[Python-Dev] List insert at index that is well out of range (original) (raw)

Tal Einat taleinat at gmail.com
Mon Sep 15 13:31:22 CEST 2014

On Mon, Sep 15, 2014 at 6:18 AM, Harish Tech <technews.full at gmail.com> wrote:

I had a list

a = [1, 2, 3] when I did a.insert(100, 100) [1, 2, 3, 100] as list was originally of size 4 and I was trying to insert value at index 100 , it behaved like append instead of throwing any errors as I was trying to insert in an index that did not even existed .

Should it not throw IndexError: list assignment index out of range exception as it throws when I attempt doing a[100] = 100 Question : 1. Any idea Why has it been designed to silently handle this instead of informing the user with an exception ? Personal Opinion : Lets see how other dynamic languages behave in such a situation : Ruby : > a = [1, 2] > a[100] = 100 > a => [1, 2, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, 100] The way ruby handles this is pretty clear and sounds meaningful (and this is how I expected to behave and it behaved as per my expectation) at least to me . So what I felt was either it should throw exception or do the way ruby handles it . Is ruby way of handling not the obvious way ? I even raised it in stackoverflow http://stackoverflow.com/questions/25840177/list-insert-at-index-that-is-well-out-of-range-behaves-like-append and got some responses .

Hello Harish,

The appropriate place to ask questions like this is python-list [1], or perhaps Stack Overflow.

If you meant to suggest changing the behavior of Python in such cases, you should first discuss this on python-list, and then post a clearly written suggestion to python-ideas [2].

This list, python-dev, is used for discussing the development of the Python language.

See the "Python Mailing Lists" page [3] for more information.

Regards,

..[1]: http://mail.python.org/mailman/listinfo/python-list ..[2]: http://mail.python.org/mailman/listinfo/python-ideas ..[3]: https://www.python.org/community/lists/

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