Split a large CSV into smaller CSVs specifying the max rows per file

csv_splitter.rb

require "csv"

def split_csv(file, max)
  csv = CSV.read(file, headers: true)
  csv_headers = csv.headers
  total_files = ((csv.length - 1)/max.to_f).ceil
  max = max.to_i
  csv = csv.to_a
  name = file.split(".csv")[0]
  path = "./csv/"
  Dir.mkdir(path) unless File.exists?(path)

  puts "Splitting #{csv.length - 1} rows into #{total_files} files"

  total_files.times do |index|
    csv_start = index * max + 1
    csv_end = csv_start + max - 1

    puts "#{path}#{name}-#{index + 1}"

    CSV.open("#{path}#{name}-#{index + 1}.csv", "w") do |writer|
      writer << csv_headers
      binding.pry unless csv[csv_start, csv_end]
      csv[csv_start, csv_end].each do |row|
        writer << row
      end
    end
  end
end

split_csv(ARGV[0], ARGV[1])