>>677
$hairetu['A'][1] = 'A1';
$hairetu['A'][5] = 'A5';
$hairetu['A'][7] = 'A7';
$hairetu['A'][9] = 'A9';
$hairetu['B'][3] = 'B3';
$hairetu['B'][4] = 'B4';
$hairetu['A'][6] = 'A6';
$hairetu['A'][12]= 'A12';

$list = array();
foreach($hairetu as $dat) {
foreach($dat as $k => $v) {
$list[$k] = $v;
}
}
ksort($list);
$list = array_slice($list, 0, 3);

var_dump($list);
とか