pull_requests: 64042989

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id node_id number state locked title user body created_at updated_at closed_at merged_at merge_commit_sha assignee milestone draft head base author_association auto_merge repo url merged_by
64042989 MDExOlB1bGxSZXF1ZXN0NjQwNDI5ODk= 802 closed 0 Multi-index indexing 4160723 Follows #767. This is incomplete (it still needs some tests and documentation updates), but it is working for both `Dataset` and `DataArray` objects. I also don't know if it is fully compatible with lazy indexing (Dask). Using the example from #767: ``` In [4]: da.sel(band_wavenumber={'band': 'foo'}) Out[4]: <xarray.DataArray (wavenumber: 2)> array([ 0.00017, 0.00014]) Coordinates: * wavenumber (wavenumber) float64 4.05e+03 4.05e+03 ``` As shown in this example, similarily to pandas, it automatically renames the dimension and assigns a new coordinate when the selection doesn't return a `pd.MultiIndex` (here it returns a `pd.FloatIndex`). In some cases this behavior may be unwanted (??), so I added a `drop_level` keyword argument (if `False` it keeps the multi-index and doesn't change the dimension/coordinate names): ``` In [5]: da.sel(band_wavenumber={'band': 'foo'}, drop_level=False) Out[5]: <xarray.DataArray (band_wavenumber: 2)> array([ 0.00017, 0.00014]) Coordinates: * band_wavenumber (band_wavenumber) object ('foo', 4050.2) ('foo', 4050.3) ``` Note that it also works with `DataArray.loc`, but (for now) in that case it always returns the multi-index: ``` In [6]: da.loc[{'band_wavenumber': {'band': 'foo'}}] Out[6]: <xarray.DataArray (band_wavenumber: 2)> array([ 0.00017, 0.00014]) Coordinates: * band_wavenumber (band_wavenumber) object ('foo', 4050.2) ('foo', 4050.3) ``` This is however inconsistent with `Dataset.sel` and `Dataset.loc` that both apply `drop_level=True` by default, due to their different implementation. Two solutions: (1) make `DataArray.loc` apply drop_level by default, or (2) use `drop_level=False` by default everywhere. 2016-03-24T14:39:38Z 2016-07-19T10:48:56Z 2016-07-19T01:15:42Z 2016-07-19T01:15:41Z 7a9e84b5708d3e8ec270a7415f9b5e54d30f13f7     0 712497c3997e72a36cafc8fb9eaafbecc76af5dc 80abe5dede7bf8a2949139f8ba083a6d74d4e3db MEMBER   13221727 https://github.com/pydata/xarray/pull/802  

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