Moved fixes into '_groupby_and_aggregate'.

Author: discort

pandas/core/resample.py

@@ -387,42 +387,32 @@ def _groupby_and_aggregate(self, how, grouper=None, *args, **kwargs):
 
         obj = self._selected_obj
 
+        result = None
         try:
             grouped = groupby(obj, by=None, grouper=grouper, axis=self.axis)
         except TypeError:
 
             # panel grouper
             grouped = PanelGroupBy(obj, grouper=grouper, axis=self.axis)
+            result = grouped.aggregate(how, *args, **kwargs)
 
-        try:
-            result = self._try_aggregate(grouped, how, *args, **kwargs)
-        except Exception:
-
-            # we have a non-reducing function
-            # try to evaluate
-            result = grouped.apply(how, *args, **kwargs)
+        if result is None:
+            try:
+                if compat.callable(how):
+                    # Check if the function is reducing or not.
+                    result = grouped._aggregate_item_by_item(how,
+                                                             *args, **kwargs)
+                else:
+                    result = grouped.aggregate(how, *args, **kwargs)
+            except Exception:
+
+                # we have a non-reducing function
+                # try to evaluate
+                result = grouped.apply(how, *args, **kwargs)
 
         result = self._apply_loffset(result)
         return self._wrap_result(result)
 
-    def _try_aggregate(self, grouped, how, *args, **kwargs):
-        """
-        Tries to aggregate a 'grouped' object.
-        When 'how' param is a callable, we aggregate item by item
-        to check if the function is reducing or not.
-
-        Parameters
-        ----------
-        grouped : GroupBy object
-        how : string / cython mapped function
-        """
-        if not compat.callable(how) or isinstance(grouped, PanelGroupBy):
-            return grouped.aggregate(how, *args, **kwargs)
-
-        # Callables might change the count of columns (GH #15169)
-        result = grouped._aggregate_item_by_item(how, *args, **kwargs)
-        return result
-
     def _apply_loffset(self, result):
         """
         if loffset is set, offset the result index