python 动态添加属性及方法及“__slots__的作用”
1.动态添加属性
class Person(object): def __init__(self, newName, newAge): self.name = newName self.age = newAge laowang = Person("老王", 10000) print(laowang.name) print(laowang.age) laowang.addr = "北京...." print(laowang.addr) laozhao = Person("老赵", 18) #print(laozhao.addr) Person.num = 100 print(laowang.num) print(laozhao.num)
2.动态添加方法
#!/usr/local/bin/python3 # -*- coding:utf-8 -*- import types class Person(object): def __init__(self,name,age): self.name = name self.age = age def eat(self): print('---%s正在吃----' %self.name) p1 = Person('p1',100) #p1.eat = eat #右边的eat指向eat 函数内存地址,赋值给p1对象的eat属性 #p1.eat() #这样调用会报错 ########那样怎么添加呢???? ##在开头导入模块types,再用如下方法: p1.eat = types.MethodType(eat,p1) p1.eat()
#####用法#################
>>> import types
>>> help(types.MethodType)
Help on class method in module builtins:
class method(object)
| method(function, instance)
##############__slots__ 的作用################
In [18]: class Person(object): ...: __slots__ = ("name","age") #####只能添加元祖中定义了的属性,不在元组内的不行 ...: In [19]: p1 = Person() In [20]: p1.name = 'haha' In [21]: p1.addr = 'beijing' --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-21-be5d7a142f3a> in <module>() ----> 1 p1.addr = 'beijing' AttributeError: 'Person' object has no attribute 'addr'