Reorganize a two-dimensional array into an array with the same key values

Array(    [0] => ArrayShanghai         )     [1] => Array                                                                                                                                     )     [2] => ArrayShanghai         )     [3] => Array                                                                                                      )     [4] => Array             (                                                                                                                  ) )According to the same title, reassemble the array into: Array(    [0] => Array        (            [title] => 111            [name] => 上海,杭州        )     [1] => Array        (                                                                                  ) )

实现代码：

function array_group_concat($ar, $field, $group_by) {

  $res = array();
  foreach($ar as $row) {
    $g = $row[$group_by];
    if(isset($res[$g])) $res[$g][$f