X-Git-Url: https://wannabe.guru.org/gitweb/?a=blobdiff_plain;ds=sidebyside;f=list_utils.py;h=993ca8af9ca9f9a633c02162e0f155fd3b3cab74;hb=d92df9c03f8510042ee1f8949d0786761f01d35e;hp=9a5d4fde0dcad7936a16ffc6f53a7a50ba0b67fa;hpb=497fb9e21f45ec08e1486abaee6dfa7b20b8a691;p=python_utils.git

diff --git a/list_utils.py b/list_utils.py
index 9a5d4fd..993ca8a 100644
--- a/list_utils.py
+++ b/list_utils.py
@@ -5,16 +5,27 @@ from typing import Any, Iterator, List
 
 
 def shard(lst: List[Any], size: int) -> Iterator[Any]:
-    """Yield successive size-sized shards from lst."""
+    """
+    Yield successive size-sized shards from lst.
+
+    >>> for sublist in shard([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], 3):
+    ...     [_ for _ in sublist]
+    [1, 2, 3]
+    [4, 5, 6]
+    [7, 8, 9]
+    [10, 11, 12]
+
+    """
     for x in range(0, len(lst), size):
         yield islice(lst, x, x + size)
 
 
 def flatten(lst: List[Any]) -> List[Any]:
-    """Flatten out a list:
+    """
+    Flatten out a list:
 
-        >>> flatten([ 1, [2, 3, 4, [5], 6], 7, [8, [9]]])
-        [1, 2, 3, 4, 5, 6, 7, 8, 9]
+    >>> flatten([ 1, [2, 3, 4, [5], 6], 7, [8, [9]]])
+    [1, 2, 3, 4, 5, 6, 7, 8, 9]
 
     """
     if len(lst) == 0:
@@ -22,3 +33,20 @@ def flatten(lst: List[Any]) -> List[Any]:
     if isinstance(lst[0], list):
         return flatten(lst[0]) + flatten(lst[1:])
     return lst[:1] + flatten(lst[1:])
+
+
+def prepend(item: Any, lst: List[Any]) -> List[Any]:
+    """
+    Prepend an item to a list.
+
+    >>> prepend('foo', ['bar', 'baz'])
+    ['foo', 'bar', 'baz']
+
+    """
+    lst.insert(0, item)
+    return lst
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()