gistfile1.rb

#!/usr/bin/env ruby

# Generate random genomes:
#
# Creates a random genome with the number of contig you specify.
# You can pass the number of characters per line and the max size
# of the contigs.
#
class RandomGenome
  # + hr: root string for the headers
  # + nc: number of contigs to generate
  # + ls: number of characters on each line
  # + ml: maximun size, in lines, of each contig
  def initialize(hr, nc, ls, ml)
    @header_root, @n_contigs, @l_size, @max_c_lines = [hr, nc, ls, ml]
  end

  def generate
    (1..@n_contigs).each do |cn|
      puts ">#{@header_root}_#{cn}\n"
      (1..my_rand).each do |ln|
        puts (1..@l_size).map {|n| rand_n }.join
      end
    end
  end

  protected

  def my_rand
    r = rand(@max_c_lines)
    r == 0 ? my_rand : r
  end

  def rand_n
    %w(A C G T N)[rand(5)]
  end
end

#
# Main
#
RandomGenome.new("original", 2, 72, 4).generate