BUG: Bug in setting with ix/loc and a mixed int/string index (GH4544)

Author: jreback

doc/source/release.rst

@@ -520,6 +520,7 @@ Bug Fixes
     chunks of the same file. Now coerces to numerical type or raises warning. (:issue:`3866`)
   - Fix a bug where reshaping a ``Series`` to its own shape raised ``TypeError`` (:issue:`4554`)
     and other reshaping issues.
+  - Bug in setting with ``ix/loc`` and a mixed int/string index (:issue:`4544`)
 
 pandas 0.12.0
 -------------

pandas/core/indexing.py

@@ -783,9 +783,25 @@ def _convert_to_indexer(self, obj, axis=0, is_setter=False):
         - No, prefer label-based indexing
         """
         labels = self.obj._get_axis(axis)
+
+        # if we are a scalar indexer and not type correct raise
+        obj = self._convert_scalar_indexer(obj, axis)
+
+        # see if we are positional in nature
         is_int_index = labels.is_integer()
+        is_int_positional = com.is_integer(obj) and not is_int_index
 
-        if com.is_integer(obj) and not is_int_index:
+        # if we are a label return me
+        try:
+            return labels.get_loc(obj)
+        except (KeyError, TypeError):
+            pass
+        except (ValueError):
+            if not is_int_positional:
+                raise
+
+        # a positional
+        if is_int_positional:
 
             # if we are setting and its not a valid location
             # its an insert which fails by definition
@@ -795,11 +811,6 @@ def _convert_to_indexer(self, obj, axis=0, is_setter=False):
 
             return obj
 
-        try:
-            return labels.get_loc(obj)
-        except (KeyError, TypeError):
-            pass
-
         if isinstance(obj, slice):
             return self._convert_slice_indexer(obj, axis)
 

pandas/tests/test_indexing.py

@@ -1070,6 +1070,26 @@ def test_ix_assign_column_mixed(self):
         df['b'].ix[[1,3]] = [100,-100]
         assert_frame_equal(df,expected)
 
+    def test_ix_get_set_consistency(self):
+
+        # GH 4544
+        # ix/loc get/set not consistent when
+        # a mixed int/string index
+        df = DataFrame(np.arange(16).reshape((4, 4)),
+                       columns=['a', 'b', 8, 'c'],
+                       index=['e', 7, 'f', 'g'])
+
+        self.assert_(df.ix['e', 8] == 2)
+        self.assert_(df.loc['e', 8] == 2)
+
+        df.ix['e', 8] = 42
+        self.assert_(df.ix['e', 8] == 42)
+        self.assert_(df.loc['e', 8] == 42)
+
+        df.loc['e', 8] = 45
+        self.assert_(df.ix['e', 8] == 45)
+        self.assert_(df.loc['e', 8] == 45)
+
     def test_iloc_mask(self):
 
         # GH 3631, iloc with a mask (of a series) should raise

pandas/tests/test_series.py

@@ -878,7 +878,7 @@ def test_setitem_float_labels(self):
         tmp = s.copy()
 
         s.ix[1] = 'zoo'
-        tmp.values[1] = 'zoo'
+        tmp.iloc[2] = 'zoo'
 
         assert_series_equal(s, tmp)