my @array;
        push @array, "one";
        push @array, "two";
        push @array, "three";
        psuh @array, "four";
        my $k=0;
        my @combos;
        for(combinations(@array))
        {
                $combos[$k] = join("|",@$_);
                $k++;
        }

sub combinations {
  return [] unless @_;
  my $first = shift;
  my @rest = combinations(@_);
  return @rest, map { [$first, @$_] } @rest;
}

##</code><code>##

$VAR1 = [
          '',
          'four',
          'three',
          'three|four',
          'two',
          'two|four',
          'two|three',
          'two|three|four',
          'one',
          'one|four',
          'one|three',
          'one|three|four',
          'one|two',
          'one|two|four',
          'one|two|three',
          'one|two|three|four'
        ];

##</code><code>##

$VAR1 = [
          'one|two|three|four'
          'two|three|four',
          'one|three|four',
          'one|two|three',
          'one|two|four',
          'three|four',
          'two|three',
          'one|three',
          'two|four',
          'one|four',
          'one|two',
          'three',
          'four',
          'two',
          'one',
	  ''          
        ];