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/pull/551#issuecomment-136588625,https://api.github.com/repos/pydata/xarray/issues/551,136588625,MDEyOklzc3VlQ29tbWVudDEzNjU4ODYyNQ==,2443309,2015-09-01T05:13:34Z,2015-09-01T05:13:34Z,MEMBER,"I started working on a second PR for this issue and ran across this issue:

``` Python
In [1]: import numpy as np
In [2]: import xray
In [3]: data = np.random.random((2, 2))
In [4]: da = xray.DataArray(data)
In [5]: ds = xray.Dataset()
In [6]: ds[(4, 5)] = da
In [7]: print(ds)
# traceback shortened
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
/Users/jhamman/Dropbox/src/xray/xray/core/dataset.py in _get_virtual_variable(variables, key)
     37     """"""
     38     if not isinstance(key, basestring):
---> 39         raise KeyError(key)
     40 
     41     split_key = key.split('.', 1)

KeyError: 4
```

It looks like we have something else to fix because it is possible to create a dataset that behaves like a dictionary but cant be written to disk or printed.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,103055174
https://github.com/pydata/xarray/pull/551#issuecomment-136175466,https://api.github.com/repos/pydata/xarray/issues/551,136175466,MDEyOklzc3VlQ29tbWVudDEzNjE3NTQ2Ng==,2443309,2015-08-30T19:08:41Z,2015-08-30T19:08:41Z,MEMBER,"I think I'm starting to fall in line with you here.  Perhaps we should just raise an error in `to_netcdf` in the even the variable name is invalid.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,103055174
https://github.com/pydata/xarray/pull/551#issuecomment-135196454,https://api.github.com/repos/pydata/xarray/issues/551,135196454,MDEyOklzc3VlQ29tbWVudDEzNTE5NjQ1NA==,2443309,2015-08-26T22:32:16Z,2015-08-26T22:32:16Z,MEMBER,"I think this is ready.  Anyone have final comments or concerns?
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,103055174
https://github.com/pydata/xarray/pull/551#issuecomment-135143005,https://api.github.com/repos/pydata/xarray/issues/551,135143005,MDEyOklzc3VlQ29tbWVudDEzNTE0MzAwNQ==,2443309,2015-08-26T19:11:11Z,2015-08-26T19:11:11Z,MEMBER,"do we also need to check `new_coord_names`?
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,103055174
https://github.com/pydata/xarray/pull/551#issuecomment-135112877,https://api.github.com/repos/pydata/xarray/issues/551,135112877,MDEyOklzc3VlQ29tbWVudDEzNTExMjg3Nw==,2443309,2015-08-26T17:19:59Z,2015-08-26T17:19:59Z,MEMBER,"82bcd8b follows the same rules as for the Dataset key names as the DataArray.name attribute.  

`c = xray.Dataset({'a': 1, ('b', 'b'): 2})` 

now raises a `TypeError`. 
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,103055174