BUG: pd.Series.interpolate(method='spline') Errort Msg, #10633

doc/source/whatsnew/v0.17.0.txt

@@ -674,11 +674,18 @@ Performance Improvements
 
 Bug Fixes
 ~~~~~~~~~
+<<<<<<< HEAD
 - Bug in ``DataFrame.to_html(index=False)`` renders unnecessary ``name`` row (:issue:`10344`)
+=======
+
+
+- Bug in ``DataFrame.to_html(index=False)`` renders unnecessary ``name`` row (:issue:`10344`) 
+>>>>>>> updating examples and the bug fix
 - Bug in ``DataFrame.apply`` when function returns categorical series. (:issue:`9573`)
 - Bug in ``to_datetime`` with invalid dates and formats supplied (:issue:`10154`)
 - Bug in ``Index.drop_duplicates`` dropping name(s) (:issue:`10115`)
 - Bug in ``pd.Series`` when setting a value on an empty ``Series`` whose index has a frequency. (:issue:`10193`)
+- Bug in ``pd.Series.interpolate`` when setting no order value on  ``Series.interpolate`` this needs to be at least 1. (:issue:`10633`) and (:issue:`10800`)
 - Bug in ``DataFrame.plot`` raises ``ValueError`` when color name is specified by multiple characters (:issue:`10387`)
 - Bug in ``Index`` construction with a mixed list of tuples (:issue:`10697`)
 - Bug in ``DataFrame.reset_index`` when index contains `NaT`. (:issue:`10388`)

pandas/core/common.py

@@ -1718,6 +1718,9 @@ def _interpolate_scipy_wrapper(x, y, new_x, method, fill_value=None,
                                     bounds_error=bounds_error)
         new_y = terp(new_x)
     elif method == 'spline':
+        # GH #10633
+        if not order:
+            raise ValueError("order needs to be specified and greater than 0")
         terp = interpolate.UnivariateSpline(x, y, k=order, **kwargs)
         new_y = terp(new_x)
     else:

pandas/tests/test_generic.py

@@ -799,6 +799,40 @@ def test_nan_interpolate(self):
         tm._skip_if_no_scipy()
         result = s.interpolate(method='polynomial', order=1)
         assert_series_equal(result, expected)
+<<<<<<< HEAD
+<<<<<<< HEAD
+
+    # GH #10633
+=======
+    # GH #10633: first attempt
+>>>>>>> d992cd0... Updated test
+=======
+
+    # GH #10633
+>>>>>>> 5a5407e... updating examples and the bug fix
+    def test_interpolate_spline(self):
+        np.random.seed(1)
+        s = pd.Series(np.arange(10)**2)
+        s[np.random.randint(0,9,3)] = np.nan
+        with tm.assertRaises(ValueError):
+            s.interpolate(method='spline')
+<<<<<<< HEAD
+<<<<<<< HEAD
+=======
+>>>>>>> 027a5e7... Updating based on feedback
+
+    def test_interpolate_spline(self):
+        np.random.seed(1)
+        t = pd.Series(np.arange(10)**2)
+        t[np.random.randint(0,9,3)] = np.nan
+        with tm.assertRaises(ValueError):
+            t.interpolate(method='spline', order=0)
+<<<<<<< HEAD
+=======
+>>>>>>> d992cd0... Updated test
+=======
+>>>>>>> 027a5e7... Updating based on feedback
+
 
     def test_nan_irregular_index(self):
         s = Series([1, 2, np.nan, 4], index=[1, 3, 5, 9])
@@ -1398,6 +1432,23 @@ def test_no_order(self):
             s.interpolate(method='polynomial')
         with tm.assertRaises(ValueError):
             s.interpolate(method='spline')
+
+<<<<<<< HEAD
+<<<<<<< HEAD
+=======
+    # GH #10633
+    def test_order_spline_interpolation(self):
+        tm._skip_if_no_scipy()
+        np.random.seed(1)
+        s = Series(np.arange(10)**2)
+        s[np.random.randint(0,9,3)] = np.nan
+        result1 = s.interpolate(method='spline', order=1)
+        expected1 = s.interpolate(method='spline', order=1)
+        assert_series_equal(result1, expected1)
+>>>>>>> 5a5407e... updating examples and the bug fix
+=======
+>>>>>>> 027a5e7... Updating based on feedback
+
 
     def test_spline(self):
         tm._skip_if_no_scipy()