Merge branch 'main' into autofilter-feature

Author: antznette1

doc/source/whatsnew/v3.0.0.rst

@@ -1278,6 +1278,7 @@ Other
 - Bug in ``divmod`` and ``rdivmod`` with :class:`DataFrame`, :class:`Series`, and :class:`Index` with ``bool`` dtypes failing to raise, which was inconsistent with ``__floordiv__`` behavior (:issue:`46043`)
 - Bug in printing a :class:`DataFrame` with a :class:`DataFrame` stored in :attr:`DataFrame.attrs` raised a ``ValueError`` (:issue:`60455`)
 - Bug in printing a :class:`Series` with a :class:`DataFrame` stored in :attr:`Series.attrs` raised a ``ValueError`` (:issue:`60568`)
+- Bug when calling :py:func:`copy.copy` on a :class:`DataFrame` or :class:`Series` which would return a deep copy instead of a shallow copy (:issue:`62971`)
 - Deprecated the keyword ``check_datetimelike_compat`` in :meth:`testing.assert_frame_equal` and :meth:`testing.assert_series_equal` (:issue:`55638`)
 - Fixed bug in :meth:`Series.replace` and :meth:`DataFrame.replace` when trying to replace :class:`NA` values in a :class:`Float64Dtype` object with ``np.nan``; this now works with ``pd.set_option("mode.nan_is_na", False)`` and is irrelevant otherwise (:issue:`55127`)
 - Fixed bug in :meth:`Series.replace` and :meth:`DataFrame.replace` when trying to replace :class:`np.nan` values in a :class:`Int64Dtype` object with :class:`NA`; this is now a no-op with ``pd.set_option("mode.nan_is_na", False)`` and is irrelevant otherwise (:issue:`51237`)

pandas/core/frame.py

@@ -12195,6 +12195,7 @@ def _get_data() -> DataFrame:
         #  simple case where we can use BlockManager.reduce
         res = df._mgr.reduce(blk_func)
         out = df._constructor_from_mgr(res, axes=res.axes).iloc[0]
+        out.name = None
         if out_dtype is not None and out.dtype != "boolean":
             out = out.astype(out_dtype)
         elif (df._mgr.get_dtypes() == object).any() and name not in ["any", "all"]:

pandas/core/generic.py

@@ -6667,8 +6667,8 @@ def copy(self, deep: bool = True) -> Self:
         )
 
     @final
-    def __copy__(self, deep: bool = True) -> Self:
-        return self.copy(deep=deep)
+    def __copy__(self) -> Self:
+        return self.copy(deep=False)
 
     @final
     def __deepcopy__(self, memo=None) -> Self:

pandas/core/indexes/base.py

@@ -1413,8 +1413,8 @@ def copy(
         return new_index
 
     @final
-    def __copy__(self, **kwargs) -> Self:
-        return self.copy(**kwargs)
+    def __copy__(self) -> Self:
+        return self.copy(deep=False)
 
     @final
     def __deepcopy__(self, memo=None) -> Self:

pandas/core/internals/blocks.py

@@ -350,7 +350,7 @@ def apply(self, func, **kwargs) -> list[Block]:
         return self._split_op_result(result)
 
     @final
-    def reduce(self, func) -> list[Block]:
+    def reduce(self, func) -> Block:
         # We will apply the function and reshape the result into a single-row
         #  Block with the same mgr_locs; squeezing will be done at a higher level
         assert self.ndim == 2
@@ -362,8 +362,7 @@ def reduce(self, func) -> list[Block]:
         else:
             res_values = result.reshape(-1, 1)
 
-        nb = self.make_block(res_values)
-        return [nb]
+        return self.make_block(res_values)
 
     @final
     def _split_op_result(self, result: ArrayLike) -> list[Block]:

pandas/core/internals/managers.py

@@ -1651,12 +1651,8 @@ def reduce(self, func: Callable) -> Self:
         # If 2D, we assume that we're operating column-wise
         assert self.ndim == 2
 
-        res_blocks: list[Block] = []
-        for blk in self.blocks:
-            nbs = blk.reduce(func)
-            res_blocks.extend(nbs)
-
-        index = Index([None])  # placeholder
+        res_blocks = [blk.reduce(func) for blk in self.blocks]
+        index = default_index(1)  # placeholder
         new_mgr = type(self).from_blocks(res_blocks, [self.items, index])
         return new_mgr
 

pandas/core/reshape/concat.py

@@ -840,7 +840,7 @@ def _make_concat_multiindex(indexes, keys, levels=None, names=None) -> MultiInde
     if (levels is None and isinstance(keys[0], tuple)) or (
         levels is not None and len(levels) > 1
     ):
-        zipped = list(zip(*keys))
+        zipped = list(zip(*keys, strict=True))
         if names is None:
             names = [None] * len(zipped)
 

pandas/tests/generic/test_generic.py

@@ -307,6 +307,11 @@ def test_copy_and_deepcopy(self, frame_or_series, shape, func):
         assert obj_copy is not obj
         tm.assert_equal(obj_copy, obj)
 
+    def test_stdlib_copy_shallow_copies(self, frame_or_series):
+        obj = frame_or_series(range(3))
+        obj_copy = copy(obj)
+        assert tm.shares_memory(obj, obj_copy)
+
 
 class TestNDFrame:
     # tests that don't fit elsewhere