反射

class Person:
    city='beijing'
    def __init__(self,name,age):
        self.name=name
        self.age=age
    def intro(self):
        return f"{self.name}" 
shark=Person("alibrother",12)
print(hasattr(Person,'city'))    判断 类的实例 shark 是否有某些属性，
print(hasattr(shark,'city'))       有则True ，否则false

getattr()获取对象属性

print(getattr(Person,'city'))
print(getattr(shark,'city'))
print(getattr(shark,'intro'))
f=getattr(shark,'name')
print(f)

setattr() 设置对象属性的值

setattr(shark,'name','leqian')  #修改对象的属性
setattr(shark,'age',20)
print(getattr(shark,'name')) 
print(getattr(shark,'age')) 

delattr() 删除属性

delattr(shark,'name')
setattr(shark,'name','alibrother')
print(getattr(shark,'name','no'))  #默认没有值，会返回no