How can I create an array from the values of another array's key?

Question

I have an array as follows:

$arr1 = array(
  0 => array(
    \'name\' => \'tom\',
    \'age\' => 22
  ),
  1 => array(
    \'name\' => \'nick\',
           


        

Answer 1

Newer versions of PHP allow using array_map() with a function expression instead of a function name:

$arr2 = array_map(function($person) {
    return $person['name'];
}, $arr1);

But if you are using a PHP < 5.3, it is much easier to use a simple loop, since array_map() would require to define a (probably global) function for this simple operation.

$arr2 = array();

foreach ($arr1 as $person) {
    $arr2[] = $person['name'];
}

// $arr2 now contains all names