[Python-Dev] List insert at index that is well out of range - behaves like append

[Harish Tech]

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 .
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