Random select player and broadcast name

How to randomly select a player and broadcast his name?

PHP:

function array_mt_rand(array $a){
  return $a[array_keys($a)[mt_rand(0, count($a) - 1)]];
}

##################################

/** @var \pocketmine\Server $server */
$player = array_mt_rand($server->getOnlinePlayers());
$server->broadcastMessage("Random player: " . $player->getName());

PHP:

function array_mt_rand(array $a){
  return array_values($a)[mt_rand(0, count($a) - 1)];
}

Might be faster, might not be.

Hi, sorry for bump this post, but I have a question:
How I can save the random player from a specific level to a public variable? I try this:

PHP:

public function setPlayer($game)
    {
        $server = $this->getServer();
        $players = $server->getLevelByName($game)->getPlayers();
        $this->randomPlayer[$game] = $players[array_rand($players)]->getName();
        foreach($server->getLevelByName($game)->getPlayers() as $p){
        $p->sendMessage(TextFormat::BOLD . TextFormat::WHITE . $this->randomPlayer[$game] . " was selected as beast!");
} /* It shows all players name! D':*/
    }

And it didn't work...
And I try to get the player name with:

PHP:

public function getRandomPlayer($game){
return $this->randomPlayer[$game];
}

PHP:

$players = $server->getOnlinePlayers();
$server->broadcastMessage($players[mt_rand(0, count($players) - 1)]->getName());

Use PHP methods that lets you to get random things
E.g. array_rand() rand() mt_rand()

Oh that's PHP 7

Actually, if you want to do so, you have to be very careful on memory leak as well as checking player online before doing things upon it.

I don't know what I can do! :'/ I try A LOT of things for save a random player name... I try to save he to a class, to an array... I don't know what I can do...

PHP:

$players = $level->getPlayers();
$randomPlayer = $players[array_rand($players)];
$this->yourVariable[$randomPlayer->getName()] = $randomPlayer->getName();

If you already save it in the key, don't waste memory saving the name on the value again. Instead, put a Boolean true for the value.