Create notification of just submitted fields, no blanks

<?php
// create custom notification which includes only submitted fields
// change the 487 here to your form ID
add_filter('gform_notification_487', 'custom_format', 10, 3);
function custom_format($notification, $form, $entry) {
        // be sure this is the name of your notification, change it if not
    if($notification['name'] == 'Admin Notification'){
        $notification['message_format'] = 'html';
        $notification['message'] = '<table width="600" border="0">';
        foreach ($entry as $key => $value) {
            // only output form fields, not entry meta
            if (is_numeric($key)) {
                // trim whitespace from $value
                $value = trim($value);
                // if the value is not empty for this field, add it to the notification
                if(!empty($value)) {
                    // get the field information from the form
                    $field = RGFormsModel::get_field($form, $key);
                    // add a line to the notification
                    $notification['message'] .= "<tr><td>" . $field['label'] ."</td><td>$value</td></tr>";
                }
            }
        }
        $notification['message'] .= '</table>';
    }
    // return the notification either way
    return $notification;
}