php将一维数组转换为每3个连续值组成的二维数组

<?php$aaa = array('aa','bb','cc','dd','ee','ff','gg','hh','ii');for($i=0;$i<3;$i++){  $bbb[] = array_slice($aaa, $i * 3 ,3);}print_r($bbb);?>

运行结果如下：

Array(  [0] => Array    (      [0] => aa      [1] => bb      [2] => cc    )  [1] => Array    (      [0] => dd      [1] => ee      [2] => ff    )  [2] => Array    (      [0] => gg      [1] => hh      [2] => ii    ))

//重新拼接已日期为key
        for($i=0;$i<12;$i++){
        $date= '2016-12-0'.($i+1);
        if($i >= 9){
        $date = '2016-12-'.($i+1);
        }
        $new_list_12[$date] = array_slice($list_12, $i * 3 ,3);
        }