Add FrozenBitset.__reversed__

sagemath · Jun 20, 2022 · d4f3d86 · d4f3d86
1 parent a6e696e
commit d4f3d86
Showing 1 changed file with 13 additions and 0 deletions.
diff --git a/src/sage/data_structures/bitset.pyx b/src/sage/data_structures/bitset.pyx
@@ -457,6 +457,19 @@ cdef class FrozenBitset:
         """
         return iter(bitset_list(self._bitset))
 
+    def __reversed__(self):
+        """
+        Return an iterator over ``self``, starting with the largest element.
+
+        EXAMPLES::
+
+            sage: list(reversed(FrozenBitset('11011')))
+            [4, 3, 1, 0]
+            sage: list(reversed(FrozenBitset('00001' * 20)))
+            [99, 94, 89, 84, 79, 74, 69, 64, 59, 54, 49, 44, 39, 34, 29, 24, 19, 14, 9, 4]
+        """
+        return reversed(bitset_list(self._bitset))
+
     cpdef FrozenBitset _larger_capacity_(self, long capacity):
         """
         Return a copy of ``self`` where the bitset has the maximum of the