Transpose associative array of indexed arrays to be indexed array of associative arrays

Question

I need to convert a PHP array that I'm getting from a form submission, so that I can use it more usefully in a db.

Array
(
  [first_name] => Array
    (
        [0] => Ben
        [1] => Tom
        [2] => Sarah
    )

  [last_name] => Array
    (
        [0] => Wills
        [1] => Main
        [2] => Bliss
    )

[email] => Array
    (
        [0] => [email protected]
        [1] => [email protected]
        [2] => [email protected]
    )
 )

to:

Array
(
[0] => Array
    (
        [first_name] => Ben
        [last_name] => Wills
        [email] => [email protected]
    )

[1] => Array
    (
        [first_name] => Tom
        [last_name] => Main
        [email] => [email protected]
    )
[2] => Array
    (
        [first_name] => Sarah
        [last_name] => Bliss
        [email] => [email protected]
    )

 )

How can I change the values' key paths so that the first level keys and the second level keys are swapped?

Answer 1

The solution using array_keys, array_values, array_map, call_user_func_array and array_combine functions:

$keys = array_keys($arr);  // supposing $arr is your initial array
$data = call_user_func_array("array_map", array_merge([null], array_values($arr)));
$result = array_map(function($v) use($keys){
    return array_combine($keys, $v);
}, $data);

print_r($result);

The output:

Array
(
    [0] => Array
        (
            [first_name] => Ben
            [last_name] => Wills
            [email] => [email protected]
        )
    [1] => Array
        (
            [first_name] => Tom
            [last_name] => Main
            [email] => [email protected]
        )
    [2] => Array
        (
            [first_name] => Sarah
            [last_name] => Bliss
            [email] => [email protected]
        )
)