From 38229dd0b49b2733833db713037745eb45c192be Mon Sep 17 00:00:00 2001
From: "D.S. McNeil" <dsm054@gmail.com>
Date: Tue, 6 Jun 2017 22:43:19 -0400
Subject: [PATCH] BUG: Fix Series.get failure on missing NaN (#8569)

---
 doc/source/whatsnew/v0.20.3.txt      | 2 +-
 pandas/core/indexes/numeric.py       | 2 ++
 pandas/tests/indexes/test_multi.py   | 8 ++++++++
 pandas/tests/indexes/test_numeric.py | 8 ++++++++
 pandas/tests/series/test_indexing.py | 6 ++++++
 5 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v0.20.3.txt b/doc/source/whatsnew/v0.20.3.txt
index 2032209c4aa232..4e39567f245f3a 100644
--- a/doc/source/whatsnew/v0.20.3.txt
+++ b/doc/source/whatsnew/v0.20.3.txt
@@ -48,7 +48,7 @@ Conversion
 Indexing
 ^^^^^^^^
 
-
+- Returning empty array instead of None when calling ``.get(np.nan)`` on a Series (:issue:`8569`)
 
 I/O
 ^^^
diff --git a/pandas/core/indexes/numeric.py b/pandas/core/indexes/numeric.py
index bdae0ac7ac5e93..72d521cbe2d60c 100644
--- a/pandas/core/indexes/numeric.py
+++ b/pandas/core/indexes/numeric.py
@@ -369,6 +369,8 @@ def get_loc(self, key, method=None, tolerance=None):
                 except (ValueError, IndexError):
                     # should only need to catch ValueError here but on numpy
                     # 1.7 .item() can raise IndexError when NaNs are present
+                    if not len(nan_idxs):
+                        raise KeyError(key)
                     return nan_idxs
         except (TypeError, NotImplementedError):
             pass
diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index ba917f33d85953..7d2e6f495311f6 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -1172,6 +1172,14 @@ def test_get_loc_level(self):
         assert result == expected
         assert new_index.equals(index.droplevel(0))
 
+    def test_get_loc_missing_nan(self):
+        # GH 8569
+        idx = MultiIndex.from_arrays([[1.0, 2.0], [3.0, 4.0]])
+        assert isinstance(idx.get_loc(1), slice)
+        pytest.raises(KeyError, idx.get_loc, 3)
+        pytest.raises(KeyError, idx.get_loc, np.nan)
+        pytest.raises(KeyError, idx.get_loc, [np.nan])
+
     def test_slice_locs(self):
         df = tm.makeTimeDataFrame()
         stacked = df.stack()
diff --git a/pandas/tests/indexes/test_numeric.py b/pandas/tests/indexes/test_numeric.py
index 29d4214fd549b5..62ac337d027273 100644
--- a/pandas/tests/indexes/test_numeric.py
+++ b/pandas/tests/indexes/test_numeric.py
@@ -371,6 +371,14 @@ def test_get_loc_na(self):
         assert idx.get_loc(1) == 1
         pytest.raises(KeyError, idx.slice_locs, np.nan)
 
+    def test_get_loc_missing_nan(self):
+        # GH 8569
+        idx = Float64Index([1, 2])
+        assert idx.get_loc(1) == 0
+        pytest.raises(KeyError, idx.get_loc, 3)
+        pytest.raises(KeyError, idx.get_loc, np.nan)
+        pytest.raises(KeyError, idx.get_loc, [np.nan])
+
     def test_contains_nans(self):
         i = Float64Index([1.0, 2.0, np.nan])
         assert np.nan in i
diff --git a/pandas/tests/series/test_indexing.py b/pandas/tests/series/test_indexing.py
index 6ded4d593a571d..a909c973c19a65 100644
--- a/pandas/tests/series/test_indexing.py
+++ b/pandas/tests/series/test_indexing.py
@@ -70,6 +70,12 @@ def test_get(self):
         result = vc.get(True, default='Missing')
         assert result == 'Missing'
 
+    def test_get_missing_nan(self):
+        # GH 8569
+        s = pd.Float64Index(range(10)).to_series()
+        assert s.get(np.nan) is None
+        assert s.get(np.nan, default='Missing') == 'Missing'
+
     def test_delitem(self):
 
         # GH 5542