// Defining a multidimensional array
$favorites = array(
	array(
		"name" => "Dave Punk",
		"mob" => "175",
		"email" => "davepunk@gmail.com",
	),
	array(
		"name" => "Monty Smith",
		"mob" => "200",
		"email" => "montysmith@gmail.com",
	),
array(
		"name" => "Monty Smith",
		"mob" => "362",
		"email" => "montysmith@gmail.com",
	),
	array(
		"name" => "John Flinch",
		"mob" => "100",
		"email" => "johnflinch@gmail.com",
	)
);
//echo $favorites[0]['mob']."\n";
function cmp($a, $b)
{
    if ($a["mob"] == $b["mob"]) {
        return 0;
    }
    return ($a["mob"] > $b["mob"]) ? -1 : 1;
}

usort($favorites,"cmp");

echo $favorites[0]['mob']."\n";
echo $favorites[1]['mob']."\n";
echo $favorites[2]['mob']."\n";
echo $favorites[3]['mob']."\n";