Sorting two arrays

sort_with

# Given two 'linked' array, you want to sort one and reorder the second to preserve the same sequence of the first:

a = [3,2,7,5,1,9,3]
b = [:a, :b, :c, :d, :e, :f, :g]

def a.sort_with(arr)
  raise "the two array must have the same size" if size!=arr.size
  h = self.collect.with_index{|e,i| [e, arr[i]]}.sort{|x,y| y.first<=>x.first}
  [h.map{|e| e.first}, h.map{|e| e.last}]
end

puts a.sort_with(b).inspect