How to attach an attribute to each element in a PHP array

Question

Suppose we have an array with one attribute for each element:

Array ( [0] => A [1] => B [2] => C [3] => D ) 

Is it possible to add the same uniform attribute to each of the elements, so that a new two-dimensional array would be obtained? Ie for attribute X:

Array ( [0] => Array ( [0] => A [1] => X)
        [1] => Array ( [0] => B [1] => X)
        [2] => Array ( [0] => C [1] => X) )

I know, I could do it using for each loop, but is there any more elegant solution (such as array_combine)?

(For assigning different values, please refer to: Assigning a value to each array element PHP )

Answer 1

You could use array_map :

$array = array ( 'A', 'B', 'C', 'D' );
$array = array_map(function($el) {
  return array($el, 'X');
}, $array);

Answer 2

array_walk could work as well.

$arr = array('A', 'B', 'C', 'D');
array_walk($arr, 'arrFunc');
function arrFunc(&$item, $key)
{
    $item = array($item, 'X'); 
}