内置对象的重写运算符 [英] Override operator of built-in object

问题描述

我想重写"dict"类的"+"运算符，以便能够轻松地合并两个字典.

I would like to override the "+" operator of the "dict" class, in order to be able to merge two dictionaries easily.

类似的东西:

def dict:
  def __add__(self,other):
    return dict(list(self.items())+list(other.items()))

通常可以重写内置类的运算符吗?

Is it possible in general to override the operator of a built-in class?

推荐答案

总之，没有:

>>> dict.__add__ = lambda x, y: None
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: can't set attributes of built-in/extension type 'dict'

您需要将dict子类化以添加运算符:

You need to subclass dict to add the operator:

import copy

class Dict(dict):

  def __add__(self, other):
    ret = copy.copy(self)
    ret.update(other)
    return ret

d1 = Dict({1: 2, 3: 4})
d2 = Dict({3: 10, 4: 20})
print(d1 + d2)

就我个人而言，我不会打扰，只是拥有一个免费的功能即可.

Personally, I wouldn't bother and would just have a free function for doing that.

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