1: Arrange data directly into a tree structure
The data structure and methods are as follows:
$items = array(
1 => array('id' => 1, 'pid' => 0, 'name' => 'Jiangxi Province'),
2 => array('id' => 2, 'pid' => 0, 'name' => 'Heilongjiang Province'),
3 => array('id' => 3, 'pid' => 1, 'name' => 'Nanchang City'),
4 => array('id' => 4, 'pid' => 2, 'name' => 'Harbin City'),
5 => array('id' => 5, 'pid' => 2, 'name' => 'Jixi City'),
6 => array('id' => 6, 'pid' => 4, 'name' => 'Xiangfang District'),
7 => array('id' => 7, 'pid' => 4, 'name' => 'Nangang District'),
8 => array('id' => 8, 'pid' => 6, 'name' => 'Hexing Road'),
9 => array('id' => 9, 'pid' => 7, 'name' => 'Xidazhi Street'),
10 => array('id' => 10, 'pid' => 8, 'name' => 'Northeast Forestry University'),
11 => array('id' => 11, 'pid' => 9, 'name' => 'Harbin Institute of Technology'),
12 => array('id' => 12, 'pid' => 8, 'name' => 'Harbin Normal University'),
13 => array('id' => 13, 'pid' => 1, 'name' => 'Ganzhou City'),
14 => array('id' => 14, 'pid' => 13, 'name' => 'Gan County'),
15 => array('id' => 15, 'pid' => 13, 'name' => 'Yudu County'),
16 => array('id' => 16, 'pid' => 14, 'name' => 'Maodian Town'),
17 => array('id' => 17, 'pid' => 14, 'name' => 'Datian Township'),
18 => array('id' => 18, 'pid' => 16, 'name' => 'Yiyuan Village'),
19 => array('id' => 19, 'pid' => 16, 'name' => 'Shangba Village'),
);
function tree($items){<!-- -->
$tree = array(); //Initialize tree structure data
foreach($items as $value){<!-- -->
if(isset($items[$value['pid']])){<!-- --> //If the current parent data exists
$items[$value['pid']]['son'][] = & amp;$items[$value['id']]; //Add son element data to the corresponding parent element. The added data is current data
}else{<!-- --> //If the current parent data does not exist
$tree[] = & amp;$items[$value['id']]; //Add the current data to the tree structure data
}
}
return $tree;
}
function genTree($items) {<!-- -->
foreach ($items as $item)
$items[$item['pid']]['son'][$item['id']] = & amp;$items[$item['id']]; //Same as above, just the key The value is different
return isset($items[0]['son']) ? $items[0]['son'] : array();
}
print_r(tree($items));
print_r(genTree($items));
The return result is as follows:
Array
(
[0] => Array
(
[id] => 1
[pid] => 0
[name] => Jiangxi Province
[son] => Array
(
[0] => Array
(
[id] => 3
[pid] => 1
[name] => Nanchang City
)
[1] => Array
(
[id] => 13
[pid] => 1
[name] => Ganzhou City
[son] => Array
(
[0] => Array
(
[id] => 14
[pid] => 13
[name] => Gan County
[son] => Array
(
[0] => Array
(
[id] => 16
[pid] => 14
[name] => Maodian Town
[son] => Array
(
[0] => Array
(
[id] => 18
[pid] => 16
[name] => Yiyuan Village
)
[1] => Array
(
[id] => 19
[pid] => 16
[name] => Shangba Village
)
)
)
[1] => Array
(
[id] => 17
[pid] => 14
[name] => Datian Township
)
)
)
[1] => Array
(
[id] => 15
[pid] => 13
[name] => Yudu County
)
)
)
)
)
[1] => Array
(
[id] => 2
[pid] => 0
[name] => Heilongjiang Province
[son] => Array
(
[0] => Array
(
[id] => 4
[pid] => 2
[name] => Harbin City
[son] => Array
(
[0] => Array
(
[id] => 6
[pid] => 4
[name] => Xiangfang District
[son] => Array
(
[0] => Array
(
[id] => 8
[pid] => 6
[name] => Hexing Road
[son] => Array
(
[0] => Array
(
[id] => 10
[pid] => 8
[name] => Northeast Forestry University
)
[1] => Array
(
[id] => 12
[pid] => 8
[name] => Harbin Normal University
)
)
)
)
)
[1] => Array
(
[id] => 7
[pid] => 4
[name] => Nangang District
[son] => Array
(
[0] => Array
(
[id] => 9
[pid] => 7
[name] => West Dazhi Street
[son] => Array
(
[0] => Array
(
[id] => 11
[pid] => 9
[name] => Harbin Institute of Technology
)
)
)
)
)
)
)
[1] => Array
(
[id] => 5
[pid] => 2
[name] => Jixi City
)
)
)
)
Array
(
[1] => Array
(
[id] => 1
[pid] => 0
[name] => Jiangxi Province
[son] => Array
(
[3] => Array
(
[id] => 3
[pid] => 1
[name] => Nanchang City
)
[13] => Array
(
[id] => 13
[pid] => 1
[name] => Ganzhou City
[son] => Array
(
[14] => Array
(
[id] => 14
[pid] => 13
[name] => Gan County
[son] => Array
(
[16] => Array
(
[id] => 16
[pid] => 14
[name] => Maodian Town
[son] => Array
(
[18] => Array
(
[id] => 18
[pid] => 16
[name] => Yiyuan Village
)
[19] => Array
(
[id] => 19
[pid] => 16
[name] => Shangba Village
)
)
)
[17] => Array
(
[id] => 17
[pid] => 14
[name] => Datian Township
)
)
)
[15] => Array
(
[id] => 15
[pid] => 13
[name] => Yudu County
)
)
)
)
)
[2] => Array
(
[id] => 2
[pid] => 0
[name] => Heilongjiang Province
[son] => Array
(
[4] => Array
(
[id] => 4
[pid] => 2
[name] => Harbin City
[son] => Array
(
[6] => Array
(
[id] => 6
[pid] => 4
[name] => Xiangfang District
[son] => Array
(
[8] => Array
(
[id] => 8
[pid] => 6
[name] => Hexing Road
[son] => Array
(
[10] => Array
(
[id] => 10
[pid] => 8
[name] => Northeast Forestry University
)
[12] => Array
(
[id] => 12
[pid] => 8
[name] => Harbin Normal University
)
)
)
)
)
[7] => Array
(
[id] => 7
[pid] => 4
[name] => Nangang District
[son] => Array
(
[9] => Array
(
[id] => 9
[pid] => 7
[name] => West Dazhi Street
[son] => Array
(
[11] => Array
(
[id] => 11
[pid] => 9
[name] => Harbin Institute of Technology
)
)
)
)
)
)
)
[5] => Array
(
[id] => 5
[pid] => 2
[name] => Jixi City
)
)
)
)
Reference: https://www.cnblogs.com/zzg521/p/6761576.html
Two: Find all children under the parent ID:
Test Data:
$arrCate = array( //Array to be sorted
array('id' => 1, 'name' => 'Top column one', 'parent_id' => 0),
array('id' => 2, 'name' => 'Top column two', 'parent_id' => 0),
array('id' => 3, 'name' => 'Column 3', 'parent_id' => 1),
array('id' => 4, 'name' => 'Column 4', 'parent_id' => 3),
array('id' => 5, 'name' => 'Column 5', 'parent_id' => 4),
array('id' => 6, 'name' => 'Column 6', 'parent_id' => 2),
array('id' => 7, 'name' => 'Column 7', 'parent_id' => 6),
array('id' => 8, 'name' => 'Column 8', 'parent_id' => 6),
array('id' => 9, 'name' => 'column nine', 'parent_id' => 7),
);
Get all children of the corresponding parent and return flat structure data
/**
* Recursive infinite-level classification to obtain all children under any node
* @param array $arrCate array to be sorted
* @param int $parent_id parent node
* @param int $level number of levels
* @return array $arrTree sorted array (flattened data)
*/
function getTree($arrCate, $parent_id = 0, $level = 0){<!-- -->
static $arrTree = []; //The variable value is still saved after the static function is executed
if(empty($arrCate)) return [];
$level + + ;
foreach($arrCate as $key => $value){<!-- -->
if($value['parent_id'] == $parent_id){<!-- -->
$value['level'] = $level;
$arrTree[] = $value;
unset($arrCate[$key]); //Unregister the current node data to reduce useless traversal
getTree($arrCate, $value['id'], $level); //Recursive call
}
}
return $arrTree;
}
print_r(getTree($arrCate));
//The output results are as follows:
Array
(
[0] => Array
(
[id] => 1
[name] => Top column one
[parent_id] => 0
[level] => 1
)
[1] => Array
(
[id] => 3
[name] => Column 3
[parent_id] => 1
[level] => 2
)
[2] => Array
(
[id] => 4
[name] => Column 4
[parent_id] => 3
[level] => 3
)
[3] => Array
(
[id] => 5
[name] => Column 5
[parent_id] => 4
[level] => 4
)
[4] => Array
(
[id] => 2
[name] => Top column two
[parent_id] => 0
[level] => 1
)
[5] => Array
(
[id] => 6
[name] => Column 6
[parent_id] => 2
[level] => 2
)
[6] => Array
(
[id] => 7
[name] => Column 7
[parent_id] => 6
[level] => 3
)
[7] => Array
(
[id] => 9
[name] => Column 9
[parent_id] => 7
[level] => 4
)
[8] => Array
(
[id] => 8
[name] => Column 8
[parent_id] => 6
[level] => 3
)
)
Get all children of the corresponding parent and return tree structure data
/**
* Convert a two-dimensional array set into a Tree
* @param $list data set
* @param string $pk primary key
* @param string $pid parent id
* @param string $child child data key
* @param int $root specifies the top-level id
* @return array $tree processed data (tree structure)
*/
function listTree($list, $pk = 'id', $pid = 'parent_id', $child = 'children', $root = 0){<!-- -->
$tree = [];
if(is_array($list)){<!-- -->
// Create an array reference based on the primary key
$refer = array();
foreach($list as $key => $data){<!-- -->
$refer[$data[$pk]] = & amp;$list[$key];
}
foreach($list as $key => $data){<!-- -->
// Determine whether parent exists
$parentId = $data[$pid];
if($root == $parentId){<!-- -->
$tree[] = & amp;$list[$key];
}else{<!-- -->
if(isset($refer[$parentId])){<!-- -->
$parent = & amp;$refer[$parentId];
$parent[$child][] = & amp;$list[$key];
}
}
}
}
return $tree;
}
print_r(listTree($arrCate));
//The output results are as follows:
Array
(
[0] => Array
(
[id] => 1
[name] => Top column one
[parent_id] => 0
[children] => Array
(
[0] => Array
(
[id] => 3
[name] => Column 3
[parent_id] => 1
[children] => Array
(
[0] => Array
(
[id] => 4
[name] => Column 4
[parent_id] => 3
[children] => Array
(
[0] => Array
(
[id] => 5
[name] => Column 5
[parent_id] => 4
)
)
)
)
)
)
)
[1] => Array
(
[id] => 2
[name] => Top column two
[parent_id] => 0
[children] => Array
(
[0] => Array
(
[id] => 6
[name] => Column 6
[parent_id] => 2
[children] => Array
(
[0] => Array
(
[id] => 7
[name] => Column 7
[parent_id] => 6
[children] => Array
(
[0] => Array
(
[id] => 9
[name] => Column 9
[parent_id] => 7
)
)
)
[1] => Array
(
[id] => 8
[name] => Column 8
[parent_id] => 6
)
)
)
)
)
)
Three: Find all parent data based on child ID and return tree structure data
Test Data:
$arrCate = array( //Array to be sorted
array('id' => 1, 'name' => 'Top column one', 'parent_id' => 0),
array('id' => 2, 'name' => 'Top column two', 'parent_id' => 0),
array('id' => 3, 'name' => 'Column 3', 'parent_id' => 1),
array('id' => 4, 'name' => 'Column 4', 'parent_id' => 3),
array('id' => 5, 'name' => 'Column 5', 'parent_id' => 4),
array('id' => 6, 'name' => 'Column 6', 'parent_id' => 2),
array('id' => 7, 'name' => 'Column 7', 'parent_id' => 6),
array('id' => 8, 'name' => 'Column 8', 'parent_id' => 6),
array('id' => 9, 'name' => 'column nine', 'parent_id' => 7),
);
Find all parent data (flattened structure):
/**
* Recursive infinite classification to obtain all parents of any node
* @param array $arrCate array to be sorted
* @param int $child_id child node
* @return array $children sorted array (flattened data)
*/
function getparent($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));
//output example
Array
(
[9] => Array
(
[id] => 9
[name] => Column 9
[parent_id] => 7
)
[7] => Array
(
[id] => 7
[name] => Column 7
[parent_id] => 6
)
[6] => Array
(
[id] => 6
[name] => Column 6
[parent_id] => 2
)
[2] => Array
(
[id] => 2
[name] => Top column two
[parent_id] => 0
)
)
Find all parent data (tree structure):
/**
* Recursive infinite classification, obtain all parents of any node
* @param array $arrCate array to be sorted
* @param int $child_id child node
* @return array $children sorted array
*/
function getparents($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'] = $v; //Splice the children into the parent's children
}
if($v['parent_id'] == 0){<!-- -->
$top_id = $v['id']; //Top node id
}
\t\t
}
\t
return $children[$top_id]; //Return the tree structure data from the top to the specified child node
\t
}
print_r(getparents($arrCate));
//Example output:
Array
(
[id] => 2
[name] => Top column two
[parent_id] => 0
[children] => Array
(
[id] => 6
[name] => Column 6
[parent_id] => 2
[children] => Array
(
[id] => 7
[name] => Column 7
[parent_id] => 6
[children] => Array
(
[id] => 9
[name] => Column 9
[parent_id] => 7
)
)
)
)
Reference: https://www.cnblogs.com/-mrl/p/13803740.html