BUG: Fix _binop for operators for serials which has more than one returns (divmod/rdivmod).

doc/source/whatsnew/v0.25.0.rst

@@ -176,6 +176,7 @@ Performance Improvements
 Bug Fixes
 ~~~~~~~~~
 
+
 Categorical
 ^^^^^^^^^^^
 
@@ -211,6 +212,7 @@ Numeric
 - Bug in :meth:`to_numeric` in which large negative numbers were being improperly handled (:issue:`24910`)
 - Bug in :meth:`to_numeric` in which numbers were being coerced to float, even though ``errors`` was not ``coerce`` (:issue:`24910`)
 - Bug in error messages in :meth:`DataFrame.corr` and :meth:`Series.corr`. Added the possibility of using a callable. (:issue:`25729`)
+- Bug in :meth:`Series.divmod` and :meth:`Series.rdivmod` which would raise an (incorrect) ``ValueError`` rather than return a pair of :class:`Series` objects as result (:issue:`25557`)
 -
 -
 -

pandas/core/ops.py

@@ -1660,18 +1660,19 @@ def _construct_result(left, result, index, name, dtype=None):
     not be enough; we still need to override the name attribute.
     """
     out = left._constructor(result, index=index, dtype=dtype)
-
+    out = out.__finalize__(left)
     out.name = name
     return out
 
 
 def _construct_divmod_result(left, result, index, name, dtype=None):
     """divmod returns a tuple of like indexed series instead of a single series.
     """
-    constructor = left._constructor
     return (
-        constructor(result[0], index=index, name=name, dtype=dtype),
-        constructor(result[1], index=index, name=name, dtype=dtype),
+        _construct_result(left, result[0], index=index, name=name,
+                          dtype=dtype),
+        _construct_result(left, result[1], index=index, name=name,
+                          dtype=dtype),
     )
 
 

pandas/core/series.py

@@ -2527,6 +2527,7 @@ def _binop(self, other, func, level=None, fill_value=None):
         -------
         Series
         """
+
         if not isinstance(other, Series):
             raise AssertionError('Other operand must be Series')
 
@@ -2543,13 +2544,13 @@ def _binop(self, other, func, level=None, fill_value=None):
 
         with np.errstate(all='ignore'):
             result = func(this_vals, other_vals)
+
         name = ops.get_op_result_name(self, other)
-        result = self._constructor(result, index=new_index, name=name)
-        result = result.__finalize__(self)
-        if name is None:
-            # When name is None, __finalize__ overwrites current name
-            result.name = None
-        return result
+        if func.__name__ in ['divmod', 'rdivmod']:
+            ret = ops._construct_divmod_result(self, result, new_index, name)
+        else:
+            ret = ops._construct_result(self, result, new_index, name)
+        return ret
 
     def combine(self, other, func, fill_value=None):
         """

pandas/tests/series/test_operators.py

@@ -741,6 +741,21 @@ def test_op_duplicate_index(self):
         expected = pd.Series([11, 12, np.nan], index=[1, 1, 2])
         assert_series_equal(result, expected)
 
+    def test_divmod(self):
+        # GH25557
+        a = Series([1, 1, 1, np.nan], index=['a', 'b', 'c', 'd'])
+        b = Series([2, np.nan, 1, np.nan], index=['a', 'b', 'd', 'e'])
+
+        result = a.divmod(b)
+        expected = divmod(a, b)
+        assert_series_equal(result[0], expected[0])
+        assert_series_equal(result[1], expected[1])
+
+        result = a.rdivmod(b)
+        expected = divmod(b, a)
+        assert_series_equal(result[0], expected[0])
+        assert_series_equal(result[1], expected[1])
+
 
 class TestSeriesUnaryOps(object):
     # __neg__, __pos__, __inv__