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  • py.面向对象,属性,类方法,静态方法,反射

    例一:BMI指数(bmi是计算而来的,
    # 但很明显它听起来像是一个属性而非方法,如果我们将其做成一个属性,更便于理解)
    #
    # 成人的BMI数值:
    # 过轻:低于18.5
    # 正常:18.5-23.9
    # 过重:24-27
    # 肥胖:28-32
    # 非常肥胖, 高于32
    #   体质指数(BMI)=体重(kg)÷身高^2(m)
    #   EX:70kg÷(1.75×1.75)=22.86

    # 1,初识属性:
    # class A:
    # def __init__(self, name, weight, height):
    # self.name = name
    # self.__weight = weight
    # self.__height = height
    #
    # @property # 属性
    # def bmi(self):
    # return self.__weight / self.__height ** 2
    #
    #
    #
    # ly = A('女司机', 54, 1.6)
    # print(ly.bmi)
    #
    # # 属性:将方法 伪装 成属性,虽然在代码层面上没有任何高深之处,
    # # 但是让其看起来更合理.
    # # 2,属性改,和删除.
    #
    # class Mes:
    # def __init__(self, name, age,password):
    # self.__name = name
    # self.__age = age
    # self.__password = password
    #
    # @property
    # def password(self):
    # '''对密码加密'''
    # self.__password = hash(self.__password + '旭哥')
    # return self.__password
    #
    # @password.setter
    # def password(self,new_password):
    # if type(new_password) is str:
    # self.__password = new_password
    # else:
    # print('请输入字符串类型')
    # @password.deleter
    # def password(self):
    # print(6666)
    # # p1 = Mes('婉容', 18)
    # # p1.name = '婉容蓉'
    # # print(p1.name)
    # # print(p1.name)
    # p1 = Mes('婉容', 18,'hao123')
    # # print(p1.password)
    # 之前对属性的更改
    # p1.name = 'alex'
    # p1.password = '123456'
    # print(p1.password)
    # del p1.password
    # print(p1.password)
    # 第一步,对属性进行改操作,自动执行 被这个@password.setter装饰器装饰的方法
    # 第二步,将新值传给这个被@password.setter装饰器装饰的方法里面,当做参数.

    # property ***
    # @password.setter *
    # @password.deleter
    #
    # class Mes:
    # def __init__(self, name, age,password):
    # self.name = name
    # self.__age = age
    # self.__password = password
    #
    # @property
    # def password(self):
    # return self.__password
    #
    # @password.setter
    # def password(self,new_password):
    # self.__password = new_password
    #
    # @password.deleter
    # def password(self):
    # del self.__password
    #
    # p1 = Mes('婉容', 18, 'hao123')
    # p1.name = 'alex'
    # print(p1.name)
    # print(p1.password)
    # p1.password = '123456' # 这是是行代码,没有真正的改.
    # print(p1.password)
    # del p1.password
    # print(p1.password)

    # 商品类 封装商品名,商品原价, 商品折扣 定义一个方法,计算商品现价.

    # class Goods:
    # def __init__(self,name,original_price,discount):
    # self.name = name
    # self.__original_price = original_price
    # self.__discount = discount
    #
    # @property
    # def price(self):
    # return self.__original_price * self.__discount
    #
    # @property
    # def original_price(self):
    # return self.__original_price
    #
    # @original_price.setter
    # def original_price(self,new_original_price):
    # self.__original_price = new_original_price
    #
    # apple = Goods('苹果',5,0.95)
    # # print(apple.price)
    # apple.original_price = 10
    # print(apple.price)


    # 类方法,静态方法

    class A:
    __name = 'alex'
    def func(self):
    print(self,'in func')

    @classmethod # 类方法
    def func1(cls):
    print(cls, 'in func1')

    def change(self,new_name):
    A.__name = new_name
    return A.__name
    @classmethod
    def change(cls,new_name):
    A.__name = new_name
    return A.__name

    a1 = A()
    a1.func()
    A.func(a1)

    # 类名去调用类方法,自动将类的空间传给类方法中的cls
    # 对象如果调用类方法,自动将类空间传给类中的cls
    A.func1()
    a1.func1()
    # 什么情况下使用类方法?
    # 直接让类去操作类中的方法,没有必要创建对象在操作的时候,用类方法.
    # a2 = A()
    # print(a2.change('wusir'))
    # # print(A.change(111,'wusir'))
    # print(A.change('wusir'))
    # 静态方法

    # class A:
    # __name = 'alex'
    # def func(self):
    # print(self,'in func')
    #
    # @classmethod # 类方法
    # def func1(cls):
    # print(cls, 'in func1')
    #
    #
    # @staticmethod # 静态方法
    # def login(username,password):
    # print('登录成功...')
    #
    # A.login('alex', '123')

    # 静态方法:在类中定义一个静态方法,无需传入你的类空间,对象空间,可以当成普通函数去用.


    反射"""""""
     反射
    # 非常非常非常非常重要的方法.
    # 通过 字符串 操作一个空间 (对象).
    # getattr()
    # hasattr()
    # setattr()
    # delattr()

    # 1,实例化一个对象去研究
    # class A:
    # country = 'China'
    #
    # def __init__(self, name, age):
    # self.name = name
    # self.age = age
    #
    #
    # a1 = A('alex', 1000)
    # print(a1.name)
    # print(getattr(a1,'name1')) 从对象中得到这个属性对应的值
    # print(hasattr(a1,'age')) 判断此对象中,有没有这个属性
    # setattr(a1,'sex','男')
    # setattr(a1,'name','wusir')
    # print(getattr(a1,'name'))
    # print(getattr(a1,'sex')) # 对一个对象设置属性
    # delattr(a1,'name') # 对一个对象属性删除
    # print(getattr(a1,'name'))

    # if hasattr(a1,'name1'):
    # getattr(a1,'name1')
    # else:
    # print('没有...')


    # 2,类中去研究.
    # class A:
    # country = 'China'
    # job = 'student'
    #
    # def __init__(self, name, age):
    # self.name = name
    # self.age = age
    # def func(self):
    # print('in func')
    # print(getattr(A,'country1',False))
    # if getattr(A,'country1',False):
    # content = input('>>>').strip() # country
    # print(A.content) #(A.'country')

    # name = '1 + 2'
    # name2 = 'name'
    # print(eval(name2))


    # print(A.country)
    # print(A.content)
    # print(eval('1+ 2'))

    # content = input('>>>').strip() # 'country'
    # 你拿到的是一个字符串类型,然后你又想对这个类进行操作
    # if hasattr(A,content):
    # print(getattr(A,content))

    # print(getattr(A,'job1','没有此值'))
    # print(getattr(A,'func'))
    # getattr(A,'func')(11)

    # 3,其他模块去研究.
    import oldboy
    print(oldboy.B.name_list)

    bobj = getattr(oldboy,'B')
    print(getattr(bobj,'name_list'))
    #
    print(getattr(oldboy.B,'name_list'))

    print(getattr(oldboy.B,'add')(3,4))
    print(getattr(oldboy,'login')('alex','123'))
    # def func():
    # pass
    # print(func())


    # 4,本模块(本文件)去研究.
    # import sys
    # def login():
    # print(55)
    #
    # def func3():
    # print(333)
    #
    # # content = input(">>>")
    # # print(content()) # 这样错的
    # print(sys.modules[__name__])
    # getattr(sys.modules[__name__],'login')()
    "
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  • 原文地址:https://www.cnblogs.com/cz007/p/9265973.html
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