Python基礎之裝飾器

裝飾器

1.普通函數

#簡單的函數和調用
def a1():
    print("i am zhangsan")
def a2():
    print("i am lisi")
a1()
a2()

2.在函數前後添加功能

def inner(func):
    print("添加1")
    func()
    print("添加2")
    return func
def a1():
    print("i am zhangsan")
def a2():
    print("i am zhangsan")

a1=inner(a1)
a1()
a2=inner(a2)
a2()

3.使用裝飾器

def mywork(func):
    def inner():
        print("添加1")
        func()
        print("添加2")
    return inner
@mywork     # @mywork就等於a1=mywork(a1)
def a1():
    print("i am zhangsan")

a1()
#執行時@mywork會把他下麵的函數當成mywork函數的參數既mywork(a1)，然後在函數inner里執行，inner內func()=a1()

4.裝飾帶參數的函數

def mywork(func):
    def inner(arg):
        print("添加1")
        func(arg)
        print("添加2")
    return inner
@mywork
def a1(arg):
    print 'i am zhangsan',arg

a1("參數1")

5.裝飾動態參數的函數

#合併無參，有參，多參  可以裝飾含有N個參數的函數
def mywork(func):
    def inner(*args,**kwargs):
        print("添加1")
        func(*args,**kwargs)
        print("添加2")
    return inner
@mywork
def a1():
    print 'i am zhangsan'
@mywork
def a2(arg):
    print 'i am zhangsan',arg
@mywork
def a3(arg1,arg2):
    print 'i am zhangsan',arg1,arg2
a1()
a2("參數1")
a3("參數1","參數2")

6.裝飾含有返回值的函數

#裝飾含有返回值的函數
def mywork(func):
    def inner(*args,**kwargs):
        print("添加1")
        aa=func(*args,**kwargs)
        print("添加2")
        return aa
    return inner
@mywork
def a3(arg1,arg2):
    print 'i am zhangsan',arg1,arg2
    li=[1,2,3,4,5,6]
    return li   #返回一個列表

list=a3("參數1","參數2")    #list等於inner的返回值
print(list)
#li列表是a3的返回值，所以給在inner函數里執行的func()賦給aa，在通過inner的返回值就能拿到列表

7.裝飾器實現登錄驗證簡單原理

def login():
    name =raw_input("輸入用戶名：")
    if name == "zhangsan":
        return  True
    else:
        return False
def mywork(func):
    def inner(*args,**kwargs):
        lo_login = login()
        if not lo_login:    #如果login()返回的是False
            return "用戶名錯誤!"
        aa=func(*args,**kwargs)
        return aa
    return inner
@mywork
def a3(arg1,arg2):
    print 'i am zhangsan',arg1,arg2
    li=[1,2,3,4,5,6]
    return li
list=a3("參數1","參數2")    #list等於inner的返回值
print(list)

8.多個裝飾器裝飾一個函數

def newwork1(func):
    def inner():
        print("newwork1前")
        func()
        print("newwork1後")
    return inner
def newwork2(func):
    def inner():
        print("newwork2前")
        func()
        print("newwork2後")
    return inner

@newwork2
@newwork1
def f1():
    print 'i am zhangsan'
f1()
'''
輸出結果：
    newwork1前
    newwork2前
    i am zhangsan
    newwork2後
    newwork1後
'''

9.裝飾器加參數

#3層裝飾器
def Filter(a1,a2):
    def outer(func):
        def wrapper(request,kargs):
            print(a1)
            result=func(request,kargs)
            print(a2)
            return result
        return wrapper
    return  outer
aa=11
bb=22
@Filter(aa,bb)
def Index(request,kargs):
    print request,kargs

Index("zhangsan","lisi")
#@Filter(aa,bb)會先執行Filter(aa,bb)函數，獲取到返回值outer後拼接成@outer，之後就變成普通的裝飾器了
#wrapper函數內可以使用a1,a2,request,kargs 4個參數