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Encoder transformer

MeanEncoderTransformer

Bases: BaseEstimator, TransformerMixin

Scikit-learn API for the feature-engine MeanEncoder.

Example: 

import pandas as pd
from sk_transformers import MeanEncoderTransformer

X = pd.DataFrame({"foo": ["a", "b", "a", "c", "b", "a", "c", "a", "b", "c"]})
y = pd.Series([1, 0, 1, 0, 1, 0, 1, 0, 1, 0])

encoder = MeanEncoderTransformer()
encoder.fit_transform(X, y)

        foo
0  0.500000
1  0.666667
2  0.500000
3  0.333333
4  0.666667
5  0.500000
6  0.333333
7  0.500000
8  0.666667
9  0.333333

Parameters:

Name Type Description Default
fill_na_value Union[int, float]

Value to fill NaN values with. Those may appear if a category is not present in the set the encoder was not fitted on.

 -999
Source code in src/sk_transformers/encoder_transformer.py 
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class MeanEncoderTransformer(BaseEstimator, TransformerMixin):
    """Scikit-learn API for the [feature-engine MeanEncoder](https://feature-
    engine.readthedocs.io/en/latest/api_doc/encoding/MeanEncoder.html).

    Example:
    ```python
    import pandas as pd
    from sk_transformers import MeanEncoderTransformer

    X = pd.DataFrame({"foo": ["a", "b", "a", "c", "b", "a", "c", "a", "b", "c"]})
    y = pd.Series([1, 0, 1, 0, 1, 0, 1, 0, 1, 0])

    encoder = MeanEncoderTransformer()
    encoder.fit_transform(X, y)
    ```
    ```
            foo
    0  0.500000
    1  0.666667
    2  0.500000
    3  0.333333
    4  0.666667
    5  0.500000
    6  0.333333
    7  0.500000
    8  0.666667
    9  0.333333
    ```

    Args:
        fill_na_value (Union[int, float]): Value to fill NaN values with.
            Those may appear if a category is not present in the set the encoder was not fitted on.
    """

    def __init__(self, fill_na_value: Union[int, float] = -999) -> None:
        self.encoder = MeanEncoder(ignore_format=False)
        self.fill_na_value = fill_na_value

    def fit(self, X: pd.DataFrame, y: pd.Series) -> "MeanEncoderTransformer":
        """Fit the MeanEncoder to the data.

        Args:
            X (pandas.DataFrame): DataFrame to fit the MeanEncoder to.
            y (pandas.Series): Target variable.

        Returns:
            MeanEncoder: Fitted MeanEncoder.
        """
        self.encoder.fit(X, y)
        return self

    def transform(self, X: pd.DataFrame) -> pd.DataFrame:
        """Transform the data using the fitted MeanEncoder.

        Args:
            X (pandas.DataFrame): DataFrame to transform.

        Returns:
            pandas.DataFrame: Transformed DataFrame.
        """
        return self.encoder.transform(X).fillna(self.fill_na_value)

fit(X, y)

Fit the MeanEncoder to the data.

Parameters:

Name Type Description Default
X pandas.DataFrame

DataFrame to fit the MeanEncoder to.

 required
y pandas.Series

Target variable.

 required

Returns:

Name Type Description
MeanEncoder MeanEncoderTransformer

Fitted MeanEncoder.
Source code in src/sk_transformers/encoder_transformer.py 
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def fit(self, X: pd.DataFrame, y: pd.Series) -> "MeanEncoderTransformer":
    """Fit the MeanEncoder to the data.

    Args:
        X (pandas.DataFrame): DataFrame to fit the MeanEncoder to.
        y (pandas.Series): Target variable.

    Returns:
        MeanEncoder: Fitted MeanEncoder.
    """
    self.encoder.fit(X, y)
    return self

transform(X)

Transform the data using the fitted MeanEncoder.

Parameters:

Name Type Description Default
X pandas.DataFrame

DataFrame to transform.

 required

Returns:

Type Description
pd.DataFrame

pandas.DataFrame: Transformed DataFrame.
Source code in src/sk_transformers/encoder_transformer.py 
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def transform(self, X: pd.DataFrame) -> pd.DataFrame:
    """Transform the data using the fitted MeanEncoder.

    Args:
        X (pandas.DataFrame): DataFrame to transform.

    Returns:
        pandas.DataFrame: Transformed DataFrame.
    """
    return self.encoder.transform(X).fillna(self.fill_na_value)