Alex (21), Billy (16), Dale (49)<br>Array
(
    [0] => Alex
    [1] => Billy
    [2] => Dale
)
<br>Dale<br>Array
(
    [Alex] => 21
    [Billy] => 16
    [Dale] => 49
)
<br>49<br>Array
(
    [Alex] => 21
    [Billy] => 16
    [Dale] => 49
    [Josh] => 18
)
<br>Array
(
    [Alex] => 18
    [Billy] => 16
    [Dale] => 49
    [Josh] => 18
)