Generate infinite column tree with php_php skills

This article mainly introduces the relevant knowledge of generating unlimited column trees in PHP. Has very good reference value. Let’s take a look at it with the editor

ColumnArray:

$arr=Array(
  Array('cid' => 2,'cname' => '新闻','pid' => 0),
  Array('cid' => 4,'cname' =>'体育','pid' => 0),
  Array('cid' => 5,'cname' => '娱乐','pid' => 0),
  Array('cid' => 7,'cname' => '热点新闻','pid' =>2),
  Array('cid' => 8,'cname' => '小众新闻','pid' => 2),
  Array('cid' => 9,'cname' => '民谣新闻','pid' => 8),
);

'pid','id'=>'id','children'=>'children')){
    $arr = array();
    foreach ($array as &$v) {
      if ($v[$field['pid']] == $pid) {
        $v['level'] = $level;
        $tem = formatTree($array, $v[$field['id']],$v['level']+1,$field);
        //判断是否存在子数组
        $tem && $v[$field['children']] = $tem;
        $arr[] = $v;
      }
    }
    return $arr;
  }
$tree = formatTree( $arr,0,1, $field = array('pid'=>'pid','id'=>'cid','children'=>'children') );
echo '
';
print_r( $tree); 
?>　
The following mainly introduces the super awesome Infinitus classification spanning tree of PHP Method, cleverly use citation in PHP to realize the tree generation method, which is much more advanced than the recursive method. Friends who need it can refer to 
function generateTree($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));
 as you can see below Printed result: 
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 be reduced to 5 lines: 
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: 
/**
 * 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);
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