Fix .isin Considers "1" and 1 equal (#34267)

Author: gabrielvf1

pandas/tests/test_algos.py

@@ -944,6 +944,33 @@ def test_different_nans_as_float64(self):
         expected = np.array([True, True])
         tm.assert_numpy_array_equal(result, expected)
 
+    @pytest.mark.xfail(reason="problem related with issue #34125")
+    def test_isin_int_df_string_search(self):
+        """Comparing df with int`s (1,2) with a string at isin() ("1")
+        -> should not match values because int 1 is not equal str 1"""
+        df = pd.DataFrame({"values": [1, 2]})
+        result = df.isin(["1"])
+        expected_false = pd.DataFrame({"values": [False, False]})
+        tm.assert_frame_equal(result, expected_false)
+
+    @pytest.mark.xfail(reason="problem related with issue #34125")
+    def test_isin_nan_df_string_search(self):
+        """Comparing df with nan value (np.nan,2) with a string at isin() ("NaN")
+        -> should not match values because np.nan is not equal str NaN """
+        df = pd.DataFrame({"values": [np.nan, 2]})
+        result = df.isin(["NaN"])
+        expected_false = pd.DataFrame({"values": [False, False]})
+        tm.assert_frame_equal(result, expected_false)
+
+    @pytest.mark.xfail(reason="problem related with issue #34125")
+    def test_isin_float_df_string_search(self):
+        """Comparing df with floats (1.4245,2.32441) with a string at isin() ("1.4245")
+        -> should not match values because float 1.4245 is not equal str 1.4245"""
+        df = pd.DataFrame({"values": [1.4245, 2.32441]})
+        result = df.isin(["1.4245"])
+        expected_false = pd.DataFrame({"values": [False, False]})
+        tm.assert_frame_equal(result, expected_false)
+
 
 class TestValueCounts:
     def test_value_counts(self):