SecureRandom effectiveness

random_iterations.rb

require 'securerandom'

REGEX = /(?=.*\d)(?=.*[a-z])(?=.*[A-Z])((?=.*[^\w])|(?=.*_))/


def run
  times = 0
  word = begin
    times += 1
    SecureRandom.urlsafe_base64
  end until word =~ REGEX
  times
end


attempts = (1..1_000_000).map do
  run
end


counts = {}
attempts.each do |i|
  counts[i] ||= 0
  counts[i] += 1
end

=begin
counts:
{2=>249217,
 1=>470640,
 3=>132049,
 4=>69634,
 5=>36868,
 9=>2948,
 10=>1533,
 6=>19600,
 7=>10347,
 8=>5420,
 12=>443,
 11=>808,
 14=>117,
 17=>26,
 13=>238,
 15=>54,
 16=>40,
 20=>5,
 19=>3,
 18=>8,
 21=>2}
=end