Merge pull request scikit-learn#6229 from dsquareindia/LabelEncode-error-msg-fix

[MRG+1] LabelEncoder now raises error for 0-D arrays

Author: amueller

sklearn/preprocessing/label.py

@@ -140,6 +140,7 @@ def transform(self, y):
         y : array-like of shape [n_samples]
         """
         check_is_fitted(self, 'classes_')
+        y = column_or_1d(y, warn=True)
 
         classes = np.unique(y)
         _check_numpy_unicode_bug(classes)

sklearn/preprocessing/tests/test_label.py

@@ -12,6 +12,7 @@
 from sklearn.utils.testing import assert_array_equal
 from sklearn.utils.testing import assert_equal
 from sklearn.utils.testing import assert_raises
+from sklearn.utils.testing import assert_raise_message
 from sklearn.utils.testing import ignore_warnings
 
 from sklearn.preprocessing.label import LabelBinarizer
@@ -168,6 +169,10 @@ def test_label_encoder():
                        [0, 1, 4, 4, 5, -1, -1])
     assert_raises(ValueError, le.transform, [0, 6])
 
+    le.fit(["apple", "orange"])
+    msg = "bad input shape"
+    assert_raise_message(ValueError, msg, le.transform, "apple")
+
 
 def test_label_encoder_fit_transform():
     # Test fit_transform