[Python-Dev] unsubscriptable vs object does not support indexing (original) (raw)

Steven D'Aprano steve at pearwood.info
Thu Sep 24 01:33:08 CEST 2009

On Thu, 24 Sep 2009 06:47:41 am Dino Viehland wrote:

> So I am +1 on unified the message and +1 on using the "does not > support indexing" one.

I'd be +1 on the unified message as well - but it seems what that message should be may be contentious (and quite a bike shed discussion at that). The bug David linked to (http://bugs.python.org/issue5760) has a preference for subscript because that's what's used elsewhere in the language.

For what it's worth, "unsubscriptable object" seems to me to be mysterious to many newbies, and even a few non-newbies. It took me something like seven years of coding to stop reading it as "unscriptable object", and I'm sure I won't be the only one.

As far as I can see, in practice, people talk about obj[i] as the item at index i, not the item at subscript i -- the term "subscript" in this context seems to be rare to non-existent except for the error message.

-- Steven D'Aprano

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