<?php 
$arr = array('superman','gossipgirl',...); 
$text = 'arbitary stuff here...'; 
$occurence_array = array(); 


foreach ($arr as $value) { 
    $first = strpos($text, $value); 
    $last = strrpos($text, $value); 
    $occurence_array[$value] = array($first,$last); 
} 
?>