Ruby snippet to produce discount codes for use in say, Eventbrite.

discount_codes.rb

require "set"

CHARS = []

("0".."9").each { |x| CHARS << x }
("A".."Z").each { |x| CHARS << x }

def create_code(prefix, length)
	code = ""
	length.times { code << random_character }
	"#{prefix}#{code}"
end

def random_character
	CHARS[rand(CHARS.length)]
end

# The actual method to call. Just load the file into irb and call this.
# filename - (string) filename to save codes to, such as codes.txt
# number - (int) number of codes to generate
# prefix - (string) a prefix to prepend to every code, like "VENDOR" or "FREE"
# length - (int) number of random characters to append
def create_codes(filename, number, prefix, length)
	codes = Set.new
	loop do
		break if codes.size >= number
		codes << create_code(prefix, length)
	end
	File.open(filename, "w") do |f| 
		codes.each { f.puts create_code(prefix, length) }
	end
end

if __FILE__ == $PROGRAM_NAME
	if ARGV.length != 4
		puts """Usage: 
ruby discount_codes.rb output_filename number_of_codes code_prefix length_of_code

"""
		exit
	end
	create_codes(ARGV[0], ARGV[1].to_i, ARGV[2], ARGV[3].to_i)
end