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装饰器

----------------装饰器----------------

 用户感觉不到   装饰器的存在

 在一个函数前后添加功能

 本身的函数不会改变

开放封闭原则

 开放 对于扩展是开放的
 封闭 对于修改是封闭的

========================装饰器的基本()结构===========================

def wrapper(func):
    def inner(*args,**kwargs):
        # 被装饰的函数执行之前的操作
        ret=func(*args,**kwargs)
        # 被装饰的函数执行之后的操作
        return ret
    return inner

@wrapper
def F(*argument):
    pass
-------------------------------------------------------------------------------------------------------

 -------------------------------------------------------------------------------------------------------
# import time
# def timmer(F):                         #    装饰器
#     def inner():
#         start_time=time.time()
#         F()
#         end_time=time.time()
#         print(end_time-start_time)
#     return inner
#
# @timmer                             #   F=timmer(F)         #   语法糖
# def F():
#     sum=0
#     for i in range(1,100000):
#         sum+=i                         # 被装饰的函数
# F()                        # 直接调用函数，还可以加上装饰器的功能
# -------------------------------------------------------------------------------------------------------
#

# 例子

# import time
#
# def timmer(func):
#
#     def inner(*args):
#
#         start=time.time()
#
#         re=func(*args)
#         print(id(func))
#
#         end=time.time()
#         print(end-start)
#
#         return re
#
#     print(id(inner))
#     return inner
#
#
# @timmer
# def qqxing(num,num2):
#     for i in range(1000000):pass
#     print(‘Hello‘)
#     return num+num2                        # 实际函数
#
# ret=qqxing(1,2)
# print(id(qqxing))
# print(ret)
# -------------------------------------------------------------------------------------------------------

#    例子 2
#
# def wrapper(func):
#     def inner(*args):
#         print(‘你正在调用%s函数‘%(func.__name__))
#         re=func(*args)
#         return re
#     return inner
#
# @wrapper
# def welcome(name):
#     print(‘welcome: %s‘%name)
# @wrapper
# def home():
#     print(‘欢迎来到home页！！‘)
#
# home()
# print(‘‘)
# welcome(‘alex‘)


# -------------------------------------------------------------------------------------------------

# def wrapper(func):
#     def inner(*args,**kwargs):
#         #
#         re=func(*args,**kwargs)
#         #
#         return re
#     return inner
#
# @wrapper
# def f(a):
#     print(a)
# f(1)

# -------------------------------------------------------------------------------------------------

装饰器

标签：lex   添加   font   例子   语法   col   return   ==   end   

原文地址：http://www.cnblogs.com/big-handsome-guy/p/7457821.html