scikit-learn/scikit-learn — pull request #1987 by jnothman (2013-05-22 09:40:10+00:00)
Title: ENH support multilabel targets in LabelEncoder

Also, support 1d-array of sequences as a multilabel format and their `np.vectorize`d processing.

This makes it easy to support multilabel data with string (or non-consecutive / negative-inclusive) labels. In particular, `bincount` and related operations that can be used on LabelEncoded multiclass targets can also be used with multilabel data.