BUG: Solves errors when calling series methods in DataFrame.query with numexpr

doc/source/whatsnew/v1.4.0.rst

@@ -426,6 +426,7 @@ Indexing
 - Bug in :meth:`Index.get_indexer_non_unique` when index contains multiple ``np.nan`` (:issue:`35392`)
 - Bug in :meth:`DataFrame.query` did not handle the degree sign in a backticked column name, such as \`Temp(°C)\`, used in an expression to query a dataframe (:issue:`42826`)
 - Bug in :meth:`DataFrame.drop` where the error message did not show missing labels with commas when raising ``KeyError`` (:issue:`42881`)
+- Bug in :meth:`DataFrame.query` where method calls in query strings led to errors when the ``numexpr`` package was installed. (:issue:`22435`)
 - Bug in :meth:`DataFrame.nlargest` and :meth:`Series.nlargest` where sorted result did not count indexes containing ``np.nan`` (:issue:`28984`)
 
 

pandas/core/computation/expr.py

@@ -702,7 +702,8 @@ def visit_Call(self, node, side=None, **kwargs):
                 if key.arg:
                     kwargs[key.arg] = self.visit(key.value).value
 
-            return self.const_type(res(*new_args, **kwargs), self.env)
+            name = self.env.add_tmp(res(*new_args, **kwargs))
+            return self.term_type(name=name, env=self.env)
 
     def translate_In(self, op):
         return op

pandas/tests/frame/test_query_eval.py

@@ -731,6 +731,26 @@ def test_check_tz_aware_index_query(self, tz_aware_fixture):
         result = df.reset_index().query('"2018-01-03 00:00:00+00" < time')
         tm.assert_frame_equal(result, expected)
 
+    def test_method_calls_in_query(self):
+        # https://github.com/pandas-dev/pandas/issues/22435
+        n = 10
+        df = DataFrame({"a": 2 * np.random.rand(n), "b": np.random.rand(n)})
+        expected = df[df["a"].astype("int") == 0]
+        result = df.query(
+            "a.astype('int') == 0", engine=self.engine, parser=self.parser
+        )
+        tm.assert_frame_equal(result, expected)
+
+        df = DataFrame(
+            {
+                "a": np.where(np.random.rand(n) < 0.5, np.nan, np.random.randn(n)),
+                "b": np.random.randn(n),
+            }
+        )
+        expected = df[df["a"].notnull()]
+        result = df.query("a.notnull()", engine=self.engine, parser=self.parser)
+        tm.assert_frame_equal(result, expected)
+
 
 @td.skip_if_no_ne
 class TestDataFrameQueryNumExprPython(TestDataFrameQueryNumExprPandas):