[python3]: python --【class】类变量（类属性）

[python3]:  python  --【class】类变量（类属性）

 

 

 

 

一、说明：

 

　　1、类变量：类变量，定义在【类内】且【函数外】。

class  object:

    #  class_variable
    icount    =    0


    def  __init__(self):
        #    using  class_variable
        object.icount    =    object.icount  +  1


    def  objnum(self):
        print(f"object_number := { object.icount }")

 

　　2、类变量的使用方法【<类名> <.> <类变量名>】：class_name . class_variable

　　　　2.1、【object.icount】

　　　　　　2.1.1：class_name = object

　　　　　　2.1.2：class_variable  =  icount

 

 

 

 

二、代码

#!/usr/bin/env python3


class object:

    #  variable of class(class_variable)
    #  using variable of class:  object.icount (class_name.class_variable)
    icount = 0

    def __init__(self, name):
        self.icount = 1
        self.__objname =  name
        object.icount = object.icount + 1
        print(f"[constructor]#  object_name:{ self.__objname },    object.icount = { object.icount } ")

    def __del__(self):
        object.icount = object.icount - 1
        print(f"[destructor]#  object_name:{ self.__objname },    object.icount = { object.icount } ")

    def object_number(self):
        print(f"\nobject_number := { object.icount }")
        print(f"self_icount := { self.icount } \n")

    def msg_name(self):
        print(f"name := { self.__objname }")


if __name__ == '__main__':
    x1 = object("f1")
    x2 = object("f2")
    x3 = object("f3")
    x4 = object("f4")

    x1.object_number()
    x2.object_number()
    x3.object_number()
    x4.object_number()

 

 

三、运行结果

[constructor]#  object_name:f1,    object.icount = 1 
[constructor]#  object_name:f2,    object.icount = 2 
[constructor]#  object_name:f3,    object.icount = 3 
[constructor]#  object_name:f4,    object.icount = 4 

object_number := 4
self_icount := 1 


object_number := 4
self_icount := 1 


object_number := 4
self_icount := 1 


object_number := 4
self_icount := 1 

[destructor]#  object_name:f1,    object.icount = 3 
[destructor]#  object_name:f2,    object.icount = 2 
[destructor]#  object_name:f3,    object.icount = 1 
[destructor]#  object_name:f4,    object.icount = 0 

 

 

四、参考内容

 

　　1、　　Python3 面向对象　　--　　https://www.runoob.com/python3/python3-class.html