Python初学者第二十三天 函数进阶装饰器

Posted 2020-10-22 fany-mok

23day

装饰器：

1、用户不执行前不调用函数，在调用的时候再执行函数

a、传函数时不加参数

user_status = False  # 用户登录了就把这个改成True
def login(func):
    def inner():
        _username = ‘alex‘
        _password = ‘abc123‘
        global user_status
        if user_status == False:
            username = input("user:")
            password = input("password:")
            if username == _username and password == _password:
                print("welcome login...")
                user_status = True
            else:
                print("wrong username or password!")

            if user_status:
                func()
    return  inner
@login
def home1():
    print("首页1")
@login   #等值于 home2 = login（home2）
def home2():
    print("首页2")
@login
def home3():
    print("首页3")
home1()
home2()
home3()

b、传函数时增加参数：

注：可以使用非固定函数*args、**kwargs。当传参数给函数时，取参数。不给函数传参数，则不取

 1 user_status = False  # 用户登录了就把这个改成True
 2 def login(func):
 3     def inner(*args,**kwargs):
 4         _username = ‘alex‘
 5         _password = ‘abc123‘
 6         global user_status
 7         if user_status == False:
 8             username = input("user:")
 9             password = input("password:")
10             if username == _username and password == _password:
11                 print("welcome login...")
12                 user_status = True
13             else:
14                 print("wrong username or password!")
15 
16             if user_status:
17                 func(*args,**kwargs)
18     return  inner
19 @login
20 def home1():
21     print("首页1")
22 # @login   #等值于 home2 = login（home2）
23 def home2(n):
24     print("首页2",n)
25 
26 def home3():
27     print("首页3")
28 home1()
29 home2(‘3p‘)
30 home3()

c、带参数的装饰器

可在外函数与内函数之间再套一层过度函数

user_status = False  # 用户登录了就把这个改成True
def login(func):
    def outer(func):
        def inner(*args,**kwargs):
            _username = ‘alex‘
            _password = ‘abc123‘
            global user_status
            if user_status == False:
                username = input("user:")
                password = input("password:")
                if username == _username and password == _password:
                    print("welcome login...")
                    user_status = True
                else:
                    print("wrong username or password!")

                if user_status:
                    func(*args,**kwargs)
        return  inner
    return outer

@login(‘qq‘) #先执行login（‘qq‘） 再将login（‘qq‘）@到home1
def home1():
    print("首页1")
# @login   #等值于 home2 = login（home2）
def home2(n):
    print("首页2",n)

def home3():
    print("首页3")
home1()
home2(‘3p‘)
home3()