BUG: fixed Series.replace with later replacements clobbering earlier ones. Still need DataFrame fix

Author: Chang She

pandas/core/frame.py

@@ -2956,7 +2956,6 @@ def _interpolate(self, to_replace, method, axis, inplace, limit):
             else:
                 return self._constructor(new_data)
 
-
     def _replace_dest_dict(self, to_replace, value, inplace):
         rs = self if inplace else self.copy()
         for k, v in value.iteritems():

pandas/core/series.py

@@ -2242,8 +2242,12 @@ def _rep_dict(rs, to_rep): # replace {[src] -> dest}
             dd = {} # group by unique destination value
             [dd.setdefault(d, []).append(s) for s, d in to_rep.iteritems()]
 
+            masks = {}
             for d, sset in dd.iteritems(): # now replace by each dest
-                rs = _rep_one(rs, sset, d)
+                masks[d] = com.mask_missing(rs.values, sset)
+
+            for d, m in masks.iteritems():
+                np.putmask(rs.values, m, d)
             return rs
 
         if np.isscalar(to_replace):

pandas/tests/test_series.py

@@ -2668,6 +2668,10 @@ def test_replace(self):
         self.assertRaises(ValueError, ser.replace, [1,2,3], [np.nan, 0])
         self.assertRaises(ValueError, ser.replace, xrange(1,3), [np.nan, 0])
 
+        ser = Series([0, 1, 2, 3, 4])
+        result = ser.replace([0, 1, 2, 3, 4], [4, 3, 2, 1, 0])
+        assert_series_equal(result, Series([4, 3, 2, 1, 0]))
+
     def test_asfreq(self):
         ts = Series([0., 1., 2.], index=[datetime(2009, 10, 30),
                                          datetime(2009, 11, 30),