fine_that_shit.php

<?php

$find_me = 'fds';

$s1 = 'asd fds gfd hg';
$s2 = 'yj5 werg 3g rth';

$a1    = explode(' ', $s1);
$a2    = explode(' ', $s2);
$token = array_search($find_me, $a1);

if ($token !== FALSE) {

    echo 'Ahhhh yeah mother fucker! The token is '.$token.' and the value for that token in string 2 is: '.$a2[$token]."\n";

} else {

    echo $find_me.' was not found in string 1.';

}