added missing Series.ix case for completeness, optimized DataFrame.ix…

…[...] to reduce unnecessary computation in some cases

pandas/core/common.py

@@ -121,7 +121,7 @@ def _need_slice(obj):
     return obj.start is not None or obj.stop is not None
 
 def _check_step(obj):
-    if obj.step is not None:
+    if obj.step is not None and obj.step != 1:
         raise Exception('steps other than 1 are not supported')
 
 def _ensure_index(index_like):

pandas/core/frame.py

@@ -2478,12 +2478,20 @@ def _fancy_getitem(self, key, axis=0):
             return self.reindex(**{axis_name : key})
 
     def _fancy_getitem_tuple(self, rowkey, colkey):
-        result = self._fancy_getitem_axis(colkey, axis=1)
+        def _is_label_like(key):
+            # select a label or row
+            return not isinstance(key, slice) and not _is_list_like(key)
+
+        # to avoid wasted computation
+        # df.ix[d1:d2, 0] -> columns first (True)
+        # df.ix[0, ['C', 'B', A']] -> rows first (False)
+        if _is_label_like(colkey):
+            return self._fancy_getitem_axis(colkey, axis=1).ix[rowkey]
+        elif _is_label_like(rowkey):
+            return self._fancy_getitem_axis(rowkey, axis=0).ix[colkey]
 
-        if isinstance(result, Series):
-            result = result[rowkey]
-        else:
-            result = result._fancy_getitem_axis(rowkey, axis=0)
+        result = self._fancy_getitem_axis(colkey, axis=1)
+        result = result._fancy_getitem_axis(rowkey, axis=0)
 
         return result
 

pandas/core/series.py

@@ -3,7 +3,7 @@
 """
 
 # pylint: disable=E1101,E1103
-# pylint: disable=W0703,W0622
+# pylint: disable=W0703,W0622,W0613
 
 import itertools
 import operator
@@ -14,12 +14,12 @@
 import numpy as np
 
 from pandas.core.common import isnull, notnull
-from pandas.core.common import (_check_step, _need_slice, _is_label_slice,
-                                _ensure_index)
+from pandas.core.common import (_need_slice, _is_label_slice,
+                                _is_list_like, _ensure_index)
 
 from pandas.core.daterange import DateRange
 from pandas.core.generic import PandasGeneric
-from pandas.core.index import Index, NULL_INDEX
+from pandas.core.index import Index
 import pandas.core.datetools as datetools
 import pandas.lib.tseries as tseries
 
@@ -1376,8 +1376,10 @@ def _fancy_getitem(self, key):
                 return self[i:j]
             else:
                 return self[key]
-        else:
+        elif _is_list_like(key):
             return self.reindex(key)
+        else:
+            return self[key]
 
     def _fancy_setitem(self, key, value):
         if _isboolarr(key):
@@ -1392,11 +1394,13 @@ def _fancy_setitem(self, key, value):
                 self[i:j] = value
             else:
                 self[key] = value
-        else:
+        elif _is_list_like(key):
             inds, mask = self.index.get_indexer(key)
             if not mask.all():
                 raise Exception('Indices %s not found' % key[-mask])
             self.put(inds, value)
+        else:
+            self[key] = value
 
 class TimeSeries(Series):
     pass

pandas/core/tests/test_frame.py

@@ -181,6 +181,10 @@ def test_getitem_fancy_2d(self):
 
         assert_frame_equal(ix[:, ['B', 'A']], f.reindex(columns=['B', 'A']))
 
+        subidx = self.frame.index[[5, 4, 1]]
+        assert_frame_equal(ix[subidx, ['B', 'A']],
+                           f.reindex(index=subidx, columns=['B', 'A']))
+
         # slicing rows, etc.
         assert_frame_equal(ix[5:10], f[5:10])
         assert_frame_equal(ix[5:10, :], f[5:10])

pandas/core/tests/test_series.py

@@ -248,6 +248,10 @@ def test_ix_getitem(self):
         mask = self.series > self.series.median()
         assert_series_equal(self.series.ix[mask], self.series[mask])
 
+        # ask for index value
+        self.assertEquals(self.series.ix[d1], self.series[d1])
+        self.assertEquals(self.series.ix[d2], self.series[d2])
+
     def test_ix_setitem(self):
         inds = self.series.index[[3,4,7]]
 
@@ -268,6 +272,12 @@ def test_ix_setitem(self):
         expected[5:16] = 6 # because it's inclusive
         assert_series_equal(result, expected)
 
+        # set index value
+        self.series.ix[d1] = 4
+        self.series.ix[d2] = 6
+        self.assertEquals(self.series[d1], 4)
+        self.assertEquals(self.series[d2], 6)
+
     def test_ix_setitem_boolean(self):
         mask = self.series > self.series.median()
 

test.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 coverage erase
 # nosetests -w pandas --with-coverage --cover-package=pandas --pdb-failure --pdb
-nosetests -w pandas/io --with-coverage --cover-package=pandas.io --pdb-failure --pdb
-# nosetests -w pandas/core --with-coverage --cover-package=pandas.core --pdb-failure --pdb
+# nosetests -w pandas/io --with-coverage --cover-package=pandas.io --pdb-failure --pdb
+nosetests -w pandas/core --with-coverage --cover-package=pandas.core --pdb-failure --pdb
 # nosetests -w pandas/stats --with-coverage --cover-package=pandas.stats
 # coverage run runtests.py