Module: RedisVoteable::Voteable::InstanceMethods

Defined in:
lib/redis_voteable/voteable.rb

Instance Method Summary (collapse)

Instance Method Details

- (Object) confidence(bound = :lower)

Calculates the (lower) bound of the Wilson confidence interval See: en.wikipedia.org/wiki/Binomial_proportion_confidence_interval#Wilson_score_interval and: www.evanmiller.org/how-not-to-sort-by-average-rating.html



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# File 'lib/redis_voteable/voteable.rb', line 114

def confidence(bound = :lower)
  #include Math
  n = up_votes + down_votes
  if n == 0
    return 0 if n == 0
  end
  z = 1.4395314800662002 # Determines confidence to estimate. 
                         #    1.0364333771448913 = 70%
                         #    1.2815515594600038 = 80%
                         #    1.4395314800662002 = 85%
                         #    1.644853646608357  = 90%
                         #    1.9599639715843482 = 95%
                         #    2.2414027073522136 = 97.5%
  p_hat = 1.0*up_votes/n
  left  = p_hat + z*z/(2*n)
  right = z * Math.sqrt( (p_hat*(1-p_hat) + z*z/(4*n)) / n )
  under = 1 + z*z/n
  return (left - right) / under unless bound == :upper
  return (left + right) / under
  #return Math.sqrt( p_hat + z * z / ( 2 * n ) - z * ( ( p_hat * ( 1 - p_hat ) + z * z / ( 4 * n ) ) / n ) ) / ( 1 + z * z / n )
end

- (Object) down_percentage 



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# File 'lib/redis_voteable/voteable.rb', line 45

def down_percentage
  return (down_votes.to_f * 100 / total_votes) unless total_votes == 0
  nil
end

- (Boolean) down_voted?(voter)

Returns true if the voter down voted the voteable.

Returns:

  • (Boolean) 


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# File 'lib/redis_voteable/voteable.rb', line 68

def down_voted?(voter)
  redis.sismember prefixed("#{class_key(voter)}:#{DOWN_VOTES}"), "#{class_key(self)}"
end

- (Object) down_voters 



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# File 'lib/redis_voteable/voteable.rb', line 96

def down_voters
  voters = redis.smembers prefixed("#{class_key(self)}:#{DOWN_VOTERS}")
  voters.map do |voter|
    tmp = voter.split(':')
    klass = tmp[0, tmp.length-1].join(':').constantize
    if klass.respond_to?('find')
      klass.find(tmp.last)
    elsif klass.respond_to?('get')
      klass.get(tmp.last)
    else
      nil
    end
  end
end

- (Object) down_votes 



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# File 'lib/redis_voteable/voteable.rb', line 26

def down_votes
  redis.scard prefixed("#{class_key(self)}:#{DOWN_VOTERS}")
end

- (Object) tally

Return the difference between up and and votes. May be negative if there are more down than up votes.



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# File 'lib/redis_voteable/voteable.rb', line 36

def tally
  up_votes - down_votes
end

- (Object) total_votes 



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# File 'lib/redis_voteable/voteable.rb', line 30

def total_votes
  up_votes + down_votes
end

- (Object) up_percentage 



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# File 'lib/redis_voteable/voteable.rb', line 40

def up_percentage
  return (up_votes.to_f * 100 / total_votes) unless total_votes == 0
  nil
end

- (Boolean) up_voted?(voter)

Returns true if the voter up voted the voteable.

Returns:

  • (Boolean) 


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# File 'lib/redis_voteable/voteable.rb', line 63

def up_voted?(voter)
  redis.sismember prefixed("#{class_key(voter)}:#{UP_VOTES}"), "#{class_key(self)}"
end

- (Object) up_voters 



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# File 'lib/redis_voteable/voteable.rb', line 81

def up_voters
  voters = redis.smembers prefixed("#{class_key(self)}:#{UP_VOTERS}")
  voters.map do |voter|
    tmp = voter.split(':')
    klass = tmp[0, tmp.length-1].join(':').constantize
    if klass.respond_to?('find')
      klass.find(tmp.last)
    elsif klass.respond_to?('get')
      klass.get(tmp.last)
    else
      nil
    end
  end
end

- (Object) up_votes 



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# File 'lib/redis_voteable/voteable.rb', line 22

def up_votes
  redis.scard prefixed("#{class_key(self)}:#{UP_VOTERS}")
end

- (Boolean) vote_value?(voter)

Returns :up, :down, or nil.

Returns:

  • (Boolean) 


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# File 'lib/redis_voteable/voteable.rb', line 56

def vote_value?(voter)
  return :up   if up_voted?(voter)
  return :down if down_voted?(voter)
  return nil
end

- (Boolean) voted?(voter)

Returns true if the voter voted on the voteable.

Returns:

  • (Boolean) 


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# File 'lib/redis_voteable/voteable.rb', line 51

def voted?(voter)
  up_voted?(voter) || down_voted?(voter)
end

- (Object) voters

Returns an array of objects that are voters that voted on this voteable. This method can be very slow, as it constructs each object. Also, it assumes that each object has a find(id) method defined (e.g., any ActiveRecord object).



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# File 'lib/redis_voteable/voteable.rb', line 77

def voters
  up_voters | down_voters
end