New features:

**Revamped coordinates**: "coordinates" now refer to all arrays that are not

used to index a dimension. Coordinates are intended to allow for keeping track

of arrays of metadata that describe the grid on which the points in "variable"

arrays lie. They are preserved (when unambiguous) even though mathematical

operations.

**Dataset math**`xray.Dataset`

objects now support all arithmetic

operations directly. Dataset-array operations map across all dataset

variables; dataset-dataset operations act on each pair of variables with the

same name.

**GroupBy math**: This provides a convenient shortcut for normalizing by the

average value of a group.

- The dataset
`__repr__`

method has been entirely overhauled; dataset

objects now show their values when printed.

- You can now index a dataset with a list of variables to return a new dataset:

`ds[['foo', 'bar']]`

.

Backwards incompatible changes:

`Dataset.__eq__`

and`Dataset.__ne__`

are now element-wise operations

instead of comparing all values to obtain a single boolean. Use the method

`Dataset.equals`

instead.

Deprecations:

`Dataset.noncoords`

is deprecated: use`Dataset.vars`

instead.

`Dataset.select_vars`

deprecated: index a`Dataset`

with a list of

variable names instead.

`DataArray.select_vars`

and`DataArray.drop_vars`

deprecated: use

`DataArray.reset_coords`

instead.