The method of infinite classification data processing

/** * Convert the returned data set to tree * @param array $list DataSet to convert * @param string $pid parent Tag field * @param string $level level tag field * @re Turn array * @author mai when fuel <[email protected]>*/functionList_to_tree ($list,$PK= ' id ',$pid= ' pid ',$child= ' _child ',$root= 0) {    //Create Tree    $tree=Array(); if(Is_array($list)) {        //creating an array reference based on a primary key        $refer=Array(); foreach($list  as $key=$data) {            $refer[$data[$PK]] =&$list[$key]; }        foreach($list  as $key=$data) {            //determine if there is a parent            $parentId=$data[$pid]; if($root==$parentId) {                $tree[] =&$list[$key]; }Else{                if(isset($refer[$parentId])) {                    $parent=&$refer[$parentId]; $parent[$child[] =&$list[$key]; }            }        }    }    return $tree;}/** * Restore List_to_tree tree to list * @param array $tree The original tree * @param string $child The key of the child node * @param string er Sort the displayed key, is generally  The primary key is arranged in ascending order * @param array $list the intermediate array for the transition, * @return Array returns an ordered list of arrays * @author Yangweijie <[email protected]> */functionTree_to_list ($tree,$child= ' _child ',er= ' id ', &$list=Array()){    if(Is_array($tree)) {        $refer=Array(); foreach($tree  as $key=$value) {            $reffer=$value; if(isset($reffer[$child])){                unset($reffer[$child]); Tree_to_list ($value[$child],$child,er,$list); }            $list[] =$reffer; }        $list= List_sort_by ($list,er,$sortby= ' ASC '); }    return $list;}

The method of infinite classification data processing