在Python中使用带有多个参数的__add__运算符 [英] Using __add__ operator with multiple arguments in Python

问题描述

我试图添加带有数字的类对象，但是我对如何添加带有两个数字的类对象感到困惑.例如，这是我假设的 add 类方法:

I am trying to add a class object with a number, but I'm confused on how to go about adding a class object with two numbers. For example, this is my hypothetical add class method:

class A:
    def __add__(self, b):
        return something

到目前为止，我知道如何添加此内容:

I know how to add this so far:

object = A()
print(object + 1)

但是，如果我想这样添加它怎么办?

But, what if I want to add it like this?

object = A()
print(object + 1 + 2)

我应该将* args用于 add 类方法吗?

Should I use *args for the add class method?

推荐答案

不，您不能使用多个参数. Python分别执行每个+运算符，这两个+运算符是不同的表达式.

No, you can't use multiple arguments. Python executes each + operator separately, the two + operators are distinct expressions.

在您的示例中，object + 1 + 2确实是(object + 1) + 2.如果(object + 1)生成的对象具有__add__方法，则Python将为第二个运算符调用该方法.

For your example, object + 1 + 2 really is (object + 1) + 2. If (object + 1) produces an object that has an __add__ method, then Python will call that method for the second operator.

例如，您可以在此处返回A的另一个实例:

You could, for example, return another instance of A here:

>>> class A:
...     def __init__(self, val):
...         self.val = val
...     def __repr__(self):
...         return f'<A({self.val})>'
...     def __add__(self, other):
...         print(f'Summing {self} + {other}')
...         return A(self.val + other)
...
>>> A(42) + 10
Summing A(42) + 10
<A(52)>
>>> A(42) + 10 + 100
Summing A(42) + 10
Summing A(52) + 100
<A(152)>

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