FIX: timeseries asfreq would drop the name of the index, closes #9854

Author: hsperr

doc/source/whatsnew/v0.16.1.txt

@@ -96,49 +96,56 @@ Bug Fixes
 - Bug in json serialization when frame has length zero.(:issue:`9805`)
 - Bug in `read_csv` where missing trailing delimiters would cause segfault. (:issue:`5664`)
 - Bug in retaining index name on appending (:issue:`9862`)
-
-
 - Bug in ``scatter_matrix`` draws unexpected axis ticklabels (:issue:`5662`)
-
 - Fixed bug in ``StataWriter`` resulting in changes to input ``DataFrame`` upon save (:issue:`9795`).
-
-
 - Bug in ``transform`` causing length mismatch when null entries were present and a fast aggregator was being used (:issue:`9697`)
-
 - Bug in ``equals`` causing false negatives when block order differed (:issue:`9330`)
-
 - Bug in ``read_sql_table`` error when reading postgres table with timezone (:issue:`7139`)
-
 - Bug in ``DataFrame`` slicing may not retain metadata (:issue:`9776`)
 - Bug where ``TimdeltaIndex`` were not properly serialized in fixed ``HDFStore`` (:issue:`9635`)
-
 - Bug in plotting continuously using ``secondary_y`` may not show legend properly. (:issue:`9610`, :issue:`9779`)
-
 - Bug in ``DataFrame.plot(kind="hist")`` results in ``TypeError`` when ``DataFrame`` contains non-numeric columns  (:issue:`9853`)
 - Bug where repeated plotting of ``DataFrame`` with a ``DatetimeIndex`` may raise ``TypeError`` (:issue:`9852`)
-
 - Bug in ``Series.quantile`` on empty Series of type ``Datetime`` or ``Timedelta`` (:issue:`9675`)
 - Bug in ``where`` causing incorrect results when upcasting was required (:issue:`9731`)
 - Bug in ``FloatArrayFormatter`` where decision boundary for displaying "small" floats in decimal format is off by one order of magnitude for a given display.precision (:issue:`9764`)
-
 - Fixed bug where ``DataFrame.plot()`` raised an error when both ``color`` and ``style`` keywords were passed and there was no color symbol in the style strings (:issue:`9671`)
 - Bug in ``read_csv`` and ``read_table`` when using ``skip_rows`` parameter if blank lines are present. (:issue:`9832`)
-
 - Bug in ``read_csv()`` interprets ``index_col=True`` as ``1`` (:issue:`9798`)
 - Bug in index equality comparisons using ``==`` failing on Index/MultiIndex type incompatibility (:issue:`9875`)
 - Bug in which ``SparseDataFrame`` could not take `nan` as a column name (:issue:`8822`)
-
 - Bug in ``Series.quantile`` on empty Series of type ``Datetime`` or ``Timedelta`` (:issue:`9675`)
-
 - Bug in ``to_msgpack`` and ``read_msgpack`` zlib and blosc compression support (:issue:`9783`)
-
 - Bug in unequal comparisons between a ``Series`` of dtype `"category"` and a scalar (e.g. ``Series(Categorical(list("abc"), categories=list("cba"), ordered=True)) > "b"``, which wouldn't use the order of the categories but use the lexicographical order. (:issue:`9848`)
 
 
+
+
+
+
+
+
+
+
+
+
+
+
+
 - Bug in unequal comparisons between categorical data and a scalar, which was not in the categories (e.g. ``Series(Categorical(list("abc"), ordered=True)) > "d"``. This returned ``False`` for all elements, but now raises a ``TypeError``. Equality comparisons also now return ``False`` for ``==`` and ``True`` for ``!=``. (:issue:`9848`)
 
 - Bug in ``MultiIndex.sortlevel()`` results in unicode level name breaks (:issue:`9875`)
-
 - Bug in which ``groupby.transform`` incorrectly enforced output dtypes to match input dtypes. (:issue:`9807`)
 
+
+
+
+
+
+
+
+
+
+
 - Bug where dividing a dataframe containing values of type ``Decimal`` by another ``Decimal`` would raise. (:issue:`9787`)
+- Bug where using DataFrames asfreq would remove the name of the index. (:issue:`9885`)

pandas/tseries/resample.py

@@ -480,6 +480,7 @@ def asfreq(obj, freq, method=None, how=None, normalize=False):
         if len(obj.index) == 0:
             return obj.copy()
         dti = date_range(obj.index[0], obj.index[-1], freq=freq)
+        dti.name = obj.index.name
         rs = obj.reindex(dti, method=method)
         if normalize:
             rs.index = rs.index.normalize()

pandas/tseries/tests/test_timeseries.py

@@ -1131,6 +1131,15 @@ def test_reindex_with_datetimes(self):
         result = ts[list(ts.index[5:10])]
         tm.assert_series_equal(result, expected)
 
+    def test_asfreq_keep_index_name(self):
+        # GH #9854
+        index_name = 'bar'
+        index = pd.date_range('20130101',periods=20,name=index_name)
+        df = pd.DataFrame([x for x in range(20)],columns=['foo'],index=index)
+
+        tm.assert_equal(index_name, df.index.name)
+        tm.assert_equal(index_name, df.asfreq('10D').index.name)
+
     def test_promote_datetime_date(self):
         rng = date_range('1/1/2000', periods=20)
         ts = Series(np.random.randn(20), index=rng)