`sklearn.pipeline`.FeatureUnion¶

class sklearn.pipeline.FeatureUnion(transformer_list, n_jobs=1, transformer_weights=None)¶

Concatenates results of multiple transformer objects.

This estimator applies a list of transformer objects in parallel to the input data, then concatenates the results. This is useful to combine several feature extraction mechanisms into a single transformer.

Parameters:

transformer_list: list of (string, transformer) tuples :

List of transformer objects to be applied to the data. The first half of each tuple is the name of the transformer.

n_jobs: int, optional :

Number of jobs to run in parallel (default 1).

transformer_weights: dict, optional :

Multiplicative weights for features per transformer. Keys are transformer names, values the weights.

Methods

`fit`(X[, y])	Fit all transformers using X.
`fit_transform`(X[, y])	Fit all transformers using X, transform the data and concatenate results.
`get_feature_names`()	Get feature names from all transformers.
`get_params`([deep])
`set_params`(**params)	Set the parameters of this estimator.
`transform`(X)	Transform X separately by each transformer, concatenate results.

__init__(transformer_list, n_jobs=1, transformer_weights=None)¶

fit(X, y=None)¶

Fit all transformers using X.

Parameters:

X : array-like or sparse matrix, shape (n_samples, n_features)

Input data, used to fit transformers.

fit_transform(X, y=None, **fit_params)¶

Fit all transformers using X, transform the data and concatenate results.

Parameters:

X : array-like or sparse matrix, shape (n_samples, n_features)

Input data to be transformed.

Returns:

X_t : array-like or sparse matrix, shape (n_samples, sum_n_components)

hstack of results of transformers. sum_n_components is the sum of n_components (output dimension) over transformers.

get_feature_names()¶

Get feature names from all transformers.

Returns:

feature_names : list of strings

Names of the features produced by transform.

set_params(**params)¶

Set the parameters of this estimator.

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