Here is a faster solution, using a hash slice: 
use Benchmark qw(:all) ;

my @a;
push @a, int (rand(10)) foreach 1..100;
my %unique;
my @awd;
cmpthese($1000, {
                  'jc' =>
                  sub { foreach my $thingy (@a) { $unique{$thingy} = 1
+; }
                        @awd = keys %unique;
                     },
                  'mk' =>
                  sub { @unique{ @a} = 1;
                        @awd = keys %unique;
                     },
                 });

[download]
The results are 
Benchmark: running jc, mk for at least 3 CPU seconds...
        jc:  3 wallclock secs ( 3.14 usr +  0.00 sys =  3.14 CPU) @ 53
+5.67/s (n=20522)
        mk:  4 wallclock secs ( 3.27 usr +  0.00 sys =  3.27 CPU) @ 14
+937.00/s (n=48844)
      Rate   jc   mk
jc  6536/s   -- -56%
mk 14937/s 129%   --

[download]
Update: $1000 is a typo should be 1000. I'll keep it as is for comparisons with the following nodes. Thanks BrowserUK and tilly!

-Mark

In reply to Re: Find unique elements in an array by kvale
in thread Find unique elements in an array by jcpunk

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