Can someone explain the following code to me?

Question

I am following along with the Rails 3 in Action book, and it is talking about override to_s in the model. The code is the following:

def to_s
           


        

Answer 1

It's string interpolation. "#{email} (#{admin? ? "Admin" : "User"})" is equivalent to

email.to_s + " (" + (admin? ? "Admin" : "User") + ")"

that is

email.to_s + " (" + if admin? then "Admin" else "User" end + ")"

As a result of being enclosed in quotes, in this context Admin and User are used as strings and not as constants.