本文研究的主要內容是Python中裝飾器相關學習總結，具體如下。

裝飾器(decorator)功能

裝飾器示例

例1:無參數的函數

from time import ctime, sleepdef timefun(func): def wrappedfunc():  print("%s called at %s"%(func.__name__, ctime()))  func() return wrappedfunc@timefundef foo(): print("I am foo")foo()sleep(2)foo()

分析如下：

上面代碼理解裝飾器執行行為可理解成

foo = timefun(foo)


1，foo先作為參數賦值給func后,foo接收指向timefun返回的wrappedfunc
2，調用foo(),即等價調用wrappedfunc()
3，內部函數wrappedfunc被引用，所以外部函數的func變量(自由變量)并沒有釋放
4，func里保存的是原foo函數對象

例2:被裝飾的函數有參數

from time import ctime, sleepdef timefun(func): def wrappedfunc(a, b):  print("%s called at %s"%(func.__name__, ctime()))  print(a, b)  func(a, b) return wrappedfunc@timefundef foo(a, b): print(a+b)foo(3,5)sleep(2)foo(2,4)

例3:被裝飾的函數有不定長參數

from time import ctime, sleepdef timefun(func): def wrappedfunc(*args, **kwargs):  print("%s called at %s"%(func.__name__, ctime()))  func(*args, **kwargs) return wrappedfunc@timefundef foo(a, b, c): print(a+b+c)foo(3,5,7)sleep(2)foo(2,4,9)

例4:裝飾器中的return

from time import ctime, sleepdef timefun(func): def wrappedfunc():  print("%s called at %s"%(func.__name__, ctime()))  func() return wrappedfunc@timefundef foo(): print("I am foo")@timefundef getInfo(): return '----hahah---'foo()sleep(2)foo()print(getInfo())

執行結果:

foo called at Sun Jun 18 00:31:53 2017
I am foo
foo called at Sun Jun 18 00:31:55 2017
I am foo
getInfo called at Sun Jun 18 00:31:55 2017
None

如果修改裝飾器為return func()，則運行結果：

foo called at Sun Jun 18 00:34:12 2017
I am foo
foo called at Sun Jun 18 00:34:14 2017
I am foo
getInfo called at Sun Jun 18 00:34:14 2017
----hahah---

小結：一般情況下為了讓裝飾器更通用，可以有return

例5:裝飾器帶參數,在原有裝飾器的基礎上，設置外部變量

from time import ctime, sleepdef timefun_arg(pre="hello"): def timefun(func):  def wrappedfunc():   print("%s called at %s %s"%(func.__name__, ctime(), pre))   return func()  return wrappedfunc return timefun@timefun_arg("itcast")def foo(): print("I am foo")@timefun_arg("python")def too(): print("I am too")foo()sleep(2)foo()too()sleep(2)too()可以理解為foo()==timefun_arg("itcast")(foo)()