PHP recursively implements infinite classification tree-PHP Tutorial-php.cn

The infinite level tree diagram can be said to be a distinctive feature of the infinite level column. Let’s take a look at two different writing methods.

1. Database design

CREATE TABLE `bg_cate` (
`cate_Id` int(30) unsigned NOT NULL AUTO_INCREMENT,
`cate_ParentId` int(30) unsigned DEFAULT &#39;0&#39;,
`cate_Name` varchar(100) NOT NULL,
`cate_Intro` varchar(500) DEFAULT NULL,
`cate_Order` int(30) unsigned DEFAULT &#39;0&#39;,
`cate_Icon` varchar(100) DEFAULT NULL,
PRIMARY KEY (`cate_Id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=34 ;
--
-- 导出表中的数据 `bg_cate`
--
INSERT INTO `bg_cate` (`cate_Id`, `cate_ParentId`, `cate_Name`, `cate_Intro`, `cate_Order`, `cate_Icon`) VALUES
(4, 0, &#39;往事如风&#39;, &#39;记录往事&#39;, 0, &#39;icons/6.gif&#39;),
(5, 0, &#39;水煮三国&#39;, &#39;品位三国智慧&#39;, 0, &#39;icons/3.gif&#39;),
(2, 0, &#39;技术学习&#39;, &#39;平时学习的一些笔记，欢迎批评指正。&#39;, 0, &#39;icons/18.gif&#39;),
(3, 0, &#39;生活点滴&#39;, &#39;记录生活点滴&#39;, 0, &#39;icons/2.gif&#39;),
(6, 0, &#39;栀子花开&#39;, &#39;青春无限&#39;, 0, &#39;icons/8.gif&#39;),
(7, 0, &#39;假日休闲&#39;, &#39;悠闲、自在&#39;, 0, &#39;icons/24.gif&#39;),
(8, 2, &#39;html&#39;, &#39;html学习&#39;, 0, &#39;icons/1.gif&#39;),
(9, 2, &#39;css&#39;, &#39;css学习&#39;, 0, &#39;icons/1.gif&#39;),
(10, 2, &#39;php&#39;, &#39;php学习&#39;, 0, &#39;icons/18.gif&#39;),
(11, 10, &#39;php基础知识&#39;, &#39;php基础知识&#39;, 0, &#39;icons/1.gif&#39;),
(12, 10, &#39;oop&#39;, &#39;oop&#39;, 0, &#39;icons/1.gif&#39;),
(13, 10, &#39;php安全&#39;, &#39;讲述php安全&#39;, 0, &#39;icons/1.gif&#39;),
(14, 10, &#39;seagull framework&#39;, &#39;seagull framework&#39;, 0, &#39;icons/1.gif&#39;),
(15, 2, &#39;javascript&#39;, &#39;javascript学习&#39;, 0, &#39;icons/1.gif&#39;),
(16, 2, &#39;设计模式&#39;, NULL, 0, &#39;icons/1.gif&#39;),
(17, 2, &#39;软件工程&#39;, &#39;软件工程学习&#39;, 0, &#39;icons/1.gif&#39;),
(18, 3, &#39;厦门生活&#39;, &#39;厦门生活&#39;, 0, &#39;icons/8.gif&#39;),
(19, 3, &#39;大学生活&#39;, &#39;大学生活&#39;, 0, &#39;icons/8.gif&#39;),
(20, 3, &#39;童年生活&#39;, &#39;童年生活&#39;, 0, &#39;icons/15.gif&#39;),
(21, 19, &#39;学习&#39;, &#39;学习&#39;, 0, &#39;icons/1.gif&#39;),
(22, 19, &#39;运动&#39;, &#39;运动&#39;, 0, &#39;icons/16.gif&#39;),
(23, 19, &#39;旅游&#39;, &#39;旅游&#39;, 0, &#39;icons/24.gif&#39;),
(24, 22, &#39;排球&#39;, &#39;排球&#39;, 0, &#39;icons/9.gif&#39;),
(25, 22, &#39;篮球&#39;, &#39;篮球&#39;, 0, &#39;icons/9.gif&#39;),
(26, 22, &#39;羽毛球&#39;, &#39;羽毛球&#39;, 0, &#39;icons/9.gif&#39;),
(27, 22, &#39;乒乓球&#39;, &#39;乒乓球&#39;, 0, &#39;icons/9.gif&#39;);

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2. Get the data from the database and put it into the array.

require_once &#39;./classes/MyDB.php&#39;;
$con = MyDB::singleton();
$sql = <<<SQL
   select * from bg_cate cate
SQL;
$data = $con->getAll($sql);
//print_r($data);

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I use the pear class library for database operations.
The data format of the final $data is as follows:

Array
(
   [0] => Array
       (
           [cate_Id] => 4
           [cate_ParentId] => 0
           [cate_Name] => 往事如风
           [cate_Intro] => 记录往事
           [cate_Order] => 0
           [cate_Icon] => icons/6.gif
       )
   [1] => Array
       (
           [cate_Id] => 5
           [cate_ParentId] => 0
           [cate_Name] => 水煮三国
           [cate_Intro] => 品位三国智慧
           [cate_Order] => 0
           [cate_Icon] => icons/3.gif
       )

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3. Convert the data from the previous step into a tree-shaped array
The code is as follows:

function getTree($data, $pId)
{
$tree = &#39;&#39;;
foreach($data as $k => $v)
{
  if($v[&#39;cate_ParentId&#39;] == $pId)
  {        //父亲找到儿子
   $v[&#39;cate_ParentId&#39;] = getTree($data, $v[&#39;cate_Id&#39;]);
   $tree[] = $v;
   //unset($data[$k]);
  }
}
return $tree;
}
$tree = getTree($data, 0);

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The final output data format of $tree is:

Array
(
   [0] => Array
       (
           [cate_Id] => 4
           [cate_ParentId] =>
           [cate_Name] => 往事如风
           [cate_Intro] => 记录往事
           [cate_Order] => 0
           [cate_Icon] => icons/6.gif
       )
   [1] => Array
       (
           [cate_Id] => 5
           [cate_ParentId] =>
           [cate_Name] => 水煮三国
           [cate_Intro] => 品位三国智慧
           [cate_Order] => 0
           [cate_Icon] => icons/3.gif
       )
   [2] => Array
       (
           [cate_Id] => 2
           [cate_ParentId] => Array
               (
                   [0] => Array
                       (
                           [cate_Id] => 8
                           [cate_ParentId] =>
                           [cate_Name] => html
                           [cate_Intro] => html学习
                           [cate_Order] => 0
                           [cate_Icon] => icons/1.gif
                       )

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4. Convert the tree array to html
The code is as follows:

function procHtml($tree)
{
$html = &#39;&#39;;
foreach($tree as $t)
{
  if($t[&#39;cate_ParentId&#39;] == &#39;&#39;)
  {
   $html .= "<li>{$t[&#39;cate_Name&#39;]}</li>";
  }
  else
  {
   $html .= "<li>".$t[&#39;cate_Name&#39;];
   $html .= procHtml($t[&#39;cate_ParentId&#39;]);
   $html = $html."</li>";
  }
}
return $html ? &#39;<ul>&#39;.$html.&#39;</ul>&#39; : $html ;
}
echo procHtml($tree);

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The code format of the output html is:

<ul>
<li>往事如风</li>
<li>水煮三国</li>
<li>技术学习
  <ul>
   <li>html</li>
   <li>css</li>
   <li>php
    <ul>
     <li>php基础知识</li>
     <li>oop</li>
     <li>php安全</li>

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5. Code integration

function getTree($data, $pId)
{
$html = &#39;&#39;;
foreach($data as $k => $v)
{
  if($v[&#39;cate_ParentId&#39;] == $pId)
  {        //父亲找到儿子
   $html .= "<li>".$v[&#39;cate_Name&#39;];
   $html .= getTree($data, $v[&#39;cate_Id&#39;]);
   $html = $html."</li>";
  }
}
return $html ? &#39;<ul>&#39;.$html.&#39;</ul>&#39; : $html ;
}
echo getTree($data, 0);

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6. Add CSS styles

PHP recursively implements infinite classification tree

##The second one is seen from open source websites, very very Introduction.

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It can be seen that the second code only uses 5 lines of code to achieve an infinite classification tree, which is very worthy of everyone's reference and learning.

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php paging library download 2. php image processing library 3. Verification code library download 4. File upload class library 5. String processing class
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