Arraygetindex is a built in lotusscript function that doesn't seem to be used much. There is a quirk.

I was wondering why ArrayGetIndex is not used by developers more.

It basically returns an index number for the position of the value in an array or null if the element does not exist, BUT if the element does not exist ireturns null.

So to test use >=0 or stick isnull( <arraygetindex>)

So how does this work with userroles and roles?

Well you could do a

forall r in roles

if r="[Admin]"  then admin=true

end forall

but a quicker way would be

 If Arraygetindex(db.QueryAccessRoles(s.EffectiveUserName),"[Admin]")>=0 Then Msgbox("[Admin] is there")

or to check that Admin is not in the roles

 If Isnull( Arraygetindex(db.QueryAccessRoles(s.EffectiveUserName),"[Admin]") ) Then Msgbox("[Admin] not there")

Example code:

Dim s As New notessession
 Dim db As notesdatabase
 Set db = s.currentdatabase
 roles = db.QueryAccessRoles(s.EffectiveUserName)
 Msgbox (Implode(roles,"--"))
 
 If Isnull( Arraygetindex(roles,"[Admin]") ) Then Msgbox("[Admin] not there")
 If  Arraygetindex(roles,"[Admin]")>=0 Then Msgbox("[Admin] is there")