How to replace a nth occurrence in a string

Question

I need a simple and fast solution to replace nth occurrence (placeholder) in a string.

For example, nth question mark in sql query should be replaced with a provide

Answer 1

Validation on input parameter not done

 function str_replace_nth($search, $replace, $subject, $nth){
  $match_arr = explode($search,$subject);
  $match_arr = array_filter($match_arr);

   foreach($match_arr as $key=>$val){

      if($key == $nth-1){ // array index start with Zero
        $match_arr[$key] .=  $replace;
      }else{
        $match_arr[$key] .=  '?';
      }

   }
   return implode('',$match_arr);
}