BUG: Fix comparison between nullable int and string

doc/source/whatsnew/v1.0.0.rst

@@ -360,6 +360,7 @@ ExtensionArray
 ^^^^^^^^^^^^^^
 
 - Bug in :class:`arrays.PandasArray` when setting a scalar string (:issue:`28118`, :issue:`28150`).
+- Bug where nullable integers could not be compared to strings (:issue:`28930`)
 -
 
 

pandas/core/arrays/integer.py

@@ -27,6 +27,7 @@
 from pandas.core import nanops, ops
 from pandas.core.algorithms import take
 from pandas.core.arrays import ExtensionArray, ExtensionOpsMixin
+from pandas.core.ops import invalid_comparison
 from pandas.core.tools.numeric import to_numeric
 
 
@@ -628,7 +629,13 @@ def cmp_method(self, other):
             with warnings.catch_warnings():
                 warnings.filterwarnings("ignore", "elementwise", FutureWarning)
                 with np.errstate(all="ignore"):
-                    result = op(self._data, other)
+                    method = getattr(
+                        self._data, "__{op_name}__".format(op_name=op_name)
+                    )
+                    result = method(other)
+
+                    if result is NotImplemented:
+                        result = invalid_comparison(self._data, other, op)
 
             # nans propagate
             if mask is None:

pandas/tests/extension/test_integer.py

@@ -168,6 +168,39 @@ def check_opname(self, s, op_name, other, exc=None):
     def _compare_other(self, s, data, op_name, other):
         self.check_opname(s, op_name, other)
 
+    @pytest.mark.parametrize("dtype", ["Int64", "Int32", "Int16", "Int8"])
+    def test_compare_unequal_to_string(self, dtype):
+        # GH 28930
+        s = pd.Series([1, None], dtype=dtype)
+        result = s == "a"
+        expected = pd.Series([False, False])
+
+        self.assert_series_equal(result, expected)
+
+    @pytest.mark.parametrize("dtype", ["Int64", "Int32", "Int16", "Int8"])
+    @pytest.mark.parametrize("op", ["__lt__", "__le__"])
+    def test_compare_lt(self, dtype, op):
+        # GH 28930
+        s = pd.Series([0, 0], dtype=dtype)
+        method = getattr(s, op)
+        result = method(1)
+
+        expected = pd.Series([True, True])
+
+        self.assert_series_equal(result, expected)
+
+    @pytest.mark.parametrize("dtype", ["Int64", "Int32", "Int16", "Int8"])
+    @pytest.mark.parametrize("op", ["__gt__", "__ge__"])
+    def test_compare_gt(self, dtype, op):
+        # GH 28930
+        s = pd.Series([0, 0], dtype=dtype)
+        method = getattr(s, op)
+        result = method(-1)
+
+        expected = pd.Series([True, True])
+
+        self.assert_series_equal(result, expected)
+
 
 class TestInterface(base.BaseInterfaceTests):
     pass