Doctrine2: Get Random Entity

gistfile1.php

<?php

public function getRandomNewsArticles($n, $ignoredId = null) {
    $idArray =
        $this->em
            ->createQueryBuilder('na')
            ->select('na.id')
            ->add('from', '\App\Entity\NewsArticle na')
            ->getQuery()
            ->getScalarResult();

    $randomKeys = array_rand($idArray, $n);

    $randomKeys = array_map(function($key) use ($idArray) {
        return $idArray[$key]['id'];
    }, $randomKeys);

    if ($ignoredId !== null) {
        unset($randomKeys[array_search($ignoredId, $randomKeys)]);
    }

    return
        $this->em
            ->createQueryBuilder('na')
            ->select('na')
            ->add('from', '\App\Entity\NewsArticle na')
            ->andWhere('na.id IN (:random_keys)')
            ->setParameter('random_keys', $randomKeys) //, \Doctrine\DBAL\Connection::PARAM_STR_ARRAY
            ->getQuery()
            ->getResult();
}