PHP分层数组-父级和子级

@deceze的建议奏效了。但是，输入数组需要更改一个参数，像这样…

$rows = array(    array(        'id' => 33,        'parent_id' => 0,    ),    array(        'id' => 34,        'parent_id' => 0,    ),    array(        'id' => 27,        'parent_id' => 33,    ),    array(        'id' => 17,        'parent_id' => 27,    ),);

从https://stackoverflow.com/a/8587437/476：

function buildTree(array $elements, $parentId = 0) {    $branch = array();    foreach ($elements as $element) {        if ($element['parent_id'] == $parentId) { $children = buildTree($elements, $element['id']); if ($children) {     $element['children'] = $children; } $branch[] = $element;        }    }    return $branch;}$tree = buildTree($rows);print_r( $tree );