MAINT Fix invalid escape sequence (scikit-learn#12064)

sklearn/cluster/tests/test_k_means.py

@@ -885,7 +885,7 @@ def test_sparse_validate_centers():
     # Test that a ValueError is raised for validate_center_shape
     classifier = KMeans(n_clusters=3, init=centers, n_init=1)
 
-    msg = "The shape of the initial centers \(\(4L?, 4L?\)\) " \
+    msg = r"The shape of the initial centers \(\(4L?, 4L?\)\) " \
           "does not match the number of clusters 3"
     assert_raises_regex(ValueError, msg, classifier.fit, X)
 
@@ -969,7 +969,7 @@ def test_sample_weight_length():
     # check that an error is raised when passing sample weights
     # with an incompatible shape
     km = KMeans(n_clusters=n_clusters, random_state=42)
-    assert_raises_regex(ValueError, 'len\(sample_weight\)', km.fit, X,
+    assert_raises_regex(ValueError, r'len\(sample_weight\)', km.fit, X,
                         sample_weight=np.ones(2))
 
 

sklearn/datasets/mlcomp.py

@@ -24,7 +24,7 @@ def _load_document_classification(dataset_path, metadata, set_=None, **kwargs):
             "in March 2017, the load_mlcomp function was deprecated "
             "in version 0.19 and will be removed in 0.21.")
 def load_mlcomp(name_or_id, set_="raw", mlcomp_root=None, **kwargs):
-    """Load a datasets as downloaded from http://mlcomp.org
+    r"""Load a datasets as downloaded from http://mlcomp.org
 
     Read more in the :ref:`User Guide <datasets>`.
 

sklearn/externals/_arff.py

@@ -641,7 +641,7 @@ def _decode_comment(self, s):
         :param s: a normalized string.
         :return: a string with the decoded comment.
         '''
-        res = re.sub('^\%( )?', '', s)
+        res = re.sub(r'^\%( )?', '', s)
         return res
 
     def _decode_relation(self, s):

sklearn/model_selection/tests/test_search.py

@@ -133,10 +133,10 @@ def assert_grid_iter_equals_getitem(grid):
 
 @pytest.mark.parametrize(
     "input, error_type, error_message",
-    [(0, TypeError, 'Parameter grid is not a dict or a list \(0\)'),
-     ([{'foo': [0]}, 0], TypeError, 'Parameter grid is not a dict \(0\)'),
+    [(0, TypeError, r'Parameter grid is not a dict or a list \(0\)'),
+     ([{'foo': [0]}, 0], TypeError, r'Parameter grid is not a dict \(0\)'),
      ({'foo': 0}, TypeError, "Parameter grid value is not iterable "
-      "\(key='foo', value=0\)")]
+      r"\(key='foo', value=0\)")]
 )
 def test_validate_parameter_grid_input(input, error_type, error_message):
     with pytest.raises(error_type, match=error_message):