PHP rename array keys in multidimensional array

Question

In an array such as the one below, how could I rename "fee_id" to "id"?

Array
(
    [0] => Array
        (
            [fee_id] => 15
            [fee_amount] => 308.5
            [year] => 2009                
        )

    [1] => Array
        (
            [fee_id] => 14
            [fee_amount] => 308.5
            [year] => 2009

        )

)

Answer 1

Copy the current 'fee_id' value to a new key named 'id' and unset the previous key?

foreach ($array as $arr)
{
  $arr['id'] = $arr['fee_id'];
  unset($arr['fee_id']);
}

There is no function builtin doing such thin afaik.

Answer 2

foreach ( $array as $k=>$v )
{
  $array[$k] ['id'] = $array[$k] ['fee_id'];
  unset($array[$k]['fee_id']);
}

This should work

Answer 3

$arrayNum = count($theArray);

for( $i = 0 ; $i < $arrayNum ; $i++ )
{
    $fee_id_value = $theArray[$i]['fee_id'];
    unset($theArray[$i]['fee_id']);
    $theArray[$i]['id'] = $fee_id_value;
}

This should work.