What happened?

Assigning a DataArray to a subset of another DataArray seems to depend on the order of the dimensions

What did you expect to happen?

I would expect xarray to automatically align the dimensions appropriately.

Minimal Complete Verifiable Example

Example 1:

```python from xarray import DataArray from numpy import zeros, ones, arange

Two arrays abc and acb, identical except for dimensional ordering

abc = DataArray(zeros((2, 3, 4)), dims=('a', 'b', 'c')) acb = DataArray(zeros((2, 4, 3)), dims=('a', 'c', 'b')) assert (abc == acb).all()

Assign a subset

bc = DataArray(ones((3, 4)), dims=('b', 'c')) abc.loc[dict(a=0)] = bc acb.loc[dict(a=0)] = bc # ValueError: could not broadcast input array from shape (3,4) into shape (4,3) ```

Example 2:

Same as example 1, but instead of raising a ValueError, runs without error, but gives incorrect results because it ignores dimension order

```python

This time, make b and c dimensions identical

abc = DataArray(zeros((2, 3, 3)), dims=('a', 'b', 'c')) acb = DataArray(zeros((2, 3, 3)), dims=('a', 'c', 'b')) assert (abc == acb).all()

Assign a subset

bc = DataArray(arange(9).reshape(3, 3), dims=('b', 'c')) abc.loc[dict(a=0)] = bc acb.loc[dict(a=0)] = bc assert (abc == acb).all() # Assertion error ```

MVCE confirmation

• [X] Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
• [X] Complete example — the example is self-contained, including all data and the text of any traceback.
• [X] Verifiable example — the example copy & pastes into an IPython prompt or Binder notebook, returning the result.
• [X] New issue — a search of GitHub Issues suggests this is not a duplicate.

Relevant log output

No response

Anything else we need to know?

No response

Environment

python from xarray import DataArray, concat a = DataArray([0], dims='a') out = concat([a, a], dim=DataArray([0, 1], dims='b')) print(out.coords)

Coordinates:

None (b) int32 0 1

I would've expected the name of the new coordinate to be the name of the DataArray variable but instead it's None.

Environment:

Hi, xarray is a superb library but my favorite icing on the cake is the out-of-the-box rich HTML display in Jupyter. I've been finding myself wanting the same thing for every class I use in python that is fundamentally a hierachically structured numerical dataset.

Has there been any discussion of generalizing the whole thing? I'd be happy to give it a shot myself, but I was hoping to pick your collective brains first, especially @benbovy and @jsignell, (who based on my very preliminary github sleuthing were early heavy-lifters?)

• [x] Closes #4362
• [x] Tests added
• [x] Passes isort . && black . && mypy . && flake8
• [ ] User visible changes (including notable bug fixes) are documented in whats-new.rst

(Not sure this is worth noting in whats-new)

```python from copy import deepcopy import numpy as np import xarray as xr

class Dummy: pass

a0 = np.array([Dummy()]) a1 = deepcopy(a0) print(a0[0] is a1[0]) # False, as expected

x0 = xr.DataArray(a0, dims='dummy') x1 = deepcopy(x0) print(x0.values[0] is x1.values[0]) # unexpectedly True ```

I think this is a bug, and would be fixed with an extra deepcopy around here