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/967#issuecomment-298117210,https://api.github.com/repos/pydata/xarray/issues/967,298117210,MDEyOklzc3VlQ29tbWVudDI5ODExNzIxMA==,1217238,2017-04-28T22:04:15Z,2017-04-28T22:04:15Z,MEMBER,"> Why would I have a xarray.core.dataset.DataVariables object as input? 

Indeed, you would not. I think my earlier comment was a little confusing here. I meant you could have name(s) of variables in a Dataset (which means either coords or data_vars) or coords on a DataArray.

>  In my mind it should only be 1.) name(s) of existing index coords, or 2.) 1D DataArray(s) with dim in self.dims

Yes, agreed.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,171077425
https://github.com/pydata/xarray/issues/967#issuecomment-297875833,https://api.github.com/repos/pydata/xarray/issues/967,297875833,MDEyOklzc3VlQ29tbWVudDI5Nzg3NTgzMw==,1217238,2017-04-28T00:33:55Z,2017-04-28T00:40:43Z,MEMBER,"> What would the signature of sortby() be then?

Maybe something like: `sortby(variables, ascending=True)`, where `variables` can be any of:
- name of a 1D variable in `coords` (on a DataArray) or `coords`/`data_vars` (on a Dataset): these get converted in a DataArray like `self[name]`.
- a 1D DataArray, with a dimension found in `self.dims`
- list of either of the above, either along the same or different dimensions (this could be added later)

So I think this covers all the use cases of `sort_index()`, but is slightly more general.

If you really want to sort a 1D DataArray by its own values, you would write `da.sortby(da)`, but I agree that that will be rare.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,171077425
https://github.com/pydata/xarray/issues/967#issuecomment-297871870,https://api.github.com/repos/pydata/xarray/issues/967,297871870,MDEyOklzc3VlQ29tbWVudDI5Nzg3MTg3MA==,1217238,2017-04-28T00:03:57Z,2017-04-28T00:03:57Z,MEMBER,"@chunweiyuan I would skip `inplace` -- it's just not worth the complexity. It certainly does not make things any faster, so there is little gain from it. If you really want it, search for `inplace` in `dataset.py` and `dataarray.py` for examples.

When you assign to `self`, it creates a local variable: it doesn't override the object instance (Python doesn't support that).

I actually like the name `sortby()`, allowing any 1D variables as the argument (not just coordinates), as long as they have distinct dimensions. This works better for xarray than it does for pandas because we always have axis/dimension names.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,171077425
https://github.com/pydata/xarray/issues/967#issuecomment-296409111,https://api.github.com/repos/pydata/xarray/issues/967,296409111,MDEyOklzc3VlQ29tbWVudDI5NjQwOTExMQ==,1217238,2017-04-22T23:50:05Z,2017-04-22T23:50:05Z,MEMBER,"If you pass in a list or array to `isel`, xarray copies the underling data like numpy does:
http://xarray.pydata.org/en/stable/indexing.html#copies-vs-views

These approach do go do slightly different code paths, but they would have equivalent performance in most cases because the indexing cost will dominate over sorting. I would prefer using `np.argsort()` only because it's slightly more general, insofar as it doesn't rely on the index having unique labels. (If you have duplicate labels, `reindex` fails.) It also avoids needing to build the hash table for index based lookups, which has a small amount of overhead.

Also, as a side note `np.sort` and `np.argsort` are slightly faster than Python's `sorted()`, because can rely on homogeneous data dtypes.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,171077425