7.1. Pipelines and composite estimators

7.1. Pipelines and composite estimators# To build a composite estimator, transformers are usually combined with other transformers or with predictors (such as classifiers or regressors). The most common tool used for composing estimators is a Pipeline. Pipelines require all steps except the last to be a transformer. The last step can be anything, a transformer, a predictor, or a clustering estimat