Wrong, it should be "getLevelByName()" Or if you already have the "Level Object" do: PHP: $level->getOnlinePlayers(); This returns a "Player array" type, you can use "count" to count the number of entries, and a "foreach" loop to access each player object
PHP: public Player[] pocketmine\Server::getOnlinePlayers(): exists;public Player[] pocketmine\level\Level::getPlayers(): exists;public * pocketmine\level\Level::getOnlinePlayers(): doesn't exist;