GH1203 Pass a dict to setter for DataFrame.loc/iloc (#1204)

* gh1203_loc_dict

* GH1203 PR feedback

Author: loicdiridollou

pandas-stubs/core/frame.pyi

@@ -176,7 +176,16 @@ class _iLocIndexerFrame(_iLocIndexer, Generic[_T]):
             | tuple[IndexType, IndexType]
             | tuple[int, IndexType]
         ),
-        value: Scalar | Series | DataFrame | np.ndarray | NAType | NaTType | None,
+        value: (
+            Scalar
+            | Series
+            | DataFrame
+            | np.ndarray
+            | NAType
+            | NaTType
+            | Mapping[Hashable, Scalar | NAType | NaTType]
+            | None
+        ),
     ) -> None: ...
 
 class _LocIndexerFrame(_LocIndexer, Generic[_T]):
@@ -239,13 +248,23 @@ class _LocIndexerFrame(_LocIndexer, Generic[_T]):
         idx: (
             MaskType | StrLike | _IndexSliceTuple | list[ScalarT] | IndexingInt | slice
         ),
-        value: Scalar | NAType | NaTType | ArrayLike | Series | DataFrame | list | None,
+        value: (
+            Scalar
+            | NAType
+            | NaTType
+            | ArrayLike
+            | Series
+            | DataFrame
+            | list
+            | Mapping[Hashable, Scalar | NAType | NaTType]
+            | None
+        ),
     ) -> None: ...
     @overload
     def __setitem__(
         self,
         idx: tuple[_IndexSliceTuple, Hashable],
-        value: Scalar | NAType | NaTType | ArrayLike | Series | list | None,
+        value: Scalar | NAType | NaTType | ArrayLike | Series | list | dict | None,
     ) -> None: ...
 
 # With mypy 1.14.1 and python 3.12, the second overload needs a type-ignore statement

tests/test_frame.py

@@ -4134,3 +4134,13 @@ def test_combine() -> None:
         ),
         pd.DataFrame,
     )
+
+
+def test_df_loc_dict() -> None:
+    """Test that we can set a dict to a df.loc result GH1203."""
+    df = pd.DataFrame(columns=["X"])
+    df.loc[0] = {"X": 0}
+    check(assert_type(df, pd.DataFrame), pd.DataFrame)
+
+    df.iloc[0] = {"X": 0}
+    check(assert_type(df, pd.DataFrame), pd.DataFrame)