WearyTraveler:

Then try an array of arrays, then you can use the number as the array index:

my @AoA;
foreach (@transactions) { #there are dozens of employee numbers…
        push @{$AoA[$_]}, $_;
}
[download]

You can use index 0 for your "unregistered" array, and the natural numbers (1..n) for your arrays. (Note: you used $_ as the value and for the array choice, so I didn't change that in the snippet above. You'll want to have a separate value and index...

Even better could be a hash of arrays, then you can use something like:

my %HoA;
foreach (@transactions) {
        my ($name, $num, $value) = ...;
        $HoA{NAME} = $name;
        $HoA{NUM}  = $num;
        push @{$HoA{VALS}}, $value;
}
[download]

Read perldoc perldsc, perldoc perllol for some hints...

...roboticus

When your only tool is a hammer, all problems look like your thumb.