Skip to content

indexing with a list of slices #10573

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Open
wants to merge 16 commits into
base: main
Choose a base branch
from
Open

indexing with a list of slices #10573

wants to merge 16 commits into from

Conversation

keewis
Copy link
Collaborator

@keewis keewis commented Jul 27, 2025 •
edited
Loading

Following the discussion in #10479, this adds support for a list-of-slices container (tentatively called MultipleSlices) to most of the indexing wrapper classes. Still missing: PandasIndexingWrapper.

It didn't look like using a separate class as suggested in #10479 (comment) would be easy, and so I've decided to instead extend _index_indexer_1d to support, which turned out to be surprisingly easy.

I'll still have to figure out how to best test this for the indexing wrapper classes other than LazilyIndexingWrapper, and I'm not really content with the API and the code duplication I have right now. I'll refactor that soon, but for now this works:

In [5]: import xarray as xr
   ...: import numpy as np
   ...: 
   ...: var = xr.DataArray(np.arange(100), dims="x")
   ...: slice_ = xr.core.indexing.MultipleSlices(
   ...:     slice(7, 12), slice(15, 32, 2), slice(50, None, 3)
   ...: )
   ...: var.isel(x=slice_)
Out[5]: 
<xarray.DataArray (x: 31)> Size: 248B
array([ 7,  8,  9, 10, 11, 15, 17, 19, 21, 23, 25, 27, 29, 31, 50, 53, 56,
       59, 62, 65, 68, 71, 74, 77, 80, 83, 86, 89, 92, 95, 98])
Dimensions without coordinates: x

cc @dcherian

  • Closes indexing by a list of slices #10479
  • Tests added
  • User visible changes (including notable bug fixes) are documented in whats-new.rst
  • New functions/methods are listed in api.rst

keewis
keewis commented Jul 30, 2025
View reviewed changes
xarray/core/indexing.py
s for s in new_slices if len(range(*s.indices(size))) > 0
)
elif isinstance(applied_indexer, integer_types):
[selected_slice] = [
Copy link
Collaborator Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

if the integer is out-of-bounds, the raised error will complain about unpacking, it should raise an IndexError instead

@keewis keewis mentioned this pull request Aug 16, 2025
Merged
@keewis
Copy link
Collaborator Author

keewis commented Aug 27, 2025

for reference, my initial use-case with sel didn't need multiple slices in the end (which I guess means it would be possible to implement this in a separate package), but selecting geometries along a virtual coordinate will need it.

So that means that contrary to what I said in the meeting today we can probably take our time here with a decision, I just don't want it to be forgotten.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers
No reviews
Assignees
No one assigned
Labels
topic-indexing
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.

indexing by a list of slices
1 participant
@keewis