One: Classes and Objects
A class is a class of things
Object: concrete thing
For example, people are a class, and the specific name is an object.
In python, variables are used to represent features, and functions are used to represent skills, so a class of things with the same features and skills is a 'class', and an object is a specific one of this class of things.
One: first acquaintance
Declare a class class lowercase. The class name is capitalized and added:, () can be written or not
class Person: #Define a human Person is the class name
role = 'person' #The role attributes of people are all people
def walk(self): #Everyone can walk, that is, there is a walking method, also called dynamic property
print("person is walking...")
Two roles of classes: attribute reference and instantiation
One: attribute reference (class name. attribute)
class Person: # define a person
role = 'person' # The role attributes of people are all people
def walk(self): # Everyone can walk, that is, there is a walking method
print("person is walking...")
print(Person.role) # View the role attribute of the person
print(Person.walk) # Refers to the walking method of people, note that this is not calling
Two: Enhanced version (class role, theoretical knowledge)
class Person: # 类名 Person
role = 'person' # static variable of class is a property shared by all objects
def attack(self): pass
print(Person.role) # The calling method provided to us by the class
print(Person.attack)
Person.role = 'Chinese'
print(Person.role)
Person.attack() # error
print(Person.__dict__) # Storage method
print(Person.__dict__['role'])
print(Person.__dict__['attack'])
Person.__dict__['role'] = '人'
Classes have only two functions:
1. Use the name in the class
Check out the names in the class:
Class name. Variable name # You can modify the value of the variable
Class name.__dict__['variable name'] # Cannot be modified
2. Create Object Instantiate Object
Objects are instances, a practical example
object = classname()
class Person: # 类名 Person
role = 'person' # static variable of class is a property shared by all objects
def __init__(self,name,sex,aggr,hp): #{}
self.name = name
self.sex = sex
self.aggr = aggr
self.hp = hp
def attack(self):
print(self.name)
print(self.sex)
obj1 = Person('alex','female',250,1)
obj2 = Person('egon','male',500,2)
print(obj1.name,obj1.sex,obj1.aggr,obj1.hp)
print(obj2.name,obj2.sex,obj2.aggr,obj2.hp)
print(obj1.__dict__)
print(obj2.__dict__)
print(obj1)
Person.attack(obj1) # Call a method in a class
obj1.attack()
Object specifics:
memory address inconsistency
Different object properties should have different values
class name (parameter)
Creates an empty object: self
Call __init__ method: initialization method
Pass parameters to the __init__ method
Complete the code in the init method
Automatically returns self to where it was instantiated
self is the object
Call a method in the class:
classname.methodname(object)
ObjectName.MethodName()
Three: Summary
#initial object oriented
'''
class Person:
role = 'person' # static variable of class is a property shared by all objects
def __init__(self):
pass
def attack(self):
1. Class: a class of transactions, such as people, computers, etc.
Object: a specific matter, such as Xiao Ming, Xiao Ming's mobile phone
2. Define a class: class Person(): The first letter of the class name Person should be capitalized () can be written or not
Add a shared attribute to the class role = 'person' The static variable of the class is an attribute shared by all objects
Use print(Person.role) when calling
3. View the name in the class:
3.1 The calling method provided by the print(Person.role) class can be modified, such as Person.role = 'Chinese'
3.2 The storage method provided by the print(Person.__dict__) class will display all the names and methods in the class
print(Person.__dict__['role'])
4. The class has only two functions:
4.1. Using names in classes
View the name in the class: 1. Class name. Variable name# You can modify the value of the variable
2. Class name.__dict__['variable name'] # Cannot be modified
4.2. Creating Objects Instantiating Objects
Objects are instances, a practical example
object = classname() #obj1=person()
5. Instantiate:
1.obj1 = Person('alex','female',1,250) # Instantiate the object first and then initialize
print(obj1.name,obj1.sex,obj1.aggr,obj1.hp)
print(obj2.name,obj2.sex,obj2.aggr,obj2.hp)
print(obj1.__dict__)
2. Call the __init__ method: initialization method
def __init__(self,name,sex,aggr,hp): #The built-in double down method of method dynamic attributes is the object self
self.name = name self is understood to be equal to an empty dictionary, self={} name in self.name is the key value, and the right side of the equal sign is the value value
self.sex = sex name, sex, etc. are attributes
self.aggr = aggr
self.hp = hp
6. The specifics of the object:
print(obj1) #object at 0x000001B8F1378A90>
print(obj2) #object at 0x000001B8F1378AC8>
1. Inconsistency of memory addresses
2. The value of different object properties should be different
7. Class name (parameter)
1. Create an empty object: self (ie obj1)
2. Call the __init__ method: initialization method
3. Pass parameters to the __init__ method
4. Complete the code in the init method
5. Automatically returns self to the place where it is instantiated, self is the object
8. Call the method in the class:
def attack(self): # custom method
print(self.name)
1. Class name. Method name (object) Person.attack(obj1)
2. Object name. Method name() obj1.attack() def attack(self): self is obj1
9. Use object-oriented steps:
1. Completing the class
First, analyze what attributes init methods exist in roles and classes.
Then analyze what behaviors in this class can be defined as methods
2. Instantiate
Pass parameters to get the object after instantiation
1. First create the object,
2. Execute the init method
3. Object call: use the object to call object properties and methods in the class
The role of the object name:
1. Use variable object name. Property name obj1.name
2. Call method object name. method name () obj1.attack ()
'''
####Man and dog battle
class Person: # 类名 Person
role = 'person' # static variable of class is a property shared by all objects
def __init__(self, name , sex , aggr , hp ): #The built-in double down method of method dynamic attributes
self.name = name # object attribute instance attribute
self.sex = sex
self.aggr = aggr
self.hp = hp
def attack(self, dog ): # custom method
print('%s打了%s'%(self.name,dog.name))
dog.hp -= self.aggr
class Dog:
def __init__(self,name,kind,aggr,hp):
self.name = name # object property
self.kind = kind
self.aggr = aggr
self.hp = hp
def bite(self,person):
print('%s咬了%s'%(self.name,person.name))
person.hp -= self.aggr
hei = Dog('Xiaohei','teddy',260,10000) # Instantiation: first create an object and then initialize
alex = Person('alex','female',1,250) # instantiate
egon = Person ('egon','male', 2,500) # Instantiation
alex.attack(hei) # Person.attack(alex,hei)
egon.attack (hei) # Person.attack (alex, hei)
print (hei.hp)
hei.bite (alex)
print(alex.hp)
#
# ## Find the area of a circle based on its radius##
# from math import pi
# class Circle:
# def __init__(self,r):
# self.r=r
# def area(self):
# return self.r**2*pi
# def perimeter(self):
# return self.r*2*pi
# circle=Circle(5)
# print(circle.area())
# print(circle. perimeter())
# ###Xiao Ming, Pharaoh###
# '''
# Xiao Ming, male, 10 years old, went up the mountain to chop wood
# # Xiao Ming, male, 10 years old, driving to the Northeast
# # Xiao Ming, male, 10 years old, loves big health care
# # Lao Zhang, male, 90 years old, went up the mountain to chop wood
# # Lao Zhang, male, 90 years old, driving to the Northeast
# # Lao Zhang, male, 90 years old, loves big health care
# # Lao Wang, male, 70 years old, went up the mountain to chop wood
# '''
# class Person:
# def __init__(self,name,sex,aggr):
# self.name=name
# self.sex = sex
# self.aggr = aggr
# def attack(self):
# print("%s%s%s went up the mountain to chop wood"%(self.name,self.sex,self.aggr ))
# print("%s%s%s drive to the northeast" % (self.name, self.sex, self.aggr))
# print("%s%s%s loves big health care" % (self.name, self.sex, self.aggr))
# obj1=Person("小明","男",10)
# obj1.attack()
# obj2=Person("Pharaoh","Male",90)
# obj2.attack()
# obj3=Person("Old Zhang","Male",75)
# ###Method Two###
# class Person:
# def __init__(self,name,sex,age):
# self.name = name
# self.age = age
# self.sex = sex
# def dirve(self):
# print('%s,%s,%s old, drive to the northeast'%(self.name,self.sex,self.age))
# def climb(self):
# print('%s,%s,%s old, go up the mountain to chop wood'%(self.name,self.sex,self.age))
# def hobby(self):
# print('%s,%s,%s old, loves big health care'%(self.name,self.sex,self.age))
# ming = Person ('Komei','Man', 10)
# ming.dirve()
# ming.climb()
# ming.hobby ()
# zhang = Person('Old Zhang','Male',90)
# zhang.dirve()
# zhang.climb()
# zhang.hobby ()