add random.shuffle_together

CHANGELOG.md

 # v2.7.47
 
+added `random.shuffle_together`

docs/index.rst

@@ -24,6 +24,7 @@ Visit the project's page at GitHub_!
            posix
            import
            files
+           random
            time
            exceptions
            processes

docs/random.rst

+shuffle_together
+================
+
+.. autofunction:: satella.random.shuffle_together

satella/__init__.py

-__version__ = '2.7.47_a1'
+__version__ = '2.7.47'

satella/random.py

+import random
+import typing as tp
+
+__all__ = ['shuffle_together']
+
+
+def shuffle_together(*args: tp.Sequence) -> tp.List:
+    """
+    args, being sequences of equal length, will be permuted in such a way
+    that their indices will still correspond to each other.
+
+    So given:
+
+    >>> a = [1, 2, 3]
+    >>> b = ['a', 'b', 'c']
+    >>> c = permute_together(a, b)
+
+    Might equal
+
+    >>> c == ([3, 1, 2], ['c', 'a', 'b'])
+    """
+
+    indices = list(range(len(args[0])))
+
+    random.shuffle(indices)
+    return [[arg[i] for arg, i in zip(arg, indices)] for arg in args]

tests/test_random.py

+import unittest
+from satella.random import shuffle_together
+
+
+class TestRandom(unittest.TestCase):
+    def test_random(self):
+        a = [(1, 2, 3), ('a', 'b', 'c')]
+        b = zip(shuffle_together(*a))
+        self.assertEqual(set(b), {(1, 'a'), (2, 'b'), (3, 'c')})
+