python-object-oriented noun parsing (class, instance, attribute, method, object)

Object Oriented Concept Summary

kind:

Abstraction of the characteristics and skills of a series of objects

　　How to understand: We abstract objects in real life into objects, such as students in school:

　　　　          1. Categorization - We can group all students into a class of students.

　　　　　　　2. Abstract the characteristics - what are the characteristics of the students? (school, name, gender, age)

　　　　　　    3. Abstract Skills – What skills do students have? (study, eat, play, sleep)

　　A. When we abstract students into a class, we can generate students one by one by constructing classes:

　　B. Note: In the real world, we abstract classes through objects.

　　　　　　  In the program, we must first define the class, in order to generate the object through the class.

# 1. First define the class abstractly from the real world 
# 2, and then generate objects through the class 
class Student:
     #Similar features 
    school = ' luffycity '

    #Similar skills 
    def lean(self):
         print ( ' is leaning ' )

    def eat(self):
        print('is eatting')

    def sleep(self):
        print('is sleeping')


# 2. After the object is generated through the class 
stu1 = Student()   #Instantiate a student object stu1 
stu2 = Student()
stu3 = Student()
print(stu1) 
print(stu2)
print(stu3)

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Class usage:

　　Add, delete, modify and check:

 

#Add 
Student.local= ' Beijing ' #Add class # Delete del Student.local #Delete class 
# Change 
Student.school= ' Luffycity ' #Change class attributes 
#Check print ( Student. __dict__ 
) #Check all print ( Student. school) #Check a single 
 

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The above case is to generate three objects with the same properties,

The __init__ method is used when we want to generate three different attributes

 

Example:

self : the instance itself, when instantiated, the python parser will automatically pass the instance itself through the self parameter.

　　If we want to instantiate multiple objects, we can pass the __init__() method and pass in the unique attributes of each object through the self parameter:

class LuffyStudent: #acquaintance
     characteristics school 
    = ' luffycity ' 
    #acquaintance skills 
    def  __init__ (self,name,sex,age):
        self.Name = name
        self.Sex=sex
        self.Age=age
    def lean(self):
        print('is leaning')
    def eat(self):
        print('is eatting')

stu1 = LuffyStudent( ' Xiao He ' , ' Female ' ,22 )
stu2 = LuffyStudent( ' Little Li ' , ' Male ' ,23 )
stu3 = LuffyStudent( ' Little Red ' , ' Female ' ,22 )

print(stu1.Name)

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Attributes:

The characteristics that objects have in common are called properties.

 　　Such as the above code: school is a common feature.

method:

All the skills of an object are called methods.

　　 Such as the above code: the common skills such as lean and eat are called methods.

Object:

　　As in the above code, by generating a class, an object is generated after instantiation

　　stu1=School() # This is called an object

 

#Object operation # Add 
stu1.local= ' Beijing ' #Add class 
# Delete del stu1.local #Delete class 
# Change stu1.school 
= ' 
Luffycity ' #Change class attributes #Check print ( 
stu1 . __dict__ ) #Check all print (stu1.school) #Check a single 
 

View Code

 

Additional instructions:

　　1. From different angles, the defined classes are completely different

　　2. The class in reality is not exactly equal to the class in the program, and the class may be split in the program.

　　3. There can be classes in the program that do not exist in reality - strategy classes.