Address comments from @jreback add new tests; skip tests on IntervalIndex

Author: nateyoder

pandas/core/base.py

@@ -839,6 +839,27 @@ def _reduce(self, op, name, axis=0, skipna=True, numeric_only=None,
         return func(**kwds)
 
     def _map_values(self, values, arg, na_action=None):
+        """An internal function that maps values using the input
+        correspondence (which can be a dict, Series, or function).
+
+        Parameters
+        ----------
+        values : np.ndarray
+            The values to be mapped
+        arg : function, dict, or Series
+            The input correspondence object
+        na_action : {None, 'ignore'}
+            If 'ignore', propagate NA values, without passing them to the
+            mapping function
+
+        Returns
+        -------
+        applied : {Index, MultiIndex}, inferred
+            The output of the mapping function applied to the index.
+            If the function returns a tuple with more than one element
+            a MultiIndex will be returned.
+
+        """
         if is_extension_type(self.dtype):
             if na_action is not None:
                 raise NotImplementedError

pandas/core/indexes/base.py

@@ -2827,7 +2827,7 @@ def get_indexer_for(self, target, **kwargs):
 
         Parameters
         ----------
-        data : {dict, DictWithoutMissing}
+        data : dict
             The dictionary from which to extract the values
 
         Returns
@@ -2904,8 +2904,14 @@ def map(self, arg, na_action=None):
             self.values, arg, na_action=na_action)
         attributes = self._get_attributes_dict()
         if new_values.size and isinstance(new_values[0], tuple):
+            if isinstance(self, MultiIndex):
+                names = self.names
+            elif attributes.get('name'):
+                names = [attributes.get('name')] * len(new_values[0])
+            else:
+                names = None
             return MultiIndex.from_tuples(new_values,
-                                          names=attributes.get('name'))
+                                          names=names)
 
         attributes['copy'] = False
         return Index(new_values, **attributes)

pandas/tests/indexes/common.py

@@ -996,3 +996,29 @@ def test_searchsorted_monotonic(self, indices):
             # non-monotonic should raise.
             with pytest.raises(ValueError):
                 indices._searchsorted_monotonic(value, side='left')
+
+    def test_map(self):
+        index = self.create_index()
+        # From output of UInt64Index mapping can't infer that we
+        #   shouldn't default to Int64
+        if isinstance(index, UInt64Index):
+            expected = Index(index.values.tolist())
+        else:
+            expected = index
+
+        tm.assert_index_equal(index.map(lambda x: x), expected)
+
+        identity_dict = {x: x for x in index}
+        tm.assert_index_equal(index.map(identity_dict), expected)
+
+        # Use values to work around MultiIndex instantiation of series
+        identity_series = Series(expected.values, index=index)
+        tm.assert_index_equal(index.map(identity_series), expected)
+
+        # empty mappable
+        nan_index = pd.Index([np.nan] * len(index))
+        series_map = pd.Series()
+        tm.assert_index_equal(index.map(series_map), nan_index)
+
+        dict_map = {}
+        tm.assert_index_equal(index.map(dict_map), nan_index)

pandas/tests/indexes/datetimelike.py

@@ -1,5 +1,5 @@
 """ generic datetimelike tests """
-
+import pandas as pd
 from .common import Base
 import pandas.util.testing as tm
 
@@ -38,3 +38,24 @@ def test_view(self, indices):
         i_view = i.view(self._holder)
         result = self._holder(i)
         tm.assert_index_equal(result, i_view)
+
+    def test_map(self):
+        expected = self.index + 1
+        tm.assert_index_equal(self.index.map(lambda x: x + 1), expected)
+
+        series_map = pd.Series(expected, self.index)
+        tm.assert_index_equal(self.index.map(series_map), expected)
+
+        dict_map = {i: e for e, i in zip(expected, self.index)}
+        tm.assert_index_equal(self.index.map(dict_map), expected)
+
+        # map to NaT
+        result = self.index.map(lambda x: pd.NaT if x == self.index[0] else x)
+        expected = pd.Index([pd.NaT] + self.index[1:].tolist())
+        tm.assert_index_equal(result, expected)
+
+        series_map = pd.Series(expected, self.index)
+        tm.assert_index_equal(self.index.map(series_map), expected)
+
+        dict_map = {i: e for e, i in zip(expected, self.index)}
+        tm.assert_index_equal(self.index.map(dict_map), expected)

pandas/tests/indexes/datetimes/test_datetimelike.py

@@ -78,27 +78,4 @@ def test_union(self):
             assert tm.equalContents(result, everything)
 
     def test_map(self):
-        expected = self.index + 1
-        tm.assert_index_equal(self.index.map(lambda x: x + 1), expected)
-
-        series_map = pd.Series(expected, self.index)
-        tm.assert_index_equal(self.index.map(series_map), expected)
-
-        dict_map = {i: e for e, i in zip(expected, self.index)}
-        tm.assert_index_equal(self.index.map(dict_map), expected)
-
-        # empty mappable
-        nan_index = Index([pd.np.nan] * len(self.index))
-        series_map = pd.Series()
-        tm.assert_index_equal(self.index.map(series_map), nan_index)
-        dict_map = {}
-        tm.assert_index_equal(self.index.map(dict_map), nan_index)
-
-        # map to NaT
-        result = self.index.map(lambda x: pd.NaT if x == self.index[0] else x)
-        expected = Index([pd.NaT] + self.index[1:].tolist())
-        tm.assert_index_equal(result, expected)
-        series_map = pd.Series(expected, self.index)
-        tm.assert_index_equal(self.index.map(series_map), expected)
-        dict_map = {i: e for e, i in zip(expected, self.index)}
-        tm.assert_index_equal(self.index.map(dict_map), expected)
+        super(TestDatetimeIndex, self).test_map()

pandas/tests/indexes/period/test_period.py

@@ -788,7 +788,9 @@ def test_pickle_freq(self):
         assert new_prng.freq == offsets.MonthEnd()
         assert new_prng.freqstr == 'M'
 
-    def test_map_with_ordinal(self):
+    def test_map(self):
+        super(TestPeriodIndex, self).test_map()
+
         index = PeriodIndex([2005, 2007, 2009], freq='A')
         result = index.map(lambda x: x.ordinal)
         exp = Index([x.ordinal for x in index])

pandas/tests/indexes/test_interval.py

@@ -395,6 +395,10 @@ def test_repr_max_seq_item_setting(self):
     def test_repr_roundtrip(self):
         super(TestIntervalIndex, self).test_repr_roundtrip()
 
+    @pytest.mark.xfail(reason='get_indexer behavior does not currently work')
+    def test_map(self):
+        super(TestIntervalIndex, self).test_map()
+
     def test_get_item(self):
         i = IntervalIndex.from_arrays((0, 1, np.nan), (1, 2, np.nan),
                                       closed='right')

pandas/tests/indexes/timedeltas/test_timedelta.py

@@ -300,6 +300,7 @@ def test_misc_coverage(self):
         assert not idx.equals(list(non_td))
 
     def test_map(self):
+        super(TestTimedeltaIndex, self).test_map()
 
         rng = timedelta_range('1 day', periods=10)