Define bucket.__iter__ (#371)

more_itertools/more.py

@@ -772,7 +772,9 @@ class bucket:
     child iterables based on a *key* function.
 
         >>> iterable = ['a1', 'b1', 'c1', 'a2', 'b2', 'c2', 'b3']
-        >>> s = bucket(iterable, key=lambda x: x[0])
+        >>> s = bucket(iterable, key=lambda x: x[0])  # Bucket by 1st character
+        >>> sorted(list(s))  # Get the keys
+        ['a', 'b', 'c']
         >>> a_iterable = s['a']
         >>> next(a_iterable)
         'a1'
@@ -846,6 +848,14 @@ def _get_values(self, value):
                     elif self._validator(item_value):
                         self._cache[item_value].append(item)
 
+    def __iter__(self):
+        for item in self._it:
+            item_value = self._key(item)
+            if self._validator(item_value):
+                self._cache[item_value].append(item)
+
+        yield from self._cache.keys()
+
     def __getitem__(self, value):
         if not self._validator(value):
             return iter(())

tests/test_more.py

@@ -822,8 +822,6 @@ def test_reverse(self):
 
 
 class BucketTests(TestCase):
-    """Tests for ``bucket()``"""
-
     def test_basic(self):
         iterable = [10, 20, 30, 11, 21, 31, 12, 22, 23, 33]
         D = mi.bucket(iterable, key=lambda x: 10 * (x // 10))
@@ -859,6 +857,24 @@ def test_validator(self):
         self.assertNotIn(0, D._cache)  # Don't store non-valid entries
         self.assertEqual(list(D[0]), [])
 
+    def test_list(self):
+        iterable = [10, 20, 30, 11, 21, 31, 12, 22, 23, 33]
+        D = mi.bucket(iterable, key=lambda x: 10 * (x // 10))
+        self.assertEqual(list(D[10]), [10, 11, 12])
+        self.assertEqual(list(D[20]), [20, 21, 22, 23])
+        self.assertEqual(list(D[30]), [30, 31, 33])
+        self.assertEqual(set(D), {10, 20, 30})
+
+    def test_list_validator(self):
+        iterable = [10, 20, 30, 11, 21, 31, 12, 22, 23, 33]
+        key = lambda x: 10 * (x // 10)
+        validator = lambda x: x != 20
+        D = mi.bucket(iterable, key, validator=validator)
+        self.assertEqual(set(D), {10, 30})
+        self.assertEqual(list(D[10]), [10, 11, 12])
+        self.assertEqual(list(D[20]), [])
+        self.assertEqual(list(D[30]), [30, 31, 33])
+
 
 class SpyTests(TestCase):
     """Tests for ``spy()``"""