Python:运算符重载特定类型 [英] Python : Operator Overloading a specific type

问题描述

我希望能够让我的类的操作符以我定义的方式与常规类型交互.比如说，我有:

I'd like to be able to have the operator of my class interact with regular types in a way that I define. Lets say, for example, I have:

class Mynum(object):
  def __init__(self, x):
   self.x = x
  def __add__(self, other):
   return self.x + other.x

a = Mynum(1)
b = Mynum(2)

print a+b

这很好用，但现在如果我尝试这样做:

This works just fine, but now if I try to do:

print a+2

我收到一个错误，因为 int 没有名为 x 的成员.如何在类中定义 Mynum + int?这听起来像是装饰器或元类的工作，但我非常不熟悉它们的用法.这个问题看似相似，但并不完全相同.>

I get an error since an int does not have a member named x. How do I define Mynum + int in the class? This sounds like a job for decorators or metaclasses, but I'm terribly unfamiliar with their usage. This question seems similar, but not quite identical.

推荐答案

def __add__(self, other):
    if isinstance(other, self.__class__):
        return self.x + other.x
    elif isinstance(other, int):
        return self.x + other
    else:
        raise TypeError("unsupported operand type(s) for +: '{}' and '{}'").format(self.__class__, type(other))

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