You don't have to; you can continue using a HoA as well, replacing (say) ->{'iEvalue'} with ->[0] and ->{'range_b'} with ->1. If you did this, the result for your sample data would be:

$VAR1 = {
          'I5EU07' => [
                        '3.4e-137',
                        '232-824'
                      ]
        };
[download]

It's pretty much the same thing, but I personally prefer using hashes over arrays unless my "keys" are naturally numeric; you have to type a bit more, but your code'll be self-documenting. It's always obvious what ->{'iEvalue'} means, even years later when you're reading someone else's code, but the same is not true for ->[0].