Rails uniq_by - Unique Results From ActiveRecord Relations

6 December 2012 by Jess Brown

I just discovered a neat method in rails called uniq_by. ( http://apidock.com/rails/Array/uniq_by )

It allows you to get a unique set of results from an active record relation.

Ruby provides a way to get unique results from an array like so:

a = [1, 2, 3, 3, 4]
a.uniq # results [1, 2, 3, 4]

But if you have an active record relation, the normal uniq won't work. Say you have a list of stores and you want to find their location, but you only want 1 location from each store/company. You can use:

Location.near("monroe, ga").uniq_by(&:store_id)

And that will give you a nice unique Array from an AR relation!