Ruby hash array to CSV

hash_array_to_csv.rb

class Array
  def to_csv(csv_filename="hash.csv")
    require 'csv'
    CSV.open(csv_filename, "wb") do |csv|
      csv << first.keys # adds the attributes name on the first line
      self.each do |hash|
        csv << hash.values
      end
    end
  end
end

# ex: [{a: 1, b: 2}, {a: 3, b: 4}].to_csv("hash.csv")

If the hashes aren't uniform then you will end up with data in the wrong columns. You should use values_at instead:

def to_csv(csv_filename = "hash.csv")
  require "csv"
  CSV.open(csv_filename, "wb") do |csv|
    keys = first.keys
    # header_row
    csv << keys
    self.each do |hash|
      csv << hash.values_at(*keys)
    end
  end
end