What are the differences between the two php arrays?

I: {code ...} ii. {code ...} the while LOOP retrieves a row of data from $ param-& amp; gt; field. In the second write method $ param_array [& #039; some_id & #039;] [& #039; values & #039;] The array eventually has only one element. I don't know what's going on? I:

while(!$param->end)            {                $param_array[$param->field['param_group_id']]['param_group_name'] = $param->field['param_group_name'];                $param_array[$param->field['param_group_id']]['values'][$param->field['param_id']]                    = $param->field['param_name'];                $param->move_next();            }

II:

while(!$param->end)            {                 $param_array[$param->field['param_group_id']] = array(                    'param_group_name' => $param->field['param_group_name'],                    'values' => array(                        $param->field['param_id'] =>  $param->field['param_name']                    )                );                $param->move_next();            }

The while LOOP retrieves a row of data from $ param-> field each time. In the second write method, $ param_array ['some _ id'] ['values'] has only one element in the array, I don't know what's going on?

Reply content:

I:

while(!$param->end)            {                $param_array[$param->field['param_group_id']]['param_group_name'] = $param->field['param_group_name'];                $param_array[$param->field['param_group_id']]['values'][$param->field['param_id']]                    = $param->field['param_name'];                $param->move_next();            }

II:

while(!$param->end)            {                 $param_array[$param->field['param_group_id']] = array(                    'param_group_name' => $param->field['param_group_name'],                    'values' => array(                        $param->field['param_id'] =>  $param->field['param_name']                    )                );                $param->move_next();            }

The while LOOP retrieves a row of data from $ param-> field each time. In the second write method, $ param_array ['some _ id'] ['values'] has only one element in the array, I don't know what's going on?

The second method is to redefine each time.$param_aray[ $param->field['param_group_id'] ]This element, when$param->field['param_group_id']Duplicate$param_aray[ $param->field['param_group_id'] ]For more information, see the DEMO:

$ Data = array ("id" => 1, "name" => "a", "group" => 2, "value" => 10 ), array ("id" => 2, "name" => "B", "group" => 1, "value" => 11 ), array ("id" => 3, "name" => "c", "group" => 2, "value" => 12 ), array ("id" => 4, "name" => "d", "group" => 1, "value" => 13 ), array ("id" => 5, "name" => "e", "group" => 2, "value" => 14 ),); /* First */$ result = array (); foreach ($ data as $ item) {$ result [$ item ['group'] ['value'] [$ item ['id'] = $ item ['value']} var_dump ($ result); /* type 2 */$ result = array (); foreach ($ data as $ item) {$ result [$ item ['group'] = array ("value" => array ($ item ['id'] => $ item ['value']) ;} var_dump ($ result );