Convert array to new format, but with the same data

format_array.hp

$oldFormat = array(
    'male' => 'Male',
    'female' => 'Female'
);

$newFormat = array_map(function($value, $label) {
    return array(
        'label' =>  $label,
        'value' =>  $value,
    );
}, array_keys($oldFormat), array_values($oldFormat));