You can get away with $keys[$index-1] and $keys[($index+1) % @keys] because the first array access, should it be negative, will access from the back of the array, and the last array access is guaranteed to be in range. So no extra checking is needed for boundaries.

-Ted

In reply to Optimized Previous and Next Accessors by tedv
in thread Finding Previous and Next in a HASH by skazat

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