1 -*- coding:utf-8 -*-
2 #How to declare a class in python:
3 # class class group
4 # object inherited parent class object base class, top-level parent class
5 class People(object):
6 n =123 #Class variable
7 name= ' I am a class variable '
8 n_list= []
9 #Initialization function, which is automatically called when an object is created
10 # __init__ built-in function
11 def __init__ (self,name,age,phone):
12 #In this function, you need to assign some attributes that should be owned when the object is created
13 # Object.Attribute name = attribute value
14 #The self here is equivalent to the object name such as: p1 = People('Zhang San', 22,110) The self here is p1
15 self.name = name #Instance variable (static attribute) The scope is the instance itself
16 self.age = age #equivalent to p1.age=age
17 self.phone = phone
18
19 def show(self): #class method, also called class function (dynamic attribute)
20 #here self is equivalent to the object name such as: p1 .show() The self here is p1, which is equivalent to People.show(p1), whoever calls the method in this class is who.
21
22 print (self.name )
23
24 print (People.n) #Class variables can be used before instantiation
25 #Create an object using the People class
26 #Basic format of creating an object: object name = class name ()
27 #When an object is created , a space will be opened in memory to store the object, which has an address 28 #The object created each time They are all a single individual, and their memory addresses are different. 29 p1 = People( ' Zhang San ' ,22,110) # p1 is also called an instance of People, also called an object 30 p2 = People( ' Li Si ' ,26,120 )
31 #Memory : The space occupied in the computer when the program is running 32 # 33 of automatic memory management in python print (p1) # <__main__.People object at 0x0000000002217E80> 34 #Get the attribute value of the object 35 #Format : object.attribute name
36 name = p1.name
37 print (name)
38 age = p1.age
39 print (age)
40 phone = p1.phone
41 print (phone)
42
43 print ( ' ------------ --- ' ,p1.n,p1.name) #Class variables and instance variables can be used directly >>--------------- 123 Zhang San
44 #If there is a class variable that is name, then also print the same variable name instance variable, no class variable is found
45
46 #Modify the attribute value of the object
47 #Format : object. attribute name = attribute value
48 p1.name= ' Li Si '
49 print (p1.name)
50
51 # The attribute value function used in python
52 # 1. The object to set the attribute value 2. The attribute name to set 3. The attribute value to set
53 setattr(p1, ' age ' ,21 )
54
55 #You can add new attributes to the object
56 # Object.Attribute name = attribute value If this attribute does not exist, then add attribute
57 p1.sex = ' male ' #equivalent to the effect of self.sex=sex in the constructor The same, but only for p1, other objects do not have this attribute
58 print (p1.sex)
59
60 #Delete the attribute of the object 61 #After the attribute of the object is deleted, it can no longer be used 62 #
AttributeError: sss The sss attribute to be deleted does not exist
63 del p1.sex
64 #Function to delete object attributes 65 # 1. Object to be deleted 2. Attribute name to be deleted 66 delattr(p1, ' phone ' ) #or del p1 .phone 67 #After deletion, p1 cannot use this property 68 # print (p1.phone) 69 70 #Change class variable with instance 71 p1.n= ' Change class variable ' 72 #Print with p1 73 print ( ' - --------p1------------ ' ,p1.n) #
>>---------p1------------- Change the class variable (equivalent to adding in the memory of p1: p1.n='change the class variable')
74 #Use p2 print
75 print ( ' ---------p2----------- ' ,p2.n) # >>---------p2----- ------ 123
76
77 People.n= ' ABCD '
78 print ( ' p1: ' ,p1.n, ' p2: ' ,p2.n) # >>p1: Change class variable p2: ABCD
79
80 p1.n_list= ' from p1 '
81 p2.n_list= ' from p2 '
82 prints('p1:',p1.n_list,'p2:',p2.n_list,'People:',People.n_list) #>>p1: from p1 p2: from p2 People: []
83
84 # setattr动态添加属性
85 attr_dict = {'iq':'150','eq':'150','color':'yellow'}
86 # for遍历
87 forkey,value in attr_dict.items():
88 # key is the attribute name, value is the attribute value
89 # setattr, you can add a string attribute name to the attribute of the object
90 # p1.key = value This method cannot Adding is equivalent to writing p1.'iq'= '150'
91 setattr(p1,key,value)
92
93 print (p1.iq)
94
95
96 # delattr dynamically deletes attribute
97 # deletes attribute 98 in object p1
attr_dict = [ ' iq ' , ' eq ' , ' color ' ]
99 100 for attr
in attr_dict:
101 # 可以使用delattr函数删除
102 delattr(p1,attr)
103
104 # 属性删除之后，就不能再使用了
105 # print (p1.iq)