Tell the end of a .each loop in ruby

If it's an either/or situation, where you're applying some code to all but the last user and then some unique code to only the last user, one of the other solutions might be more appropriate.

However, you seem to be running the same code for all users, and some additional code for the last user. If that's the case, this seems more correct, and more clearly states your intent:

users.each do |u|
  #code for everyone
end

users.last.do_stuff() # code for last user

users.each_with_index do |u, index|
  # some code
  if index == users.size - 1
    # code for the last user
  end
end