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
40839365,MDExOlB1bGxSZXF1ZXN0NDA4MzkzNjU=,495,closed,0,ENH: finite difference method `diff`,358378,"adds `diff` method to both `DataArray` and `Dataset`. closes #490 

Still to be done:
- tests

Possible enhancements:
- allow numeric `axis` instead of `dim` for `DataArray` objects. The signature would then be `DataArray.diff(dim=None, n=1, axis=None)` and I would need to check that exactly one of `dim` and `axis` is `None`. I find it a bit ugly; `DataArray.diff(n=1, dim=None, axis=None)` would be nicer in my view.  But then the signatures for `DataArray.diff` and `Dataset.diff` would be different, which is also not nice.
- allow specifying the new coordinate array explicitly via a `coord` kwarg instead of just taking the coordinate values of the upper bounds.

What do you think?
",2015-07-25T16:33:20Z,2015-08-21T18:13:00Z,2015-08-21T18:12:57Z,2015-08-21T18:12:57Z,e9b0a8dbdbd936e0a1a279c8c1b3657e7a0318fb,,,0,a112dcec81196275148ea2b895a12c801415231b,4b69878f20033e853ab67d44788ec89defc3ed16,CONTRIBUTOR,,13221727,https://github.com/pydata/xarray/pull/495,
55875449,MDExOlB1bGxSZXF1ZXN0NTU4NzU0NDk=,718,closed,0,Update index.rst,358378,"fix link to mailing list
",2016-01-13T09:57:40Z,2016-01-13T16:37:56Z,2016-01-13T16:37:56Z,2016-01-13T16:37:56Z,8a41d6e2e17c1970baa888e4c88f1d1a98508b2f,,,0,926eafb547bd17af17ddcaa4399375bc6abb441d,ac6c1c2d69ccb586ae770e9a26b5e0c8c171a99d,CONTRIBUTOR,,13221727,https://github.com/pydata/xarray/pull/718,