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/1028#issuecomment-267509336,https://api.github.com/repos/pydata/xarray/issues/1028,267509336,MDEyOklzc3VlQ29tbWVudDI2NzUwOTMzNg==,1217238,2016-12-16T03:33:40Z,2016-12-16T03:33:40Z,MEMBER,Can we update this for optional indexes? (now on master),"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,180638999
https://github.com/pydata/xarray/pull/1028#issuecomment-259476665,https://api.github.com/repos/pydata/xarray/issues/1028,259476665,MDEyOklzc3VlQ29tbWVudDI1OTQ3NjY2NQ==,1217238,2016-11-09T17:43:31Z,2016-11-09T17:43:31Z,MEMBER,"I kind of like Option C, given that we have guaranteed level names and variables to have no conflicts.

Did you go for allowing `set_index()` to rename variables?
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,180638999
https://github.com/pydata/xarray/pull/1028#issuecomment-255498340,https://api.github.com/repos/pydata/xarray/issues/1028,255498340,MDEyOklzc3VlQ29tbWVudDI1NTQ5ODM0MA==,1217238,2016-10-22T01:18:40Z,2016-10-22T01:18:40Z,MEMBER,"> We need to choose whether to use dim=indexes kwargs or fixed arg/kwarg relative to a given dimension for the signatures of .set_index(), .reset_index() and .reorder_levels().

For `set_index` and `reorder_levels`, I like the kwargs or a dictionary. It's nice and explicit. But for `reset_index`, I think we probably want a list.

It's not at all obvious to me what `array.reset_index(x=None)` does. It could just as easily mean ""reset nothing from `x`"" as ""reset `x` to have a null index"". In fact, the former seems more consistent with how we handle levels. In contrast, `array.reset_index(['x'])` pretty clearly means that the `'x'` index should be reset.

> Do we also allow .set_index() to rename the dimension(s) if needed, instead of doing .set_index(...).rename(...) ? Is this a common use case that is worth it?

My inclination is yes -- this feels like a common thing to do. But we could also safely add this later.

> After discussion in #1017, it seems that we need an easy way to (re)set indexes either to no index or to range(n).

We definitely need a way to reset indexes to the default, but after #1017, I'm not sure we will need a way to set them to `range(n)`.

Unfortunately, if `x` is a normal (non-multi) Index, `array.reset_index('x')` is not well defined. We need a name for the variable that was formerly named `x` (or could drop it, e.g., with `array.reset_index('x', drop=True)` or `array.drop('x')`), otherwise it will still be the index for the x-axis. Or, I suppose we could rename the `x` dimension to something else.

One option is to add some sort of prefix or suffix to the index name when it becomes a new variable, e.g., `array.reset_index('x')` renames the coordinate `x` to `x_`. This seems like a probably safe choice, though I hate to add more automatic names to the API.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,180638999