Series.eq supports list-like python objects

databricks/koalas/series.py

@@ -658,6 +658,14 @@ def eq(self, other) -> bool:
         d    False
         Name: b, dtype: bool
         """
+        if isinstance(other, (list, tuple)):
+            if len(self) == len(other):
+                other = ks.Series(other)
+            else:
+                raise ValueError("Lengths must be equal")
+        # pandas always returns False for all items with dict and set.
+        elif isinstance(other, (dict, set)):
+            return self != self
         return self == other
 
     equals = eq

databricks/koalas/tests/test_ops_on_diff_frames.py

@@ -1370,6 +1370,28 @@ def test_index_ops(self):
         else:
             self.assert_eq(kidx1 * 10 + kidx3, (pidx1 * 10 + pidx3).rename(None))
 
+    def test_series_eq(self):
+        pser = pd.Series([1, 2, 3, 4, 5, 6], name="x")
+        kser = ks.from_pandas(pser)
+
+        # other = Series
+        pandas_other = pd.Series([np.nan, 1, 3, 4, np.nan, 6], name="x")
+        koalas_other = ks.from_pandas(pandas_other)
+        self.assert_eq(pser.eq(pandas_other), kser.eq(koalas_other).sort_index())
+
+        # other = Index
+        pandas_other = pd.Index([np.nan, 1, 3, 4, np.nan, 6], name="x")
+        koalas_other = ks.from_pandas(pandas_other)
+        self.assert_eq(pser.eq(pandas_other), kser.eq(koalas_other).sort_index())
+
+        # other = list
+        other = [np.nan, 1, 3, 4, np.nan, 6]
+        self.assert_eq(pser.eq(other), kser.eq(other).sort_index())
+
+        # other = tuple
+        other = (np.nan, 1, 3, 4, np.nan, 6)
+        self.assert_eq(pser.eq(other), kser.eq(other).sort_index())
+
 
 class OpsOnDiffFramesDisabledTest(ReusedSQLTestCase, SQLTestUtils):
     @classmethod
@@ -1511,3 +1533,17 @@ def test_mask(self):
 
         with self.assertRaisesRegex(ValueError, "Cannot combine the series or dataframe"):
             kdf1.mask(kdf2 > -250)
+
+    def test_series_eq(self):
+        pser = pd.Series([1, 2, 3, 4, 5, 6], name="x")
+        kser = ks.from_pandas(pser)
+
+        others = (
+            ks.Series([np.nan, 1, 3, 4, np.nan, 6], name="x"),
+            ks.Index([np.nan, 1, 3, 4, np.nan, 6], name="x"),
+            [np.nan, 1, 3, 4, np.nan, 6],
+            (np.nan, 1, 3, 4, np.nan, 6),
+        )
+        for other in others:
+            with self.assertRaisesRegex(ValueError, "Cannot combine the series or dataframe"):
+                kser.eq(other)

databricks/koalas/tests/test_series.py

@@ -2639,3 +2639,28 @@ def test_backfill(self):
             # Test `inplace=True`
             kser.backfill(inplace=True)
             self.assert_eq(expected, kser)
+
+    def test_eq(self):
+        pser = pd.Series([1, 2, 3, 4, 5, 6], name="x")
+        kser = ks.from_pandas(pser)
+
+        # other = Series
+        self.assert_eq(pser.eq(pser), kser.eq(kser))
+
+        # other = dict
+        other = {1: None, 2: None, 3: None, 4: None, np.nan: None, 6: None}
+        self.assert_eq(pser.eq(other), kser.eq(other))
+
+        # other = set
+        other = {1, 2, 3, 4, np.nan, 6}
+        self.assert_eq(pser.eq(other), kser.eq(other))
+
+        # other = list with the different length
+        other = [np.nan, 1, 3, 4, np.nan]
+        with self.assertRaisesRegex(ValueError, "Lengths must be equal"):
+            self.assert_eq(pser.eq(other), kser.eq(other))
+
+        # other = tuple with the different length
+        other = (np.nan, 1, 3, 4, np.nan)
+        with self.assertRaisesRegex(ValueError, "Lengths must be equal"):
+            self.assert_eq(pser.eq(other), kser.eq(other))