本文翻译自：what does it mean if an object is subscriptable or not?

哪些类型的对象属于“可订阅”域？

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#1楼

参考：https://stackoom.com/question/uRY/如果一个对象是可订阅的-这意味着什么

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#2楼

It basically means that the object implements the __getitem__() method. 它基本上意味着该对象实现了__getitem__()方法。 In other words, it describes objects that are "containers", meaning they contain other objects. 换句话说，它描述了作为“容器”的对象，这意味着它们包含其他对象。 This includes lists, tuples, and dictionaries. 这包括列表，元组和词典。

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#3楼

A scriptable object is an object that records the operations done to it and it can store them as a "script" which can be replayed. 可编写脚本的对象是一个记录对其执行的操作的对象，它可以将它们存储为可以重放的“脚本”。

For example, see: Application Scripting Framework 例如，请参阅： Application Scripting Framework

Now, if Alistair didn't know what he asked and really meant "subscriptable" objects (as edited by others), then (as mipadi also answered) this is the correct one: 现在，如果Alistair不知道他问的是什么并且真正意味着“可订阅的”对象（由其他人编辑），那么（正如mipadi也回答）这是正确的：

A subscriptable object is any object that implements the __getitem__ special method (think lists, dictionaries). 可订阅对象是实现__getitem__特殊方法的任何对象（思考列表，字典）。

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#4楼

Off the top of my head, the following are the only built-ins that are subscriptable: 在我的脑海中，以下是唯一可订阅的内置插件：

string:  "foobar"[3] == "b"
tuple:   (1,2,3,4)[3] == 4
list:    [1,2,3,4][3] == 4
dict:    {"a":1, "b":2, "c":3}["c"] == 3

But mipadi's answer is correct - any class that implements __getitem__ is subscriptable 但是mipadi的答案是正确的 - 任何实现__getitem__类都是可订阅的

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#5楼

I had this same issue. 我有同样的问题。 I was doing 我在做

arr = []
arr.append["HI"]

So using [ was causing error. 因此使用[导致错误。 It should be arr.append("HI") 它应该是arr.append("HI")

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#6楼

The meaning of subscript in computing is: "a symbol (notionally written as a subscript but in practice usually not) used in a program, alone or with others, to specify one of the elements of an array." 计算中下标的含义是：“一个符号（在概念上写成，但在实践中通常不是），在程序中单独使用或与其他程序一起使用，以指定数组的一个元素。”

Now, in the simple example given by @user2194711 we can see that the appending element is not able to be a part of the list because of two reasons:- 现在，在@ user2194711给出的简单示例中，我们可以看到附加元素不能成为列表的一部分，原因有两个： -

1) We are not really calling the method append; 1）我们并没有真正调用方法追加; because it needs () to call it. 因为它需要()来调用它。

2) The error is indicating that the function or method is not subscriptable; 2）错误表明该函数或方法不可订阅; means they are not indexable like a list or sequence. 意味着它们不像列表或序列那样可索引。

Now see this:- 现在看到这个： -

>>> var = "myString"
>>> def foo(): return 0
... 
>>> var[3]
't'
>>> foo[3]
Traceback (most recent call last):File "<stdin>", line 1, in <module>
TypeError: 'function' object is not subscriptable

That means there are no subscripts or say elements in function like they occur in sequences; 这意味着没有下标或说出function元素，就像它们出现在序列中一样; and we cannot access them like we do, with the help of [] . 在[]的帮助下，我们无法像我们一样访问它们。

Also; 也; as mipadi said in his answer; 正如米帕迪在回答中说的那样; It basically means that the object implements the __getitem__() method. 它基本上意味着该对象实现了__getitem__()方法。 (if it is subscriptable). （如果是可订阅的）。 Thus the error produced: 因此产生的错误：

arr.append["HI"]

TypeError: 'builtin_function_or_method' object is not subscriptable TypeError：'builtin_function_or_method'对象不可订阅