I think that  last; bit is messing your results.. Do you really want to break the moment you found a match? In this case, you'll find yourself for half of the array, and your neighbour for the other half - sounds confusing to me..

Also, from your example it's not clear what you are counting - if we had a couple of rows like "I1 TTTT", and "I2 TTAT", currently you'd increase {TTTT}{I1}, when you see "I2 TTAT" - is that what you want? Perhaps you ought to be increasing {TTAT}{I1}, ie {$item2}{$tid}, or possibly {TTTT}{I2}?

Last question, can you have repeated elements in your array, and if so, what should be the behaviour?

Ok, now I'll suggest a rewrite, based on my assumptions what this should be doing, but don't be too disappointed if they were wrong. I prefer returning a new ref out of the sub, rather than passing one in: 

my $transaction_map_mismatch = get_trans_array_mismatch(\@to_proc,$d);

print Dumper $transaction_map_mismatch;

#--------Sub------------
sub get_trans_array_mismatch {
    my $transaction_array   = shift;
    my $d                   = shift;

    my $trans_map_ref = {map {(split)[1]=>{}} @$transaction_array};

    foreach (@{$transaction_array}) {
        my ($tid, $item) = split;

        foreach (grep {hd($item,$_) <= $d} keys %$trans_map_ref) {
            $trans_map_ref->{$_}{$tid}++;
        }
    }
    return $trans_map_ref;
}

[download]
Not efficient, in the slightest, but I think it does the job, or at least matches your desired output

In reply to Re: Element Count from Array to HoH by ivancho
in thread Element Count from Array to HoH by monkfan

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