split out grouper.py

Author: jreback

pandas/core/groupby/__init__.py

@@ -1,4 +1,4 @@
 from pandas.core.groupby.groupby import GroupBy  # flake8: noqa
 from pandas.core.groupby.generic import (
     SeriesGroupBy, DataFrameGroupBy, PanelGroupBy)  # flake8: noqa
-from pandas.core.groupby.ops import Grouper  # flake8: noqa
+from pandas.core.groupby.grouper import Grouper  # flake8: noqa

pandas/core/groupby/groupby.py

@@ -342,7 +342,7 @@ def __init__(self, obj, keys=None, axis=0, level=None,
         self.mutated = kwargs.pop('mutated', False)
 
         if grouper is None:
-            from pandas.core.groupby.ops import _get_grouper
+            from pandas.core.groupby.grouper import _get_grouper
             grouper, exclusions, obj = _get_grouper(obj, keys,
                                                     axis=axis,
                                                     level=level,
@@ -1518,7 +1518,7 @@ def nth(self, n, dropna=None):
 
             # create a grouper with the original parameters, but on the dropped
             # object
-            from pandas.core.groupby.ops import _get_grouper
+            from pandas.core.groupby.grouper import _get_grouper
             grouper, _, _ = _get_grouper(dropped, key=self.keys,
                                          axis=self.axis, level=self.level,
                                          sort=self.sort,