PHP program to generate an array with a range taken from a string

<?php

function string_range($str1) 

{

  preg_match_all("/([0-9]{1,2})-?([0-9]{0,2}) ?,?;?/", $str1, $a);

  $x = array ();

  foreach ($a[1] as $k => $v) 

  {

    $x  = array_merge ($x, range ($v, (empty($a[2][$k])?$v:$a[2][$k])));

  }

  return ($x);

}

$test_string = '1-2 18-20 9-11';

print_r(string_range($test_string));

?>

@php_program