BUG: Enable Series.equals to compare iterables to non-iterables

Author: avinashpancham

doc/source/whatsnew/v1.2.0.rst

@@ -246,6 +246,7 @@ Timezones
 Numeric
 ^^^^^^^
 - Bug in :func:`to_numeric` where float precision was incorrect (:issue:`31364`)
+- Bug in :meth: `Series.equals` where a ``ValueError`` was raised when iterables were compared to non-iterables (:issue:`35267`)
 -
 
 Conversion

pandas/_libs/lib.pyx

@@ -581,6 +581,13 @@ def array_equivalent_object(left: object[:], right: object[:]) -> bool:
                     return False
             elif (x is C_NA) ^ (y is C_NA):
                 return False
+            # Only compare scalars to scalars and arrays to arrays
+            elif cnp.PyArray_IsAnyScalar(x) != cnp.PyArray_IsAnyScalar(y):
+                return False
+            # Check if arrays have the same type
+            elif not (cnp.PyArray_IsPythonScalar(x) or cnp.PyArray_IsPythonScalar(y)) \
+            and not (isinstance(x, type(y)) or isinstance(y, type(x))):
+                return False
             elif not (PyObject_RichCompareBool(x, y, Py_EQ) or
                       (x is None or is_nan(x)) and (y is None or is_nan(y))):
                 return False

pandas/tests/series/methods/test_equals.py

@@ -31,9 +31,8 @@ def test_equals_list_array():
     s2 = s1.copy()
     assert s1.equals(s2)
 
-    # TODO: Series equals should also work between single value and list
-    # s1[1] = 9
-    # assert not s1.equals(s2)
+    s1[1] = 9
+    assert not s1.equals(s2)
 
 
 def test_equals_false_negative():