html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/4892#issuecomment-803491262,https://api.github.com/repos/pydata/xarray/issues/4892,803491262,MDEyOklzc3VlQ29tbWVudDgwMzQ5MTI2Mg==,5635139,2021-03-21T00:35:57Z,2021-03-21T00:35:57Z,MEMBER,"It's a good issue!

I would have thought `.sel` should default to using labels. I recognize that boolean indexing is really helpful — and think we should try and support it more (e.g. https://github.com/pydata/xarray/issues/1887).

And I recognize `.sel` delegates to `.isel` in some cases — e.g. where there are no indexes on a dimension. 

But here, I propose we prioritize the labels above the boolean indexing in `.sel`. People can still use `.isel` if they want bool indexing in the method call syntax:

```python

In [4]: test = xr.DataArray(
   ...:      np.ones((3,2)),
   ...:      dims=[""ternary"",""binary""],
   ...:      coords={""ternary"":[3,7,9],""binary"":[False,True]}
   ...: )

In [5]: test.sel(binary=[True,False])
Out[5]:
<xarray.DataArray (ternary: 3, binary: 1)>
array([[1.],
       [1.],
       [1.]])
Coordinates:
  * ternary  (ternary) int64 3 7 9
  * binary   (binary) bool False

In [6]: test.isel(binary=[True,False])
Out[6]:
<xarray.DataArray (ternary: 3, binary: 1)>
array([[1.],
       [1.],
       [1.]])
Coordinates:
  * ternary  (ternary) int64 3 7 9
  * binary   (binary) bool False
```

I would also be OK removing the `.sel` delegation to `.isel` if it causes complications. IIUC the main use case is a single method call to index labels and dimensions without labels. But that's easy to replace with two method calls, I think?","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,806218687