PERF: DataFrame(ndarr, copy=True)

Author: topper-123

doc/source/whatsnew/v2.1.0.rst

@@ -195,6 +195,7 @@ Performance improvements
 - Performance improvement in :meth:`MultiIndex.set_levels` and :meth:`MultiIndex.set_codes` when ``verify_integrity=True`` (:issue:`51873`)
 - Performance improvement in :func:`factorize` for object columns not containing strings (:issue:`51921`)
 - Performance improvement in :class:`Series` reductions (:issue:`52341`)
+- Constructing :class:`DataFrame` instances from a 2d ``ndarray`` using ``copy=True`` now ensures the copied array is contiguous, giving performance improvements for many operations (:issue:`52438`)
 -
 
 .. ---------------------------------------------------------------------------

pandas/core/internals/construction.py

@@ -312,7 +312,8 @@ def ndarray_to_mgr(
             if (dtype is None or astype_is_view(values.dtype, dtype))
             else False
         )
-        values = np.array(values, copy=_copy)
+        _order = "F" if _copy else "K"
+        values = np.array(values, copy=_copy, order=_order)
         values = _ensure_2d(values)
 
     else:

pandas/tests/frame/test_constructors.py

@@ -2123,6 +2123,7 @@ def test_constructor_ndarray_copy(
             df = DataFrame(arr, copy=True)
             arr[6] = 6
             assert not (df.values[6] == 6).all()
+            assert df._mgr.arrays[0].flags.c_contiguous
         else:
             arr = float_frame.values.copy()
             # default: copy to ensure contiguous arrays