fix Error Indexing DafaFrame with a 0-d array

closes pandas-dev#21946

Author: illegalnumbers

pandas/core/indexes/base.py

@@ -4178,6 +4178,8 @@ def _validate_indexer(self, form, key, kind):
             pass
         elif is_integer(key):
             pass
+        elif key.ndim == 0:
+            self._invalid_indexer(form, key)
         elif kind in ['iloc', 'getitem']:
             self._invalid_indexer(form, key)
         return key

pandas/core/indexing.py

@@ -2693,7 +2693,7 @@ def is_nested_tuple(tup, labels):
 def is_list_like_indexer(key):
     # allow a list_like, but exclude NamedTuples which can be indexers
     return is_list_like(key) and not (isinstance(key, tuple) and
-                                      type(key) is not tuple)
+                                      type(key) is not tuple) and not np.array(key).ndim == 0
 
 
 def is_label_like(key):

pandas/tests/indexing/test_indexing.py

@@ -890,6 +890,12 @@ def test_no_reference_cycle(self):
         del df
         assert wr() is None
 
+    def test_zero_index_iloc_raises(self):
+        df = pd.DataFrame([[1, 2], [3, 4]], columns=['a', 'b'])
+        ar = np.array(0)
+        tm.assert_raises_regex(TypeError, 'Cannot index by location index with a non-integer key',
+                               lambda: df.iloc[ar])
+
 
 class TestSeriesNoneCoercion(object):
     EXPECTED_RESULTS = [