Ruby random string generator with particular length

random_string_generator.rb

class RandomStringGenerator
  def without_numbers(length)
    random_string(length, alphabet)
  end

  def with_numbers(length)
    random_string(length, alphabet + numbers)
  end

  private
  def random_string(length, charset)
    Array.new(length) { charset.sample }.join
  end

  def alphabet
    @alphabet ||= Array('A'..'Z') + Array('a'..'z')
  end

  def numbers
    @numbers ||= Array(0 .. 9)
  end
end

➜  ~  pry
[1] (pry) main: 0> class RandomStringGenerator
[1] (pry) main: 0*   def without_numbers(length)
[1] (pry) main: 0*     random_string(length, alphabet)
[1] (pry) main: 0*   end
[1] (pry) main: 0*
[1] (pry) main: 0*   def with_numbers(length)
[1] (pry) main: 0*     random_string(length, alphabet + numbers)
[1] (pry) main: 0*   end
[1] (pry) main: 0*
[1] (pry) main: 0*   private
[1] (pry) main: 0*   def random_string(length, charset)
[1] (pry) main: 0*     Array.new(length) { charset.sample }.flatten.join
[1] (pry) main: 0*   end
[1] (pry) main: 0*
[1] (pry) main: 0*   def alphabet
[1] (pry) main: 0*     @alphabet ||= Array('A'..'Z') + Array('a'..'z')
[1] (pry) main: 0*   end
[1] (pry) main: 0*
[1] (pry) main: 0*   def numbers
[1] (pry) main: 0*     @numbers ||= Array(0 .. 9)
[1] (pry) main: 0*   end
[1] (pry) main: 0* end
[3] (pry) main: 0>
[4] (pry) main: 0> RandomStringGenerator.new.with_numbers(4)
=> "44sl"
[5] (pry) main: 0> RandomStringGenerator.new.without_numbers(4)
=> "CeNl"

Nice and easy. Thanks for sharing.