Adds shuffle/scramble to list_utils.

[python_utils.git] / list_utils.py

diff --git a/list_utils.py b/list_utils.py
index d70159a1b2dadb61640eae20f029608cabd2f46e..7f28ade922a4b733ee29ea0c68bc957ff587c51b 100644 (file)
--- a/list_utils.py
+++ b/list_utils.py
@@ -1,8 +1,11 @@
 #!/usr/bin/env python3
 
+"""Some useful(?) utilities for dealing with Lists."""
+
+import random
 from collections import Counter
 from itertools import islice
-from typing import Any, Iterator, List, Mapping, Sequence, Tuple
+from typing import Any, Iterator, List, MutableSequence, Sequence, Tuple
 
 
 def shard(lst: List[Any], size: int) -> Iterator[Any]:
@@ -230,9 +233,31 @@ def _permute(seq: str, path: str):
         yield from _permute(cdr, path + car)
 
 
-def binary_search(
-    lst: Sequence[Any], target: Any, *, sanity_check=False
-) -> Tuple[bool, int]:
+def shuffle(seq: MutableSequence[Any]) -> MutableSequence[Any]:
+    """Shuffles a sequence into a random order.
+
+    >>> random.seed(22)
+    >>> shuffle([1, 2, 3, 4, 5])
+    [3, 4, 1, 5, 2]
+
+    >>> shuffle('example')
+    'empaelx'
+
+    """
+    if isinstance(seq, str):
+        import string_utils
+
+        return string_utils.shuffle(seq)
+    else:
+        random.shuffle(seq)
+        return seq
+
+
+def scramble(seq: MutableSequence[Any]) -> MutableSequence[Any]:
+    return shuffle(seq)
+
+
+def binary_search(lst: Sequence[Any], target: Any, *, sanity_check=False) -> Tuple[bool, int]:
     """Performs a binary search on lst (which must already be sorted).
     Returns a Tuple composed of a bool which indicates whether the
     target was found and an int which indicates the index closest to
@@ -267,9 +292,7 @@ def binary_search(
     return _binary_search(lst, target, 0, len(lst) - 1)
 
 
-def _binary_search(
-    lst: Sequence[Any], target: Any, low: int, high: int
-) -> Tuple[bool, int]:
+def _binary_search(lst: Sequence[Any], target: Any, low: int, high: int) -> Tuple[bool, int]:
     if high >= low:
         mid = (high + low) // 2
         if lst[mid] == target: