php无限极分类组装成分类树的巧妙代码

作者:包包大人   时间:2018-03-20 18:24:02   来源:原创   阅读:281   评论:0  

现在的分类数据库设计基本都是:每一个分类有一个id主键字段,一个pid指向父类的id,这样便可实现无限级分类,取出的数据就是如下的格式:

$arr = array(  
        array("id" => 1 , "pid" => 0 , 'cat' => '栏目一'),  
        array("id" => 2 , "pid" => 0 , 'cat' => '栏目二'),  
        array("id" => 3 , "pid" => 1 , 'cat' => '栏目三'),  
        array("id" => 4 , "pid" => 2 , 'cat' => '栏目四'),  
        array("id" => 5 , "pid" => 1 , 'cat' => '栏目五'),  
        array("id" => 6 , "pid" => 5 , 'cat' => '栏目六'),  
        array("id" => 7 , "pid" => 5 , 'cat' => '栏目七'),  
        array("id" => 8 , "pid" => 6 , 'cat' => '栏目八'),  
        array("id" => 9 , "pid" => 1 , 'cat' => '栏目九'),  
        array("id" => 10 , "pid" => 0 , 'cat' => '栏目十'),  
        array("id" => 11 , "pid" => 10 , 'cat' => '栏目十一'),  
        array("id" => 12 , "pid" => 11 , 'cat' => '栏目十二'),  
        array("id" => 13 , "pid" => 2 , 'cat' => '栏目十三'),  
        array("id" => 14, "pid" => 13 , 'cat' => '栏目十四')  
    );

不多说,直接上处理代码:

//生成无限极分类树  
    function make_tree($arr){  
        $refer = array();  
        $tree = array();  
        foreach($arr as $k => $v){  
            $refer[$v['id']] = & $arr[$k];  //创建主键的数组引用  
        }  

        foreach($arr as $k => $v){  
            $pid = $v['pid'];   //获取当前分类的父级id  
            if($pid == 0){  
                $tree[] = & $arr[$k];   //顶级栏目  
            }else{  
                if(isset($refer[$pid])){  
                    $refer[$pid]['subcat'][] = & $arr[$k];  //如果存在父级栏目,则添加进父级栏目的子栏目数组中  
                }  
            }  
        }  

        return $tree;  
    }

测试运行:

$cat = make_tree($arr);  
print_r($cat);

运行结果:

Array  
    (  
        [0] => Array  
            (  
                [id] => 1  
                [pid] => 0  
                [cat] => 栏目一  
                [subcat] => Array  
                    (  
                        [0] => Array  
                            (  
                                [id] => 3  
                                [pid] => 1  
                                [cat] => 栏目三  
                            )  

                        [1] => Array  
                            (  
                                [id] => 5  
                                [pid] => 1  
                                [cat] => 栏目五  
                                [subcat] => Array  
                                    (  
                                        [0] => Array  
                                            (  
                                                [id] => 6  
                                                [pid] => 5  
                                                [cat] => 栏目六  
                                                [subcat] => Array  
                                                    (  
                                                        [0] => Array  
                                                            (  
                                                                [id] => 8  
                                                                [pid] => 6  
                                                                [cat] => 栏目八  
                                                            )  

                                                    )  

                                            )  

                                        [1] => Array  
                                            (  
                                                [id] => 7  
                                                [pid] => 5  
                                                [cat] => 栏目七  
                                            )  

                                    )  

                            )  

                        [2] => Array  
                            (  
                                [id] => 9  
                                [pid] => 1  
                                [cat] => 栏目九  
                            )  

                    )  

            )  

        [1] => Array  
            (  
                [id] => 2  
                [pid] => 0  
                [cat] => 栏目二  
                [subcat] => Array  
                    (  
                        [0] => Array  
                            (  
                                [id] => 4  
                                [pid] => 2  
                                [cat] => 栏目四  
                            )  

                        [1] => Array  
                            (  
                                [id] => 13  
                                [pid] => 2  
                                [cat] => 栏目十三  
                                [subcat] => Array  
                                    (  
                                        [0] => Array  
                                            (  
                                                [id] => 14  
                                                [pid] => 13  
                                                [cat] => 栏目十四  
                                            )  

                                    )  

                            )  

                    )  

            )  

        [2] => Array  
            (  
                [id] => 10  
                [pid] => 0  
                [cat] => 栏目十  
                [subcat] => Array  
                    (  
                        [0] => Array  
                            (  
                                [id] => 11  
                                [pid] => 10  
                                [cat] => 栏目十一  
                                [subcat] => Array  
                                    (  
                                        [0] => Array  
                                            (  
                                                [id] => 12  
                                                [pid] => 11  
                                                [cat] => 栏目十二  
                                            )  

                                    )  

                            )  

                    )  

            )  

    )

如果大家需要这样的组装格式,或者需要该格式方便后续的处理,可以尝试此方法,希望这篇文章能帮到大家

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