Add basic slicing support to pylibcudf's gpumemoryview

python/pylibcudf/pylibcudf/column.pxd

@@ -53,6 +53,7 @@ cdef class Column:
         # _children: List[Column]
         list _children
         size_type _num_children
+        object __weakref__
 
     cdef column_view view(self)
     cdef mutable_column_view mutable_view(self)

python/pylibcudf/pylibcudf/gpumemoryview.pxd

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright (c) 2023-2025, NVIDIA CORPORATION.
+# SPDX-FileCopyrightText: Copyright (c) 2023-2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 from libc.stdint cimport uint64_t, uintptr_t
 
@@ -9,3 +9,4 @@ cdef class gpumemoryview:
     cdef readonly object obj
     cdef readonly dict cai
     cdef readonly uint64_t nbytes
+    cdef object __weakref__

python/pylibcudf/pylibcudf/gpumemoryview.pyi

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright (c) 2024-2025, NVIDIA CORPORATION.
+# SPDX-FileCopyrightText: Copyright (c) 2024-2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 from collections.abc import Mapping
@@ -9,6 +9,7 @@ class gpumemoryview:
     @property
     def __cuda_array_interface__(self) -> Mapping[str, Any]: ...
     def __len__(self) -> int: ...
+    def byte_slice(self, s: slice) -> gpumemoryview: ...
     @property
     def ptr(self) -> int: ...
     @property

python/pylibcudf/pylibcudf/gpumemoryview.pyx

@@ -1,13 +1,25 @@
-# SPDX-FileCopyrightText: Copyright (c) 2023-2025, NVIDIA CORPORATION.
+# SPDX-FileCopyrightText: Copyright (c) 2023-2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 from libc.stddef cimport size_t
+from libc.stdint cimport uintptr_t, uint64_t
 import functools
 import operator
 
 from .types cimport DataType, size_of, type_id
 
 
+cdef gpumemoryview _slice(gpumemoryview parent, uintptr_t ptr, uint64_t nbytes):
+    cdef gpumemoryview v = gpumemoryview.__new__(gpumemoryview)
+    v.ptr = ptr
+    v.nbytes = nbytes
+    v.obj = parent
+    # always returns a raw byte view regardless of the source dtype.
+    # TODO: Need to propagate stream from parent.cai if present
+    v.cai = {"data": (ptr, parent.cai["data"][1]), "shape": (nbytes,), "typestr": "|u1", "version": 3}
+    return v
+
+
 __all__ = ["gpumemoryview"]
 
 
@@ -59,6 +71,7 @@ cdef class gpumemoryview:
         self.obj = obj
         self.cai = cai
         # TODO: Need to respect readonly
+        # TODO: Need to synchronize on stream if present in cai
         self.ptr = cai["data"][0]
 
         # Compute the buffer size.
@@ -83,6 +96,40 @@ cdef class gpumemoryview:
         return self.nbytes
 
     def __len__(self):
-        return self.obj.__cuda_array_interface__["shape"][0]
+        return self.cai["shape"][0]
+
+    def byte_slice(self, s):
+        """Return a byte-range sub-view of this buffer.
+
+        Parameters
+        ----------
+        s : slice
+            Byte-based slice.
+
+        Returns
+        -------
+        gpumemoryview
+            A ``|u1`` view of the requested byte range. The returned view
+            holds a reference to the parent buffer, keeping it alive.
+
+        Raises
+        ------
+        TypeError
+            If ``s`` is not a slice.
+        ValueError
+            If the slice step is not 1. Out-of-range or reversed ranges
+            return a zero-length view rather than raising.
+        """
+        if not isinstance(s, slice):
+            raise TypeError(
+                f"byte_slice requires a slice, not {type(s).__name__}"
+            )
+        start, stop, step = s.indices(self.nbytes)
+        if step != 1:
+            raise ValueError("byte_slice only supports step=1 slices")
+        length = stop - start
+        if length <= 0:
+            return _slice(self, self.ptr + start, 0)
+        return _slice(self, self.ptr + start, length)
 
     __hash__ = None

python/pylibcudf/tests/test_gpumemoryview.py

@@ -1,7 +1,8 @@
-# SPDX-FileCopyrightText: Copyright (c) 2025, NVIDIA CORPORATION.
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 import itertools
+import weakref
 
 import numpy as np
 import pytest
@@ -63,3 +64,40 @@ def test_len(np_array, stream):
 
     assert len(gpumemview) == len(np_array_view)
     assert gpumemview.nbytes == np_array.nbytes
+
+
+@pytest.mark.parametrize(
+    "s",
+    [
+        slice(1, 3),
+        slice(None, 2),
+        slice(3, None),
+        slice(2, 2),
+        slice(0, 10000),
+    ],
+)
+def test_slice(np_array, s):
+    gv = plc.Column.from_array(np_array.view("u1")).data()
+    result = plc.Column.from_array(gv.byte_slice(s)).to_pylist()
+    assert result == np_array.view("u1")[s].tolist()
+
+
+def test_slice_fails(np_array):
+    gv = plc.Column.from_array(np_array.view("u1")).data()
+    with pytest.raises(TypeError, match="requires a slice"):
+        gv.byte_slice(0)
+    with pytest.raises(ValueError, match="step=1"):
+        gv.byte_slice(slice(None, None, 2))
+
+
+def test_slice_keeps_parent_alive():
+    col = plc.Column.from_array(np.arange(10, dtype="u1"))
+    gv = col.data()
+    col_ref = weakref.ref(col)
+    gv_ref = weakref.ref(gv)
+    s = gv.byte_slice(slice(2, 5))
+    del col, gv
+    assert col_ref() is None
+    assert gv_ref() is not None
+    del s
+    assert gv_ref() is None