Renaming a key in a multidimensional array

Question

I want to change key name in a multidimensional array.

My array:

Array
(
    [0] => Array
        (
            [id] => 1
            [fruit namé] => Banana
        )
    [1] => Array
        (
            [id] => 2
            [fruit namé] => Apple
        )
)

My function:

function renameFields($old, $new, $arr) {
    foreach ($arr as $k=>$v) {
        $arr[$k][$new] = $arr[$k][$old];
        unset($arr[$k][$old]);
    }
}

renameFields("fruit namé", "name", $arr);

-

It works for id but not when there an accent like fruit namé.

-

EDIT
I know it's a bad practice to have some special char as key, but this datas came from a French system...

Answer 1

You need to either a) pass $arr to your function by reference or b) have renameFields return the updated array.

Your code currently modifies a copy of the $arr array (because that's what gets passed to renameFields when it's called), and never updates the one that exists outside of the renameFields function.

So, you need to either do:

function renameFields($old, $new, &$arr) {
    foreach ($arr as $k=>$v) {
        $arr[$k][$new] = $arr[$k][$old];
        unset($arr[$k][$old]);
    }
}

renameFields("fruit name", "name", $arr);

Which will pass $arr by reference.

Or:

function renameFields($old, $new, $arr) {
    foreach ($arr as $k=>$v) {
        $arr[$k][$new] = $arr[$k][$old];
        unset($arr[$k][$old]);
    }

    return $arr;
}

$arr = renameFields("fruit name", "name", $arr);

Which will have the function return the updated array and then you need to then update the variable.

P.S. You don't need global $arr; in either case here.

Answer 2

It isn't a good idea to use spaces in your key names. You can do it but it's bad practice.

Here is what I came up with:

$my_array = array(
    array(
        'id' => 1,
        'fruit name' => 'Banana'
    ),
    array(
        'id' => 2,
        'fruit name' => 'Apple'
    )
);

function renameFields($old, $new, $arr) {
    $new_a = array();
    foreach ($arr as $a) {
        $new_a[] = array(
            'id' => $a['id'],
            $new => $a[$old] 
        );
    }
    return $new_a;
}

$new_array = renameFields("fruit name", "name", $my_array);

echo "<pre>";
print_r($new_array);
echo "</pre>";

It is a much better idea to pass the array to the function rather than using a global.