嵌套数组在codeigniter中创建一个下拉列表

Question

1. 我有这样的菜单存储在数据库中

    INSERT INTO `mycms_menus` (`menu_id`, `title`, `pos`, `parent_menu_id`) VALUES (1, 'Menu principal', 0, 0), (2, 'Menu secondaire', 0, 0), (3, 'SUBMENU 1-1', 0, 1), (4, 'SUBMENU 2-1', 0, 2), (5, 'SUBMENU 1-2', 0, 1), (6, 'SUBMENU 2-2', 0, 2), (7, 'submenu 2-3', 0, 2), (10, 'submenu 1-2-1', 0, 5); 

2. 我使用函数将其转换为嵌套数组（multidim）

    function _flat_to_nested($source) { $nodes = array(); $tree = array(); foreach ($source as &$node) { $node->children = array(); $id = $node->menu_id; $parent_id = $node->parent_menu_id; $nodes[$id] =& $node; if (array_key_exists($parent_id, $nodes)) { $nodes[$parent_id]->children[] =& $node; } else { $tree[] =& $node; } } return $tree; } 

它返回一个结构化数组，如：

    Array
    (
        [0] => stdClass Object
            (
                [menu_id] => 1
                [title] => Menu principal
                [pos] => 0
                [parent_menu_id] => 0
                [children] => Array
                    (
                        [0] => stdClass Object
                            (
                                [menu_id] => 3
                                [title] => SUBMENU 1-1
                                [pos] => 0
                                [parent_menu_id] => 1
                                [children] => Array
                                    (
                                    )

                            )

                        [1] => stdClass Object
                            (
                                [menu_id] => 5
                                [title] => SUBMENU 1-2
                                [pos] => 0
                                [parent_menu_id] => 1
                                [children] => Array
                                    (
                                        [0] => stdClass Object
                                            (
                                                [menu_id] => 10
                                                [title] => submenu 1-2-1
                                                [pos] => 0
                                                [parent_menu_id] => 5
                                                [children] => Array
                                                    (
                                                    )

                                            )

                                    )

                            )

                    )

            )

        [1] => stdClass Object
            (
                [menu_id] => 2
                [title] => Menu secondaire
                [pos] => 0
                [parent_menu_id] => 0
                [children] => Array
                    (
                        [0] => stdClass Object
                            (
                                [menu_id] => 4
                                [title] => SUBMENU 2-1
                                [pos] => 0
                                [parent_menu_id] => 2
                                [children] => Array
                                    (
                                    )

                            )

                        [1] => stdClass Object
                            (
                                [menu_id] => 6
                                [title] => SUBMENU 2-2
                                [pos] => 0
                                [parent_menu_id] => 2
                                [children] => Array
                                    (
                                    )

                            )

                        [2] => stdClass Object
                            (
                                [menu_id] => 7
                                [title] => submenu 2-3
                                [pos] => 0
                                [parent_menu_id] => 2
                                [children] => Array
                                    (
                                    )

                            )

                    )

            )

    )

3.但是在这里我卡住了，因为我需要从codeigniter html helper转换要在form_dropdown中使用的嵌套数组，它需要类似的数组但结构不同：

    $options = array(
        'menu_id'  => 'menu title',
        '##' => 'text',
        'optgroup text' => array(
            'menu_id'  => 'menu title',
            '##' => 'text',
            ),
        ),
    );
    echo form_dropdown('name',$options,null)

这会将嵌套数组转换为带有嵌套optgroup的下拉列表。

我无法将表格菜单数据转换为可与下拉帮助器一起使用的嵌套下拉菜单，因此我希望有人可以给我提示或提示来实现这一目标。 事先感谢thanx我知道我可能会重写整个过程，所以欢迎任何想法

Answer 1

object[0]
    =>[0]
    =>[1]

...是您当前的结构

它要从这棵树中提取大量工作（recursivley）...我可以建议另一种方法吗？

我想到了另一种算法，现在想不起来，它使用了lft和rt指针（啊，我的想法是空白）...替代，您可以尝试在SQL中使用“树和层次结构”

Answer 2

我终于成功了，没有改变。 我从链接和xpath之类的线性存储中获得了一些启发。

这是我结束的课程（有些代码不是我提供的）。 它只是一个基础，我没有在其他项目中进行过测试，因此它可能包含错误或无法为您完成工作，但是您可以尝试一下。

它将把平面数组转换为不同种类的多维/嵌套数组。 包括转换为html下拉列表和html列表：

抱歉，有很多代码。

编辑：经过更多测试后，嵌套的optgroups不会像预期的那样被浏览器呈现，因此我不建议您使用嵌套的opgroups。 我将切换到结合了某些CSS的单选按钮。

  <?php 
  /**
   *
   * CLASS
   * *********************************************************************
   * several functions to convert a menu, from a FLAT array into a MULTIDIM/NESTED array 
   * or into an HTML dropdown OR HTML list
   * *********************************************************************
   ** ::_flat_to_nested ** convert FLAT into MULTIDIM/NESTED
   *
   ** ::_nested_to_ul ** convert MULTIDIM/NESTED into HTML LIST
   *
   ** ::_nested_to_dropdown ** convert MULTIDIM/NESTED into HTML SELECT/OPTGROUP/OPTION
   *    no nested optgroup allowed 
   *    <optgroup> tag can only contains <options> tags = w3c standards
   *
   ** ::_nested_to_dropdown_html ** convert MULTIDIM/NESTED into HTML SELECT/OPTGROUP/OPTION
   *    multiple nested optgroups allowed
   *

   * USAGE:
   *   $list = {array of objects}
   *   $t = new myNested;
   *   $result = $t->index( $list );
   *
   */
  class myNested {

    //results
    var $parserStrFin="";

    //iterations
    var $it=0;

    //level
    var $profondeur=0;


    /**
     * convert flat array into ...
     *
     * @return several formatted arrays 
     */
    function index($list=array())
    {

      $nested    = $this->_flat_to_nested($list);
      $dropdown  = $this->_nested_to_dropdown_html($nested);
      $dropdown2 = $this->_nested_to_dropdown($nested);
      $htmlist   = $this->_nested_to_ul($nested);


      //trick to convert recursivelly all objects into arrays
      // $dropdown  = json_decode(json_encode($dropdown), true);
      // $dropdown2 = json_decode(json_encode($dropdown2), true);

      return array(
        'list'      => $list,
        'nested'    => $nested,
        'dropdown'  => $dropdown,
        'dropdown2' => $dropdown2,
        'htmlist'   => $htmlist,
      );
    }


    /**
     * 
     * convert MULTIDIM/NESTED into HTML SELECT/OPTGROUP/OPTION
     * no nested optgroup allowed 
     * <optgroup> tag can only contains <options> tags = w3c standards
     *
     * @param array $array
     * @param bool $_autoCall
     * @param int $profondeur
     * @param int $it
     * @return str html string to use into <select> tag
     */
    private function _nested_to_dropdown( $array=array(), $_autoCall=false, $profondeur="", $it=0 )
    {

      //first call, reset
      if (!$_autoCall)
      {
        $this->fin=array();
        $this->root=null;
        $this->it=0;
        $this->profondeur=0;
        $this->xpath="";
        $this->parserStrFin="";
      }

      //items count
      $this->it++;


      //dim after dim
      foreach( $array as $value )
      {

        if ( count($value->children)>0 )
        {
          //if item contains children
          $this->profondeur++;

          if (!$this->root) {
            $this->root =& $this->fin;//change current node
          }

          $this->root[$value->title] = array();//prep optgroup

          $this->xpath .= $value->title."/"; //linear path

          $this->root = & $this->root[$value->title]; //define this node as root

          $this->root[$value->menu_id] = $value->title;//the optgroup is added as a normal option to be selectable

          $this->_nested_to_dropdown( $value->children, true, $this->profondeur, $this->it );//process with children
        }
        elseif ( count($value->children)==0 && isset($value->title) ) {

          //items without children
          //title is a string, without chukd: extremity reached
          $this->root[$value->menu_id] = $value->title; //each child as new option

        }

      }//foreach


      //after an item without children is added
      // returns one dim up
      if ($this->profondeur) {
        $this->profondeur--;

        $regs=array();
        $regs = explode('/',$this->xpath);
        $regs = array_filter($regs);//clear empty values

        //one dim up in the path
        $regs = array_slice($regs, 0, $this->profondeur);


        if ($regs) {

          //goes from dim 0 to dim ##
          $n =& $this->fin;
          foreach ($regs as $v) {
            $n =& $n[$v];//fin[lv1], puis fin[lv1][lv2]
          }


          //set the new root for next items
          $this->root = & $n;

          //xpath
          $this->xpath=implode('/',$regs);//reset

        }
        else{
          //reset
          $this->root =& $this->fin;
          $this->xpath='';
        }

      }

      return $this->fin;
    }


    /**
     *
     * convert MULTIDIM/NESTED into HTML SELECT/OPTGROUP/OPTION
     * multiple nested optgroups allowed !
     * 
     * @param <array> $array
     * @param <bool> $_autoCall
     * @param <str/int> $profondeur
     * @param <int> $it
     * @return <str> html string
     *
    **/
    function _nested_to_dropdown_html( $array=array(), $_autoCall=false, $profondeur="", $it=0 )
    {

      if (!$_autoCall)
      {
        $this->parserStrFin="";
        $this->it=0;
        $this->profondeur=0;
      }

      $this->it++;

      foreach( $array as $value )
      {

        if ( count($value->children)>0 )
        {
          $p = 15 * $this->profondeur;//or in your .css:  optgroup>optgroup {padding-left: 15px};
          $this->profondeur++;
          $this->parserStrFin .= '<optgroup class="submenu-title" style="padding-left:'.$p.'px" label="'.$value->title.'">'."\n";
          $this->parserStrFin .= '  <option class="submenu-item" value="'.$value->menu_id.'">'.$value->title.'</option>'."\n";
          $this->_nested_to_dropdown_html( $value->children, true, $this->profondeur, $this->it );
        }
        elseif ( count($value->children)==0 && isset($value->title) ) {
          $this->parserStrFin .= '  <option class="submenu-item" value="'.$value->menu_id.'">'.$value->title.'</option>'."\n";

        }

      }

      if ($this->profondeur)       { $this->parserStrFin .= '</optgroup>'."\n"; $this->profondeur--; } //prof = 0, on ferme le UL FirstLevelListTypeTag

      return $this->parserStrFin;
    }



    /**
     * convett FLAT en MULTIDIM/NESTED
     *
     * @param array flat $list
     * @return array multi
     * @source: php.net
     *
     * NOTE: array must be well sorted: parents items must be parsed before any of their child
     */
    private function _flat_to_nested($source)
    {
      $nodes = array();
      $tree = array();
      foreach ($source as &$node) {
        $node->children = array();
        $id = $node->menu_id;
        $parent_id = $node->parent_menu_id;
        $nodes[$id] =& $node;
        if (array_key_exists($parent_id, $nodes)) {
          $nodes[$parent_id]->children[] =& $node;
        } else {
          $tree[] =& $node;
        }
      }

      return $tree;

    }



    /**
     * convert MULTIDIM/NESTED into HTML LIST
     * 
     * @param array $array
     * @param bool $_autoCall
     * @param int $profondeur
     * @param int $it
     * @return <str> html list 
     *
    **/
    function _nested_to_ul( $array=array(), $_autoCall=false, $profondeur="", $it=0 )
    {

      if (!$_autoCall)
      {
        $this->parserStrFin="";
        $this->it=0;
        $this->profondeur=0;
      }

      $firstListType = 'ul';//first level list type
      $itemsListType = 'ul';//sub level list type

      $tag = (empty($this->profondeur) && $this->it==0) ? $firstListType : $itemsListType;
      $this->parserStrFin .= "\n".'<'.$tag.' class="level-'.$this->profondeur.'">'."\n";

      $this->it++;

      foreach( $array as $value )
      {

        if ( count($value->children)>0)
        {
          $this->profondeur++;
          $this->parserStrFin .= '  <li class="submenu-title"><h3>'. $value->title .'</h3>'."\n";
          $this->_nested_to_ul( $value->children, true, $this->profondeur, $this->it );
        }
        elseif ( count($value->children)==0 && isset($value->title) ) {
          $this->parserStrFin .= '  <li class="submenu-item">'. '<a href="#'.$value->menu_id.'">'.$value->title.'</a>' .'</li>'."\n";

        }

      }


      if ($this->profondeur == 0)       { $this->parserStrFin .= "</".$firstListType.">\n"; $this->profondeur--; }
      else if (($this->profondeur > 0)) { $this->parserStrFin .= "</".$itemsListType.">\n</li>\n"; $this->profondeur--; }

      return $this->parserStrFin;
    }

  }

  //SAMPLE USAGE:

  //DATAS:
    //the class uses FLAT array containing "objects" so here's the datas
    $list='a:8:{i:0;O:8:"stdClass":4:{s:7:"menu_id";s:1:"1";s:5:"title";s:14:"Menu principal";s:3:"pos";s:1:"0";s:14:"parent_menu_id";s:1:"0";}i:1;O:8:"stdClass":4:{s:7:"menu_id";s:1:"2";s:5:"title";s:15:"Menu secondaire";s:3:"pos";s:1:"0";s:14:"parent_menu_id";s:1:"0";}i:2;O:8:"stdClass":4:{s:7:"menu_id";s:1:"3";s:5:"title";s:11:"SUBMENU 1-1";s:3:"pos";s:1:"0";s:14:"parent_menu_id";s:1:"1";}i:3;O:8:"stdClass":4:{s:7:"menu_id";s:1:"4";s:5:"title";s:11:"SUBMENU 2-1";s:3:"pos";s:1:"0";s:14:"parent_menu_id";s:1:"2";}i:4;O:8:"stdClass":4:{s:7:"menu_id";s:1:"5";s:5:"title";s:11:"SUBMENU 1-2";s:3:"pos";s:1:"0";s:14:"parent_menu_id";s:1:"1";}i:5;O:8:"stdClass":4:{s:7:"menu_id";s:1:"6";s:5:"title";s:11:"SUBMENU 2-2";s:3:"pos";s:1:"0";s:14:"parent_menu_id";s:1:"2";}i:6;O:8:"stdClass":4:{s:7:"menu_id";s:1:"7";s:5:"title";s:11:"submenu 2-3";s:3:"pos";s:1:"0";s:14:"parent_menu_id";s:1:"2";}i:7;O:8:"stdClass":4:{s:7:"menu_id";s:2:"10";s:5:"title";s:13:"submenu 1-2-1";s:3:"pos";s:1:"0";s:14:"parent_menu_id";s:1:"5";}}';
    $list=unserialize($list);

  //EXEC!
  $t = new myNested;
  $result = $t->index( $list );

  //RETURNS:
  $source = $result['list'];
  $nested = $result['nested'];
  $dropdown = $result['dropdown'];
  $dropdown2 = $result['dropdown2'];
  $htmlist = $result['htmlist'];

  echo '<pre style="border:1px solid #C00; color: #C00; background:#FFFFFE;">';
  echo "<B>SOURCE=</B>:<br/>"; print_r($source); echo "<hr/>";
  echo "<B>NESTED=</B>:<br/>"; print_r($nested); echo "<hr/>";
  echo "<B>DROPDOWN=</B>:<br/>"; highlight_string($dropdown); echo "<hr/>";
  echo "<B>DROPDOWN2=</B>:<br/>"; print_r($dropdown2); echo "<hr/>";
  echo "<B>HTMLIST=</B>:<br/>"; print_r($htmlist); echo "<hr/>";
  echo '</pre>';



  ?>