 'at', encoding='utf-8') as f:
                f.write(msg)

            res = func(*args, **kwargs)
            return res
        return inner
    return wrapper

@my_log('log.txt')
def f1():
    print('i am f1')

f1()

　　

4、基于迭代器的方式，用while循环迭代取值字符串、列表、元组、字典、集合、文件对象

my_obj = '2333'
my_obj_i = my_obj.__iter__()
while True:
    try:
        print(my_obj_i.__next__())
    except StopIteration:
        break

　　

my_obj = [1,2,3]
my_obj_i = my_obj.__iter__()
while True:
    try:
        print(my_obj_i.__next__())
    except StopIteration:
        break

　　

my_obj = (4,5,6)
my_obj_i = my_obj.__iter__()
while True:
    try:
        print(my_obj_i.__next__())
    except StopIteration:
        break

　　

my_obj = {1:1, 2:2, 3:3}
my_obj_i = my_obj.__iter__()
while True:
    try:
        print(my_obj_i.__next__())
    except StopIteration:
        break

　　

my_obj = {1,2,3}
my_obj_i = my_obj.__iter__()
while True:
    try:
        print(my_obj_i.__next__())
    except StopIteration:
        break

　　

with open('aaa.txt', mode='rt', encoding='utf-8')
    while True:
        try:
            print(f.__next__())
        except StopIteration:
            break

　　5自定义迭代器实现range功能

def my_range(start, end, step=1):
    while start < end:
        yield start
        start += step


g = my_range(1,5)

for i in g:
    print(i)