use strict;

my @array = (1, 2, 3, 5, 7, 8, 9, 11, 14);
my @new_array;

# If it works: @new_array = ('1-3', 5, '7-9', 11, 14);

my $x = 0;
my $y = 0;

while ($x <= $#array) {
	$new_array[$y] = $array[$x];

	if ($array[$x] + 1 == $array[$x+1]) {
		while ($array[$x] + 1 == $array[$x+1]) { $x++ }
		$new_array[$y] .= "-$array[$x]";
	}

	$x++;
	$y++;
}

print join(', ', @new_array), "\n";