#!/usr/bin/perl -w
use strict;

use Data::Dump qw(pp);

my @all_arrays = ([1 .. 20],
                  [10 .. 30],
                  [19 .. 40],
                 );

my %unique_descriptive;

foreach my $num (map{@$_}@all_arrays)
{
   $unique_descriptive{$num}{count}++;
   push @{$unique_descriptive{$num}{values}}, $num;
}

#print pp(\%unique_descriptive);  

# example for num=10
#10 => { count => 2, "values" => [10, 10] },

my @sorted_keys = sort{ $unique_descriptive{$a}{count} <=> $unique_descriptive{$b}{count} 
                                                        or
                                                     $a <=> $b
                      }keys %unique_descriptive;

foreach my $key (@sorted_keys)
{
   printf "%2d=", $key;   #make the print out look nice
   print pp($unique_descriptive{$key}),"\n";
}

__END__

##</code><code>##

 1={ count => 1, "values" => [1] }
 2={ count => 1, "values" => [2] }
 3={ count => 1, "values" => [3] }
 4={ count => 1, "values" => [4] }
 5={ count => 1, "values" => [5] }
 6={ count => 1, "values" => [6] }
 7={ count => 1, "values" => [7] }
 8={ count => 1, "values" => [8] }
 9={ count => 1, "values" => [9] }
31={ count => 1, "values" => [31] }
32={ count => 1, "values" => [32] }
33={ count => 1, "values" => [33] }
34={ count => 1, "values" => [34] }
35={ count => 1, "values" => [35] }
36={ count => 1, "values" => [36] }
37={ count => 1, "values" => [37] }
38={ count => 1, "values" => [38] }
39={ count => 1, "values" => [39] }
40={ count => 1, "values" => [40] }
10={ count => 2, "values" => [10, 10] }
11={ count => 2, "values" => [11, 11] }
12={ count => 2, "values" => [12, 12] }
13={ count => 2, "values" => [13, 13] }
14={ count => 2, "values" => [14, 14] }
15={ count => 2, "values" => [15, 15] }
16={ count => 2, "values" => [16, 16] }
17={ count => 2, "values" => [17, 17] }
18={ count => 2, "values" => [18, 18] }
21={ count => 2, "values" => [21, 21] }
22={ count => 2, "values" => [22, 22] }
23={ count => 2, "values" => [23, 23] }
24={ count => 2, "values" => [24, 24] }
25={ count => 2, "values" => [25, 25] }
26={ count => 2, "values" => [26, 26] }
27={ count => 2, "values" => [27, 27] }
28={ count => 2, "values" => [28, 28] }
29={ count => 2, "values" => [29, 29] }
30={ count => 2, "values" => [30, 30] }
19={ count => 3, "values" => [19, 19, 19] }
20={ count => 3, "values" => [20, 20, 20] }

##</code><code>##

#!/usr/bin/perl -w
use strict;
use 5.010;  #for new //= operator

use Data::Dump qw(pp);

my @all_arrays = ([1 .. 20],
                  [10 .. 30],
                  [19 .. 40],
                 );

my @unique_descriptive;

foreach my $num (map{@$_}@all_arrays)
{
   $unique_descriptive[$num]++;  #simple peg counter
}

# add a column to the 2-D array with row number
# undef counts as freq of zero, the //=0 does that

my $i=0;
@unique_descriptive = map{[$i++,$_//=0]}@unique_descriptive;

@unique_descriptive = sort{ $a->[1] <=> $b->[1]  #by freq
                                    or
                            $a->[0] <=> $b->[0]  #by peg number
                          }@unique_descriptive;

foreach my $row (@unique_descriptive)
{
   print "num = $row->[0] \tfreq=$row->[1]\n" if ($row->[1] > 0);
}

##</code><code>##

__END__
num = 1     freq=1
num = 2     freq=1
num = 3     freq=1
num = 4     freq=1
num = 5     freq=1
num = 6     freq=1
num = 7     freq=1
num = 8     freq=1
num = 9     freq=1
num = 31    freq=1
num = 32    freq=1
num = 33    freq=1
num = 34    freq=1
num = 35    freq=1
num = 36    freq=1
num = 37    freq=1
num = 38    freq=1
num = 39    freq=1
num = 40    freq=1
num = 10    freq=2
num = 11    freq=2
num = 12    freq=2
num = 13    freq=2
num = 14    freq=2
num = 15    freq=2
num = 16    freq=2
num = 17    freq=2
num = 18    freq=2
num = 21    freq=2
num = 22    freq=2
num = 23    freq=2
num = 24    freq=2
num = 25    freq=2
num = 26    freq=2
num = 27    freq=2
num = 28    freq=2
num = 29    freq=2
num = 30    freq=2
num = 19    freq=3
num = 20    freq=3