gistfile1.rb

result_hash = Hash.new([0, ""])

File.read("path/to/file").each_line do |line| # something like that
  line.each do |column_name, value| # a line is not an hash or nested array, but could possibly convert somehow
    if result_hash[column_name][0] < value.length
      result_hash[column_name][0] = value.length
      result_hash[column_name][1] = line[factual_id]
    end
  end
end