Dirtier maybe, quicker not:

use strict;
use warnings;
use Benchmark qw(cmpthese);

my @XYZ = qw(Mary Mary Mary Mary Joe Joe Joe);

cmpthese
  (
  -1,
    {
    'GF' => sub {my %unique; @unique{@XYZ} = (); keys %unique;},
    'DW' => sub {keys %{{map {$_=>undef} @XYZ}};},
    'RJ' => sub {keys %{(grep \@{$_}{@XYZ}, {})[0]};},
    }
  );

[download]

Benchmark results:

       Rate   DW   RJ   GF
DW  71543/s   -- -62% -73%
RJ 188025/s 163%   -- -28%
GF 260808/s 265%  39%   --

[download]

Updated to include Roy Johnson's "dirtier" version

Perl is Huffman encoded by design.

In reply to Re^3: removing duplicate entries from an array by GrandFather
in thread removing duplicate entries from an array by Anonymous Monk

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