类与对象

#先定义类
class LuffyStudent:
    school=‘luffycity‘                                        #数据属性

    def learn(self):                                           #函数属性
        print(‘is learning‘)

    def eat(self):                                              #函数属性
        print(‘is sleeping‘)


#后产生对象
stu1=LuffyStudent()
stu2=LuffyStudent()
stu3=LuffyStudent()

print(LuffyStudent.__dict__)
print(LuffyStudent.__dict__[‘school‘])
print(LuffyStudent.__dict__[‘learn‘])

print(LuffyStudent.school) #LuffyStudent.__dict__[‘school‘]

LuffyStudent.country = ‘China‘ #LuffyStudent.[‘country‘] = ‘China‘

 del LuffyStudent.country

LuffyStudent.school = ‘Luffycity‘

s1=LuffyStudent()
s2=LuffyStudent()
s3=LuffyStudent()

#如此，s1、s2、s3都一样了，而这三者除了相似的属性之外还各种不同的属性，这就用到了__init__

#注意：该方法是在对象产生之后才会执行，只用来为对象进行初始化操作，可以有任意代码，但一定不能有返回值
class LuffyStudent:
    ......
    def __init__(self,name,age,sex):
        self.name=name
        self.age=age
        self.sex=sex
    ......

s1=LuffyStudent(‘Tom‘,‘male‘,18) #先调用类产生空对象s1，然后调用luffyStudent.__init__(s1,‘Tom‘,‘male‘,18)
s2=LuffyStudent(‘Rose‘,‘female‘,38)
s3=LuffyStudent(‘Jack‘,‘male‘,78)

stu1=LuffyStudent(‘王二丫‘,‘女‘,18) #LuffyStudent.__init__(stu1,‘王二丫‘,‘女‘,18)

print(stu1.dict)

stu1.Name=‘李二丫‘
print(stu1.dict)
print(stu1.Name)

del stu1.Name
print(stu1.dict)

stu1.class_name=‘python开发‘
print(stu1.dict)