Merge pull request #7341 from cpcloud/hayd-gh2073

FIX: resample with fill_method and how #2073

Author: cpcloud

doc/source/v0.14.1.txt

@@ -89,6 +89,7 @@ Bug Fixes
 ~~~~~~~~~
 
 - Bug in ``Index.min`` and ``max`` doesn't handle ``nan`` and ``NaT`` properly (:issue:`7261`)
+- Bug in ``resample`` where ``fill_method`` was ignored if you passed ``how`` (:issue:`7261`)
 - Bug in ``TimeGrouper`` doesn't exclude column specified by ``key`` (:issue:`7227`)
 - Bug in ``DataFrame`` and ``Series`` bar and barh plot raises ``TypeError`` when ``bottom``
   and ``left`` keyword is specified (:issue:`7226`)

pandas/tseries/resample.py

@@ -252,6 +252,11 @@ def _resample_timestamps(self):
                 # downsample
                 grouped = obj.groupby(grouper, axis=self.axis)
                 result = grouped.aggregate(self._agg_method)
+                # GH2073
+                if self.fill_method is not None:
+                    result = result.fillna(method=self.fill_method,
+                                           limit=self.limit)
+
             else:
                 # upsampling shortcut
                 if self.axis:

pandas/tseries/tests/test_resample.py

@@ -869,6 +869,14 @@ def test_monthly_upsample(self):
             expected = expected.asfreq(targ, 'ffill').to_period()
             assert_series_equal(result, expected)
 
+    def test_fill_method_and_how_upsample(self):
+        # GH2073
+        s = Series(range(9),
+                   index=date_range('2010-01-01', periods=9, freq='Q'))
+        last = s.resample('M', fill_method='ffill')
+        both = s.resample('M', how='last', fill_method='ffill').astype('int64')
+        assert_series_equal(last, both)
+
     def test_weekly_upsample(self):
         targets = ['D', 'B']