Expand and sort print page ranges

sort_print_page_ranges.php

$in = "498,500-504,540,542-546,592,594-598,650-654,658,698,700-704,758,810,54-70";
$r = explode(",", $in );

$r2 = $r;
foreach ($r2 as $k => $v) {
	if (strpos($v, "-") !== false) {
		//var_dump($v);
		$ab = explode("-", $v);
		$r[$k] = $ab[0];
		for ($i = $ab[0]+1; $i <= $ab[1]; $i++) {
			$r[] = $i;
		}			
	}
}

asort($r);
$r = array_unique($r);
echo implode(",", $r); //54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,498,500,501,502,503,504,540,542,543,544,545,546,592,594,595,596,597,598,650,651,652,653,654,658,698,700,701,702,703,704,758,810