use strict;
use warnings;

my $str = 'Lumber:</td><td align="right"><b>10;';
my $str = 'Lumber:</td><td align="right"><b>10;';
my %hits;

++$hits{lc $1} if $str =~ /(lumber|clay|iron|crop):<\/td><td align="right"><b>\d+/i;

print join ', ', sort keys %hits;

##</code><code>##

lumber