相同數組的組合為新數組

array (size=2)  'id' => int 139  'key' => string '11111' array (size=2)  'id' => int 139  'key' => string '22222' array (size=2)  'id' => int 159  'key' => string '33333'array (size=2)  'id' => int 159  'key' => string '44444'

合并為

array (size=2)  'id' => int 139  'key' => string '11111，22222' array (size=2)  'id' => int 159  'key' => string '33333，44444'

回複內容：

array (size=2)  'id' => int 139  'key' => string '11111' array (size=2)  'id' => int 139  'key' => string '22222' array (size=2)  'id' => int 159  'key' => string '33333'array (size=2)  'id' => int 159  'key' => string '44444'

合并為

array (size=2)  'id' => int 139  'key' => string '11111，22222' array (size=2)  'id' => int 159  'key' => string '33333，44444'

$arr = [    ["id"=>139, "key"=>"111"],    ["id"=>139, "key"=>"222"],    ["id"=>159, "key"=>"333"],    ["id"=>159, "key"=>"444"]];$res = [];foreach( $arr as $item ) $res[ $item['id'] ][] = $item['key'];

