I'm implementing row level security for our dashboards. I can capture the username in tableau easily enough with the username function. The problem is that our usernames come across as email@example.com while the user security table only stores firstname.lastname@example.org. So what I need to do in order to be able to match them is somehow trim the strings so that my calculation can be "If yourname = yourname then etc.". Is there a formula besides Ltrim etc. to capture just the yourname portion of those two fields?