ENH: rename function now has errors keyword

doc/source/release.rst

@@ -154,6 +154,8 @@ API Changes
 - ``Series.iteritems()`` is now lazy (returns an iterator rather than a list). This was the documented behavior prior to 0.14. (:issue:`6760`)
 - ``Panel.shift`` now uses ``NDFrame.shift``. It no longer drops the ``nan`` data and retains its original shape.  (:issue:`4867`)
 
+- ``rename`` function can now accept ``errors`` keyword to suppress error raised by a passed function, or raise ValueError when any of label in a passed dict is not found in the target axis.
+
 Deprecations
 ~~~~~~~~~~~~
 

doc/source/v0.14.0.txt

@@ -199,6 +199,8 @@ API changes
 - ``Series.iteritems()`` is now lazy (returns an iterator rather than a list). This was the documented behavior prior to 0.14. (:issue:`6760`)
 - ``Panel.shift`` now uses ``NDFrame.shift``. It no longer drops the ``nan`` data and retains its original shape.  (:issue:`4867`)
 
+- ``rename`` function can now accept ``errors`` keyword to suppress error raised by a passed function, or raise ValueError when any of label in a passed dict is not found in the target axis. From this version, passing a dict with labels which isn't included in the axis results in FutureWarning, and will raise ValueError in future version.
+
 
 MultiIndexing Using Slicers
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~

pandas/core/generic.py

@@ -524,6 +524,10 @@ def swaplevel(self, i, j, axis=0):
         inplace : boolean, default False
             Whether to return a new %(klass)s. If True then value of copy is
             ignored.
+        errors : {'ignore', 'raise'}, default 'raise'
+            If 'raise', ValueError is raised when any of label in the dict doesn't exist in target axis.
+            Also, errors raised by passed function is not suppressed.
+            If 'ignore', suppress errors and rename only labels which doesn't trigger errors.
 
         Returns
         -------
@@ -538,19 +542,46 @@ def rename(self, *args, **kwargs):
         copy = kwargs.get('copy', True)
         inplace = kwargs.get('inplace', False)
 
+        # default should be 'raise' in future version
+        errors = kwargs.get('errors', None)        
+        # errors = kwargs.get('errors', 'raise')
+
         if (com._count_not_none(*axes.values()) == 0):
             raise TypeError('must pass an index to rename')
 
         # renamer function if passed a dict
-        def _get_rename_function(mapper):
+        def _get_rename_function(mapper, axis):
             if isinstance(mapper, (dict, ABCSeries)):
+                if errors != 'ignore':
+                    # once cast a view to list for python 3
+                    labels = np.array(list(mapper.keys()))
+                    axis = self._get_axis(axis)
+                    indexer = axis.get_indexer(labels)
+                    mask = indexer == -1
+                    if mask.any():
+                        msg = 'labels %s not contained in axis' % labels[mask]
+
+                        if errors is None:
+                            # should be removed in future version
+                            warnings.warn("%s will results in ValueError in the future."
+                                "Use 'errors' keyword to suppress/force error" % msg,
+                                FutureWarning)
+                        else:
+                            raise ValueError(msg)
+
                 def f(x):
                     if x in mapper:
                         return mapper[x]
                     else:
                         return x
             else:
-                f = mapper
+                def f(x):
+                    try:
+                        return mapper(x)
+                    except Exception:
+                        if errors != 'ignore':
+                            raise
+                        return x
 
             return f
 
@@ -562,7 +593,8 @@ def f(x):
             v = axes.get(self._AXIS_NAMES[axis])
             if v is None:
                 continue
-            f = _get_rename_function(v)
+
+            f = _get_rename_function(v, axis)
 
             baxis = self._get_block_manager_axis(axis)
             result._data = result._data.rename(f, axis=baxis, copy=copy)

pandas/tests/test_frame.py

@@ -9031,15 +9031,53 @@ def test_rename(self):
         index = MultiIndex.from_tuples(tuples_index, names=['foo', 'bar'])
         columns = MultiIndex.from_tuples(tuples_columns, names=['fizz', 'buzz'])
         renamer = DataFrame([(0,0),(1,1)], index=index, columns=columns)
+
+        with tm.assert_produces_warning():
+            # should raise ValueError in future version
+            renamed = renamer.rename(index={'foo1': 'foo3', 'bar2': 'bar3'},
+                                     columns={'fizz1': 'fizz3', 'buzz2': 'buzz3'})
+            new_index = MultiIndex.from_tuples([('foo3', 'bar1'), ('foo2', 'bar3')])
+            new_columns = MultiIndex.from_tuples([('fizz3', 'buzz1'), ('fizz2', 'buzz3')])
+            self.assert_numpy_array_equal(renamed.index, new_index)
+            self.assert_numpy_array_equal(renamed.columns, new_columns)
+            self.assertEquals(renamed.index.names, renamer.index.names)
+            self.assertEquals(renamed.columns.names, renamer.columns.names)
+
+        self.assertRaises(ValueError, renamer.rename, index={'foo1': 'foo3', 'bar2': 'bar3'},
+                                     columns={'fizz1': 'fizz3', 'buzz2': 'buzz3'}, errors='raise')
+
         renamed = renamer.rename(index={'foo1': 'foo3', 'bar2': 'bar3'},
-                                 columns={'fizz1': 'fizz3', 'buzz2': 'buzz3'})
+                                 columns={'fizz1': 'fizz3', 'buzz2': 'buzz3'}, errors='ignore')
         new_index = MultiIndex.from_tuples([('foo3', 'bar1'), ('foo2', 'bar3')])
         new_columns = MultiIndex.from_tuples([('fizz3', 'buzz1'), ('fizz2', 'buzz3')])
         self.assert_numpy_array_equal(renamed.index, new_index)
         self.assert_numpy_array_equal(renamed.columns, new_columns)
         self.assertEquals(renamed.index.names, renamer.index.names)
         self.assertEquals(renamed.columns.names, renamer.columns.names)
 
+        # error handling
+        data = {1: {'A': 0, 'B': 1}, '2': {'C':1, 'D': 2}}
+        df = DataFrame(data)
+
+        # errors = default
+        with tm.assert_produces_warning():
+            # should raise ValueError in future version
+            renamed = df.rename(columns={'1': 'One', '2': 'Two'})
+            self.assertEqual(renamed.columns.tolist(), [1, 'Two'])
+        self.assertRaises(TypeError, df.rename, columns=lambda x: x + 1)
+
+        # errors = raise
+        self.assertRaises(ValueError, df.rename,
+                          columns={'1': 'One', '2': 'Two'}, errors='raise')
+        self.assertRaises(TypeError, df.rename, columns=lambda x: x + 1, errors='raise')
+
+        # errors = ignore
+        renamed = df.rename(columns={'1': 'One', '2': 'Two'}, errors='ignore')
+        self.assertEqual(renamed.columns.tolist(), [1, 'Two'])
+
+        renamed = df.rename(columns=lambda x: x + 1, errors='ignore')
+        self.assertEqual(renamed.columns.tolist(), [2, '2'])
+
     def test_rename_nocopy(self):
         renamed = self.frame.rename(columns={'C': 'foo'}, copy=False)
         renamed['foo'] = 1.