无限极分类

function getTreeFromArray($data, $pid = 0, $key = 'id', $pKey = 'parent_id', $childKey = 'child', $maxDepth = 0, $level = 0){    static $depth = 0;    $depth++;    $level++;    $tree = array();    if (intval($maxDepth) <= 0) {        $maxDepth = count($data) * count($data);    }    if ($maxDepth == 1) {        $data[0]['level'] = $level;        return $data;    }    if ($depth > $maxDepth) {    }    foreach ($data as $rk => $rv) {        if ($rv[$pKey] == $pid) {            $rv['level'] = $level;            $rv[$childKey] = getTreeFromArray($data, $rv[$key], $key, $pKey, $childKey, $maxDepth, $level);            $tree[] = $rv;        }    }    return $tree;}