id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
425905002,MDU6SXNzdWU0MjU5MDUwMDI=,2854,Assign values to DataArray after interpolating Dataset produces an error,6095790,closed,0,,,2,2019-03-27T11:27:46Z,2019-04-04T21:58:24Z,2019-04-04T21:58:24Z,NONE,,,,"#### Code Sample, a copy-pastable example if possible
```python
import numpy as np
import xarray as xr
da = xr.DataArray(
np.random.random((3, 4)),
dims=[""assets"", ""year""],
coords={""year"": range(2010, 2018, 2)}
)
# Interpolate directly the DataArray
new_da = da.interp(year=[2011, 2015])
new_da.loc[{""year"": 2015}] = 42 # WORKS!
print(new_da)
# Interpolate DataArray as part of a Dataset
dset = xr.Dataset({""my_array"": da.copy()}).interp(year=[2011, 2015])
new_da = dset.my_array
new_da.loc[{""year"": 2015}] = 42 # DOESN'T WORK!
print(new_da)
```
#### Problem description
Assigning a value to some locations of a DataArray after it has been interpolated raises an IndexError. This does not occur when the DataArray is interpolated independently, only occurs when the DataArray has been interpolated as part of a Dataset.
This problem is not present in xarray<0.12.0
#### Expected Output
The above example should print `new_da` in both cases, with the values corresponding to year 2015 replaced by 42. That works in the first case, but fails in the second raising IndexError.
Although I am not sure if it is the cause of this error, I have found that in the first case the array indexes are present and contain [2011, 2015], but they are an empty OrderDict in the second case.
#### Output of ``xr.show_versions()``
INSTALLED VERSIONS
------------------
commit: None
python: 3.7.1 (default, Nov 6 2018, 18:46:03)
[Clang 10.0.0 (clang-1000.11.45.5)]
python-bits: 64
OS: Darwin
OS-release: 18.2.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: None
LOCALE: en_GB.UTF-8
libhdf5: 1.10.2
libnetcdf: 4.4.1.1
xarray: 0.12.0
pandas: 0.23.4
numpy: 1.15.4
scipy: 1.1.0
netCDF4: 1.4.2
pydap: None
h5netcdf: None
h5py: None
Nio: None
zarr: None
cftime: 1.0.3.4
nc_time_axis: None
PseudonetCDF: None
rasterio: None
cfgrib: None
iris: None
bottleneck: 1.2.1
dask: None
distributed: None
matplotlib: 3.0.2
cartopy: None
seaborn: 0.9.0
setuptools: 40.5.0
pip: 18.1
conda: None
pytest: 4.0.2
IPython: 7.1.1
sphinx: None
","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/2854/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue
427398236,MDU6SXNzdWU0MjczOTgyMzY=,2856,Roundtripping between a dimension coordinate and scalar coordinate on a Dataset,6628425,closed,0,,,4,2019-03-31T13:42:39Z,2019-04-04T21:58:24Z,2019-04-04T21:58:24Z,MEMBER,,,,"#### Code Sample, a copy-pastable example if possible
In xarray 0.12.0 the following example produces a Dataset with no indexes:
```
In [1]: import xarray as xr
In [2]: da = xr.DataArray([1], [('x', [0])], name='a')
In [3]: da.to_dataset().isel(x=0).expand_dims('x').indexes
Out[3]:
```
#### Expected Output
In xarray 0.11.3 the roundtrip sequence above properly recovers the initial index along the `'x'` dimension:
```
In [1]: import xarray as xr
In [2]: da = xr.DataArray([1], [('x', [0])], name='a')
In [3]: da.to_dataset().isel(x=0).expand_dims('x').indexes
Out[3]: x: Int64Index([0], dtype='int64', name='x')
```
#### Output of ``xr.show_versions()``
```
INSTALLED VERSIONS
------------------
commit: None
python: 3.6.7 | packaged by conda-forge | (default, Feb 28 2019, 02:16:08)
[GCC 4.2.1 Compatible Clang 4.0.1 (tags/RELEASE_401/final)]
python-bits: 64
OS: Darwin
OS-release: 18.2.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8
libhdf5: 1.10.1
libnetcdf: 4.6.1
xarray: 0.12.0
pandas: 0.24.2
numpy: 1.13.1
scipy: 0.19.1
netCDF4: 1.4.0
pydap: None
h5netcdf: 0.5.1
h5py: 2.8.0
Nio: None
zarr: None
cftime: 1.0.0
nc_time_axis: None
PseudonetCDF: None
rasterio: None
cfgrib: None
iris: None
bottleneck: 1.2.0
dask: 0.17.5
distributed: 1.21.8
matplotlib: 2.0.2
cartopy: None
seaborn: None
setuptools: 40.5.0
pip: 9.0.1
conda: None
pytest: 3.10.0
IPython: 6.4.0
sphinx: 1.7.4
```