Python learning "Fourth" Python Function (ii)

First, the decoration device

Adorner: Essentially a function that adds additional functionality to other functions

The principle of adorners:

• Do not modify the source code of the modified function
• Do not modify how the modified function is called

Knowledge Reserve for Decorators:

Adorner = higher order function + function nesting + closure

Second, higher order function

Definition of higher order functions:

• The receive parameter of a function is a functional name
• The return value of a function is a functional name
• Any one of the above conditions can be a higher-order function

Import Timedeffun1 (): Time.sleep (0.5)    Print("Hello")defComputing_run_time (fun):"""calculate function Run time:p Aram fun:: Return:"""start_time=Time.time () fun () End_time=time.time ()Print("Run time%s"% (End_time-start_time)) Computing_run_time (FUN1)"""Advantage: Without modifying the function source code, add additional functional disadvantage to the function: Change the calling mode"""

the receive parameter of the function is the name of the functor

Import Timedeffun1 (): Time.sleep (0.5)    Print("Hello")defComputing_run_time (fun):"""calculate function Run time:p Aram fun:: Return:"""Fun ()returnfunfun1=computing_run_time (FUN1) fun1 ()"""Pros: No change to function call method disadvantage: Cannot add new function for function"""

The return value of the function is the name of the functor

Note: Only higher-order functions do not meet the needs of adorners

Three, function nesting and closure

"" "Closure: the first must be an internally defined function that contains a reference definition for an outer scope instead of a global domain name word: The code for the intrinsic function contains a reference to the code of the external function, but must not be a reference to the global scope" "" Def Fun1 ():    print ("fun1 ")    name = 1    def fun2 (): Print (        " fun2 ")        print (name)        def fun3 (): Print (            " fun3 ")            print (name )        fun3 ()    fun2 () fun1 ()

　　

　　

Python learning "Fourth" Python Function (ii)