数组随机取值。解决方案

$json = <<album.' ,曲目:'.$row->truck.'
';
}

$data = json_decode($json);
foreach($data as $v) $r[$v->truck] = $v;
$data = $r;
$ar = array_rand($data, 4);
foreach($ar as $k) {
    echo '唱片:'.$data[$k]->album.' ,曲目:'.$data[$k]->truck.'
';
}