The pluck method, a new feature added in Ruby on Rails 3.2, is very convenient.

・pluck (ActiveRecord::Calculations) - APIdock

Instead of creating a single-column array with map like this:

blog_titles = Blog.all.map(&:title)

With the pluck method, you can write it like this:

blog_titles = Blog.pluck(:title)

Moreover, it has better performance, so there’s no reason not to use pluck.

・The Amazing Performance of the pluck Method Introduced in Rails 3.2 - (ﾟ∀ﾟ)o彡 sasata299’s blog

＿人人人人人人人人人＿ ＞　pluck ステキ！　＜ ￣Y^Y^Y^Y^Y^Y^Y^Y￣

・#318 Upgrading to Rails 3.2 - RailsCasts

That’s all from the Gemba.