gistfile1.rb

require 'csv'
require 'YAML'

Customer = Struct.new(:cust_id,
                      :elect_or_gas, 
                      :disconnect_doc, 
                      :move_in_date, 
                      :move_out_date, 
                      :bill_year,
                      :bill_month,
                      :span_days,
                      :meter_read_date,
                      :meter_read_type,
                      :consumption,
                      :exception_code, 
                      :data) {
  def initialize *fields
    self.data = fields
  end
}

class Parser
  attr_accessor :customers 

  def initialize filename
    self.customers = [] 
    deserialize_users filename
  end

  def deserialize_users filename
    CSV.foreach(filename, col_sep: "|")  do |row|
      next if row.empty?
      #sanitized_values(cust_id, elect_or_gas, disconnect_doc, move_in_date, move_out_date, bill_year, bill_month, span_days, meter_read_date, meter_read_type, consumption, exception_code = row)
      customers << Customer.new(*row)
    end
    customers
  end

  def serialize_users
    CSV.open("./serialized_users.yaml", "w") do |csv| #is 'a' better?
      customers.each do |c|
        csv << [c.data]  #why an array of hashes is better? and how?
      end
    end
  end
end

class Reporting 

  def initialize data
    @p = Parser.new data
  end

  #STATISTICS

  def unique_customers
    @p.customers.uniq {|customer| customer.cust_id }
  end

  def customers_with_electricity 
    @p.customers.select { |customer| customer.elect_or_gas == "1" && customer.elect_or_gas != "2" }
  end

  def customers_with_gas
    @p.customers.select { |customer| customer.elect_or_gas != "1" && customer.elect_or_gas == "2" }
  end

  #REPORT

  def show_all_data
    print "\n\nALL CUSTOMERS AND DATA\n\n"
    puts @p.customers.map { |customer| customer.data.map { |item| item.to_s.center 15 }.join '|' }
  end

  def show_unique_customers
    print "\n\nUNIQUE CUSTOMERS\n\n"
    unique_customers.map {|customer| puts customer.data.map { |item| item.to_s.center 15}.join'|' }
    puts "\nNumber of unique customers: #{unique_customers.count -1}"
  end


  def show_customers_with_electricity
    print "\n\nCUSTOMERS WITH ELECTRICITY ONLY\n\n"
    customers_with_electricity.map {|customer| puts customer.data.map { |item| item.to_s.center 15}.join'|'}
    puts "\nNumber of customers with electricity: #{customers_with_electricity.count}"
  end

  def show_customers_with_gas
    print "\n\nCUSTOMER WITH GAS ONLY\n\n"
    customers_with_gas.map {|customer| puts customer.data.map { |item| item.to_s.center 15}.join'|'}
    puts "\nNumber of customers with gas: #{customers_with_gas.count}"
  end

end

r = Reporting.new "./pulse_data.txt"

r.show_all_data
r.show_unique_customers
r.show_customers_with_gas    
r.show_customers_with_electricity