Question

Let’s assume I have the following multidimensional array (retrieved from MySQL or a service):

array(
    array(
        [id] => xxx,
        [name] => blah
    ),
    array(
        [id] => yyy,
        [name] => blahblah
    ),
    array(
        [id] => zzz,
        [name] => blahblahblah
    ),
)

Can we get an array of ids in one “built-in” php function call? or one line of code?
I am aware of the traditional looping and getting the value but I don’t need this:

foreach($users as $user) {
    $ids[] = $user['id'];
}
print_r($ids);

Maybe some array_map() and call_user_func_array() can do the magic.

Answer 1

Since PHP 5.5, you can use array_column:

$ids = array_column($users, 'id');

This is the preferred option on any modern project. However, if you must support PHP<5.5, the following alternatives exist:

Since PHP 5.3, you can use array_map with an anonymous function, like this:

$ids = array_map(function ($ar) {return $ar['id'];}, $users);

Before ^{_{(Technically PHP 4.0.6+)}}, you must create an anonymous function with create_function instead:

$ids = array_map(create_function('$ar', 'return $ar["id"];'), $users);