BuddyPress.org

@tubruk

in your child theme, wherever you want to hide fields that have no data, you can put a simple if statement, something like:

if (bp_get_profile_field_data(‘field=your-field-id’) === “”) :
// don’t display code
else:
// display code
endif;

Which file to edit, all depends where it is you are wanting to display / hide the profile field. The most likely file for displaying profile fields is profile-loop.php in members/single/profile, but that already skips blank fields (using a call to bp_field_has_data(); that function has to be used inside the profile field loop).