Question

php 面试遇到一个问题，思考出了一点门道，但是不知道该怎么写这个函数！

class 前面的数字应该是对应的层级，id前面的数字，应该是就是这个ID，写出那个效果应该用什么？递归么？ 但是不知道怎么归！！$arr = [ [ '1_class'=>'a', '2_class'=>'b', '3_class'=>'c', '1_id'=>1, '2_id'=>2, '3_id'=>3, ], [ '1_class'=>'a', '2_class'=>'b', '1_id'=>1, '2_id'=>2, ], [ '1_class'=>'aa', '2_class'=>'bb', '3_class'=>'cc', '1_id'=>11, '2_id'=>22, '3_id'=>33, ],];

Answer 1

看要求转换前和转换后的结构都有些不实用，野路子。按字面写了..

<?php //ver.>5.4.0
$arr = [ 
   ['1_class'=>'a', '2_class'=>'b', '3_class'=>'c', 
    '1_id'=>1, '2_id'=>2, '3_id'=>3 ], 
   ['1_class'=>'a', '2_class'=>'b', '1_id'=>1, '2_id'=>2, ], 
   ['1_class'=>'aa', '2_class'=>'bb', '3_class'=>'cc', 
    '1_id'=>11, '2_id'=>22, '3_id'=>33] ];
$o=[];
foreach($arr as $rec){
   $i=1; $clsKey=$i.'_class'; $cur=&$o; 
   while(array_key_exists($clsKey, $rec)) {
      $eid=$rec[$i.'_id'];
      if(!array_key_exists($clsKey, $cur))
         $cur[$eid]=['value' =>$eid, 'label'=>$rec[$clsKey], 'children'=>[]];      
      $i++; $clsKey=$i.'_class';
      $cur=&$cur[$eid]['children'];
   }
}
echo '<pre>'.print_r($o,true).'</pre>';

Array
(
    [1] => Array
        (
            [value] => 1
            [label] => a
            [children] => Array
                (
                    [2] => Array
                        (
                            [value] => 2
                            [label] => b
                            [children] => Array
                                (
                                )

                        )

                )

        )

    [11] => Array
        (
            [value] => 11
            [label] => aa
            [children] => Array
                (
                    [22] => Array
                        (
                            [value] => 22
                            [label] => bb
                            [children] => Array
                                (
                                    [33] => Array
                                        (
                                            [value] => 33
                                            [label] => cc
                                            [children] => Array
                                                (
                                                )

                                        )

                                )

                        )

                )

        )

)

Answer 2

看不懂啊兄弟

Answer 3

//这么简单都不会?
   function get_children($value,$lv=1) {
        $lv ++;
        if($value[$lv.'_class']){
            $res = [
                'value'=>$value[$lv.'_id'],
                'label'=>$value[$lv.'_class'],
                'children'=>$this->get_children($value,$lv),
            ]; 
            return $res;
        }else{
            return [];
        }
    }
$arr = [ 
            [ '1_class'=>'a', '2_class'=>'b', '3_class'=>'c', '1_id'=>1, '2_id'=>2, '3_id'=>3, ], 
            [ '1_class'=>'a', '2_class'=>'b', '1_id'=>1, '2_id'=>2, ],
            [ '1_class'=>'aa', '2_class'=>'bb', '3_class'=>'cc', '1_id'=>11, '2_id'=>22, '3_id'=>33, ]
        ];
        $newlist = [];
        foreach($arr as $val){
            if($val['1_class']){
                $newlist[] = [
                    'value'=>$val['1_id'],
                    'label'=>$val['1_class'],
                    'children'=>get_children($val,1),
                ]; 
            }
        }
        var_dump($newlist);exit;

追问

这样组成的数据是这样的，实际上，第二个和第三个他们应该合并在一起。和图片的数据结构不相符~

追答

$arr = [ 
            [ '1_class'=>'a', '2_class'=>'b', '3_class'=>'c', '1_id'=>1, '2_id'=>2, '3_id'=>3, ], 
            [ '1_class'=>'a', '2_class'=>'b', '1_id'=>1, '2_id'=>2, ],
            [ '1_class'=>'aa', '2_class'=>'bb', '3_class'=>'cc', '1_id'=>11, '2_id'=>22, '3_id'=>33, ]
        ];
        $newlist = [];
        foreach($arr as $val){
            if($val['1_class']){
                $newlist[$val['1_class']]['value'] = $val['1_id'];
                $newlist[$val['1_class']]['label'] = $val['1_class'];
                $newlist[$val['1_class']]['children'][] = $this->get_children($val,1);
            }
        }
        var_dump($newlist);exit;
        //多一层套路就不会了? 老师教会你10以内的加法运算,还要教你100以内加法运算?