I suppose that ONE user has MANY friendships; In this case, when you call 'friendships' on a 'user':

users = user.friendships

you will get an Array of Friendship objects. And of course, calling (mapping) 'first_name' and 'last_name' methods on Friendship object raise an exception. You should call those methods on a User object if you have corresponding attributes/columns/methods defined in User model.

works:

users = user.friendships.map(&:first_name).join(", ")

not working

users = user.friendships.map(&:first_name, :last_name).join(", ")

thanks for helping

pete