php实现无限级分类的树形结构

一：将数据直接排列成树形结构

数据结构和方法如下：

$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'),
);





function tree($items){
	$tree = array();	//初始化树结构数据
	foreach($items as $value){
		if(isset($items[$value['pid']])){	//如果当前父级数据存在
			$items[$value['pid']]['son'][] = &$items[$value['id']];	//在对应父级元素添加 son 元素数据，添加的数据为当前数据
		}else{	//如果当前父级数据不存在
			$tree[] = &$items[$value['id']];	//将当前数据添加到树结构数据里
		}
	}
	return $tree;	
}

function genTree($items) {
    foreach ($items as $item)
        $items[$item['pid']]['son'][$item['id']] = &$items[$item['id']];	//与上方法一样，只是键值不一样
    return isset($items[0]['son']) ? $items[0]['son'] : array();
}


print_r(tree($items));
print_r(genTree($items));

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返回结果如下：

参考：https://www.cnblogs.com/zzg521/p/6761576.html

二：根据父级ID找到其下所有子级：

测试数据：

$arrCate = array(  //待排序数组
    array('id' => 1, 'name' => '顶级栏目一', 'parent_id' => 0),
    array('id' => 2, 'name' => '顶级栏目二', 'parent_id' => 0),
    array('id' => 3, 'name' => '栏目三', 'parent_id' => 1),
    array('id' => 4, 'name' => '栏目四', 'parent_id' => 3),
    array('id' => 5, 'name' => '栏目五', 'parent_id' => 4),
    array('id' => 6, 'name' => '栏目六', 'parent_id' => 2),
    array('id' => 7, 'name' => '栏目七', 'parent_id' => 6),
    array('id' => 8, 'name' => '栏目八', 'parent_id' => 6),
    array('id' => 9, 'name' => '栏目九', 'parent_id' => 7),
);
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获取对应父级的所有子级，返回扁平化结构数据

获取对应父级的所有子级，返回树形结构数据

三：根据子级ID查找所有父级数据，并返回树形结构数据

测试数据：

$arrCate = array(  //待排序数组
    array('id' => 1, 'name' => '顶级栏目一', 'parent_id' => 0),
    array('id' => 2, 'name' => '顶级栏目二', 'parent_id' => 0),
    array('id' => 3, 'name' => '栏目三', 'parent_id' => 1),
    array('id' => 4, 'name' => '栏目四', 'parent_id' => 3),
    array('id' => 5, 'name' => '栏目五', 'parent_id' => 4),
    array('id' => 6, 'name' => '栏目六', 'parent_id' => 2),
    array('id' => 7, 'name' => '栏目七', 'parent_id' => 6),
    array('id' => 8, 'name' => '栏目八', 'parent_id' => 6),
    array('id' => 9, 'name' => '栏目九', 'parent_id' => 7),
);
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找到所有父级数据（扁平化结构）：

/**
 * 递归无限级分类，获取任意节点的所有父级
 * @param array $arrCate 待排序的数组
 * @param int $child_id 子级节点
 * @return array $children 排序后的数组（扁平化数据）
 */
function getparent($arrCate, $child_id = 9){
	static $children = [];
	foreach($arrCate as $key => $value){
		if($value['id'] == $child_id){
			$children[$value['id']] = $value;
			getparent($arrCate,$value['parent_id']);
		}	
	}
	return $children;
}
print_r(getparent($arrCate));

//输出示例

Array
(
   [9] => Array
       (
           [id] => 9
           [name] => 栏目九
           [parent_id] => 7
       )
   [7] => Array
       (
           [id] => 7
           [name] => 栏目七
           [parent_id] => 6
       )
   [6] => Array
       (
           [id] => 6
           [name] => 栏目六
           [parent_id] => 2
       )
   [2] => Array
       (
           [id] => 2
           [name] => 顶级栏目二
           [parent_id] => 0
       )
)

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找到所有父级数据（树形结构）：

/**
 * 递归无限级分类，获取任意节点的所有父级
 * @param array $arrCate 待排序的数组
 * @param int $child_id 子级节点
 * @return array $children 排序后的数组
 */
function getparents($arrCate, $child_id = 9){
	static $children = [];
	foreach($arrCate as $key => $value){
		if($value['id'] == $child_id){
			$children[$value['id']] = $value;
			getparents($arrCate,$value['parent_id']);
		}	
	}

	foreach($children as $k => $v){
		if($v['parent_id'] != 0){
			$children[$v['parent_id']]['children'] = $v;	//将子级拼接进父级的children里
		}
		if($v['parent_id'] == 0){	
			$top_id = $v['id'];		//最顶级节点id
		}
		
	}
	
	return $children[$top_id];	//返回最顶级到指定子级节点的树形结构数据
	
}
print_r(getparents($arrCate));

//示例输出：
Array
(
   [id] => 2
   [name] => 顶级栏目二
   [parent_id] => 0
   [children] => Array
       (
           [id] => 6
           [name] => 栏目六
           [parent_id] => 2
           [children] => Array
               (
                   [id] => 7
                   [name] => 栏目七
                   [parent_id] => 6
                   [children] => Array
                       (
                           [id] => 9
                           [name] => 栏目九
                           [parent_id] => 7
                       )
               )
       )
)
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参考：https://www.cnblogs.com/-mrl/p/13803740.html

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原文地址：https://blog.csdn.net/weixin_43741253/article/details/133815239