BUG: eval and query not working with ea dtypes

doc/source/whatsnew/v2.0.0.rst

@@ -1020,6 +1020,7 @@ Conversion
 - Bug in :meth:`Series.to_numpy` converting to NumPy array before applying ``na_value`` (:issue:`48951`)
 - Bug in :func:`to_datetime` was not respecting ``exact`` argument when ``format`` was an ISO8601 format (:issue:`12649`)
 - Bug in :meth:`TimedeltaArray.astype` raising ``TypeError`` when converting to a pyarrow duration type (:issue:`49795`)
+- Bug in :meth:`DataFrame.eval` and :meth:`DataFrame.query` raising for extension array dtypes (:issue:`29618`, :issue:`50261`, :issue:`31913`)
 -
 
 Strings

pandas/core/computation/common.py

@@ -26,3 +26,20 @@ def result_type_many(*arrays_and_dtypes):
     except ValueError:
         # we have > NPY_MAXARGS terms in our expression
         return reduce(np.result_type, arrays_and_dtypes)
+    except TypeError:
+        from pandas.core.dtypes.cast import find_common_type
+        from pandas.core.dtypes.common import is_extension_array_dtype
+
+        arr_and_dtypes = list(arrays_and_dtypes)
+        ea_dtypes, non_ea_dtypes = [], []
+        for arr_or_dtype in arr_and_dtypes:
+            if is_extension_array_dtype(arr_or_dtype):
+                ea_dtypes.append(arr_or_dtype)
+            else:
+                non_ea_dtypes.append(arr_or_dtype)
+
+        if non_ea_dtypes:
+            np_dtype = np.result_type(*non_ea_dtypes)
+            return find_common_type(ea_dtypes + [np_dtype])
+
+        return find_common_type(ea_dtypes)

pandas/core/computation/eval.py

@@ -9,6 +9,8 @@
 
 from pandas.util._validators import validate_bool_kwarg
 
+from pandas.core.dtypes.common import is_extension_array_dtype
+
 from pandas.core.computation.engines import ENGINES
 from pandas.core.computation.expr import (
     PARSERS,
@@ -333,6 +335,16 @@ def eval(
 
         parsed_expr = Expr(expr, engine=engine, parser=parser, env=env)
 
+        if (
+            is_extension_array_dtype(parsed_expr.terms.return_type)
+            or getattr(parsed_expr.terms, "operand_types", None) is not None
+            and any(
+                is_extension_array_dtype(elem)
+                for elem in parsed_expr.terms.operand_types
+            )
+        ):
+            engine = "python"
+
         # construct the engine and evaluate the parsed expression
         eng = ENGINES[engine]
         eng_inst = eng(parsed_expr)

pandas/tests/frame/test_query_eval.py

@@ -3,6 +3,7 @@
 import numpy as np
 import pytest
 
+from pandas.compat import is_platform_windows
 from pandas.errors import UndefinedVariableError
 import pandas.util._test_decorators as td
 
@@ -1273,3 +1274,70 @@ def func(*_):
 
         with pytest.raises(TypeError, match="Only named functions are supported"):
             df.eval("@funcs[0].__call__()")
+
+    def test_ea_dtypes(self, any_numeric_ea_and_arrow_dtype):
+        # GH#29618
+        df = DataFrame(
+            [[1, 2], [3, 4]], columns=["a", "b"], dtype=any_numeric_ea_and_arrow_dtype
+        )
+        result = df.eval("c = b - a")
+        expected = DataFrame(
+            [[1, 2, 1], [3, 4, 1]],
+            columns=["a", "b", "c"],
+            dtype=any_numeric_ea_and_arrow_dtype,
+        )
+        tm.assert_frame_equal(result, expected)
+
+    def test_ea_dtypes_and_scalar(self):
+        # GH#29618
+        df = DataFrame([[1, 2], [3, 4]], columns=["a", "b"], dtype="Float64")
+        result = df.eval("c = b - 1")
+        expected = DataFrame(
+            [[1, 2, 1], [3, 4, 3]], columns=["a", "b", "c"], dtype="Float64"
+        )
+        tm.assert_frame_equal(result, expected)
+
+    def test_ea_dtypes_and_scalar_operation(self, any_numeric_ea_and_arrow_dtype):
+        # GH#29618
+        df = DataFrame(
+            [[1, 2], [3, 4]], columns=["a", "b"], dtype=any_numeric_ea_and_arrow_dtype
+        )
+        result = df.eval("c = 2 - 1")
+        expected = DataFrame(
+            {
+                "a": Series([1, 3], dtype=any_numeric_ea_and_arrow_dtype),
+                "b": Series([2, 4], dtype=any_numeric_ea_and_arrow_dtype),
+                "c": Series(
+                    [1, 1], dtype="int64" if not is_platform_windows() else "int32"
+                ),
+            }
+        )
+        tm.assert_frame_equal(result, expected)
+
+    @pytest.mark.parametrize("dtype", ["int64", "Int64", "int64[pyarrow]"])
+    def test_query_ea_dtypes(self, dtype):
+        if dtype == "int64[pyarrow]":
+            pytest.importorskip("pyarrow")
+        # GH#50261
+        df = DataFrame({"a": Series([1, 2], dtype=dtype)})
+        ref = {2}  # noqa:F841
+        result = df.query("a in @ref")
+        expected = DataFrame({"a": Series([2], dtype=dtype, index=[1])})
+        tm.assert_frame_equal(result, expected)
+
+    @pytest.mark.parametrize("dtype", ["int64", "Int64", "int64[pyarrow]"])
+    def test_query_ea_equality_comparison(self, dtype):
+        # GH#50261
+        if dtype == "int64[pyarrow]":
+            pytest.importorskip("pyarrow")
+        df = DataFrame(
+            {"A": Series([1, 1, 2], dtype="Int64"), "B": Series([1, 2, 2], dtype=dtype)}
+        )
+        result = df.query("A == B")
+        expected = DataFrame(
+            {
+                "A": Series([1, 2], dtype="Int64", index=[0, 2]),
+                "B": Series([1, 2], dtype=dtype, index=[0, 2]),
+            }
+        )
+        tm.assert_frame_equal(result, expected)