The problem is a bit difficult. do not go to the php Tutorial if you are dizzy.

The problem is a bit difficult. do not enter pai_^ array (0 => array ('id' => '10', 'title' => 'A ', 'type' => '1', 'bian '=> '1 '),
1 => array ('id' => '10', 'title' => 'A', 'type' => '1', 'bian '=> 2 ),
2 => array ('id' => '11', 'title' => 'B', 'type' => '2 ', 'bian '=> '1 '),
3 => array ('id' => '11', 'title' => 'C', 'type' => '2 ', 'bian '=> '2 '),
)
When type = 1 removes duplicate IDs and the key is changed to id, when type = 2, the KEY is changed to id_bian format and is eventually converted to the following array
Array (0 => array ('10' => '', '11 _ 1' =>'', '11 _ 2' => ''),)
Then merge with the following array
Array (0 => array ('10' => '1', '11 _ 2' => '1 '),
1 => array ('10' => '1', '11 _ 2' => '1 '),
2 => array ('11 _ 1' => '1', '11 _ 2' => '1 '),
3 => array ('10' => '2', '11 _ 2' => '1 '),
)
Finally
Array (0 => array ('10' => '1', '11 _ 1' => '', '11 _ 2' => '1 '),
1 => array ('10' => '1', '11 _ 1 => '', 11_2 '=> '1 '),
2 => array ('10' => '', '11 _ 1' => '1', '11 _ 2' => '1 '),
3 => array ('10' => '2', '11 _ 1' => '', '11 _ 2' => '1 '),
)

Reply to discussion (solution)

$a = array ( 0 => array ( 'id' => '10', 'title' => 'a','type' => '1', 'bian'=>'1'),  1 => array ( 'id' => '10', 'title' => 'a','type' => '1', 'bian'=>'2'),  2 => array ( 'id' => '11', 'title' => 'b','type' => '2', 'bian'=>'1'), 3 => array ( 'id' => '11', 'title' => 'c','type' => '2', 'bian'=>'2'),  );$b = array ( 0 => array ( '10' => '1','11_2' => '1'),  1 => array ( '10' => '1','11_2' => '1'), 2 => array ( '11_1' => '1','11_2' => '1'), 3 => array ( '10' => '2','11_2' => '1'),  );$t = array();foreach($a as $item) {  if($item['type'] == '1') {    $t[$item['id']] = '';  }else $t[$item['id'].'_'.$item['bian']] = '';}$c = array();foreach($b as $v) {  $r = array();  foreach($t as $k=>$n) $r[$k] = @$v[$k];  $c[] = $r;}print_r($c);

Array(    [0] => Array        (            [10] => 1            [11_1] =>             [11_2] => 1        )    [1] => Array        (            [10] => 1            [11_1] =>             [11_2] => 1        )    [2] => Array        (            [10] =>             [11_1] => 1            [11_2] => 1        )    [3] => Array        (            [10] => 2            [11_1] =>             [11_2] => 1        ))

$a = array ( 0 => array ( 'id' => '10', 'title' => 'a','type' => '1', 'bian'=>'1'),  1 => array ( 'id' => '10', 'title' => 'a','type' => '1', 'bian'=>'2'),  2 => array ( 'id' => '11', 'title' => 'b','type' => '2', 'bian'=>'1'), 3 => array ( 'id' => '11', 'title' => 'c','type' => '2', 'bian'=>'2'),  );$b = array ( 0 => array ( '10' => '1','11_2' => '1'),  1 => array ( '10' => '1','11_2' => '1'), 2 => array ( '11_1' => '1','11_2' => '1'), 3 => array ( '10' => '2','11_2' => '1'),  );$t = array();foreach($a as $item) {  if($item['type'] == '1') {    $t[$item['id']] = '';  }else $t[$item['id'].'_'.$item['bian']] = '';}$c = array();foreach($b as $v) {  $r = array();  foreach($t as $k=>$n) $r[$k] = @$v[$k];  $c[] = $r;}print_r($c);

Array(    [0] => Array        (            [10] => 1            [11_1] =>             [11_2] => 1        )    [1] => Array        (            [10] => 1            [11_1] =>             [11_2] => 1        )    [2] => Array        (            [10] =>             [11_1] => 1            [11_2] => 1        )    [3] => Array        (            [10] => 2            [11_1] =>             [11_2] => 1        ))

If you append $ t to $ C as an element, do you want to traverse it again?
Append an array ('10' => '', '11 _ 1' =>'', '11 _ 2' => '') as the $ c

I don't quite understand what you mean

I don't quite understand what you mean

$a = array ( 0 => array ( 'id' => '10', 'title' => 'a','type' => '1', 'bian'=>'1'),  1 => array ( 'id' => '10', 'title' => 'a','type' => '1', 'bian'=>'2'),  2 => array ( 'id' => '11', 'title' => 'b','type' => '2', 'bian'=>'1'), 3 => array ( 'id' => '11', 'title' => 'c','type' => '2', 'bian'=>'2'),  );$b = array ( 0 => array ( '10' => '1','11_2' => '1'),  1 => array ( '10' => '1','11_2' => '1'), 2 => array ( '11_1' => '1','11_2' => '1'), 3 => array ( '10' => '2','11_2' => '1'),  );$t = array();foreach($a as $item) {  if($item['type'] == '1') {    $t[$item['id']] = '';  }else $t[$item['id'].'_'.$item['bian']] = '';}$c = array();foreach($b as $v) {  $r = array();  foreach($t as $k=>$n) $r[$k] = @$v[$k];  $c[] = $r;}print_r($c);

Is the result of array a inserted into $ c? is it necessary to traverse $ c once?

Not traversing $ c.