PHP method to implement infinite classification tree list sample code

This article mainly introduces the method of simple implementation of infinite classification tree list in PHP. It analyzes the techniques of PHP to implement tree list through array, which has certain reference value. , Friends who need it can refer to

The example of this article describes how to simply implement an infinite classification tree list in PHP. Share it with everyone for your reference. The details are as follows:

$items = array( 
  1 => array('id' => 1, 'pid' => 0, 'name' => '江西省'), 
  2 => array('id' => 2, 'pid' => 0, 'name' => '黑龙江省'),
  3 => array('id' => 3, 'pid' => 1, 'name' => '南昌市'), 
  4 => array('id' => 4, 'pid' => 2, 'name' => '哈尔滨市'),
  5 => array('id' => 5, 'pid' => 2, 'name' => '鸡西市'), 
  6 => array('id' => 6, 'pid' => 4, 'name' => '香坊区'), 
  7 => array('id' => 7, 'pid' => 4, 'name' => '南岗区'), 
  8 => array('id' => 8, 'pid' => 6, 'name' => '和兴路'), 
  9 => array('id' => 9, 'pid' => 7, 'name' => '西大直街'), 
  10 => array('id' => 10, 'pid' => 8, 'name' => '东北林业大学'),
  11 => array('id' => 11, 'pid' => 9, 'name' => '哈尔滨工业大学'),
  12 => array('id' => 12, 'pid' => 8, 'name' => '哈尔滨师范大学'),
  13 => array('id' => 13, 'pid' => 1, 'name' => '赣州市'), 
  14 => array('id' => 14, 'pid' => 13, 'name' => '赣县'), 
  15 => array('id' => 15, 'pid' => 13, 'name' => '于都县'), 
  16 => array('id' => 16, 'pid' => 14, 'name' => '茅店镇'), 
  17 => array('id' => 17, 'pid' => 14, 'name' => '大田乡'), 
  18 => array('id' => 18, 'pid' => 16, 'name' => '义源村'), 
  19 => array('id' => 19, 'pid' => 16, 'name' => '上坝村'), 
  20 => array('id' => 20, 'pid' => 0, 'name' => '广东省'), 
  21 => array('id' => 21, 'pid' => 20, 'name' => '广州市'),
); 
$t = array(); 
foreach ($items as $id => $item) { 
  if ($item['pid']) { 
    $items[$item['pid']][$item['id']] = &$items[$item['id']];
    $t[] = $id; 
  } 
} 
foreach($t as $u) { 
  unset($items[$u]); 
} 
echo "<pre class="brush:php;toolbar:false">"; 
print_r($items);

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