How to Call Custom User Profile Fields from Array?

I have a user profile array that, when I use print_r returns the following:

Array ( [0] => Array ( [first_name] => Array ( [0] => Andrea ) [last_name] => Array ( [0] => Weiss ) [nickname] => Array ( [0] => Andrea ) …(more metas)…

How can I call the different metas? The following code used to work, but doesn’t work since the latest update.

`foreach($adminauthors as $author) {
$display_name = $author[nickname];
echo $display_name;
}’

Thanks.