Order coords to match dims in repr

[jsignell]

Demo

From #712:

In [4]: from collections import * 
   ...: import numpy as np 
   ...: from xarray import * 
   ...:  
   ...: d1 = DataArray(np.empty((2, 2)), coords=OrderedDict([("foo", [0, 1]), ("bar", [0, 1])]), dims=["foo", "bar"]) 
   ...: d2 = DataArray(np.empty((2, 2)), coords=OrderedDict([("bar", [0, 1]), ("foo", [0, 1])]), dims=["bar", "foo"]) 
   ...:  
   ...: ds = Dataset({"d1": d1, "d2": d2}) 
   ...:  
   ...: print(ds.d1) 
   ...: print(ds.d2)     
<xarray.DataArray 'd1' (foo: 2, bar: 2)> Size: 32B
array([[4.70561893e-310, 0.00000000e+000],
       [4.54093764e-293, 1.78484740e+161]])
Coordinates:
  * foo      (foo) int64 16B 0 1
  * bar      (bar) int64 16B 0 1
<xarray.DataArray 'd2' (bar: 2, foo: 2)> Size: 32B
array([[ 9.98924668e+201,  8.70970817e-191],
       [-2.16505045e+052,  8.30088883e-055]])
Coordinates:
  * bar      (bar) int64 16B 0 1
  * foo      (foo) int64 16B 0 1

from collections import *
import numpy as np
import xarray as xr

d1 = DataArray(np.empty((2, 2)), coords=OrderedDict([("foo", [0, 1]), ("bar", [0, 1])]))
d2 = DataArray(np.empty((2, 2)), coords=OrderedDict([("bar", [0, 1]), ("foo", [0, 1])]))

ds = Dataset({"d1": d1, "d2": d2})

print(ds.d1)
print(ds.d2)

From #4515:

import xarray as xr
import numpy as np

ds = xr.Dataset()
ds.coords["as"] = 10
ds["var"] = xr.DataArray(np.ones((10,)), dims="x", coords={"x": np.arange(10)})
ds

• Closes DataArrays should display their coordinates in the natural order #712
• Tests added - shockingly this didn't break any tests, but I'll add some
• User visible changes (including notable bug fixes) are documented in whats-new.rst
• New functions/methods are listed in api.rst