Python学习笔记（二十一）——小甲鱼第四十二讲

0、工厂函数是类对象，调用它们的时候是创建一个相应的实例对象

 

1、a+b时会根据a的__add__魔法方法进行加法操作

 

2、当类的属性名和方法名相同时属性名会覆盖方法名

 

 

4、鸭子风格

 

 

0、

>>>

class Nstr(str):

    def __sub__(self,other):

        return self.replace(other,'')

运行结果

>>> a = Nstr('I love you iiiiiii')

>>> b = Nstr('i')

>>> a - b

'I love you '

 

1、

class Nstr(str):

    def __lshift__(self,other):

        return self[other:] + self[:other]

    def __rshift__(self,other):

        return self[:-other] + self[-other:]

 

运行结果

>>> a = Nstr('I love you')

>>> a << 3

'ove youI l'

>>> a >> 3

'I love you'

 

2、

class Nstr():

    def __init__(self,arg=''):

        if isinstance(arg,str):

            self.total = 0

            for each in arg:

                self.total += ord(each)

        else:

            print('参数错误')

 

           

    def __add__(self,other):

        return self.total + other.total

 

    def __sub__(self,other):

        return self.total - other.total

   

    def __mul__(self,other):

        return self.total * other.total

   

    def __floordiv__(self,other):

        return self.total // other.total

 

运行结果

>>> a = Nstr('love')

>>> b = Nstr('happy')

>>> a + b

984

>>> a - b

-108

>>> a * b

239148

>>> a // b

0

>>>