递归实现无限级分类

<?php
Class Category{
    //排序数组
    static public function unlimitedForLevel($cate,$html="&nbsp;&nbsp;--",$pid=0,$level=0){
        
        $arr = array();
        
        foreach($cate as $v){
            
            if($v['pid'] == $pid){
                
                $v['level'] = $level+1;
                
                $v['html'] = str_repeat($html,$level);
                
                $arr[] = $v;
                
                $arr = array_merge($arr,self::unlimitedForLevel($cate,$html,$v['id'],$level+1));
            }
            
        }
        
        return $arr;
    }
    //组合数组 用于做导航栏
    static public function unlimitedForLayer($cate,$name='child',$pid=0){
        
        $arr = array();
        
        foreach($cate as $v){
            
            if($v['pid']==$pid){
                
                $v['child'] = self::unlimitedForLayer($cate,$name,$v['id']);
                
                $arr[] = $v;
            }
        }
        
        return $arr;
    }
    
    //传递一个子分类ID获得父级目录 用户制作当前位置导航条
    Static Public function getParents($cate,$id){
        
        $arr = array();
        
        foreach($cate as $v){
            
            if($v['id']==$id){
                
                $arr[] = $v;
                
                $arr = array_merge(self::getParents($cate,$v['pid']),$arr);
                
            }
        }
        
        return $arr;
        
    }
    
    //传递一个父级分类ID返回所有子分类ID
    
    Static Public function getChildsId($cate,$pid){
        
        $arr = array();
        
        foreach($cate as $v){
            
            if($v['pid']==$pid){
                
                $arr[] = $v['id'];
                
                $arr = array_merge($arr,self::getChildsId($cate,$v['id']));
            }
        }
        
        return $arr;
        
    }
    
    //传递一个父类ID获得其所有子集分类
    Static Public function getChilds($cate ,$pid){
        
        $arr = array();
        
        foreach($cate as $v){
            
            if($v['pid']==$pid){
                
                $arr[] = $v;
                
                $arr = array_merge($arr,self::getChilds($cate,$v['id']));
            }
        }
        
        return $arr;
        
    }
}


?>