PHP 7 & foreach loop error?

$resourceId = '48,51';

$sectors = explode(",", $resourceId); //Prints Array ( [0] => 48 [1] => 51 ) 

foreach ($sectors as $key => $value) {
    $page = $modx->getObject('modResource', $value);
    $output = $page->get('pagetitle'); 
}

return $output;

$sectors = array(0 => 48, 1 => 51);

foreach ($sectors as $key => $value) {
    $page = $modx->getObject('modResource', $value);
    $output = $page->get('pagetitle'); 
}

return $output;

$page = $modx->getObject('modResource', (int) $value);

$sectors = explode(",", $resourceId); //Prints Array ( [0] => 48 [1] => 51 ) 

$sectors = array(0 => 48, 1 => 51);

$sectors = explode(",", $resourceId);
$sectors = array_map('intval', $sectors);