add allow_slice

Author: LirongMa

pandas/core/dtypes/inference.py

@@ -393,7 +393,7 @@ def is_hashable(obj: object, allow_slice: bool=None) -> TypeGuard[Hashable]:
     allow_slice: bool or None
         - If True: return True if the object is hashable (including slices).
         - If False: return True if the object is hashable and not a slice.
-        - If None: return True of the object is hashable. without checking for slice type.
+        - If None: return True if the object is hashable. without checking for slice type.
 
     Returns
     -------
@@ -426,12 +426,20 @@ def is_hashable(obj: object, allow_slice: bool=None) -> TypeGuard[Hashable]:
     # Reconsider this decision once this numpy bug is fixed:
     # https://github.com/numpy/numpy/issues/5562
 
+    def _contains_slice(x: object) -> bool:
+        # Check if object is a slice or a tuple containing a slice
+        if isinstance(x, tuple):
+            return any(isinstance(v, slice) for v in x)      
+        elif isinstance(x, slice):
+            return True
+        return False
+
     try:
         hash(obj)
     except TypeError:
         return False
-    else:
-        if allow_slice is False and isinstance(obj, slice):
+    else:       
+        if allow_slice is False and _contains_slice(obj):
             return False
         return True
 

pandas/tests/dtypes/test_inference.py

@@ -451,17 +451,47 @@ class UnhashableClass1:
     class UnhashableClass2:
         def __hash__(self):
             raise TypeError("Not hashable")
+            
+    class HashableSlice:
+        def __init__(self, start, stop, step=None):
+            self.slice = slice(start, stop, step)
+
+        def __eq__(self, other):
+            return isinstance(other, HashableSlice) and self.slice == other.slice
+
+        def __hash__(self):
+            return hash((self.slice.start, self.slice.stop, self.slice.step))
+
+        def __repr__(self):
+            return f"HashableSlice({self.slice.start}, {self.slice.stop}, {self.slice.step})"
+
 
     hashable = (1, 3.14, np.float64(3.14), "a", (), (1,), HashableClass())
-    not_hashable = ([], UnhashableClass1())
+    not_hashable = ([], UnhashableClass1(), slice(1, 2, 3))
     abc_hashable_not_really_hashable = (([],), UnhashableClass2())
+    hashable_slice = (HashableSlice(1, 2), HashableSlice(1, 2, 3))
+    tuple_with_slice = ((slice(1, 2), 3), 1, "a")
 
     for i in hashable:
         assert inference.is_hashable(i)
+        assert inference.is_hashable(i, allow_slice=True)
+        assert inference.is_hashable(i, allow_slice=False)
     for i in not_hashable:
         assert not inference.is_hashable(i)
+        assert not inference.is_hashable(i, allow_slice=True)
+        assert not inference.is_hashable(i, allow_slice=False)
     for i in abc_hashable_not_really_hashable:
         assert not inference.is_hashable(i)
+        assert not inference.is_hashable(i, allow_slice=True)
+        assert not inference.is_hashable(i, allow_slice=False)
+    for i in hashable_slice:
+        assert inference.is_hashable(i)
+        assert inference.is_hashable(i, allow_slice=True)       
+        assert inference.is_hashable(i, allow_slice=False)
+    
+    assert not inference.is_hashable(tuple_with_slice)
+    assert not inference.is_hashable(tuple_with_slice, allow_slice=True)
+    assert not inference.is_hashable(tuple_with_slice, allow_slice=False)
 
     # numpy.array is no longer collections.abc.Hashable as of
     # https://github.com/numpy/numpy/pull/5326, just test