How to parse CSV data with Ruby

Ruby alternatives for parsing CSV files

• Ruby String#split (slow)
• Built-in CSV (ok, recommended)
• ccsv (fast & recommended if you have control over CSV format)
• CSVScan (fast & recommended if you have control over CSV format)
• Excelsior (fast & recommended if you have control over CSV format)

CSV library benchmarks can be found here and here

Parsing with plain Ruby

filename = 'data.csv'
file = File.new(filename, 'r')

file.each_line("\n") do |row|
  columns = row.split(",")
  
  break if file.lineno > 10
end

This option has several problems...

Parsing with the built-in CSV library

require 'csv'

CSV.open('data.csv', 'r', ';') do |row|
  puts row
end

require 'csv'

CSV.foreach("changes.csv", quote_char: '"', col_sep: ';', row_sep: :auto, headers: true) do |row|
  puts row[0]
  puts row['xxx']
end

Parsing with the ccsv library

ccsv is hosted on GitHub.

require 'rubygems'
require 'ccsv'

Ccsv.foreach(file) do |values|
  puts values[0]
end

Parsing with the CSVScan library

CSVScan can be downloaded from here.

require "csvscan"

open("data.csv") do |io|
  CSVScan.scan(io)  do|row|
    puts row
  end
end