如何在Python中覆盖[]运算符? [英] How to override the [] operator in Python?

问题描述

为Python中的类覆盖[]运算符(下标表示法)的方法的名称是什么?

What is the name of the method to override the [] operator (subscript notation) for a class in Python?

推荐答案

您需要使用

You need to use the __getitem__ method.

class MyClass:
    def __getitem__(self, key):
        return key * 2

myobj = MyClass()
myobj[3] #Output: 6

如果要设置值，则需要实现 __setitem__方法，否则会发生这种情况:

And if you're going to be setting values you'll need to implement the __setitem__ method too, otherwise this will happen:

>>> myobj[5] = 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: MyClass instance has no attribute '__setitem__'

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