API: restore inplace=TRue returns self, add FutureWarnings. re #1893

Author: wesm

RELEASE.rst

@@ -31,6 +31,16 @@ pandas 0.10.1
 
   - Add data inferface to World Bank WDI pandas.io.wb (#2592)
 
+**API Changes**
+
+  - Restored inplace=True behavior returning self (same object) with
+    deprecation warning until 0.11 (GH1893_)
+  - ``HDFStore``
+    - refactored HFDStore to deal with non-table stores as objects, will allow future enhancements
+    - removed keyword ``compression`` from ``put`` (replaced by keyword
+      ``complib`` to be consistent across library)
+    - warn `PerformanceWarning` if you are attempting to store types that will be pickled by PyTables
+
 **Improvements to existing features**
 
   - ``HDFStore``
@@ -111,15 +121,6 @@ pandas 0.10.1
   - Fix buggy interaction with usecols argument in read_csv when there is an
     implicit first index column (GH2654_)
 
-**API Changes**
-
-  - ``HDFStore``
-
-    - refactored HFDStore to deal with non-table stores as objects, will allow future enhancements
-    - removed keyword ``compression`` from ``put`` (replaced by keyword
-      ``complib`` to be consistent across library)
-    - warn `PerformanceWarning` if you are attempting to store types that will be pickled by PyTables
-
 .. _GH512: https://github.com/pydata/pandas/issues/512
 .. _GH1277: https://github.com/pydata/pandas/issues/1277
 .. _GH2070: https://github.com/pydata/pandas/issues/2070

pandas/core/frame.py

@@ -2755,6 +2755,15 @@ def set_index(self, keys, drop=True, append=False, inplace=False,
         index._cleanup()
 
         frame.index = index
+
+        if inplace:
+            import warnings
+            warnings.warn("set_index with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
+        else:
+            return frame
+
         return frame if not inplace else None
 
     def reset_index(self, level=None, drop=False, inplace=False, col_level=0,
@@ -2854,7 +2863,13 @@ def _maybe_cast(values):
             new_obj.insert(0, name, _maybe_cast(values))
 
         new_obj.index = new_index
-        return new_obj if not inplace else None
+        if inplace:
+            import warnings
+            warnings.warn("reset_index with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
+        else:
+            return new_obj
 
     delevel = deprecate('delevel', reset_index)
 
@@ -3014,6 +3029,10 @@ def drop_duplicates(self, cols=None, take_last=False, inplace=False):
             inds, = (-duplicated).nonzero()
             self._data = self._data.take(inds)
             self._clear_item_cache()
+            import warnings
+            warnings.warn("drop_duplicates with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
         else:
             return self[-duplicated]
 
@@ -3168,6 +3187,10 @@ def sort_index(self, axis=0, by=None, ascending=True, inplace=False):
                 self._data = self._data.take(indexer)
 
             self._clear_item_cache()
+            import warnings
+            warnings.warn("sort/sort_index with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
         else:
             return self.take(indexer, axis=axis)
 
@@ -3210,6 +3233,10 @@ def sortlevel(self, level=0, axis=0, ascending=True, inplace=False):
                 self._data = self._data.take(indexer)
 
             self._clear_item_cache()
+            import warnings
+            warnings.warn("sortlevel with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
         else:
             return self.take(indexer, axis=axis)
 
@@ -3337,6 +3364,10 @@ def fillna(self, value=None, method=None, axis=0, inplace=False,
 
         if inplace:
             self._data = new_data
+            import warnings
+            warnings.warn("fillna with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
         else:
             return self._constructor(new_data)
 
@@ -3384,6 +3415,11 @@ def replace(self, to_replace, value=None, method='pad', axis=0,
         """
         self._consolidate_inplace()
 
+        if inplace:
+            import warnings
+            warnings.warn("replace with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+
         if value is None:
             return self._interpolate(to_replace, method, axis, inplace, limit)
         else:
@@ -3416,7 +3452,7 @@ def replace(self, to_replace, value=None, method='pad', axis=0,
 
                 if inplace:
                     self._data = new_data
-                    return None
+                    return self
                 else:
                     return self._constructor(new_data)
             else:
@@ -3427,7 +3463,7 @@ def replace(self, to_replace, value=None, method='pad', axis=0,
                                                   inplace=inplace)
                     if inplace:
                         self._data = new_data
-                        return None
+                        return self
                     else:
                         return self._constructor(new_data)
 
@@ -3534,7 +3570,13 @@ def rename(self, index=None, columns=None, copy=True, inplace=False):
         if columns is not None:
             result._rename_columns_inplace(columns_f)
 
-        return result if not inplace else None
+        if inplace:
+            import warnings
+            warnings.warn("rename with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
+        else:
+            return result
 
     def _rename_index_inplace(self, mapper):
         self._data = self._data.rename_axis(mapper, axis=1)

pandas/core/series.py

@@ -937,7 +937,11 @@ def reset_index(self, level=None, drop=False, name=None, inplace=False):
                 self.index = new_index
                 # set name if it was passed, otherwise, keep the previous name
                 self.name = name or self.name
-                return
+                import warnings
+                warnings.warn("Series.reset_index with inplace=True will "
+                              "return None from pandas 0.11 onward",
+                              FutureWarning)
+                return self
             else:
                 return Series(self.values.copy(), index=new_index,
                               name=self.name)
@@ -2469,8 +2473,13 @@ def fillna(self, value=None, method=None, inplace=False,
         -------
         filled : Series
         """
+        if inplace:
+            import warnings
+            warnings.warn("Series.fillna with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+
         if not self._can_hold_na:
-            return self.copy() if not inplace else None
+            return self.copy() if not inplace else self
 
         if value is not None:
             if method is not None:
@@ -2496,7 +2505,10 @@ def fillna(self, value=None, method=None, inplace=False,
             else:
                 result = Series(values, index=self.index, name=self.name)
 
-        return result if not inplace else None
+        if inplace:
+            return self
+        else:
+            return result
 
     def ffill(self, inplace=False, limit=None):
         return self.fillna(method='ffill', inplace=inplace, limit=limit)
@@ -2596,7 +2608,13 @@ def _rep_dict(rs, to_rep):  # replace {[src] -> dest}
             raise ValueError('Unrecognized to_replace type %s' %
                              type(to_replace))
 
-        return result if not inplace else None
+        if inplace:
+            import warnings
+            warnings.warn("Series.replace with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
+        else:
+            return result
 
     def isin(self, values):
         """
@@ -2944,7 +2962,13 @@ def rename(self, mapper, inplace=False):
         result = self if inplace else self.copy()
         result.index = [mapper_f(x) for x in self.index]
 
-        return result if not inplace else None
+        if inplace:
+            import warnings
+            warnings.warn("Series.rename with inplace=True  will return None"
+                          " from pandas 0.11 onward", FutureWarning)
+            return self
+        else:
+            return result
 
     @property
     def weekday(self):

pandas/io/tests/test_parsers.py

@@ -54,6 +54,9 @@ def read_table(self, *args, **kwargs):
         raise NotImplementedError
 
     def setUp(self):
+        import warnings
+        warnings.filterwarnings(action='ignore', category=FutureWarning)
+
         self.dirpath = curpath()
         self.csv1 = os.path.join(self.dirpath, 'test1.csv')
         self.csv2 = os.path.join(self.dirpath, 'test2.csv')

pandas/io/tests/test_pytables.py

@@ -32,6 +32,8 @@ class TestHDFStore(unittest.TestCase):
     scratchpath = '__scratch__.h5'
 
     def setUp(self):
+        warnings.filterwarnings(action='ignore', category=FutureWarning)
+
         self.path = '__%s__.h5' % tm.rands(10)
         self.store = HDFStore(self.path)
 

pandas/sparse/tests/test_sparse.py

@@ -37,6 +37,9 @@
 
 from test_array import assert_sp_array_equal
 
+import warnings
+warnings.filterwarnings(action='ignore', category=FutureWarning)
+
 
 def _test_data1():
     # nan-based