PHP：将当前Joomla用户名设置为变量

how can I set in a php-script the username of the user, that is logged in at the moment, as a variable? I know, how I can get and display the current username, but how can I set this as a variable?

This is the code, which I want to set as a variable:

<?php
    $user = JFactory::getUser();
    $user->username;
?>

Thanks for your help.

It looks like you are already almost doing it.

<?php
    $user = JFactory::getUser();
    $username = $user->username;
?>

Though, $user->username is already containing this information, so I think that is why everyone is confused.