From: Joel Pearson Date: 2013-01-12T19:07:51+09:00 Subject: Re: what is the difference between a.map! and a.map? You'll find this symbol on quite a few methods in Ruby, in general there will only be a method with "!" (modify the object in place) if there's also one which returns a new object without changing the original. Look up "Ruby Bang Methods" for more info. -- Posted via http://www.ruby-forum.com/.