scikit-learn/scikit-learn — pull request #1173 by amueller (2012-09-20 16:43:43+00:00)
Title: WIP Feature stacker

This estimator provides a Y piece for the pipeline.
I used it to combine word ngrams and char ngrams into a single transformer.

If you think this is helpful, I'll add some docs and an example.
With this, together with ``Pipeline``, one can build arbitrary complex graphs (with one source and one sink) of estimators in sklearn :)