ruby - rails - Find objects with duplicate attributes -

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if have array of object foo how can find , return objects duplicate values specific attributes? instance, want return objects have duplicate values both foo.x , foo.y

i using rails 3.2 , ruby 1.9

i looking like:

one = foo.create!(:x => 1, :y => 2, :z => 3) 2 = foo.create!(:x => 1, :y => 2, :z => 6) 3 = foo.create!(:x => 4, :y => 2, :z => 3)  arr = [one, two, three]  arr.return_duplicates_for_columns(foo.x, foo.y) = [one, two]

i'm not sure solution or how work you, should work.

foos = foo.some_ar_query_that_returns_some_foos grouped_foos = foo.group_by {|f| [f.x, f.y]}

grouped_foos hash. keys array of x , y values. values array of foo instances same values. element of hash size of value more 1 has duplicates.


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