While using an array (as suggested by Abigail-II) is far more memory efficient a hash of hashes is a nice structure too. If you were using an array you would just access the elements like $thermos{$i_want}->[0] for the first element. All you need to do is remember if you were putting entropy or enthalpy there. Anyway here is a short hash example. As you can see it is pretty readable as we access the thermos properties by name rather than number. For small arrays of properties an array is fine. As you get more properties a hash is nicer.

my @thermos  = map { "Thermos$_" } 1..10;
my @enthalpy = 11..20;
my @entropy  = 21..30;

my %thermos = map { $thermos[$_] => { enthalpy => $enthalpy[$_], entro
+py => $entropy[$_] } } 0.. $#thermos;

my $i_want = "Thermos3";

if ( exists $thermos{$i_want} ) {
    print <<STUFF;
Thermos:  $i_want
Enthalpy: $thermos{$i_want}->{enthalpy}
Entropy:  $thermos{$i_want}->{entropy}

STUFF
}
else {
    print "Don't have the thermos: $i_want!\n";
}

use Data::Dumper;
print Dumper \%thermos;
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cheers

tachyon

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