Python--装饰器

参考网址：

　　http://www.cnblogs.com/rhcad/archive/2011/12/21/2295507.html

　　http://www.cnblogs.com/huxi/archive/2011/03/01/1967600.html

1：对已有的对象添加额外功能，且不修改对象内部代码

2：python语法糖的使用

一：不带参数

#!/usr/bin/python
# -*- coding:utf-8 -*-

# 16 Oct. 2015
# Author:  Huang Junkai

import time

def time_calu1(func):
def _extra():
start = time.clock()
func()
end = time.clock()
print 'total time:', end - start
return _extra

def time_calu2(func):
start = time.clock()
func()
end = time.clock()
print 'total time:', end - start
return func

@time_calu2
def func():
print 'Wow! Success'

func()
func()

time_calu1与time_calu2的区别：

　　前者是一次性的，只对第一个func()有效，即28~19行代码等效于‘ func = time_calu1(func); func() ’

　　后者可保证对每次调用的func()，都有效

二：带参数

#!/usr/bin/python
# -*- coding:utf-8 -*-

# 16 Oct. 2015
# Author:  Huang Junkai

import time

def time_calu1(func):
def _extra(a, b):
start = time.clock()
result = func(a, b)
end = time.clock()
print 'used:', end - start
return result
return _extra

def time_calu2(func):
start = time.clock()
func()
end = time.clock()
print 'used:', end - start
return func

@time_calu1
def foo(a, b):
# print 'Wow! Success: the result is %s' % (a + b)
return a + b

result = foo(1, 2)
print result