python第十二课

超、凢脫俗 2023-06-03 04:50 5阅读 0赞

#复习
    #作业
    #装饰器的进阶
        #functools.wraps
        #带参数的装饰kkd
        #多个装饰器装饰同一个函数
    #装饰器
    #开发原则: 开放封闭原则
    #装饰器的作用:在不改变原函数的调用方式的情况下,在函数前后添加功能
    #装饰器的本质:闭包函数
    # from functools import wraps
    # def wrapper(func): #func=holiday
    #     @wraps(func)
    #     def inner(*args,**kwargs):
    #         print('在被装饰的函数执行之前做的事')
    #         ret=func(*args,**kwargs)
    #         print('在被装饰的函数执行之后做的事')
    #         return ret
    #     return inner
    #
    # @wrapper #holiday=wrapper(holiday)
    # def holiday(day):
    #     '''这是一个放假通知'''
    #     print('全体放假%s天'%day)
    #     return '爱你启丽'
    #
    # print(holiday.__name__)
    # print(holiday.__doc__)
    # ret=holiday(3) #inner
    # print(set)
    #
    # # def outer(*args,**kwargs):
    # #     print(args)
    # #     print(*args)
    # #     def inner(*args):
    # #         print('inner : ',args)
    # #     inner(*args)
    # #
    # # outer(1,2,3,4) #==outer(*[1,2,3,4]) #==outer(*(1,2,3,4))
    #
    # #1.编写装饰器,为多个函数加上认证的功能(用户的帐号密码来源于文件),
    # #要求登陆成功一次,后续的函数都无需再输入用户名和密码
    # FLAG=False
    # def login(func):
    #     def inner(*args,**kwargs):
    #         global FLAG
    #         '''登陆程序'''
    #         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 == '222222':
    #                 FLAG=True
    #                 ret=func(*args,**kwargs) # func是被装饰的函数
    #                 return ret
    #             else:
    #                 print('登陆失败')
    #     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()
    # shoplist_del()
    
    #1.编写下载网页内容的函数,要求功能是:用户传入一个url,函数返回下载页面的结果
    import os
    from urllib.request import urlopen
    def cache(func):
        def inner(*args,**kwargs):
            if os.path.getsize('web_cache'):
                with open('web_cache','rb') as f: #判断文件中是否有内容
                    return f.read()
            ret=func(*args,**kwargs) #get() 请求网页
            with open('web_cache','wb') as f: #将请求的结果写到文件里
                f.write(b'****'+ret)
            return ret
        return inner
    
    @cache
    def get(url):
        code=urlopen(url).read
        return code
    ret=get('http://www.baidu.com')
    print(ret)
    ret=get('http://www.baidu.com')
    print(ret)

#生成器函数
    # def generator():
    #     print(1)
    #     return 'a'
    # ret = generator()
    # print(ret)
    
    #只要含有yield关键字的函数都是生成器的函数
    #yield 不能和return工用且需要写在函数内
    # def generator():
    #     print(1)
    #     yield 'a'
    # #生成器函数:执行之后会得到一个生成器作为返回值
    # ret = generator()
    # print(ret)
    # print(ret.__next__())
    
    # def generator():
    #     print(1)
    #     yield 'a'
    #     print(2)
    #     yield 'b'
    # g=generator()
    # for i in g:
    #     print(i)
    # ret=g.__next__()
    # print(ret)
    # ret=g.__next__()
    # print(ret)
    
    #娃哈哈%i
    # def wahaha():
    #     for i in range(100):
    #         yield '娃哈哈%s'%i
    #
    # g=wahaha()
    # count=0
    # for i in g:
    #     count +=1
    #     print(i)
    #     if count>50:
    #         break
    # #print('*******',g.__next__())
    # count=0
    # for i in g:
    #     count +=1
    #     print(i)
    #     if count>100:
    #         break
    
    #带参数的装饰器
    #500个函数
    import time
    FLAG=True
    def timmer_out(flag):
        def timmer(func):
            def inner(*args,**kwargs):
                if flag:
                    start=time.time()
                    ret=func(*args,**kwargs)
                    end=time.time()
                    print(end-start)
                    return ret
                else:
                    ret=func(*args,**kwargs)
                    return ret
            return inner
        return timmer
    #timmer=timmer_out(FLAG)
    @timmer_out(FLAG) #wahaha=timmer(wahaha)
    def wahaha():
        time.sleep(0.1)
        print('wahawaha')
    @timmer_out(FLAG)
    def erguotou():
        time.sleep(0.1)
        print('ergoutoutoutotu')
    
    wahaha()
    erguotou()

def tail(filename):
        f=open('file',encoding='utf-8')
        while True:
            line=f.readline()
            if line.strip():
                yield line.strip()
    g=tail('file')
    for i in g:
        if '启丽' in i:
            print('我喜欢',i)

转载于:https://www.cnblogs.com/huangjianfeng/p/11334678.html