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;

[download]

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

In reply to Re: hashes ? by tachyon
in thread hashes ? by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.