encoders

Package Contents

Classes Summary

OneHotEncoder

A transformer that encodes categorical features in a one-hot numeric array.

TargetEncoder

A transformer that encodes categorical features into target encodings.

Contents

class evalml.pipelines.components.transformers.encoders.OneHotEncoder(top_n=10, features_to_encode=None, categories=None, drop='if_binary', handle_unknown='ignore', handle_missing='error', random_seed=0, **kwargs)[source]

A transformer that encodes categorical features in a one-hot numeric array.

Parameters
  • top_n (int) – Number of categories per column to encode. If None, all categories will be encoded. Otherwise, the n most frequent will be encoded and all others will be dropped. Defaults to 10.

  • features_to_encode (list[str]) – List of columns to encode. All other columns will remain untouched. If None, all appropriate columns will be encoded. Defaults to None.

  • categories (list) – A two dimensional list of categories, where categories[i] is a list of the categories for the column at index i. This can also be None, or “auto” if top_n is not None. Defaults to None.

  • drop (string, list) – Method (“first” or “if_binary”) to use to drop one category per feature. Can also be a list specifying which categories to drop for each feature. Defaults to ‘if_binary’.

  • handle_unknown (string) – Whether to ignore or error for unknown categories for a feature encountered during fit or transform. If either top_n or categories is used to limit the number of categories per column, this must be “ignore”. Defaults to “ignore”.

  • handle_missing (string) – Options for how to handle missing (NaN) values encountered during fit or transform. If this is set to “as_category” and NaN values are within the n most frequent, “nan” values will be encoded as their own column. If this is set to “error”, any missing values encountered will raise an error. Defaults to “error”.

  • random_seed (int) – Seed for the random number generator. Defaults to 0.

Attributes

hyperparameter_ranges

{}

model_family

ModelFamily.NONE

modifies_features

True

modifies_target

False

name

One Hot Encoder

Methods

categories

Returns a list of the unique categories to be encoded for the particular feature, in order.

clone

Constructs a new component with the same parameters and random state.

default_parameters

Returns the default parameters for this component.

describe

Describe a component and its parameters

fit

Fits component to data

fit_transform

Fits on X and transforms X

get_feature_names

Return feature names for the categorical features after fitting.

load

Loads component at file path

needs_fitting

Returns boolean determining if component needs fitting before

parameters

Returns the parameters which were used to initialize the component

save

Saves component at file path

transform

One-hot encode the input data.

categories(self, feature_name)[source]

Returns a list of the unique categories to be encoded for the particular feature, in order.

Parameters

feature_name (str) – the name of any feature provided to one-hot encoder during fit

Returns

the unique categories, in the same dtype as they were provided during fit

Return type

np.ndarray

clone(self)

Constructs a new component with the same parameters and random state.

Returns

A new instance of this component with identical parameters and random state.

default_parameters(cls)

Returns the default parameters for this component.

Our convention is that Component.default_parameters == Component().parameters.

Returns

default parameters for this component.

Return type

dict

describe(self, print_name=False, return_dict=False)

Describe a component and its parameters

Parameters
  • print_name (bool, optional) – whether to print name of component

  • return_dict (bool, optional) – whether to return description as dictionary in the format {“name”: name, “parameters”: parameters}

Returns

prints and returns dictionary

Return type

None or dict

fit(self, X, y=None)[source]

Fits component to data

Parameters
  • X (list, pd.DataFrame or np.ndarray) – The input training data of shape [n_samples, n_features]

  • y (list, pd.Series, np.ndarray, optional) – The target training data of length [n_samples]

Returns

self

fit_transform(self, X, y=None)

Fits on X and transforms X

Parameters
  • X (pd.DataFrame) – Data to fit and transform

  • y (pd.Series) – Target data

Returns

Transformed X

Return type

pd.DataFrame

get_feature_names(self)[source]

Return feature names for the categorical features after fitting.

Feature names are formatted as {column name}_{category name}. In the event of a duplicate name, an integer will be added at the end of the feature name to distinguish it.

For example, consider a dataframe with a column called “A” and category “x_y” and another column called “A_x” with “y”. In this example, the feature names would be “A_x_y” and “A_x_y_1”.

Returns

The feature names after encoding, provided in the same order as input_features.

Return type

np.ndarray

static load(file_path)

Loads component at file path

Parameters

file_path (str) – Location to load file

Returns

ComponentBase object

needs_fitting(self)

Returns boolean determining if component needs fitting before calling predict, predict_proba, transform, or feature_importances. This can be overridden to False for components that do not need to be fit or whose fit methods do nothing.

property parameters(self)

Returns the parameters which were used to initialize the component

save(self, file_path, pickle_protocol=cloudpickle.DEFAULT_PROTOCOL)

Saves component at file path

Parameters
  • file_path (str) – Location to save file

  • pickle_protocol (int) – The pickle data stream format.

Returns

None

transform(self, X, y=None)[source]

One-hot encode the input data.

Parameters
  • X (pd.DataFrame) – Features to one-hot encode.

  • y (pd.Series) – Ignored.

Returns

Transformed data, where each categorical feature has been encoded into numerical columns using one-hot encoding.

Return type

pd.DataFrame

class evalml.pipelines.components.transformers.encoders.TargetEncoder(cols=None, smoothing=1.0, handle_unknown='value', handle_missing='value', random_seed=0, **kwargs)[source]

A transformer that encodes categorical features into target encodings.

Parameters
  • cols (list) – Columns to encode. If None, all string columns will be encoded, otherwise only the columns provided will be encoded. Defaults to None

  • smoothing (float) – The smoothing factor to apply. The larger this value is, the more influence the expected target value has on the resulting target encodings. Must be strictly larger than 0. Defaults to 1.0

  • handle_unknown (string) – Determines how to handle unknown categories for a feature encountered. Options are ‘value’, ‘error’, nd ‘return_nan’. Defaults to ‘value’, which replaces with the target mean

  • handle_missing (string) – Determines how to handle missing values encountered during fit or transform. Options are ‘value’, ‘error’, and ‘return_nan’. Defaults to ‘value’, which replaces with the target mean

  • random_seed (int) – Seed for the random number generator. Defaults to 0.

Attributes

hyperparameter_ranges

{}

model_family

ModelFamily.NONE

modifies_features

True

modifies_target

False

name

Target Encoder

Methods

clone

Constructs a new component with the same parameters and random state.

default_parameters

Returns the default parameters for this component.

describe

Describe a component and its parameters

fit

Fits component to data

fit_transform

Fits on X and transforms X

get_feature_names

Return feature names for the input features after fitting.

load

Loads component at file path

needs_fitting

Returns boolean determining if component needs fitting before

parameters

Returns the parameters which were used to initialize the component

save

Saves component at file path

transform

Transforms data X.

clone(self)

Constructs a new component with the same parameters and random state.

Returns

A new instance of this component with identical parameters and random state.

default_parameters(cls)

Returns the default parameters for this component.

Our convention is that Component.default_parameters == Component().parameters.

Returns

default parameters for this component.

Return type

dict

describe(self, print_name=False, return_dict=False)

Describe a component and its parameters

Parameters
  • print_name (bool, optional) – whether to print name of component

  • return_dict (bool, optional) – whether to return description as dictionary in the format {“name”: name, “parameters”: parameters}

Returns

prints and returns dictionary

Return type

None or dict

fit(self, X, y)[source]

Fits component to data

Parameters
  • X (list, pd.DataFrame or np.ndarray) – The input training data of shape [n_samples, n_features]

  • y (list, pd.Series, np.ndarray, optional) – The target training data of length [n_samples]

Returns

self

fit_transform(self, X, y)[source]

Fits on X and transforms X

Parameters
  • X (pd.DataFrame) – Data to fit and transform

  • y (pd.Series) – Target data

Returns

Transformed X

Return type

pd.DataFrame

get_feature_names(self)[source]

Return feature names for the input features after fitting.

Returns

The feature names after encoding

Return type

np.array

static load(file_path)

Loads component at file path

Parameters

file_path (str) – Location to load file

Returns

ComponentBase object

needs_fitting(self)

Returns boolean determining if component needs fitting before calling predict, predict_proba, transform, or feature_importances. This can be overridden to False for components that do not need to be fit or whose fit methods do nothing.

property parameters(self)

Returns the parameters which were used to initialize the component

save(self, file_path, pickle_protocol=cloudpickle.DEFAULT_PROTOCOL)

Saves component at file path

Parameters
  • file_path (str) – Location to save file

  • pickle_protocol (int) – The pickle data stream format.

Returns

None

transform(self, X, y=None)[source]

Transforms data X.

Parameters
  • X (pd.DataFrame) – Data to transform.

  • y (pd.Series, optional) – Target data.

Returns

Transformed X

Return type

pd.DataFrame