有参装饰器、迭代器，生成器

1. 编写有参函数装饰器

def auth(db_type):
    def deco(func):
        def wrapper(*args, **kwargs):
            name = input('name:').strip()
            psd = input('password:').strip()
            if db_type == 'file':
                print('基于文件验证')
                if name == 'avery' and psd == '123':
                    print('login successful')
                    res = func(*args, **kwargs)
                    return res
                else:
                    print('error')
            elif db_type == 'mysql':
                print('基于mysql验证')
                res = func(*args, **kwargs)
                return res
            elif db_type == 'ldap':
                print('基于ldap验证')
                res = func(*args, **kwargs)
                return res
            else:
                print('wrong type')

        return wrapper

    return deco


@auth(db_type='file')  # @deco # index = deco(index) # index = wrapper
def index(x, y):
    print('index->>%s:%s' % (x, y))

@auth(db_type='mysql')  # deco # index = deco(index) # index = wrapper
def home(name):
    print('home>>%s' % name)

@auth(db_type='ldap')
def transfer():
    print('transfer')


index(2,3)
home("avery")
transfer()

2. 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

d = {}
def add_dict(key):
    def wrapper(func):
        def inner(*args, **kwargs):
            global d
            d[key] = func
            return func(*args, **kwargs)
        return inner
    return wrapper

@add_dict('1')
def index():
    pass
@add_dict('2')
def home():
    pass
index()
home()

print(d)

3. 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
time.strftime('%Y-%m-%d %X')
'''

import time


def timer(func):
    def wrapper(*args, **kwargs):
        file = input('filename:').strip()
        with open(r'{}'.format(file), mode='at', encoding='utf-8') as f1:
            f1.write(time.strftime(f'%Y-%m-%d %X {func.__name__} run\n'))
        res = func()
        return res

    return wrapper


@timer
def index():
    print('Hello')


@timer
def home():
    print('Home')


index()
home()

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

str_demo = '1234'
list_demo = [1, 2, 3, 4]
tuple_demo = (1, 2, 3, 4)
dict_demo = {'k1': 1, 'k2': 2, 'k3': 3, 'k4': 4}
set_demo = {1, 2, 3}

def wrapper(func):
    print('该对象为{}'.format(type(func)))
    while True:
        try:
            print(next(func))
        except StopIteration:
            break

wrapper(iter(str_demo))
wrapper(iter(list_demo))
wrapper(iter(tuple_demo))
wrapper(iter(dict_demo))
wrapper(iter(set_demo))

5. 自定义迭代器实现range功能

def ranges_s(start, stop, step=1):
    while start < stop:
        yield start
        start += step


for i in ranges_s(0, 5):
    print(i)