Python Learning Notes-(eight) decorators, generators & iterators

1. Decorative Device 1.1 Definition:

essentially a function that decorates other functions-that is, adding additional functionality to other functions

1.2 Adorner principle:

1) cannot modify the source code of the decorated function;

2) cannot modify the calling mode of the decorated function;

1.3 Implement the Adorner knowledge Reserve:

The 1.3.1 function is the "variable"

Defining a function is equivalent to assigning a function body to a functional name.

1.3.2 Higher order functions

See the previous study notes

1.3.3 Nested Functions

Definition: Use DEF to declare a new function in a function body

# def foo ():         #定义函数foo () ...    m=3            #定义变量m =3;    ... def bar ():     #在foo内定义函数bar ()        n=4        #定义局部变量n =4 ...        print (m+n)  #m相当于函数bar () global variables ...    bar ( )         #foo () function call function Bar () # foo ()             #调用foo () function 7

1.3.4 Decorator

Higher order function + nested function = = Adorner

• Fixed function parameters

# import time# def timer (func):    ... def deco (name):        ... start_time = Time.time () ...        func (name)        ...  Stop_time = Time.time () ...        print ("The Func Run time is%s"% (stop_time-start_time)) ...    return deco# @timer # def Test (name):    ... time.sleep (3) ...    print ("In the test!--%s"% name) # test (' CC ')

• Function parameters are not fixed

2. Iterators & Generators 2.1 List-generated 2.2 iterators 2.3 Generators 3.json&pickle serialization of data 4. Program Catalog Specification

Python Learning Notes-(eight) decorators, generators & iterators