What is the data structure you want to end up with? Do you want a single hash with all of the items as keys (a unique list of all items in your file)? If so, then it's a lot easier than that. 
use strict;
use warnings;

my $datafile = 'data.txt';
open( my $fh, $datafile )
    or die "Cannot open '$datafile' for reading: $!\n";

my %items;
while ( defined( my $line = <$fh> ) )
{
    chomp( $line );
    $line =~ s/[\r\n]*$//;

    my @values = split /--/, $line;
    @items{ @values } = undef;
}

close $fh;

# At this point, you have %items, which is a lookup table.

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Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

In reply to Re: Generating Hashes from arrays of arbitrary size by dragonchild
in thread Generating Hashes from arrays of arbitrary size by Anonymous Monk

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