PHP is super awesome Infinitus classification spanning tree method, php_PHP tutorial

PHP’s super awesome Infinitus classification spanning tree method, php

Are you still using recursive traversal of Infinitus classification that wastes time and memory? After reading this article, I think you should change it.

This is a very concise PHP Infinitus classification spanning tree method that I saw on OSChina. I happened to quote it and compiled it for sharing.

Copy code The code is as follows:
function generateTree($items){
$tree = array();
foreach($items as $item){
If(isset($items[$item['pid']])){
$items[$item['pid']]['son'][] = &$items[$item['id']];
         }else{
               $tree[] = &$items[$item['id']];
}
}
Return $tree;
}
$items = array(
1 => array('id' => 1, 'pid' => 0, 'name' => 'Anhui Province'),
2 => array('id' => 2, 'pid' => 0, 'name' => 'Zhejiang Province'),
3 => array('id' => 3, 'pid' => 1, 'name' => 'Hefei City'),
4 => array('id' => 4, 'pid' => 3, 'name' => 'Changfeng County'),
5 => array('id' => 5, 'pid' => 1, 'name' => 'Anqing City'),
);
print_r(generateTree($items));

You can see the results printed below:

Copy code The code is as follows:
Array
(
[0] => Array
(
                                                                  [id] => 1
                                                                                              [pid] =>                                     [name] => Anhui Province
[son] => Array
(
                                                                                                                                                                                                                                                                                                                 (
                                                                                                                                                                      [pid] => 1
Hefei City
[name] => Hefei City
[son] => Array
                          (
                                                                                                                                                                                    (
                                                                                                                  [pid] => 3
                                                                                                                                                                                                                      )

)

)

[1] = & gt; Array
                 (
                                                                                                                                                                                                                           [pid] => 1
[name] => Anqing City
)

)

)

[1] => Array
(
                                                                      [id] => 2
                                                                                              [pid] =>                                           [name] => Zhejiang Province
)

)

The above spanning tree method can also be reduced to 5 lines:

Copy code The code is as follows: function generateTree($items){
foreach($items as $item)
$items[$item['pid']]['son'][$item['id']] = &$items[$item['id']];
Return isset($items[0]['son']) ? $items[0]['son'] : array();
}

The above tree-structured method of Infinitus classification data is worth learning from. But I think the actual use of this code is not obvious. If you want to take out the formatted tree data, you still have to recurse:

Copy code The code is as follows: /**
* How to get data formatted tree data
​*/
$tree = generateTree($items);
function getTreeData($tree){
foreach($tree as $t){
echo $t['name'].'
';
If(isset($t['son'])){
               getTreeData($t['son']);
}
}
}
getTreeData($tree);

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