Process oriented

class	Stu:
	name=""
	sex = ""
	score = 0
	def dayin(self):
			print(self.name,self.sex,self.score)
zs=Stu()
zs.name="Zhang San"
zs.sex="male"
zs.score=89
zs.dayin()

ls=Stu()
ls.name="Li Si"
ls.sex="female"
ls.score="99"
ls.dayin()

Define a simple class:

class Dog():
	def sleep(self):
			print("Puppy sleeping")
	def chifan(self):
			print("Puppy eating")
zangao=Dog()
zangao.sleep()
zangao.chifan()

xuehao=Dog()
xuehao.sleep()
xuehao.chifan()

Setting initial value with parameters

class People():
	def __init__(self,name):
			priont(id(self))
			self.name=name
	def dayin(self):
			print(id(self))
			print("My name is",self.name)
zs=People("Zhang San")
print(id(zs))
zs.dayin()
ls=People("Li Si")
print(id(ls))
ls.dayin()

Add properties outside the class:

class Person():
	def dayin(self):
			print("My name is",self.name)
zs=Persom()
zs.name="Zhang San"
zs.dayin()

ls=persom()
ls.name="Li Si"
ls.dayin()

Define a teacher's class. When initializing, assign a value to the name, age and length of service
Definition method: self introduction
Define a method: lecture (), write a joke

class teacher():
	def __init__(self,name,age,gl):
				self.name=name
				self.age=age
				self.gl=gl
	def  js(self):
				print("My name is",self.name)
				print("Age",self.age)
				print("Working years",self.gl)
	def jk(self):
				print("joke")
zs=teacher("Wang Wu",48,10)
zs.js()
zs.jk()

External assignment, adding without assignment.

class A():
		def  __init__(self):
					pass
		def  hsl(self,x):
				self.name=x
		def show(self):
				print(self.name)
	x=A()
	x.hsl("Zhang San")
    	x.show()

class X():
		def hehe(self): 
				print(self.name)
z=X()
z.name="pig"
z.hehe()

Calculate the area and perimeter of a circle

class Yuan():
		def __init__(self,r):
				self.r=r
		def zhouchang(self):
				return 2*3.1415*self.r
		def mianji(self):
				area=3.14*self.r*self.r
				return	area
yi=Yuan(2)
print(y1.mianji())
print(y1.zhouchang())

y2=Yuan(3)
print(y2.mianji())
print(y2.zhouchang())

Class properties and object properties

class Stu():
		count=1999	#Class attribute, outside method
		def __init__(self,name):
				self.name=name#self attributes are all object attributes
		def showSelf(self):#self attributes are all object attributes
				print(self.name)
print(Stu.count)
a=Stu("Zhang San")
print(a.name)

When a class attribute and an object attribute have the same name, (you can think of the class attribute as a global variable and the object attribute as a local variable), the object attribute is used first.

    class Stu():
    		conut=0
    		def  __init__(self,name):
    				self.name=name
    				Stu.count+=1
    		def  showSelf(self):
    				print(self.name)
    print(Stu.count)
    a=Stu("Zhang San")
    print(a.count)
    b=Stu("Li Si")
    print(Stu.count)
    print(a.count)

**Delete function error:**

    class X():
    		def  __init__(self,name,age):
    					self.name=name
    					self.age=age
    zs=X('Zhang San',18)
    print(zs.name)
    del zs.name		#Report errors
    print(zs.age)
    print(zs.name)
**A,Design a student class with object attributes, name,id
B,Design an operation class, in which there is an empty list and a method to add students. Input student number, name, age and gender to the list id There is a method to delete students. Students in the list can't be deleted by student number**
class Student():
	def __init__(self,name,id)
				self.name=name
				self.id=id
class Oper():
	def  __init__(self):
				self.stu_lb=[]
	def addStudent(self):
		id=input("Please input ID")
		for stu in self.stu_lb:
			if stu.id==id:
					print("repeat ID")
					break
		else:
				name=input("Please enter a name")
				stu=Student(name,id)
				self.stu_lb.append(stu)
		self.dayin()
	def delStudent(self):
		id=input("Please enter the ID")
		for sty in self.stu_lb:
			if stu.id==id:
					print("delete",stu.name)
					self.stu_lb.remove(stu)
					break
		else:
				print("No one else")
		self.dayin()
	def dayin(self):
		for stu in self.stu_lb:
				print(stu.name,stu.id)
o=Oper()
o.addStudent()
o.addStudent()
o.delStudent()

Class properties and instance properties

class Student():
		count=9
		def __init__(self,name,age):
				self.name=name
				self.age=age
		def  say(self):
				print(self.name,self.age)
		@classmethod  #Class method, related to class
		def cM(cls):
				print(id(cls))
				print(id(Student))
				print(cls.count,'------')
		@staticmethod
		def hehe(a,b)
				print(a+b)
				print("I have nothing to do with you, but it's not appropriate to write it elsewhere")
zs=Student("Zhang San",18)
Student.cM()

Teachers' salaries and taxes

class Teacher():
		sl=0
		tax=0.002
		def __init__(self,name,salary):
				self.name=name
				self.salary=salary
				Teacher.sl+=1
		@classmethod
		def cM(cls):
			print(cls.sl)
		@staticmethod
		def gz(a,b):
			c=(a+b)*Teacher.tax
			print(c)
zs=Teacher("Zhang San",10000)
ls=Teacher("Li Si",2000)
Teacher.dayin()
Teacher.jisuan(zs.salary,ls.salary)		

Return to format

class Stu():
	def __init__(self,name,age):
			self.name=name
			self.age=age
	def  __str__(self):
			return"My name is{},Age{}".format(self.name,self.age)
zs=Stu("Zhang San"，19)
b=str(zs)
print(b)