BUG: check is_named_tuple for objects that are not subclass of tuple pandas-dev#40682

Author: fangchenli

pandas/core/dtypes/inference.py

@@ -315,7 +315,7 @@ def is_named_tuple(obj) -> bool:
     >>> is_named_tuple((1, 2))
     False
     """
-    return isinstance(obj, tuple) and hasattr(obj, "_fields")
+    return isinstance(obj, abc.Sequence) and hasattr(obj, "_fields")
 
 
 def is_hashable(obj) -> bool:

pandas/tests/io/test_sql.py

@@ -2189,6 +2189,43 @@ def test_bigint_warning(self):
         with tm.assert_produces_warning(None):
             sql.read_sql_table("test_bigintwarning", self.conn)
 
+    def test_row_object_is_named_tuple(self):
+        # GH 40682
+        # Test for the is_named_tuple() function
+        # Placed here due to its usage of sqlalchemy
+
+        from sqlalchemy import (
+            Column,
+            Integer,
+            String,
+        )
+        from sqlalchemy.orm import (
+            declarative_base,
+            sessionmaker,
+        )
+
+        BaseModel = declarative_base()
+
+        class Test(BaseModel):
+            __tablename__ = "test_Frame"
+            id = Column(Integer, primary_key=True)
+            foo = Column(String(50))
+
+        BaseModel.metadata.create_all(self.conn)
+        Session = sessionmaker(bind=self.conn)
+        session = Session()
+
+        df = pd.DataFrame({"id": [0, 1], "foo": ["hello", "world"]})
+        df.to_sql("test_Frame", con=self.conn, index=False, if_exists="replace")
+
+        session.commit()
+        foo = session.query(Test.id, Test.foo)
+        print(foo)
+        df = pd.DataFrame(foo)
+        session.close()
+
+        assert list(df.columns) == ["id", "foo"]
+
 
 class _TestMySQLAlchemy:
     """