ElggBatch::valid PHP Method

    public function valid()
    {
        if (!is_array($this->results)) {
            return false;
        }
        $key = key($this->results);
        return $key !== null && $key !== false;
    }

<?php

if (subsite_manager_on_subsite()) {
    register_error(elgg_echo("subsite_manager:action:error:on_subsite"));
    forward(REFERER);
}
// this could take a while
set_time_limit(0);
$subsite_options = array("type" => "site", "subtype" => Subsite::SUBTYPE, "limit" => false, "joins" => array("JOIN " . get_config("dbprefix") . "sites_entity se ON se.guid = e.guid"), "order_by" => "se.name ASC");
$batch = new ElggBatch("elgg_get_entities", $subsite_options);
$batch->rewind();
if ($batch->valid()) {
    // create a temp file for storage
    $fh = tmpfile();
    $headers = array("name", "url", "site time created (unix)", "site time created (YYYY-MM-DD HH:MM:SS)", "member count", "last activity (unix)", "last activity (YYYY-MM-DD HH:MM:SS)", "admin name", "admin email", "admin profile");
    fwrite($fh, "\"" . implode("\";\"", $headers) . "\"" . PHP_EOL);
    foreach ($batch as $subsite) {
        $member_count = $subsite->getMembers(array("count" => true));
        $last_activity = subsite_manager_get_subsite_last_activity($subsite->getGUID());
        $last_activity_readable = date("Y-m-d G:i:s", $last_activity);
        $admin_guids = $subsite->getAdminGuids();
        $output = array($subsite->name, $subsite->url, $subsite->time_created, date("Y-m-d G:i:s", $subsite->time_created), $member_count, $last_activity, $last_activity_readable);
        if (!empty($admin_guids)) {
            foreach ($admin_guids as $admin_guid) {
                $admin = get_user($admin_guid);
                if (!empty($admin)) {
                    $admin_output = $output;
                    $admin_output[] = $admin->name;
                    $admin_output[] = $admin->email;
                    $admin_output[] = $admin->getURL();
                    // write to file