Merge 2087608 into 6182a61

more_itertools/more.py

@@ -19,7 +19,7 @@
 from sys import maxsize, version_info
 from collections.abc import Sequence
 
-from .recipes import consume, flatten, take
+from .recipes import consume, flatten, powerset, take
 
 __all__ = [
     'adjacent',
@@ -54,6 +54,7 @@
     'numeric_range',
     'one',
     'padded',
+    'partitions',
     'peekable',
     'replace',
     'rlocate',
@@ -2306,3 +2307,30 @@ def replace(iterable, pred, substitutes, count=None, window_size=1):
         # yield the first item from the window.
         if w and (w[0] is not _marker):
             yield w[0]
+
+
+def _is_collection(iterable):
+    return hasattr(iterable, '__getitem__') and hasattr(iterable, '__len__')
+
+
+def partitions(iterable):
+    """Yield all possible partitions of *iterable*.
+    Partition x is defined so that:
+    1. list(x) = [x_0, ..., x_n]
+    2. x_0 + ... + x_n = list(iterable)
+    3. all(isinstance(x_i, (type(iterable), list)) for x_i in x) == True
+    4. 1 <= n <= ilen(iterable)
+    5. isinstance(x, list) == True
+
+        >>> iterable = 'abcd'
+        >>> list(partitions(iterable))
+        [['abcd'], ['a', 'bcd'], ['ab', 'cd'], ['abc', 'd'], \
+['a', 'b', 'cd'], ['a', 'bc', 'd'], ['ab', 'c', 'd'], ['a', 'b', 'c', 'd']]
+
+    """
+    collection = iterable if _is_collection(iterable) else list(iterable)
+    n = len(collection)
+    if n > 0:
+        for partition_indexes in powerset(range(1, n)):
+            yield [collection[i:j] for i, j in zip((0, ) + partition_indexes,
+                                                   partition_indexes + (n, ))]

more_itertools/tests/test_more.py

@@ -2311,3 +2311,26 @@ def test_iterable_substitutes(self):
         actual = list(mi.replace(iterable, pred, substitutes))
         expected = ['_', '_', 1, '_', '_', 3, '_', '_']
         self.assertEqual(actual, expected)
+
+
+class PartitionsTest(TestCase):
+    def test_basic(self):
+        iterable = 'abcd'
+        actual = list(mi.partitions(iterable))
+        expected = [
+            ['abcd'],
+            ['a', 'bcd'],
+            ['ab', 'cd'],
+            ['abc', 'd'],
+            ['a', 'b', 'cd'],
+            ['a', 'bc', 'd'],
+            ['ab', 'c', 'd'],
+            ['a', 'b', 'c', 'd']
+        ]
+        self.assertEqual(actual, expected)
+
+    def test_empty(self):
+        iterable = []
+        actual = list(mi.partitions(iterable))
+        expected = []
+        self.assertEqual(actual, expected)