Replace utils.hashable(x) with isinstance(x, Hashable)

Author: Guido Imperiale

xarray/core/dataset.py

@@ -33,7 +33,7 @@
 from .options import OPTIONS, _get_keep_attrs
 from .pycompat import dask_array_type
 from .utils import (Frozen, SortedKeysDict, _check_inplace,
-                    decode_numpy_dict_values, either_dict_or_kwargs, hashable,
+                    decode_numpy_dict_values, either_dict_or_kwargs,
                     maybe_wrap_array)
 from .variable import IndexVariable, Variable, as_variable, broadcast_variables
 
@@ -1096,7 +1096,7 @@ def __getitem__(self, key: object) -> 'Union[DataArray, Dataset]':
         if utils.is_dict_like(key):
             return self.isel(**cast(Mapping, key))
 
-        if hashable(key):
+        if isinstance(key, Hashable):
             return self._construct_dataarray(key)
         else:
             return self._copy_listed(np.asarray(key))

xarray/core/groupby.py

@@ -1,6 +1,7 @@
 import datetime
 import functools
 import warnings
+from typing import Hashable
 
 import numpy as np
 import pandas as pd
@@ -11,7 +12,7 @@
 from .common import ALL_DIMS, ImplementsArrayReduce, ImplementsDatasetReduce
 from .options import _get_keep_attrs
 from .pycompat import integer_types
-from .utils import hashable, maybe_wrap_array, peek_at, safe_cast_to_index
+from .utils import maybe_wrap_array, peek_at, safe_cast_to_index
 from .variable import IndexVariable, Variable, as_variable
 
 
@@ -228,7 +229,7 @@ def __init__(self, obj, group, squeeze=False, grouper=None, bins=None,
             raise TypeError("can't specify both `grouper` and `bins`")
 
         if not isinstance(group, (DataArray, IndexVariable)):
-            if not hashable(group):
+            if not isinstance(group, Hashable):
                 raise TypeError('`group` must be an xarray.DataArray or the '
                                 'name of an xarray variable or dimension')
             group = obj[group]

xarray/core/utils.py

@@ -515,16 +515,6 @@ def is_uniform_spaced(arr, **kwargs) -> bool:
     return bool(np.isclose(diffs.min(), diffs.max(), **kwargs))
 
 
-def hashable(v: Any) -> bool:
-    """Determine whether `v` can be hashed.
-    """
-    try:
-        hash(v)
-    except TypeError:
-        return False
-    return True
-
-
 def not_implemented(*args, **kwargs):
     return NotImplemented
 

xarray/tests/test_utils.py

@@ -234,15 +234,6 @@ def test_relative_tolerance(self):
         assert utils.is_uniform_spaced([0, 0.97, 2], rtol=0.1)
 
 
-class Test_hashable:
-
-    def test_hashable(self):
-        for v in [False, 1, (2, ), (3, 4), 'four']:
-            assert utils.hashable(v)
-        for v in [[5, 6], ['seven', '8'], {9: 'ten'}]:
-            assert not utils.hashable(v)
-
-
 @requires_dask
 def test_dask_array_is_scalar():
     # regression test for GH1684