Ruby on Rails - How to arrange elements of array in particular order

Question

My array is:

[{:age=>28, :name=>"John", :id=>1}, {:name=>"David", :age=>20, :id=>2}]

Order:

[:id, :name, :age] or ['id', 'name', 'age']

The result should be:

[{:id=>1, :name=>"John", :age=>28}, {:id=>2, :name=>"David", :age=>20}]

P/s: I am using Ruby 1.8.7 and Rails 2.3.5

Thanks

Answer 1

As others have said, you cannot do that with Ruby 1.87 or prior. Here is one way to do that with Ruby 1.9+:

arr = [{:age=>28, :name=>"John", :id=>1}, {:name=>"David", :age=>20, :id=>2}]
order = [:id, :name, :age]

arr.map { |h| Hash[order.zip(h.values_at(*order))] }
  #=> [{:id=>1, :name=>"John", :age=>28}, {:id=>2, :name=>"David", :age=>20}] 

In Ruby 2.0+, you can write:

arr.map { |h| order.zip(h.values_at(*order)).to_h }

I thought 1.8.7 went out with the steam engine.