$c5 is just $a2[$i+4] so the corresponding key is just $index[$i+4], right?

Update: Since the only thing you ever print out is $c5, you can 

$c4=$a2[$i+3];
$c5=$a2[$i+4];
$i5 = $index[$i+4]; # This is new
$c6=$a2[$i+5];

[download]
and then your output might be: 
{
 $peak=$c5;
 print "$i5 = $peak\n";
}

[download]
Caution: Contents may have been coded under pressure.

In reply to Re: Accessing keys through values by Roy Johnson
in thread Accessing keys through values by cybersmithuk

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