ENH: GH13473 Add errors parameter to DataFrame.rename

Author: MaxVanDeursen

pandas/core/frame.py

@@ -3940,7 +3940,8 @@ def rename(self, *args, **kwargs):
         level : int or level name, default None
             In case of a MultiIndex, only rename labels in the specified
             level.
-
+        errors : {'ignore', 'raise'}, default 'ignore'
+            If 'ignore', suppress error and existing labels are renamed.
         Returns
         -------
         DataFrame
@@ -3949,6 +3950,11 @@ def rename(self, *args, **kwargs):
         --------
         DataFrame.rename_axis
 
+        Raises
+        ------
+        KeyError
+            If any of the labels is not found in the selected axis.
+
         Examples
         --------
 

pandas/core/generic.py

@@ -981,11 +981,18 @@ def rename(self, *args, **kwargs):
         level : int or level name, default None
             In case of a MultiIndex, only rename labels in the specified
             level.
+        errors : {'ignore', 'raise'}, default 'ignore'
+            If 'ignore', suppress error and existing labels are renamed.
 
         Returns
         -------
         renamed : %(klass)s (new object)
 
+        Raises
+        ------
+        KeyError
+            If any of the labels is not found in the selected axis.
+
         See Also
         --------
         NDFrame.rename_axis
@@ -1065,6 +1072,7 @@ def rename(self, *args, **kwargs):
         inplace = kwargs.pop('inplace', False)
         level = kwargs.pop('level', None)
         axis = kwargs.pop('axis', None)
+        errors = kwargs.pop('errors', 'ignore')
         if axis is not None:
             # Validate the axis
             self._get_axis_number(axis)
@@ -1085,10 +1093,15 @@ def rename(self, *args, **kwargs):
             if v is None:
                 continue
             f = com._get_rename_function(v)
-
             baxis = self._get_block_manager_axis(axis)
             if level is not None:
                 level = self.axes[axis]._get_level_number(level)
+
+            # GH 13473
+            labels_missing = (self.axes[axis].get_indexer_for(v) == -1).any()
+            if errors == 'raise' and labels_missing:
+                raise KeyError('{} not found in axis'.format(v))
+
             result._data = result._data.rename_axis(f, axis=baxis, copy=copy,
                                                     level=level)
             result._clear_item_cache()

pandas/tests/frame/test_alter_axes.py

@@ -871,6 +871,25 @@ def test_rename_bug2(self):
                              columns=["a"])
         tm.assert_frame_equal(df, expected)
 
+    def test_rename_errors(self):
+        # GH 13473
+        # rename now works with errors parameter
+
+        # Error has to be thrown and is thrown
+        df = DataFrame(columns=['A', 'B', 'C', 'D'])
+        with pytest.raises(KeyError):
+            df.rename(columns={'A': 'a', 'E': 'e'}, errors='raise')
+
+        # Error should be ignored
+        renamed = df.rename(columns={'A': 'a', 'E': 'e'})
+        expected = DataFrame(columns=['a', 'B', 'C', 'D'])
+        tm.assert_frame_equal(renamed, expected)
+
+        # Correct behaviour with raising errors.
+        renamed = df.rename(columns={'A': 'a'}, errors='raise')
+        expected = DataFrame(columns=['a', 'B', 'C', 'D'])
+        tm.assert_frame_equal(renamed, expected)
+
     def test_reorder_levels(self):
         index = MultiIndex(levels=[['bar'], ['one', 'two', 'three'], [0, 1]],
                            codes=[[0, 0, 0, 0, 0, 0],