Merge branch 'master' into widepanel-refactor

* master:
  BUG: fixed GH #56
  BUG: in as_matrix with subset of columns with single-block
  always copy data when inserting into DataFrame. failing reverse op dtype=object unit test

Author: wesm

pandas/core/frame.py

@@ -786,11 +786,14 @@ def _insert_item(self, key, value):
         Series/TimeSeries will be conformed to the DataFrame's index to
         ensure homogeneity.
         """
+        # Need to make sure new columns (which go into the BlockManager as new
+        # blocks) are always copied
+
         if hasattr(value, '__iter__'):
             if isinstance(value, Series):
                 if value.index.equals(self.index):
-                    # no need to copy
-                    value = value.values
+                    # copy the values
+                    value = value.values.copy()
                 else:
                     value = value.reindex(self.index).values
             else:
@@ -800,6 +803,8 @@ def _insert_item(self, key, value):
                     value = np.array(value)
                     if value.dtype.type == np.str_:
                         value = np.array(value, dtype=object)
+                else:
+                    value = value.copy()
         else:
             value = np.repeat(value, len(self.index))
 

pandas/core/internals.py

@@ -373,6 +373,8 @@ def as_matrix(self, items=None):
             if items is None or blk.items.equals(items):
                 # if not, then just call interleave per below
                 mat = blk.values
+            else:
+                mat = self.reindex_columns(columns).as_matrix()
         else:
             if items is None:
                 mat = self._interleave(self.items)

pandas/core/series.py

@@ -35,6 +35,10 @@ def _arith_method(op, name):
         '__sub__' : '__rsub__',
         '__div__' : '__rdiv__',
         '__mul__' : '__rmul__',
+        '__radd__' : '__add__',
+        '__rsub__' : '__sub__',
+        '__rdiv__' : '__div__',
+        '__rmul__' : '__mul__',
     }
     def wrapper(self, other):
         from pandas.core.frame import DataFrame
@@ -445,6 +449,14 @@ def copy(self):
     __div__ = _arith_method(operator.div, '__div__')
     __truediv__ = _arith_method(operator.truediv, '__truediv__')
     __pow__ = _arith_method(operator.pow, '__pow__')
+    __truediv__ = _arith_method(operator.truediv, '__truediv__')
+
+    __radd__ = _arith_method(operator.add, '__add__')
+    __rmul__ = _arith_method(operator.mul, '__mul__')
+    __rsub__ = _arith_method(lambda x, y: y - x, '__sub__')
+    __rdiv__ = _arith_method(lambda x, y: y / x, '__div__')
+    __rtruediv__ = _arith_method(lambda x, y: y / x, '__truediv__')
+    __rpow__ = _arith_method(lambda x, y: y ** x, '__pow__')
 
     # Inplace operators
     __iadd__ = __add__

pandas/tests/test_frame.py

@@ -89,6 +89,13 @@ def test_setitem(self):
         self.assertEqual(smaller['col10'].dtype, np.object_)
         self.assert_((smaller['col10'] == ['1', '2']).all())
 
+    def test_setitem_always_copy(self):
+        s = self.frame['A'].copy()
+        self.frame['E'] = s
+
+        self.frame['E'][5:10] = np.nan
+        self.assert_(notnull(s[5:10]).all())
+
     def test_setitem_boolean(self):
         df = self.frame.copy()
         values = self.frame.values
@@ -1277,6 +1284,11 @@ def test_as_matrix(self):
         mat = self.mixed_frame.as_matrix(['foo', 'A'])
         self.assertEqual(mat[0, 0], 'bar')
 
+        # single block corner case
+        mat = self.frame.as_matrix(['A', 'B'])
+        expected = self.frame.reindex(columns=['A', 'B']).values
+        assert_almost_equal(mat, expected)
+
     def test_values(self):
         pass
 

pandas/tests/test_series.py

@@ -453,6 +453,21 @@ def test_operators_corner(self):
         expected = self.ts.values[:-5] + int_ts.values
         self.assert_(np.array_equal(added[:-5], expected))
 
+    def test_operators_reverse_object(self):
+        # GH 56
+        arr = Series(np.random.randn(10), index=np.arange(10),
+                     dtype=object)
+
+        def _check_op(arr, op):
+            result = op(1., arr)
+            expected = op(1., arr.astype(float))
+            assert_series_equal(result.astype(float), expected)
+
+        _check_op(arr, operator.add)
+        _check_op(arr, operator.sub)
+        _check_op(arr, operator.mul)
+        _check_op(arr, operator.div)
+
     def test_operators_frame(self):
         # rpow does not work with DataFrame
         df = DataFrame({'A' : self.ts})