Merge multiple csv files into one in Ruby

merge_csv.rb

require "csv"

def csv_headers
  ["Your", "Headers", "Here"]
end

files = Dir["file_names_*.csv"].sort_by { |f| "if you want to sort the files" }
file_contents = files.map { |f| CSV.read(f) }

csv_string = CSV.generate do |csv|
  csv << csv_headers
  file_contents.each do |file|
    file.shift                  # remove the headers of each file
    file.each do |row|
      csv << row
    end
  end
end

File.open("one_csv_to_rule_them_all.csv", "w") { |f| f << csv_string }

Just thought, since I used this as a starting point and then re-wrote it I would post what I did.

require "csv"
# create new csv for the final output with the final header:w
CSV.open("final.csv", "wb", write_headers: true, headers: ["your", "headers"]) do |csv|
  Dir["data_files/*.csv"].each do |path|  # for each of your csv files
    CSV.foreach(path, headers: true, return_headers: false) do |row| # don't output the headers in the rows
      csv << row # append to the final file
    end
  end
end