Stream deduplicate

src/morgslib/morgslib.py

@@ -56,6 +56,9 @@ class Stream(Generic[T]):
             out[fxn(item)].append(item)
         return Stream(out.items())
 
+    def deduplicate(self) -> Stream[T]:
+        return Stream(dict.fromkeys(self.iter))
+
     def apply(self, fxn: Callable[[Iterator[T]], Iterable[Tn]|Tn]) -> Stream[Tn]:
         return Stream(fxn(self.iter))
     

src/morgslib/msl_tests.py

@@ -21,6 +21,9 @@ class TestStringMethods(unittest.TestCase):
     def test_group(self):
         self.assertEqual(Stream([1, 2, 3, 4, 5]).group(lambda x: x%3).to(dict), {0: [3], 1: [1, 4], 2: [2, 5]})
 
+    def test_deduplicate(self):
+        self.assertEqual(Stream([1, 2, 3, 2, 5, 3, 4]).deduplicate().to(list), [1, 2, 3, 5, 4])
+
     def test_apply_single(self):
         self.assertEqual(Stream([1, 2, 3, 4, 5]).apply(sum).to_single(int), 15)
     def test_apply_multi(self):