#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my @data = ( qw/ 2 3 3 3 5 7 8 12 32 44 55 12 3 23 43 33 1 4 25 43 42 1 4 5 3 3 3 /);

my $mode = mode( { NUMBERS => \@data } );

sub mode {
    my %opt = %{ shift @_ };
    print Dumper \%opt;
}

__END__

##</code><code>##

$VAR1 = {
          'NUMBERS' => [
                         '2',
                         '3',
                         '3',
                         '3',
                         '5',
                         '7',
                         '8',
                         '12',
                         '32',
                         '44',
                         '55',
                         '12',
                         '3',
                         '23',
                         '43',
                         '33',
                         '1',
                         '4',
                         '25',
                         '43',
                         '42',
                         '1',
                         '4',
                         '5',
                         '3',
                         '3',
                         '3'
                       ]
        };

##</code><code>##

#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my @data = ( qw/ 2 3 3 3 5 7 8 12 32 44 55 12 3 23 43 33 1 4 25 43 42 1 4 5 3 3 3 /);

my $mode = mode( { NUMBERS => \@data } );

sub mode {
      my %opt = %{ shift @_ };
      while (my ($key, $val) = each %opt) {
            print "k:$key v:$val\n";
      }   
}

__END__

##</code><code>##

k:NUMBERS v:ARRAY(0x7fef9a82a168)

##</code><code>##

my @i_numbers = $opt{NUMBERS};

##</code><code>##

my $i_numbers = $opt{NUMBERS}; # $i_numbers is an arrayref

# or

my @i_numbers = @{ $opt{NUMBERS} }; # dereference the arrayref as you get it from the hash

##</code><code>##

#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my @data = ( qw/ 2 3 3 3 5 7 8 12 32 44 55 12 3 23 43 33 1 4 25 43 42 1 4 5 3 3 3 /);

my $mode = mode( { 'NUMBERS' => \@data } ); # I quote hash keys so I don't 
                                            # mistake them for constants
                                            # and use them as barewords.
print "Mode : $mode\n";

sub mode {
      my %count = (); 
      my %opt = %{ shift @_ };
      for ( @{ $opt{'NUMBERS'} } ) {  # no need to sort the array here
          $count{ $_ }++;
      }   
      my @key = sort{ $count{$b} <=> $count{$a} } keys %count;
      return $key[0];
}

__END__