Finding and display custom user variables

Question

I have create a series of user fields. Some of these fields reference taxonomy terms, require a mobile number or are just basic text fields. I used the below to print one of the fields (the number field) inside my page.tpl.php.

global $user;
$user = user_load($user->uid); // Make sure the user object is fully loaded
$number = $user->field_phone_number['und'][0]['value'];

if (isset($number) && !empty($number)) :
print 'Cell: ' . $number;
endif;

My question is how would I go about finding the information I need to print the other fields? The potion that reads ['und'][0]['value']; in particularly is where i'm stuck. I have used devel before to find this information for node variables but I cant find similar information for custom user variables.

Answer 1

It's easier to have Xdebug installed so that you can add breakpoints, pause execution and inspect surrounding variables. Alternatively, you can use Kint to print out variables.