PHP: equivalent of MySQL's function SUBSTRING_INDEX ?

Question

I love the SUBSTRING_INDEX function in MySQL, especially because you can use negative indexes to start searching from the right side of the string.

Is there an equiv

Answer 1

I was curious and tested another method using a preg/match setup, then refactored it to allow for any number of delimiters/count. I added in the count check the other example was using, but I would probably also recommend some kind of sanitization of the delimiter field.

function substring_index($subject, $delim, $count){
  if($count < 0){
    $notRe = '[^\\'.$delim.']*';
    $elem = array();
    for($x=1;$x<=$count;$x++){
      array_push($elem,$notRe);
    }
    $re = '/^('.implode('\\'.$delim,$elem).')/';
    preg_match($re, $subject,$m);
    if(count($m) == 2) {
      return $m[1];
    }
  }
}