Pandas labels deprecation (pydata#3016)

* Pandas deprecation

* allow for older versions of pandas

* update docs

Author: max-sixty

xarray/core/dataarray.py

@@ -1351,7 +1351,7 @@ def stack(self, dimensions=None, **dimensions_kwargs):
         >>> stacked = arr.stack(z=('x', 'y'))
         >>> stacked.indexes['z']
         MultiIndex(levels=[['a', 'b'], [0, 1, 2]],
-                   labels=[[0, 0, 0, 1, 1, 1], [0, 1, 2, 0, 1, 2]],
+                   codes=[[0, 0, 0, 1, 1, 1], [0, 1, 2, 0, 1, 2]],
                    names=['x', 'y'])
 
         See also
@@ -1394,7 +1394,7 @@ def unstack(self, dim=None):
         >>> stacked = arr.stack(z=('x', 'y'))
         >>> stacked.indexes['z']
         MultiIndex(levels=[['a', 'b'], [0, 1, 2]],
-                   labels=[[0, 0, 0, 1, 1, 1], [0, 1, 2, 0, 1, 2]],
+                   codes=[[0, 0, 0, 1, 1, 1], [0, 1, 2, 0, 1, 2]],
                    names=['x', 'y'])
         >>> roundtripped = stacked.unstack()
         >>> arr.identical(roundtripped)

xarray/core/pdcompat.py

@@ -57,15 +57,15 @@ def remove_unused_levels(self):
     --------
     >>> i = pd.MultiIndex.from_product([range(2), list('ab')])
     MultiIndex(levels=[[0, 1], ['a', 'b']],
-               labels=[[0, 0, 1, 1], [0, 1, 0, 1]])
+               codes=[[0, 0, 1, 1], [0, 1, 0, 1]])
     >>> i[2:]
     MultiIndex(levels=[[0, 1], ['a', 'b']],
-               labels=[[1, 1], [0, 1]])
+               codes=[[1, 1], [0, 1]])
     The 0 from the first level is not represented
     and can be removed
     >>> i[2:].remove_unused_levels()
     MultiIndex(levels=[[1], ['a', 'b']],
-               labels=[[0, 0], [0, 1]])
+               codes=[[0, 0], [0, 1]])
     """
     import pandas.core.algorithms as algos
 

xarray/tests/test_dataarray.py

@@ -1762,8 +1762,12 @@ def test_stack_unstack(self):
 
         # test GH3000
         a = orig[:0, :1].stack(dim=('x', 'y')).dim.to_index()
-        b = pd.MultiIndex(levels=[pd.Int64Index([]), pd.Int64Index([0])],
-                          labels=[[], []], names=['x', 'y'])
+        if pd.__version__ < '0.24.0':
+            b = pd.MultiIndex(levels=[pd.Int64Index([]), pd.Int64Index([0])],
+                              labels=[[], []], names=['x', 'y'])
+        else:
+            b = pd.MultiIndex(levels=[pd.Int64Index([]), pd.Int64Index([0])],
+                              codes=[[], []], names=['x', 'y'])
         pd.util.testing.assert_index_equal(a, b)
 
         actual = orig.stack(z=['x', 'y']).unstack('z').drop(['x', 'y'])