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
1632718954,I_kwDOAMm_X85hUVBq,7652,Saving and loading an array of strings changes datatype to object,6897215,closed,0,,,13,2023-03-20T19:15:03Z,2023-11-17T15:26:01Z,2023-11-17T15:26:01Z,NONE,,,,"### What is your issue?

See the code below
```python
import xarray as xr
# Make an xarray with an array of strings
da = xr.DataArray(
    data=[[""a"", ""b""], [""c"", ""d""]],
    dims=[""x"", ""y""],
    coords={""x"": [0, 1], ""y"": [0, 1]},
)
da.to_netcdf(""test.nc"", mode='w')
# Load the xarray back in
da_loaded = xr.load_dataarray(""test.nc"")
assert da.dtype == da_loaded.dtype, ""Dtypes don't match""
```

Now `da_loaded.dtype` is `dtype('O')`.

Same happens with `engine=""h5netcdf""`.

```
import xarray
xarray.show_versions()
```
```
INSTALLED VERSIONS
------------------
commit: None
python: 3.11.0 | packaged by conda-forge | (main, Jan 14 2023, 12:26:40) [Clang 14.0.6 ]
python-bits: 64
OS: Darwin
OS-release: 22.3.0
machine: arm64
processor: arm
byteorder: little
LC_ALL: en_US.UTF-8
LANG: en_US.UTF-8
LOCALE: ('en_US', 'UTF-8')
libhdf5: 1.12.2
libnetcdf: None

xarray: 2023.2.0
pandas: 1.5.3
numpy: 1.24.2
scipy: 1.10.0
netCDF4: None
pydap: None
h5netcdf: 1.1.0
h5py: 3.8.0
Nio: None
zarr: None
cftime: None
nc_time_axis: None
PseudoNetCDF: None
rasterio: None
cfgrib: None
iris: None
bottleneck: None
dask: None
distributed: None
matplotlib: 3.7.0
cartopy: None
seaborn: 0.12.2
numbagg: None
fsspec: 2023.1.0
cupy: None
pint: None
sparse: None
flox: None
numpy_groupies: None
setuptools: 67.3.2
pip: 23.0
conda: None
pytest: 7.2.1
mypy: 1.0.1
IPython: 8.10.0
sphinx: 5.3.0
```","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/7652/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue
207283854,MDU6SXNzdWUyMDcyODM4NTQ=,1265,variable length of a dimension in DataArray,6897215,closed,0,,,7,2017-02-13T17:22:38Z,2020-12-26T15:05:59Z,2020-12-26T15:05:59Z,NONE,,,,"I am having the following issue, say I have this code where I find eigenvalues of some system composed of the variables `A`, `B`, `C`, and `D`.

In my example the number of eigenvalues (`num_eigs`) is constant. 

However, in general this number is not constant. Is there a way in `xarray` to handle this issue?

```
import numpy as np
import xarray as xr
A = np.linspace(0, 40, 10)
B = np.linspace(0, 1, 20)
C = np.linspace(0, 1, 30)
D = np.linspace(-3, 3, 40)

num_eigs = 4

# pretend like this is taking the eigenvalues of a matrix composed with A, B, C, and D
res = np.random.rand(len(A), len(B), len(C), len(D), num_eigs)

# now I need to set the last dimension to `range(res.shape[-1]))`
da = xr.DataArray(res, coords=
    [('A', A), ('B', B), ('C', C), ('D', D), ('eig', range(res.shape[-1]))])
```


For those that ask why I would need this: I do numerics in quantum mechanics and create quantum systems with certain parameters. Some of these parameters could be the system size. This would result in different Hamiltonians (a matrix describing the system) and therefore in a different number of eigenvalues.","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/1265/reactions"", ""total_count"": 2, ""+1"": 2, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue