PHP 将二维数组转成1维数组 键名保持不变 并且去掉空元素

array(
    0=>array(
        'zhangsan' => 'zhangsan (dae) abc'
    )

    1=>array(
        'lisi' => 'lisi (dae) abc'
    )
       
        2=>array()
)

转成
array(
    'zhangsan' => 'zhangsan (dae) abc',
    'lisi' => 'lisi (dae) abc',
)

$a = array(
    0=>array(
        'zhangsan' => 'zhangsan (dae) abc'
    ),
    1=>array(
        'lisi' => 'lisi (dae) abc'
    ),
    2=>array()
);

$list = array();
foreach ($a as $v) {
    if (!$v) {
        continue;
    }
    $list[key($v)] = $v[key($v)];
}