# -*- coding: utf-8 -*-
"""
Copyright Sylvain Bouveret, Yann Chevaleyre and François Durand
sylvain.bouveret@imag.fr, yann.chevaleyre@dauphine.fr, fradurand@gmail.com
This file is part of Whalrus.
Whalrus is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Whalrus is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Whalrus. If not, see <http://www.gnu.org/licenses/>.
"""
from whalrus.converters_ballot.converter_ballot import ConverterBallot
from whalrus.converters_ballot.converter_ballot_general import ConverterBallotGeneral
from whalrus.converters_ballot.converter_ballot_to_levels_range import ConverterBallotToLevelsRange
from whalrus.ballots.ballot_veto import BallotVeto
from whalrus.ballots.ballot_plurality import BallotPlurality
from whalrus.ballots.ballot_one_name import BallotOneName
from whalrus.ballots.ballot_levels import BallotLevels
from whalrus.scales.scale_interval import ScaleInterval
from whalrus.scales.scale_from_list import ScaleFromList
from whalrus.scales.scale_from_set import ScaleFromSet
from whalrus.scales.scale_range import ScaleRange
import logging
[docs]class ConverterBallotToLevelsListNonNumeric(ConverterBallot):
"""
Default converter to a :class:`BallotLevels` using a :class:`ScaleFromList` of levels that are not numbers.
This converter works essentially the same as :class:`ConverterBallotToLevelsInterval`, but it then maps the
evaluation to levels of the scale.
Parameters
----------
scale : ScaleFromList
The scale.
borda_unordered_give_points : bool
When converting a :class:`BallotOrder` that is not a :class:`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. :class:`ScorerBorda`.
Examples
--------
Typical usages:
>>> converter = ConverterBallotToLevelsListNonNumeric(
... scale=ScaleFromList(['Bad', 'Medium', 'Good', 'Very Good', 'Great', 'Excellent']))
>>> b = BallotLevels({'a': 1, 'b': .2}, candidates={'a', 'b', 'c'}, scale=ScaleInterval(-1, 1))
>>> converter(b).as_dict
{'a': 'Excellent', 'b': 'Very Good'}
>>> b = BallotLevels({'a': 5, 'b': 4}, candidates={'a', 'b', 'c'}, scale=ScaleRange(0, 5))
>>> converter(b).as_dict
{'a': 'Excellent', 'b': 'Great'}
>>> b = BallotLevels({'a': 4, 'b': 0}, candidates={'a', 'b', 'c'}, scale=ScaleFromSet({-1, 0, 4}))
>>> converter(b).as_dict
{'a': 'Excellent', 'b': 'Medium'}
>>> converter(BallotOneName('a', candidates={'a', 'b', 'c'})).as_dict
{'a': 'Excellent', 'b': 'Bad', 'c': 'Bad'}
>>> converter(BallotPlurality('a', candidates={'a', 'b', 'c'})).as_dict
{'a': 'Excellent', 'b': 'Bad', 'c': 'Bad'}
>>> converter(BallotVeto('a', candidates={'a', 'b', 'c'})).as_dict
{'a': 'Bad', 'b': 'Excellent', 'c': 'Excellent'}
>>> converter('a > b > c > d').as_dict
{'a': 'Excellent', 'b': 'Very Good', 'c': 'Good', 'd': 'Bad'}
"""
def __init__(self, scale: ScaleFromList, borda_unordered_give_points: bool = True):
self.scale = scale
self.borda_unordered_give_points = borda_unordered_give_points
def __call__(self, x: object, candidates: set =None) -> BallotLevels:
x = ConverterBallotGeneral()(x, candidates=None)
if isinstance(x, BallotLevels) and any([level in self.scale.levels for level in x.values()]):
if all([level in self.scale.levels for level in x.values()]):
return BallotLevels(x.as_dict, scale=self.scale)
else:
# Cf. test_ConverterBallotToLevelsListNonNumeric for an explanation of this edge case.
logging.warning('Not all levels of ballot ``%s`` are in the scale.' % x)
x = ConverterBallotToLevelsRange(
scale=ScaleRange(low=0, high=len(self.scale.levels) - 1),
borda_unordered_give_points=self.borda_unordered_give_points
)(x, candidates=None)
return BallotLevels({c: self.scale.levels[v] for c, v in x.items()},
candidates=x.candidates, scale=self.scale).restrict(candidates=candidates)