in core/frame.py

removed mask method
made other optional kw parm in where
changed __setitem__ to use where (rather than mask)

pandas/core/frame.py

@@ -1776,7 +1776,7 @@ def __getitem__(self, key):
             return self._getitem_multilevel(key)
         elif isinstance(key, DataFrame):
             if key.values.dtype == bool:
-                return self.mask(key)
+                return self.where(key)
             else:
                 raise ValueError('Cannot index using non-boolean DataFrame')
         else:
@@ -4867,7 +4867,7 @@ def combineMult(self, other):
         """
         return self.mul(other, fill_value=1.)
 
-    def where(self, cond, other, inplace=False):
+    def where(self, cond, other=NA, inplace=False):
         """
         Return a DataFrame with the same shape as self and whose corresponding
         entries are from self where cond is True and otherwise are from other.
@@ -4901,21 +4901,6 @@ def where(self, cond, other, inplace=False):
         rs = np.where(cond, self, other)
         return self._constructor(rs, self.index, self.columns)
 
-    def mask(self, cond):
-        """
-        Returns copy of self whose values are replaced with nan if the
-        corresponding entry in cond is False
-
-        Parameters
-        ----------
-        cond: boolean DataFrame or array
-
-        Returns
-        -------
-        wh: DataFrame
-        """
-        return self.where(cond, NA)
-
 _EMPTY_SERIES = Series([])
 
 

pandas/tests/test_frame.py

@@ -142,7 +142,6 @@ def test_getitem_boolean(self):
         self.assertRaises(ValueError, self.tsframe.__getitem__, self.tsframe)
 
         # test df[df >0] works
-
         bif = self.tsframe[self.tsframe > 0]
         bifw = DataFrame(np.where(self.tsframe>0,self.tsframe,np.nan),index=self.tsframe.index,columns=self.tsframe.columns)
         self.assert_(isinstance(bif,DataFrame))
@@ -5215,8 +5214,6 @@ def test_where(self):
         for k, v in rs.iteritems():
             assert_series_equal(v, np.where(cond[k], df[k], other5))
 
-        assert_frame_equal(rs, df.mask(cond))
-
         err1 = (df + 1).values[0:2, :]
         self.assertRaises(ValueError, df.where, cond, err1)