BUG #19860 Corrected use of mixed indexes with .at

pandas/core/indexes/base.py

@@ -3115,8 +3115,8 @@ def get_value(self, series, key):
                 iloc = self.get_loc(key)
                 return s[iloc]
             except KeyError:
-                if (len(self) > 0 and
-                        self.inferred_type in ['integer', 'boolean']):
+                if (len(self) > 0
+                        and (self.holds_integer() or self.is_boolean())):
                     raise
                 elif is_integer(key):
                     return s[key]
@@ -3129,7 +3129,7 @@ def get_value(self, series, key):
             return self._engine.get_value(s, k,
                                           tz=getattr(series.dtype, 'tz', None))
         except KeyError as e1:
-            if len(self) > 0 and self.inferred_type in ['integer', 'boolean']:
+            if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
                 raise
 
             try:

pandas/core/indexing.py

@@ -2354,7 +2354,7 @@ def _convert_key(self, key, is_setter=False):
                     raise ValueError("At based indexing on an integer index "
                                      "can only have integer indexers")
             else:
-                if is_integer(i):
+                if is_integer(i) and not ax.holds_integer():
                     raise ValueError("At based indexing on an non-integer "
                                      "index can only have non-integer "
                                      "indexers")

pandas/tests/indexing/test_indexing.py

@@ -666,6 +666,20 @@ def test_index_type_coercion(self):
                     idxr(s2)['0'] = 0
                     assert s2.index.is_object()
 
+    @pytest.mark.parametrize("index,val", [
+        (Index([0, 1, '2']), '1'),
+        (Index([0, 1, '2']), 2),
+    ])
+    def test_mixed_index_not_contains(self, index, val):
+        assert val not in index
+
+    @pytest.mark.parametrize("index,val", [
+        (Index([0, 1, '2']), 0),
+        (Index([0, 1, '2']), '2'),
+    ])
+    def test_mixed_index_contains(self, index, val):
+        assert val in index
+
 
 class TestMisc(Base):
 
@@ -710,6 +724,27 @@ def test_float_index_at_iat(self):
         for i in range(len(s)):
             assert s.iat[i] == i + 1
 
+    def test_mixed_index_at_iat(self):
+        s = Series([1, 2, 3, 4, 5], index=['a', 'b', 'c', 1, 2])
+        for el, item in s.iteritems():
+            assert s.at[el] == item
+        for i in range(len(s)):
+            assert s.iat[i] == i + 1
+
+    def test_mixed_index_assignment(self):
+        s = Series([1, 2, 3, 4, 5], index=['a', 'b', 'c', 1, 2])
+        s.at['a'] = 11
+        assert s.iat[0] == 11
+        s.at[1] = 22
+        assert s.iat[3] == 22
+
+    def test_mixed_index_no_fallback(self):
+        s = Series([1, 2, 3, 4, 5], index=['a', 'b', 'c', 1, 2])
+        with pytest.raises(KeyError):
+            s.at[0]
+        with pytest.raises(KeyError):
+            s.at[4]
+
     def test_rhs_alignment(self):
         # GH8258, tests that both rows & columns are aligned to what is
         # assigned to. covers both uniform data-type & multi-type cases