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
1214290591,I_kwDOAMm_X85IYJqf,6510,Feature request: raise more informative error message for `xr.open_dataset(list_of_paths)`,12237157,open,0,,,4,2022-04-25T10:22:25Z,2022-04-29T16:47:56Z,,CONTRIBUTOR,,,,"### Is your feature request related to a problem?

I sometimes use `xr.open_dataset` instead of `xr.open_mfdataset` on multiple paths. I propose to raise a more informative error message than `ValueError: did not find a match in any of xarray's currently installed IO backends ['netcdf4', 'h5netcdf', 'scipy', 'cfgrib']. Consider explicitly selecting one of the installed engines via the ``engine`` parameter, or installing additional IO dependencies, see:
https://docs.xarray.dev/en/stable/getting-started-guide/installing.html
https://docs.xarray.dev/en/stable/user-guide/io.html`.

```python
import xarray as xr

xr.__version__ # '2022.3.0'

ds = xr.tutorial.load_dataset(""air_temperature"")

ds.isel(time=slice(None,1500)).to_netcdf(""file1.nc"")
ds.isel(time=slice(1500,None)).to_netcdf(""file2.nc"")

xr.open_mfdataset([""file1.nc"",""file2.nc""]) # works
xr.open_mfdataset(""file?.nc"") # works

# I understand what I need to do here
xr.open_dataset(""file?.nc"") # fails FileNotFoundError: No such file or directory: b'/dir/file?.nc'

# I dont here; I also first try to check whether one of these files is corrupt
xr.open_dataset([""file1.nc"",""file2.nc""]) # fails ValueError: did not find a match in any of xarray's currently installed IO backends ['netcdf4', 'h5netcdf', 'scipy', 'cfgrib']. Consider explicitly selecting one of the installed engines via the ``engine`` parameter, or installing additional IO dependencies, see: links
```

### Describe the solution you'd like

directing the user towards the solution, i.e. ""found path as list, please use open_mfdataset""

### Describe alternatives you've considered

_No response_

### Additional context

_No response_","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/6510/reactions"", ""total_count"": 6, ""+1"": 6, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,issue
1120583442,I_kwDOAMm_X85Cyr8S,6230,[PERFORMANCE]: `isin` on `CFTimeIndex`-backed `Coordinate` slow ,12237157,open,0,,,5,2022-02-01T12:04:02Z,2022-02-07T23:40:48Z,,CONTRIBUTOR,,,,"### Is your feature request related to a problem?

I want to do `coord1.isin.coord2` and it is quite slow when coords are large and of object type `CFTimeIndex`.

```python
import xarray as xr
import numpy as np

n=1000
coord1 = xr.cftime_range(start='2000', freq='MS', periods=n)
coord2 = xr.cftime_range(start='2000', freq='3MS', periods=n)

# cftimeindex: very fast
%timeit coord1.isin(coord2) # 743 µs ± 1.33 µs

# np.isin on index.asi8
%timeit np.isin(coord1.asi8,coord2.asi8) # 7.83 ms ± 14.1 µs

da = xr.DataArray(np.random.random((n,n)),dims=['a','b'],coords={'a':coord1,'b':coord2})

# when xr.DataArray coordinate slow
%timeit da.a.isin(da.b) # 94.9 ms ± 959 µs

# when converting xr.DataArray coordinate back to index slow
%timeit np.isin(da.a.to_index(), da.b.to_index()) # 97.4 ms ± 819 µs

# when converting xr.DataArray coordinate back to index asi
%timeit np.isin(da.a.to_index().asi8, da.b.to_index().asi8) # 7.89 ms ± 15.2 µs
```

### Describe the solution you'd like

faster `coord1.isin.coord2` by default. could we re-route here, e.g. to the alternative?

conversion from `coordinate` `to_index()` is costly I guess

### Describe alternatives you've considered

`np.isin(coord1.to_index().asi8, coord2.to_index().asi8` brings me nice speedups in https://github.com/pangeo-data/climpred/pull/724

### Additional context

unsure whether this issue should go here on in `cftime`","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/6230/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,issue