note frozenwithjoy <p>A few things to help you out:</p> <ul> <li>Your code doesn't compile, because there is a semi-colon missing at the end of <c>@array = $form =~ /[A-Z][a-z]?|\d+/ig</c> <li>You assign the result of <c>getweight()</c>, which is in list context, to a scalar. As a result, <c>$weight</c> just equals 6 (the number of elements in the array). If I were you, I'd skip the subroutine and array and make weight a hash directly from the get-go: </ul> <c> #!/usr/bin/env perl use strict; use warnings; use feature 'say'; use Data::Printer; print "Enter a chemical formula: "; chomp( my $form = <> ); my %weight = $form =~ /[A-Z][a-z]?|\d+/ig; p %weight; __END__ Enter a chemical formula: C12H22O11 { C 12, H 22, O 11 } </c> 1006165 1006165