RuleScorePositional

class whalrus.RuleScorePositional(*args, converter: whalrus.converters_ballot.converter_ballot.ConverterBallot = None, points_scheme: list = None, **kwargs)[source]

A positional scoring rule.

Parameters

Examples

>>> RuleScorePositional(['a > b > c', 'b > c > a'], points_scheme=[3, 2, 1]).gross_scores_
{'a': 4, 'b': 5, 'c': 3}

Since this voting rule needs strict orders, problems may occur as soon as there is indifference in the ballots. To avoid these issues, specify the ballot converter explicitly:

>>> RuleScorePositional(['a > b ~ c', 'b > c > a'], points_scheme=[1, 1, 0],
...     converter=ConverterBallotToStrictOrder(priority=Priority.ASCENDING)).gross_scores_
{'a': 1, 'b': 2, 'c': 1}
property average_score_

The average score.

Type

Number

property average_score_as_float_

The average score as a float. It is the same as average_score_, but converted to a float.

Type

float

property best_score_as_float_

The best score as a float. It is the same as RuleScore.best_score_, but converted to a float.

Type

float

compare_scores(one: numbers.Number, another: numbers.Number) → int

Compare two scores.

Parameters
  • one (object) – A score.

  • another (object) – A score.

Returns

0 if they are equal, a positive number if one is greater than another, a negative number otherwise.

Return type

int

property cotrailers_

“Cotrailers”. The set of candidates with the worst score.

Type

NiceSet

property cowinners_

Cowinners. The set of candidates with the best score.

Type

NiceSet

property gross_scores_

The gross scores of the candidates. For each candidate, this dictionary gives the sum of its scores, multiplied by the weights of the corresponding voters. This is the numerator in the candidate’s average score.

Type

NiceDict

property gross_scores_as_floats_

Gross scores as floats. It is the same as gross_scores_, but converted to floats.

Type

NiceDict

property n_candidates_

Number of candidates.

Type

int

property scores_as_floats_

Scores as floats. It is the same as scores_, but converted to floats.

Type

NiceDict

property strict_order_

Result of the election as a strict order over the candidates. The first element is the winner, etc. This may use the tie-breaking rule.

Type

list

property trailer_

The “trailer” of the election. This is the last candidate in strict_order_ and also the unfavorable choice of the tie-breaking rule in cotrailers_.

Type

object

property weights_

The weights used for the candidates. For each candidate, this dictionary gives the total weight for this candidate, i.e. the total weight of all voters who assign a score to this candidate. This is the denominator in the candidate’s average score.

Type

NiceDict

property weights_as_floats_

Weights as floats. It is the same as weights_, but converted to floats.

Type

NiceDict

property winner_

The winner of the election. This is the first candidate in strict_order_ and also the choice of the tie-breaking rule in cowinners_.

Type

object

property worst_score_as_float_

The worst score as a float. It is the same as RuleScore.worst_score_, but converted to a float.

Type

float