Reference implementation tree generation method in PHP

This article mainly introduces the method of generating reference implementation tree in PHP. Interested friends can refer to it. I hope it will be helpful to everyone.

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

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.

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;
}
$items = array(
    1 => array('id' => 1, 'pid' => 0, 'name' => '安徽省'),
    2 => array('id' => 2, 'pid' => 0, 'name' => '浙江省'),
    3 => array('id' => 3, 'pid' => 1, 'name' => '合肥市'),
    4 => array('id' => 4, 'pid' => 3, 'name' => '长丰县'),
    5 => array('id' => 5, 'pid' => 1, 'name' => '安庆市'),
);
print_r(generateTree($items));

You can see the printed results below:

The code is as follows:

Array
(
    [0] => Array
        (
            [id] => 1
            [pid] => 0
            [name] => 安徽省
            [son] => Array
                (
                    [0] => Array
                        (
                            [id] => 3
                            [pid] => 1
                            [name] => 合肥市
                            [son] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 4
                                            [pid] => 3
                                            [name] => 长丰县
                                        )
 
                                )
 
                        )
 
                    [1] => Array
                        (
                            [id] => 5
                            [pid] => 1
                            [name] => 安庆市
                        )
 
                )
 
        )
 
    [1] => Array
        (
            [id] => 2
            [pid] => 0
            [name] => 浙江省
        )
 
)

The above spanning tree method can also be simplified Go to line 5:

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 infinite 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:

The code is as follows:

/**
 * 如何取数据格式化的树形数据
 */
$tree = generateTree($items);
function getTreeData($tree){
    foreach($tree as $t){
        echo $t[&#39;name&#39;].&#39;<br>&#39;;
        if(isset($t[&#39;son&#39;])){
            getTreeData($t[&#39;son&#39;]);
        }
    }
}
getTreeData($tree);

Summary : The above is the entire content of this article, I hope it will be helpful to everyone's study.

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