PHP implements a method of inserting an array without affecting the original order, PHP array_PHP tutorial

function array_intsort($array,$num) {
 $array_right = $array_left = array();
 $length = count($array);
 if ($num < $array[0]) {
  array_unshift($array,$num);
  return $array;
 } else {
  for($i=0; $i < $length; $i++) {
   if ($i + 1 < $length) {
    if ($array[$i] < $num && $num < $array[$i+1]) {
     $array_right = array_slice($array,$i + 1);    
     $array_left = array_slice($array,0,$i);
     $array_left[] = $num;
     break;
    }
   } else {
    $array_left = $array;
    $array_left[] = $num;
   }
  }
  return array_merge($array_left,$array_right);
 }
}