CODE EXAMPLE FOR PHP

php get unique values by key from array

$array = array(
	array('group' => 'test', 'name' => 'Jane'),
    array('group' => 'test', 'name' => 'John'),
    array('group' => 'admin', 'name' => 'superadmin')
);
$unique_values_by_key = array_unique(array_column($array, 'group'));