python 装饰器

1.在执行目标函数前附加一些内容或者功能：

1 2 3 4 5 6 7 8 9 10

def demo(func):     print('before exec %s '%func.__name__)     func()     print('after exec %s '%func.__name__)     return func def func():     print('hello world')   func = demo(func) func()

2.使用语法糖@来装饰函数

1 2 3 4 5 6 7 8 9

def demo(func):     print('before exec %s '%func.__name__)     func()     print('after exec %s '%func.__name__)     return func @demo def func():     print('hello world') func()

3.使用内嵌包装饰函数保证每次新函数都被调用

1 2 3 4 5 6 7 8 9 10

def demo(func):     def inner():         print('before exec %s '%func.__name__)         func()         print('after exec %s '%func.__name__)     return inner @demo def func():     print('hello world') func()

4.对带参数的函数进行装饰

1 2 3 4 5 6 7 8 9 10 11 12

def demo(func):     def inner(a,b):         print('before exec %s '%func.__name__)         ret = func(a,b)         print('after exec %s '%func.__name__)         return ret     return inner @demo def func(a,b):     print('hello world')     return a+b print(func(1,2))

5.对参数数量不确定的函数进行装饰

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

def demo(func):     def inner(*args,**kwargs):         print('before exec %s '%func.__name__)         ret = func(*args,**kwargs)         print('after exec %s '%func.__name__)         return ret     return inner @demo def func(a,b):     print('hello world func')     return a+b @demo def func1(a,b,c):     print('hello world func1')     return a+b+c print(func(1,2)) print(func1(1,2,3))

6.装饰器带参数

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

def demo(arg):     def warper(func):         def inner(*args,**kwargs):             print('before exec %s %s'%(func.__name__,arg))             ret = func(*args,**kwargs)             print('after exec %s %s '%(func.__name__,arg))             return ret         return inner     return warper @demo('qq') def func(a,b):     print('hello world func')     return a+b @demo('wechat') def func1(a,b,c):     print('hello world func1')     return a+b+c print(func(1,2)) print(func1(1,2,3))

7.多个装饰器装饰一个函数

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

def wrapper1(func):     def inner():         print('wrapper1 ,before func')         func()         print('wrapper1 ,after func')     return inner   def wrapper2(func):     def inner():         print('wrapper2 ,before func')         func()         print('wrapper2 ,after func')     return inner   @wrapper2 @wrapper1 def f():     print('in f')   f()

8.装饰器带类参数

+ View Code

9.装饰器带类参数，并分拆公共类到其他py文件中，同时演示了对一个函数应用多个装饰器

+ View Code

　　

+ View Code