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/1434#issuecomment-388660444,https://api.github.com/repos/pydata/xarray/issues/1434,388660444,MDEyOklzc3VlQ29tbWVudDM4ODY2MDQ0NA==,1217238,2018-05-13T22:27:28Z,2018-05-13T22:27:28Z,MEMBER,"@ctw I'm not sure why #1438 was closed (I think that was by mistake), but we would still need a fix along those lines to fix this issue.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,232350436
https://github.com/pydata/xarray/issues/1434#issuecomment-305036355,https://api.github.com/repos/pydata/xarray/issues/1434,305036355,MDEyOklzc3VlQ29tbWVudDMwNTAzNjM1NQ==,1217238,2017-05-30T23:20:14Z,2017-05-30T23:20:14Z,MEMBER,"> Is there an advantage to using pandas for concatenation over numpy.concatenate?

Yes, otherwise we loose pandas (d)type information. For example, a `MultiIndex` gets turned into a `dtype=object` array of tuples.","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,232350436
https://github.com/pydata/xarray/issues/1434#issuecomment-305034234,https://api.github.com/repos/pydata/xarray/issues/1434,305034234,MDEyOklzc3VlQ29tbWVudDMwNTAzNDIzNA==,1217238,2017-05-30T23:08:48Z,2017-05-30T23:08:48Z,MEMBER,"Thanks for the report, I'm marking this as a bug.

The issue is with [these lines](https://github.com/pydata/xarray/blob/master/xarray/core/variable.py#L1232-L1242
) in `IndexVariable.concat`. We defer to pandas for concatenating coordinate labels, but pandas doesn't handle structured dtypes properly (it converts them to `dtype=object`). This is part of why we have [`PandasIndexAdapter`](https://github.com/pydata/xarray/blob/8df660b37692e42965a672563941d85ed6d55229/xarray/core/indexing.py#L494).

It seems like we now need some more complex logic for toggling between pandas `Index.append()` and `numpy.concatenate`, based on the Index dtypes.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,232350436