From 6c28f1ed4245f8bcb71148cd7472dac25a9fc3c4 Mon Sep 17 00:00:00 2001
From: bmweiner <bmweiner@users.noreply.github.com>
Date: Sun, 10 Jan 2016 15:05:49 -0500
Subject: [PATCH] Alters feature 'combining' behavior, see issue #51.
---
sklearn_pandas/dataframe_mapper.py | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/sklearn_pandas/dataframe_mapper.py b/sklearn_pandas/dataframe_mapper.py
index 9a59f6d..9162072 100644
--- a/sklearn_pandas/dataframe_mapper.py
+++ b/sklearn_pandas/dataframe_mapper.py
@@ -27,6 +27,10 @@ def _build_transformer(transformers):
return transformers
+def _sparse_to_dense(extracted):
+ return [x.toarray() if sparse.issparse(x) else x for x in extracted]
+
+
class DataFrameMapper(BaseEstimator, TransformerMixin):
"""
Map Pandas data frame column subsets to their own
@@ -120,13 +124,12 @@ def transform(self, X):
# If any of the extracted features is sparse, combine sparsely.
# Otherwise, combine as normal arrays.
- if any(sparse.issparse(fea) for fea in extracted):
- stacked = sparse.hstack(extracted).tocsr()
- # return a sparse matrix only if the mapper was initialized
- # with sparse=True
- if not self.sparse:
- stacked = stacked.toarray()
+ if self.sparse:
+ if any(sparse.issparse(fea) for fea in extracted):
+ # fails if array in extracted has dtype=object
+ return sparse.hstack(extracted).tocsr()
+ else:
+ # convert to sparse
+ return sparse.csr_matrix(np.hstack(extracted))
else:
- stacked = np.hstack(extracted)
-
- return stacked
+ return np.hstack(_sparse_to_dense(extracted))