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;
}