$users_in_range 配列のユーザー ID を内破しようとしています
<?PHP
$users_in_range = users_in_range($lat, $long, 500, true);
// implode users into mysql friendly list
$comma_separated = implode(",", $users_in_range);
echo $comma_separated;
// this is just for output while debugging
foreach ($users_in_range as $userid => $miles_away) {
echo "UserID=<b>$userid</b> is <b>$miles_away</b> miles away from me.<br />";
}
?>