unset()索引数组

$arr = ['0'=>['aa'],'1'=>['c'],'2'=>['bb','cc']];
unset($arr['1']);
echo '<pre>';
print_r($arr);
echo PHP_EOL;
print_r(array_values($arr));

Array
(
    [0] => Array
        (
            [0] => aa
        )

    [2] => Array
        (
            [0] => bb
            [1] => cc
        )

)

Array
(
    [0] => Array
        (
            [0] => aa
        )

    [1] => Array
        (
            [0] => bb
            [1] => cc
        )

)

unset索引数组指定元素后,并不会把后面元素移动到前面

需要借助array_values()函数移动下