This might be faster than your inner loop: 

splice @arr, $from, $to-$from+1, map 1+$_, @arr[$from..$to];

[download]

...but I haven't tested it. If we had a full runnable example, we could do some Benchmarking.

In reply to Re: Optimizing a double loop by kyle
in thread Optimizing a double loop by roibrodo

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