Module: Random::RangeExtensions

Included in:
Range
Defined in:
lib/standard/facets/random.rb

Overview

Random extensions for Range class.

Instance Method Summary collapse

Instance Method Details

#at_rand ⇒ Object

Return a random element from the range.

(1..4).at_rand           #~> 2
(1..4).at_rand           #~> 4

(1.5..2.5).at_rand       #~> 2.06309842754533
(1.5..2.5).at_rand       #~> 1.74976944931541

('a'..'z').at_rand       #~> 'q'
('a'..'z').at_rand       #~> 'f'

CREDIT: Lavir the Whiolet, Thomas Sawyer



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# File 'lib/standard/facets/random.rb', line 69

def at_rand
  first, last = first(), last()
  if first.respond_to?(:random_delta)  # TODO: work on this!!!
    begin
      first.random_delta(last, exclude_end?)
    rescue
      to_a.at_rand
    end
  else
    to_a.at_rand
  end
  ##elsif first.respond_to?(:succ)
  ##  # optimized algorithm
  ##  if (Fixnum === first || Bignum === first) &&
  ##     (Fixnum === last  || Bignum === last)
  ##    last -= 1 if exclude_end?
  ##    return nil if last < first
  ##    return Random.number(last - first + 1) + first
  ##  end
  ##  # standard algorithm
  ##  return to_a.at_rand
  ##elsif Numeric === first && Numeric === last
  ##  return nil if last < first
  ##  return nil if exclude_end? && last == first
  ##  return (last - first) * Random.number + first
  ##else
  ##  return nil
  ##end
end