<?php 
$foo = array(
    (object) array("test" => "123.123.123"),
    (object) array("test" => "312.312.312"),
    (object) array("test" => "456.456.456"),
    (object) array("test" => "789.789.789")
);

print_r($foo);


$bar = array_map(function ($n) {
    return $n->test;
}, $foo);

print_r($bar);
?>