From a1ff90be63667ac4384ec74e82406dbcd1e05165 Mon Sep 17 00:00:00 2001
From: Spencer Clark <spencerkclark@gmail.com>
Date: Sat, 2 Feb 2019 01:56:12 -0500
Subject: [PATCH] dropna() for a Series indexed by a CFTimeIndex (#2734)

* Support dropna() for a Series indexed by a CFTimeIndex

* Add a what's new entry

* Use == instead of is
---
 doc/whats-new.rst                | 5 +++--
 xarray/coding/cftimeindex.py     | 8 +++++---
 xarray/tests/test_cftimeindex.py | 8 ++++++++
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/doc/whats-new.rst b/doc/whats-new.rst
index 0149d119595..169950813fd 100644
--- a/doc/whats-new.rst
+++ b/doc/whats-new.rst
@@ -50,13 +50,14 @@ Enhancements
 - Add ``tolerance`` option to ``resample()`` methods ``bfill``, ``pad``,
   ``nearest``. (:issue:`2695`)
   By `Hauke Schulz <https://github.com/observingClouds>`_.
-
 - :py:meth:`~xarray.DataArray.integrate` and
   :py:meth:`~xarray.Dataset.integrate` are newly added.
   See :ref:`_compute.using_coordinates` for the detail.
   (:issue:`1332`)
   By `Keisuke Fujii <https://github.com/fujiisoup>`_.
-
+- :py:meth:`pandas.Series.dropna` is now supported for a
+  :py:class:`pandas.Series` indexed by a :py:class:`~xarray.CFTimeIndex`
+  (:issue:`2688`). By `Spencer Clark <https://github.com/spencerkclark>`_.
 
 Bug fixes
 ~~~~~~~~~
diff --git a/xarray/coding/cftimeindex.py b/xarray/coding/cftimeindex.py
index f1a05d31a0c..1456f8ce3b3 100644
--- a/xarray/coding/cftimeindex.py
+++ b/xarray/coding/cftimeindex.py
@@ -335,11 +335,13 @@ def _maybe_cast_slice_bound(self, label, side, kind):
     # e.g. series[1:5].
     def get_value(self, series, key):
         """Adapted from pandas.tseries.index.DatetimeIndex.get_value"""
-        if not isinstance(key, slice):
-            return series.iloc[self.get_loc(key)]
-        else:
+        if np.asarray(key).dtype == np.dtype(bool):
+            return series.iloc[key]
+        elif isinstance(key, slice):
             return series.iloc[self.slice_indexer(
                 key.start, key.stop, key.step)]
+        else:
+            return series.iloc[self.get_loc(key)]
 
     def __contains__(self, key):
         """Adapted from
diff --git a/xarray/tests/test_cftimeindex.py b/xarray/tests/test_cftimeindex.py
index 97be993d842..358c9df0497 100644
--- a/xarray/tests/test_cftimeindex.py
+++ b/xarray/tests/test_cftimeindex.py
@@ -585,6 +585,14 @@ def test_indexing_in_series_iloc(series, index):
     assert series.iloc[:2].equals(expected)
 
 
+@pytest.mark.skipif(not has_cftime, reason='cftime not installed')
+def test_series_dropna(index):
+    series = pd.Series([0., 1., np.nan, np.nan], index=index)
+    expected = series.iloc[:2]
+    result = series.dropna()
+    assert result.equals(expected)
+
+
 @pytest.mark.skipif(not has_cftime, reason='cftime not installed')
 def test_indexing_in_dataframe_loc(df, index, scalar_args, range_args):
     expected = pd.Series([1], name=index[0])