Selection sort in Ruby

gistfile1.rb

class Array
  def selection_sort
    tmp = self.dup
    res = []
    res.push tmp.delete_min until tmp.empty?
    res
  end
  def delete_min
    min_index = find_index { |v| v == self.min }
    delete_at(min_index)
  end
end

p [3,1,5,6,10,9].selection_sort
# [1, 3, 5, 6, 9, 10]