装饰器的补充(叠加多个装饰器,有参装饰器,三元表达式,生成式,匿名函数)

Posted 2021-01-23 孑乚目分

1,叠加多个装饰器

　　1),加载顺序(outter函数的调用顺序):自下而上

　　2),执行顺序(wrapper函数的执行顺序):自上而下

def outter1(func1): #func1=wrapper2的内存地址
    print(‘加载了outter1‘)
    def wrapper1(*args,**kwargs):
        print(‘执行了wrapper1‘)
        res1=func1(*args,**kwargs)
        return res1
    return wrapper1

def outter2(func2): #func2=wrapper3的内存地址
    print(‘加载了outter2‘)
    def wrapper2(*args,**kwargs):
        print(‘执行了wrapper2‘)
        res2=func2(*args,**kwargs)
        return res2
    return wrapper2

def outter3(func3): # func3=最原始的那个index的内存地址
    print(‘加载了outter3‘)
    def wrapper3(*args,**kwargs):
        print(‘执行了wrapper3‘)
        res3=func3(*args,**kwargs)
        return res3
    return wrapper3



@outter1 # outter1(wrapper2的内存地址)======>index=wrapper1的内存地址
@outter2 # outter2(wrapper3的内存地址)======>wrapper2的内存地址
@outter3 # outter3(最原始的那个index的内存地址)===>wrapper3的内存地址
def index():
    print(‘from index‘)

 

import time


#时间统计函数
def timmer(func):
    def wrapper(*args, **kwargs):
        start = time.time()
        res = func(*args, **kwargs)
        stop = time.time()
        print(‘run %s‘ % (stop - start))
        return res

    return wrapper


#账户登录验证函数
def duth(func):
    def wrapper(*args, **kwargs):
        name = input(‘please input your name:‘)
        pwd = input(‘please input your password:‘)
        if name == ‘egom‘ and pwd == ‘123‘:
            print(‘login successful‘)
            res = func(*args, **kwargs)
            return res
        else:
            print(‘your name or password error‘)
    return wrapper


@timmer
@duth
#装饰器将下面函数的函数名当做参数,然后将运行的结果在赋值给原函数index

#
def index():
    time.sleep(1)
    print(‘from index‘)


index()

 

 

2,有参装饰器

current_user = {‘user‘:None}

def duth(engine=‘file‘):
    def outter(func):
        def wrapper(*args,**kwargs):

            #确认current字典内是否有存在的数据
            if current_user[‘user‘] is not None:
                res = func(*args,**kwargs)
                return res

            name = input(‘your name :‘).strip()
            password = input(‘your password :‘).strip()

            #基于‘file‘文件认证
            if engine == ‘file‘:
                if name == ‘egon‘ and password == ‘123‘:
                    print(‘login successful‘)
                    current_user[‘user‘]=name
                    res=func(*args,**kwargs)
                    return res
                else:
                    print(‘your name or password error‘)

            elif engine == ‘mysql‘ :
                print(‘基于mysql认证‘)

            elif engine == ‘ldap‘ :
                print(‘基于ldap认证‘)

            else:
                print(‘hello‘)

        return wrapper
    return outter

 

3,三元表达式

def max2(x,y):
    if x > y:
        return x
    else:
        return y

res=max2(10,20)

x=10
y=20

# res=x if x > y else y
# print(res)


res=‘OK‘ if False else ‘No‘
print(res)

 

4,生成式

　　列表生成式

l=[]
for i in range(10):
    if i > 4:
        l.append(i**2)



l=[i**2 for i in range(10) if i > 4]
print(l)

 

names=[‘egon‘,‘alex_sb‘,‘kevin_sb‘,‘hxx_sb‘,‘cxx_sb‘]
sbs=[]
for name in names:
    if name.endswith(‘sb‘):
        sbs.append(name)


sbs=[name.upper() for name in names if name.endswith(‘sb‘)]

 

 

　　字典生成器

res={i:i**2 for i in range(10) if i > 3}
print(res)


print({i for i in ‘hello‘})

 

　5,匿名函数