When creating a calculated field, the functions are split into different sections. The User functions focus specifically on the user that is signed in. It is useful for recalling or creating a Boolean function based of the signed in users information.
These first three functions ask Tableau to return specific information about the user that is signed in:
FULLNAME – Returns the full name of the current user.
USERNAME - Returns the username of the current user when signed in.
USERDOMAIN – Returns the domain name for the current user when signed to Tableau server. Whilst on Tableau desktop, returns the Windows domain.
These next three functions ask Tableau to return a true or false answer based on the signed in user. These can be particularly useful when making a dashboard where different users or sets of users are restricted to seeing content that is specific to them:
ISFULLNAME – Returns true if the users full name is the same as the full name specified. Returns false if the names don’t match. Can be used to show specific information to specific people. Can be used to hide information from some people.
ISMEMBEROF – Returns true if the current user is a member of a group that is specified in the string.
ISUSERNAME – Returns true if the current username is the same as the username specified.