用PHP中的平面数组构建树

你忘了

unset()

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['id']] = $element; unset($elements[$element['id']]);        }    }    return $branch;}