ConverterBallotToGrades¶

class whalrus.ConverterBallotToGrades(scale: whalrus.scales.scale.Scale = None, borda_unordered_give_points: bool = True)[source]¶

Default converter to a BallotLevels using numeric grades.

This is a default converter to a BallotLevels using numeric grades. It tries to infer the type of input and converts it to a BallotLevels, with a numeric scale. It is a wrapper for the specialized converters ConverterBallotToLevelsInterval, ConverterBallotToLevelsRange, and ConverterBallotToLevelsListNumeric.

Parameters

scale (numeric Scale) – If specified, then the ballot will be converted to this scale. If it is None, then any ballot that is of class BallotLevels and numeric will be kept as it is, and any other ballot will converted to a BallotLevels using a ScaleInterval with bounds 0 and 1.
borda_unordered_give_points (bool) – When converting a BallotOrder that is not a BallotLevels, we use Borda scores as a calculation step. This parameter decides whether the unordered candidates of the ballot give points to the ordered candidates. Cf. ScorerBorda.

Examples

Typical usages:

>>> ballot = BallotLevels({'a': 100, 'b': 57}, scale=ScaleRange(0, 100))
>>> ConverterBallotToGrades(scale=ScaleInterval(low=0, high=10))(ballot).as_dict
{'a': 10, 'b': Fraction(57, 10)}
>>> ConverterBallotToGrades(scale=ScaleRange(low=0, high=10))(ballot).as_dict
{'a': 10, 'b': 6}
>>> ConverterBallotToGrades(scale=ScaleFromSet({0, 2, 4, 10}))(ballot).as_dict
{'a': 10, 'b': 4}

>>> ballot = BallotLevels({'a': 'Good', 'b': 'Medium'},
...                       scale=ScaleFromList(['Bad', 'Medium', 'Good']))
>>> ConverterBallotToGrades()(ballot).as_dict
{'a': 1, 'b': Fraction(1, 2)}

For more examples, cf. ConverterBallotToLevelsInterval, ConverterBallotToLevelsRange, and ConverterBallotToLevelsListNumeric.