fun with CSVs

extended_csv.rb

require 'csv'

class ExtendedCSV
  attr_accessor :filepaths

  def initialize filepaths
    @filepaths = [*filepaths]
  end

  def + other_extended_csv
    self.class.new self.filepaths + other_extended_csv.filepaths
  end

  def content
    return @content if defined? @content

    @content ||= []
    @filepaths.each_with_index do |csv_filepath, i|
      csv = CSV.parse(File.read(csv_filepath))
      csv.shift unless i == 0

      csv.each do |row|
        @content << row
      end
    end

    @content
  end

  def == other_extended_csv
    content == other_extended_csv.content
  end

  def content_length
    content.length
  end

  def write! outfile = nil
    outfile ||= default_outfile_name
    
    CSV.open(outfile, "wb") do |csv|
      content.each do |row|
        csv << row
      end
    end

    puts "wrote #{@filepaths.length} files to #{outfile}"
  end

private

  def default_outfile_name
    "#{Time.now.strftime("%Y%m%d%H%M%S")}_#{@filepaths.length}_files.csv"
  end
end

first  = ExtendedCSV.new 'first.csv'
second = ExtendedCSV.new 'second.csv'
parts  = ExtendedCSV.new ['first.csv', 'second.csv']
whole  = ExtendedCSV.new 'first_and_second_already_combined.csv'

# using the + operator
puts (whole == (first + second)) ? "matchy!" : "no matchy!"

# using the initializer
puts "whole contains #{whole.content_length} records"
puts "parts contain #{parts.content_length} records"
puts (whole == parts) ? "matchy!" : "no matchy!"

moved to: https://github.com/jeffreyiacono/extended_csv