Brian Candler wrote:
> Charles Hixson wrote in post #1084111:
>> I'm trying to figure out a good way to extend an Array, when the items
>> may not be added in index order, and I don't know the final highest
>> index.  Does anyone have any suggestions?
> This happens automatically.
>
>>> a = [:foo, :bar]
> =>  [:foo, :bar]
>>> a[10] = :baz
> =>  :baz
>>> a
> =>  [:foo, :bar, nil, nil, nil, nil, nil, nil, nil, nil, :baz]
>
> As others have said: using a Hash may be more efficient, if there are
> large gaps - but then you may have to sort the keys if you want to
> iterate over it in order. It depends on your use case.
>
Rereading your post, I see I missed a crucial part of it:

a[10] = :baz
=>  a == [:foo, :bar, nil, nil, nil, nil, nil, nil, nil, nil, :baz]

And THAT was the part I really needed to get the first time.