Learning Data Mining with Python - Second Edition

More complex pipelines

URL: http://scikit-learn.org/stable/modules/pipeline.html#featureunion-composite-feature-spaces

The Pipelines we have used here follow a single stream—the output of one step is the input of another step.

Pipelines follow the transformer and estimator interfaces as well—this allows us to embed Pipelines within Pipelines. This is a useful construct for very complex models, but becomes very powerful when combined with Feature Unions, as shown in the preceding link.This allows us to extract multiple types of features at a time and then combine them to form a single dataset. For more details, see this example: http://scikit-learn.org/stable/auto_examples/feature_stacker.html.