If your initial array is already "huge", then you will likely run out of ram long before you manage to generate your HoHoA.

If your array has

1. 1000 elements, creating this HoHoA will require ~ 100 MB;
2. for 2000, ~ 400 MB
3. for 4000, ~ 1.2 GB

Which approximates to O(n²)* memory consumption, so depending upon what you classify as a huge array, you are likely to run out of memory long before performance will ever be a concern.

*Update: ² not ³. Thanks radion.

In most cases, once you get beyond fairly small sized arrays, for/foreach will outperform map as the latter needs to allocate substantial amounts of memory in order to build a temporary list to accomodate the array, whereas the former iterates the array without requiring to allocate extra space.