Table data get item doesn't work with negative indices

[Antyos]

Describe the bug
Getting or setting table data with slice notation, e.g. table.data[0, 0], doesn't work with negative indices.

I could probably do a PR, but I am not sure if the fix should be implemented at the widgets.Table level, or lower.

To Reproduce

from magicgui import widgets

tbl = widgets.Table([[1, 2, 3], [4, 5, 6]])

print(f"Value at [0, 2]: {tbl.data[0, 2]}")    # Value at [0, 2]: 3
print(f"Value at [0, -1]: {tbl.data[0, -1]}")  # Value at [0, -1]: None

Expected behavior

I would expect tbl.data[0, -1] to be function like all other negative indices in Python.

At the very least, if they don't work, supplying a negative index should raise an IndexError (although I think most people would find this surprising)

Screenshots
N/A

Environment (please complete the following information):

• OS: Windows 11
• backend: PyQt6 v6.9.1
• magicgui version: 0.10.3.dev3+g2d985e7a4

[tlambert03]

Thanks!  A PR would be appreciated.  I’m away from computer at the moment, so can’t tell you exactly where it should go, but do you want to take a stab at it?  (I suspect the proper place will be relatively obvious once we look)On Jul 15, 2026, at 10:58 PM, Andrew Glick ***@***.***> wrote:Antyos created an issue (pyapp-kit/magicgui#735) Describe the bug Getting or setting table data with slice notation, e.g. table.data[0, 0], doesn't work with negative indices. I could probably do a PR, but I am not sure if the fix should be implemented at the widgets.Table level, or lower. To Reproduce from magicgui import widgets tbl = widgets.Table([[1, 2, 3], [4, 5, 6]]) print(f"Value at [0, 2]: {tbl.data[0, 2]}") # Value at [0, 2]: 3 print(f"Value at [0, -1]: {tbl.data[0, -1]}") # Value at [0, -1]: None Expected behavior I would expect tbl.data[0, -1] to be function like all other negative indices in Python. At the very least, if they don't work, supplying a negative index should raise an IndexError (although I think most people would find this surprising) Screenshots N/A Environment (please complete the following information): OS: Windows 11 backend: PyQt6 v6.9.1 magicgui version: 0.10.3.dev3+g2d985e7a4 —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[Antyos]

Hey, sorry for the delay on getting back to this.

The call stack for tbl.data[0, -1] seems to start with DataView:

magicgui/src/magicgui/widgets/_table.py

Lines 652 to 670 in 2d985e7

	def __getitem__(self, idx: IndexKey | tuple[IndexKey, IndexKey]) -> Any:
	"""Get index."""
	if isinstance(idx, (int, slice)):
	return self.__getitem__((idx, slice(None))) # type: ignore
	obj = self._obj
	if isinstance(idx, tuple):
	assert len(idx) == 2, "Table Widget only accepts 2 arguments to __getitem__"
	r_idx, c_idx = idx
	if isinstance(r_idx, int):
	if isinstance(c_idx, int):
	return obj._get_cell(r_idx, c_idx)
	if isinstance(c_idx, slice):
	return obj._get_rowi(r_idx, c_idx)
	elif isinstance(r_idx, slice):
	if isinstance(c_idx, int):
	return obj._get_column(c_idx, r_idx)
	if isinstance(c_idx, slice):
	return [obj._get_rowi(r, c_idx) for r in obj._iter_slice(r_idx, 0)]
	raise ValueError(f"Not a valid idx for __getitem__ {idx!r}")

Which then utilizes the Table._get_cell()

magicgui/src/magicgui/widgets/_table.py

Lines 422 to 429 in 2d985e7

	def _iter_slice(self, slc: slice, axis: int) -> Iterator[int]:
	yield from range(*slc.indices(self.shape[axis]))
	def _get_cell(self, row: int, col: int) -> Any:
	return self._widget._mgui_get_cell(row, col)
	def _set_cell(self, row: int, col: int, value: Any) -> None:
	return self._widget._mgui_set_cell(row, col, value)

And ultimately ends up in the Qt native backend:

magicgui/src/magicgui/backends/_qtpy/widgets.py

Lines 1515 to 1535 in 2d985e7

	def _mgui_get_cell(self, row: int, col: int) -> Any:
	"""Get current value of the widget."""
	item = self._qwidget.item(row, col)
	if item:
	return item.data(_DATA_ROLE)
	widget = self._qwidget.cellWidget(row, col)
	if widget:
	return getattr(widget, "_magic_widget", widget)
	def _mgui_set_cell(self, row: int, col: int, value: Any) -> None:
	"""Set current value of the widget."""
	if value is None:
	self._qwidget.setItem(row, col, None)
	self._qwidget.removeCellWidget(row, col)
	return
	if isinstance(value, Widget):
	self._qwidget.setCellWidget(row, col, value.native)
	return
	item = QtW.QTableWidgetItem(str(value))
	item.setData(_DATA_ROLE, value)
	self._qwidget.setItem(row, col, item)

It seems to me like the best place to make the fix would be in the Qt backend for the table widget, as it is ultimately Qt which doesn't support negative indices, and magicgui itself should support as much "native" python syntax as high up as it can.

[tlambert03]

that works for me!