From: jko170 Date: 2007-03-15T23:50:05+09:00 Subject: What does this do? : Looking at this piece of code, what does the colon do? def partner_to(user) raise ArgumentError unless user user.id == recipient_id ? sender : recipient end I got the code from this rails post: http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/7fdccddde9b97ffc/6112294580b9e0ce?lnk=gst&q=internal+mail&rnum=1#6112294580b9e0ce I'm just asking because I've never seen the colon used before.