Raise error when creating index of tuples with name parameter a string

Author: Dr-Irv

pandas/indexes/multi.py

@@ -20,6 +20,7 @@
                                  is_object_dtype,
                                  is_iterator,
                                  is_list_like,
+                                 is_string_like,
                                  is_scalar)
 from pandas.types.missing import isnull, array_equivalent
 from pandas.core.common import (_values_from_object,
@@ -490,6 +491,11 @@ def _set_names(self, names, level=None, validate=True):
         that it only acts on copies
         """
 
+        # GH 15110
+        # Don't allow a single string for names in a MultiIndex
+        if names is not None and is_string_like(names):
+            raise ValueError('Names should not be a single string for a '
+                             'MultiIndex.')
         names = list(names)
 
         if validate and level is not None and len(names) != len(level):

pandas/tests/indexes/test_multi.py

@@ -2554,3 +2554,12 @@ def test_unsortedindex(self):
 
         with assertRaises(KeyError):
             df.loc(axis=0)['q', :]
+
+    def test_tuples_with_name_string(self):
+        # GH 15110 and GH 14848
+
+        li = [(0, 0, 1), (0, 1, 0), (1, 0, 0)]
+        with assertRaises(ValueError):
+            pd.Index(li, name='abc')
+        with assertRaises(ValueError):
+            pd.Index(li, name='a')