BUG: pandas.cut and negative values #14652

doc/source/whatsnew/v0.19.2.txt

@@ -25,3 +25,4 @@ Bug Fixes
 
 - compat with ``dateutil==2.6.0`` for testing (:issue:`14621`)
 - allow ``nanoseconds`` in ``Timestamp.replace`` kwargs (:issue:`14621`)
+- Bug in ``pd.cut`` (:issue:`14652`)

pandas/tools/tests/test_tile.py

@@ -271,6 +271,18 @@ def test_series_retbins(self):
                                     np.array([0, 0, 1, 1], dtype=np.int8))
         tm.assert_numpy_array_equal(bins, np.array([0, 1.5, 3]))
 
+    def test_single_bin(self):
+        # issue 14652
+        expected = Series([0, 0])
+
+        s = Series([9., 9.])
+        result = cut(s, 1, labels=False)
+        tm.assert_series_equal(result, expected)
+
+        s = Series([-9., -9.])
+        result = cut(s, 1, labels=False)
+        tm.assert_series_equal(result, expected)
+
 
 def curpath():
     pth, _ = os.path.split(os.path.abspath(__file__))

pandas/tools/tile.py

@@ -98,8 +98,8 @@ def cut(x, bins, right=True, labels=None, retbins=False, precision=3,
         mn, mx = [mi + 0.0 for mi in rng]
 
         if mn == mx:  # adjust end points before binning
-            mn -= .001 * mn
-            mx += .001 * mx
+            mn -= .001 * abs(mn)
+            mx += .001 * abs(mx)
             bins = np.linspace(mn, mx, bins + 1, endpoint=True)
         else:  # adjust end points after binning
             bins = np.linspace(mn, mx, bins + 1, endpoint=True)