Introduction to the implementation method of generating classification tree by PHP Infinitus classification

This article mainly introduces the method of PHP to implement Infinitus classification to generate a classification tree. It briefly analyzes the principles and implementation methods of Infinitus classification in the form of examples, and involves PHP array traversal and judgment related operation skills. Friends who need it can refer to it. Next

The example in this article describes the method of generating a classification tree for Infinitus classification using PHP. I share it with you for your reference. The details are as follows:

The current classification database design is basically: each classification has an id primary key field, and a pid points to the id of the parent class, so that unlimited levels of classification can be achieved. The retrieved data is in the following format:

$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')
);

Without further ado, let’s go directly to the processing code:

//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;
}

Test run:

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

Running result:

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
                    )
                )
            )
        )
    )
)

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