Ruby transformation to merge an Array of Hashes into another Array of Hash?

Question

I have

 [
   {:date => "2012-05", :post => 1}, 
   {:date => "2012-12", :post => 1}, 
   {:date => "2013-02", :post => 1}, 
   {:date => "2012-05", :online => 1}
 ]

And I want to get:

[
  {:date => "2012-05", :post => 1, :online => 1}, 
  {:date => "2012-12", :post => 1 }, 
  {:date => "2013-02", :post => 1 }
]

Anyone sees how to apply Ruby hash/array methods to achieve this?

Answer 1

q.group_by { |x| x[:date] }.values.map { |e| e.reduce :merge }