LagFeatures#

class feature_engine.timeseries.forecasting.LagFeatures(variables=None, periods=1, freq=None, sort_index=True, missing_values='raise', drop_original=False)[source]#

LagFeatures adds lag features to the dataframe. A lag feature is a feature with information about a prior time step.

LagFeatures has the same functionality as pandas shift() with the exception that only one of periods or freq can be indicated at a time. LagFeatures builds on top of pandas shift() in that multiple lags can be created at the same time and the features with names will be concatenated to the original dataframe.

To be compatible with LagFeatures, the dataframe’s index must have unique values and no NaN.

LagFeatures works only with numerical variables. You can pass a list of variables to lag. Alternatively, LagFeatures will automatically select and lag all numerical variables found in the training set.

More details in the User Guide.

Parameters
variables: list, default=None

The list of numerical variables to transform. If None, the transformer will automatically find and select all numerical variables.

periods: int, list of ints, default=1

Number of periods to shift. Can be a positive integer or list of positive integers. If list, features will be created for each one of the periods in the list. If the parameter freq is specified, periods will be ignored.

freq: str, list of str, default=None

Offset to use from the tseries module or time rule. See parameter freq in pandas shift(). It is the same functionality. If freq is a list, lag features will be created for each one of the frequency values in the list. If freq is not None, then this parameter overrides the parameter periods.

sort_index: bool, default=True

Whether to order the index of the dataframe before creating the lag features.

missing_values: string, default=’raise’

Indicates if missing values should be ignored or raised. If ‘raise’ the transformer will return an error if the the datasets to fit or transform contain missing values. If ‘ignore’, missing data will be ignored when learning parameters or performing the transformation.

drop_original: bool, default=False

If True, the original variables to transform will be dropped from the dataframe.

Attributes
variables_:

The group of variables that will be lagged.

feature_names_in_:

List with the names of features seen during fit.

n_features_in_:

The number of features in the train set used in fit.

See also

pandas.shift

Methods

fit:

This transformer does not learn parameters.

fit_transform:

Fit to data, then transform it.

get_feature_names_out:

Get output feature names for transformation.

get_params:

Get parameters for this estimator.

set_params:

Set the parameters of this estimator.

transform:

Add lag features.

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

This transformer does not learn parameters.

Parameters
X: pandas dataframe of shape = [n_samples, n_features]

The training dataset.

y: pandas Series, default=None

y is not needed in this transformer. You can pass None or y.

fit_transform(X, y=None, **fit_params)[source]#

Fit to data, then transform it.

Fits transformer to X and y with optional parameters fit_params and returns a transformed version of X.

Parameters
Xarray-like of shape (n_samples, n_features)

Input samples.

yarray-like of shape (n_samples,) or (n_samples, n_outputs), default=None

Target values (None for unsupervised transformations).

**fit_paramsdict

Additional fit parameters.

Returns
X_newndarray array of shape (n_samples, n_features_new)

Transformed array.

get_feature_names_out(input_features=None)[source]#

Get output feature names for transformation.

Parameters
input_features: list, default=None

Input features. If input_features is None, then the names of all the variables in the transformed dataset (original + new variables) is returned. Alternatively, only the names for the lag features derived from input_features will be returned.

Returns
feature_names_out: list

The feature names.

:rtype:py:class:~typing.List
get_params(deep=True)[source]#

Get parameters for this estimator.

Parameters
deepbool, default=True

If True, will return the parameters for this estimator and contained subobjects that are estimators.

Returns
paramsdict

Parameter names mapped to their values.

set_params(**params)[source]#

Set the parameters of this estimator.

The method works on simple estimators as well as on nested objects (such as Pipeline). The latter have parameters of the form <component>__<parameter> so that it’s possible to update each component of a nested object.

Parameters
**paramsdict

Estimator parameters.

Returns
selfestimator instance

Estimator instance.

transform(X)[source]#

Adds lag features.

Parameters
X: pandas dataframe of shape = [n_samples, n_features]

The data to transform.

Returns
X_new: Pandas dataframe, shape = [n_samples, n_features + lag_features]

The dataframe with the original plus the new variables.

:rtype:py:class:~pandas.core.frame.DataFrame