code review changes

Author: aileronajay

doc/source/whatsnew/v0.20.0.txt

@@ -53,6 +53,7 @@ Other enhancements
 - ``pd.cut`` and ``pd.qcut`` now support datetime64 and timedelta64 dtypes (issue:`14714`)
 - ``Series`` provides a ``to_excel`` method to output Excel files (:issue:`8825`)
 - The ``usecols`` argument in ``pd.read_csv`` now accepts a callable function as a value  (:issue:`14154`)
+- The ``pd.Series.interpolate`` now supports timedelta as index type(:issue:`6424`)
 
 .. _whatsnew_0200.api_breaking:
 

pandas/core/missing.py

@@ -188,7 +188,7 @@ def _interp_limit(invalid, fw_limit, bw_limit):
         if method in ('values', 'index'):
             inds = np.asarray(xvalues)
             # hack for DatetimeIndex, #1646
-            if (needs_i8_conversion(inds.dtype.type)):
+            if needs_i8_conversion(inds.dtype.type):
                 inds = inds.view(np.int64)
             if inds.dtype == np.object_:
                 inds = lib.maybe_convert_objects(inds)

pandas/tests/series/test_missing.py

@@ -893,14 +893,21 @@ def test_spline_error(self):
 
     def test_interp_timedelta64(self):
         # GH 6424
-        tm._skip_if_no_scipy()
         df = Series([1, np.nan, 3],
                     index=pd.to_timedelta([1, 2, 3]))
         result = df.interpolate(method='time')
         expected = Series([1., 2., 3.],
                           index=pd.to_timedelta([1, 2, 3]))
         assert_series_equal(result, expected)
 
+        # test for non uniform spacing
+        df = Series([1, np.nan, 3],
+                    index=pd.to_timedelta([1, 2, 4]))
+        result = df.interpolate(method='time')
+        expected = Series([1., 1.666667, 3.],
+                          index=pd.to_timedelta([1, 2, 4]))
+        assert_series_equal(result, expected)
+
 
 if __name__ == '__main__':
     import nose