Question

I have a collection like this:

UserLevels
   id
   blah_id
   blah2_id
   ..
   ..

Now I want to further file this collection with all rows that have

blah2_id = 3

I don’t need to hit the database again as I already have this collection, and this collection will have maybe 5-10 rows in it anyhow at most.

What’s the best way to do this? Or what options do I have.

Answer 1

The first option that springs to mind is Array#select (Ruby 1.9 only):

@collection = UserLevel.all
@filtered_collection = @collection.select { |l| l.blah2_id == 3 }

Ruby’s Array class is quite powerful, and is worth investigating: http://www.ruby-doc.org/core/classes/Array.html

In Ruby 1.8, the equivalent method is Enumerable#find_all:

@filtered_collection = @collection.find_all { |l| l.blah2_id == 3 }