Home >Backend Development >PHP Tutorial >请教一个简单的递归
请教一个简单的递归
- WBOYOriginal
- 2016-06-23 14:10:38757browse
$arr = array(
array(
'id' => 1,
'parentid' => 0,
'title' => 'a'
),
array(
'id' => 2,
'parentid' => 1,
'title' => 'a-1'
),
array(
'id' => 3,
'parentid' => 1,
'title' => 'a-1'
),
array(
'id' => 4,
'parentid' => 2,
'title' => 'a-1-1'
)
);
递归转换为数组如下:
$arr = array(
array(
'id' => 1,
'parentid' => 0,
'title' => 'a',
'child' => array(
array(
'id' => 2,
'parentid' => 1,
'title' => 'a-1',
'child' => array(
......
)
array(
'id' => 3,
'parentid' => 2,
'title' => 'a-2'
)
),
......
);
请问要如何写这个递归呢?
回复讨论(解决方案)
function findChildren($list, $p=0){ $r = array(); foreach($list as $id=>$item){ if($item['parentid'] == $p) { $r[$id] = $item; if($t = findChildren($list, $item['id']) ) $r[$id]['children'][] = $t; } } return $r;} $arr = array( array( 'id' => 1, 'parentid' => 0, 'title' => 'a' ), array( 'id' => 2, 'parentid' => 1, 'title' => 'a-1' ), array( 'id' => 3, 'parentid' => 1, 'title' => 'a-1' ), array( 'id' => 4, 'parentid' => 2, 'title' => 'a-1-1' ) );print_r(findChildren($arr));Array (
[0] => Array
(
[id] => 1
[parentid] => 0
[title] => a
[children] => Array
(
[0] => Array
(
[1] => Array
(
[id] => 2
[parentid] => 1
[title] => a-1
[children] => Array
(
[0] => Array
(
[3] => Array
(
[id] => 4
[parentid] => 2
[title] => a-1-1
)
)
)
)
[2] => Array
(
[id] => 3
[parentid] => 1
[title] => a-1
)
)
)
)
)