I'm looking for a collection that offers list semantics, but also allows array semantics. Say I have a list with the following items:

apple orange carrot pear 

then my container array would:

container[0] == apple 
container[1] == orangle 
container[2] == carrot 

Then say I delete the orange element:

container[0] == apple 
container[1] == carrot 

I don't particularly care if sort order is maintained, I'd just like the array values to function as accelerators to the list items, and I want to collapse gaps in the array without having to do an explicit resizing.