Cleanest way to create a Hash from an Array

Question

I seem to run into this very often. I need to build a Hash from an array using an attribute of each object in the array as the key.

Lets say I need a hash of example us

Answer 1

You can add to_hash to Array yourself.

class Array
  def to_hash(&block)
    Hash[*self.map {|e| [block.call(e), e] }.flatten]
  end
end

ary = [collection of ActiveRecord objects]
ary.to_hash do |element|
  element.id
end