Stop duplicate results from FFDB in Perl

[edatz]

Hi, I'm picking the field the way I want from a flatfile database in Perl.

However I do not know how to get rid of the duplicates.

use strict;
use warnings;
use CGI::Carp qw(warningsToBrowser fatalsToBrowser);
print "Content-type: text/html\n\n";

foreach my $rec (<DATA>) {
 my @fd=split /\|/, "$rec";
 my $dt=$fd[3];
 my @tmm = ('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
 my $tyr = substr $dt,0,+4; # year  (nums 1-4)
 my $tmo = substr $dt,4,+2; # month (nums 5&6)
 $tmo=$tmo-1; # compensate for 0 in month
 my $dts = "$tmm[$tmo] $tyr";

 print qq ~<a href="#">$dts</a><br>~;   # How do I stop the duplicates?

}
exit(0);

=holdResults
This is how it shows with the duplicates
Jan 2012
Jan 2012
Dec 2011
Dec 2011
Nov 2010

It should show
Jan 2012
Dec 2011
Nov 2010
=cut

__DATA__
5|EEE|eeeeee|201201|
4|DDD|dddddd|201201|
3|CCC|cccccc|201112|
2|BBB|bbbbbb|201112|
1|AAA|aaaaaa|201011|

We did try something about repeats a year or so back,

my $dts{$_}++; next if $dts{$_} > 1;

but I think there's an error in it (not sure how to use it anyways).

Hope someone can help, Many Thanks.

[Sixtease]

my %occurred;
foreach my $rec (<DATA>) {
 my @fd=split /\|/, "$rec";
 my $dt=$fd[3];
 my @tmm = ('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
 my $tyr = substr $dt,0,+4; # year  (nums 1-4)
 my $tmo = substr $dt,4,+2; # month (nums 5&6)
 $tmo=$tmo-1; # compensate for 0 in month
 my $dts = "$tmm[$tmo] $tyr";

 next if $occurred{$dts};
 $occurred{$dts} = 1;

 print qq ~<a href="#">$dts</a><br>~;   # How do I stop the duplicates?

}

[edatz]

Hi Sixtease, right I see. The hash.

After I posted this I wondered about hashes but got nowhere, the line

$occurred{$dts} = 1;

is something I didn't realize.

Does the stuff.
Thank you very much.

[edatz]

Just did a test with a file of mock blog entries (size 2.5mb) and this code handled it with ease.

It's used for my blog archive drop down and should more than suffice for the next few years.

Thanks again.