Initial revision

1 files changed, 24 insertions, 0 deletions

diff --git a/list_utils.py b/list_utils.py
new file mode 100644
index 0000000..9a5d4fd
--- /dev/null
+++ b/list_utils.py
@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+
+from itertools import islice
+from typing import Any, Iterator, List
+
+
+def shard(lst: List[Any], size: int) -> Iterator[Any]:
+    """Yield successive size-sized shards from lst."""
+    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([ 1, [2, 3, 4, [5], 6], 7, [8, [9]]])
+        [1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+    """
+    if len(lst) == 0:
+        return lst
+    if isinstance(lst[0], list):
+        return flatten(lst[0]) + flatten(lst[1:])
+    return lst[:1] + flatten(lst[1:])