src.fairreckitlib.data.filter.categorical_filter

 1"""Module to filter on categories, like country or gender.
 2
 3Classes:
 4
 5    CategoricalFilter: Filter the dataframe on categorical data, such as country or gender.
 6
 7Functions:
 8
 9    create_categorical_filter: Create an instance of CategoricalFilter.
10
11This program has been developed by students from the bachelor Computer Science at
12Utrecht University within the Software Project course.
13© Copyright Utrecht University (Department of Information and Computing Sciences)
14"""
15
16from typing import Any, Dict, List
17import numpy
18import pandas as pd
19from .filter_constants import FILTER_CATEGORICAL
20from .base_filter import DataFilter
21
22
23class CategoricalFilter(DataFilter):
24    """Filter the dataframe on categorical data, such as country or gender.
25
26    Public method:
27        filter
28    """
29
30    def get_type(self) -> str:
31        """Get the type of the filter.
32
33        Returns:
34            The type name of the filter.
35        """
36        return FILTER_CATEGORICAL
37
38    def filter(self, dataframe: pd.DataFrame, column_name='',
39               conditions: List[Any]=None) -> pd.DataFrame:
40        """Filter on a list of categories.
41
42        Args:
43            dataframe: Dataframe to be filtered.
44            column_name (str): Name of the column where the conditions need to be met.
45            conditions (List[Any]): A list of values,
46                where values of the column_name in the resulting dataframe meet some condition.
47
48        Returns:
49            A filtered dataframe.
50        """
51        if column_name not in dataframe.columns:
52            return self.__empty_df__(dataframe)
53        conditions = self._handle_none_value(conditions)
54        df_filter = dataframe[column_name].isin(conditions)
55        return dataframe[df_filter].reset_index(drop=True)
56
57    def _filter(self, dataframe: pd.DataFrame) -> pd.DataFrame:
58        """Private filter used in run(). Requires configuration file."""
59        return self.filter(dataframe, self.get_name(), self.params['values'])
60
61    @staticmethod
62    def _handle_none_value(conditions: List[Any]):
63        """Change None value to empty value: numpy.NaN."""
64        if conditions is None:
65            return []
66        if None in conditions:
67            conditions.append(numpy.NaN)
68        return conditions
69
70
71def create_categorical_filter(name: str, params: Dict[str, Any], **kwargs) -> DataFilter:
72    """Create an instance of the class CategoricalFilter.
73
74    Args:
75        name: Name of the filter.
76        params: Configuration file.
77        **kwargs: Contains dataset and matrix_name.
78
79    Returns:
80        An instance of the CategoricalFilter class.
81    """
82    return CategoricalFilter(name, params, **kwargs)