执行结果：
before myfunc() called.
myfunc(1,2) called.
after myfunc() called. result: 3
before myfunc() called.
myfunc(3,4) called.
after myfunc() called. result: 7
第六步：对参数数量不确定的函数进行装饰
# -*- coding:utf-8 -*-
'''参数用(*args, **kwargs)，自动适应变参和命名参数'''
def deco(func):
def _deco(*args, **kwargs):
print ("before %s called." % func.__name__)
ret = func(*args, **kwargs)
print (" after %s called. result: %s" % (func.__name__, ret))
return ret
return _deco
@deco
def myfunc1(a, b):
print (" myfunc(%s,%s) called." % (a, b))
return a+b
@deco
def myfunc2(a, b, c):
print (" myfunc2(%s,%s,%s) called." % (a, b, c))
return a+b+c
myfunc1(1, 2)
myfunc1(3, 4)
myfunc2(1, 2, 3)
myfunc2(3, 4, 5)
#结果
before myfunc1 called.
myfunc(1,2) called.
after myfunc1 called. result: 3
before myfunc1 called.
myfunc(3,4) called.
after myfunc1 called. result: 7
before myfunc2 called.
myfunc2(1,2,3) called.
after myfunc2 called. result: 6
before myfunc2 called.
myfunc2(3,4,5) called.
after myfunc2 called. result: 12
第七步：装饰器带可变参数
# -*- coding:utf-8 -*-
'''在装饰器第四步4的基础上，让装饰器带参数，和上一示例相比在外层多了一层包装。装饰函数名实际上应更有意义些'''
def deco(arg):
def _deco(func):
def __deco():
print ("before %s called [%s]." % (func.__name__, arg))
func()
print ("after %s called [%s]." % (func.__name__, arg))
return __deco
return _deco
@deco("mymodule1") #装饰器参数是一个字符串，本身没有含义
def myfunc():
print (" myfunc() called.")
@deco("mymodule2")
def myfunc2():
print (" myfunc2() called.")
myfunc() #调用过程等价于：deco("mymodule1")()()-->_deco()()-->__deco()
myfunc2()
#解析三组闭包：
1. deco("mymodule1")()()+arg-->返回_deco函数对象
2. _deco()()+arg+func -->返回__deco函数对象
3. __deco()+arg+func --返回函数最终执行结果
执行结果：
before myfunc called [mymodule1].
myfunc() called.
after myfunc called [mymodule1].
before myfunc2 called [mymodule2].
myfunc2() called.
after myfunc2 called [mymodule2].
装饰器顺序：
当同时对一个函数使用多个不同的装饰器进行装饰时，这个时候装饰器的顺序就很重要了。
代码示例：
@A
@B
@C
def f():
pass
等价于：
f = A(B(C(f)))
Linux公社的RSS地址：https://www.linuxidc.com/rssFeed.aspx