From 35b666224a05fbd249b1c51a0a48fb95b246fe9a Mon Sep 17 00:00:00 2001
From: Evgeny Fadeev <evgeny.fadeev@gmail.com>
Date: Fri, 10 Jul 2009 19:15:28 -0400
Subject: adding all files again

---
 utils/lists.py | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 utils/lists.py

(limited to 'utils/lists.py')

diff --git a/utils/lists.py b/utils/lists.py
new file mode 100644
index 00000000..426d9cd3
--- /dev/null
+++ b/utils/lists.py
@@ -0,0 +1,86 @@
+"""Utilities for working with lists and sequences."""
+
+def flatten(x):
+    """
+    Returns a single, flat list which contains all elements retrieved
+    from the sequence and all recursively contained sub-sequences
+    (iterables).
+
+    Examples:
+    >>> [1, 2, [3, 4], (5, 6)]
+    [1, 2, [3, 4], (5, 6)]
+
+    From http://kogs-www.informatik.uni-hamburg.de/~meine/python_tricks
+    """
+    result = []
+    for el in x:
+        if hasattr(el, '__iter__') and not isinstance(el, basestring):
+            result.extend(flatten(el))
+        else:
+            result.append(el)
+    return result
+
+def batch_size(items, size):
+    """
+    Retrieves items in batches of the given size.
+
+    >>> l = range(1, 11)
+    >>> batch_size(l, 3)
+    [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10]]
+    >>> batch_size(l, 5)
+    [[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]]
+    """
+    return [items[i:i+size] for i in xrange(0, len(items), size)]
+
+def batches(items, number):
+    """
+    Retrieves items in the given number of batches.
+
+    >>> l = range(1, 11)
+    >>> batches(l, 1)
+    [[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]]
+    >>> batches(l, 2)
+    [[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]]
+    >>> batches(l, 3)
+    [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10]]
+    >>> batches(l, 4)
+    [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10]]
+    >>> batches(l, 5)
+    [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]
+
+    Initial batches will contain as many items as possible in cases where
+    there are not enough items to be distributed evenly.
+
+    >>> batches(l, 6)
+    [[1, 2], [3, 4], [5, 6], [7, 8], [9], [10]]
+    >>> batches(l, 7)
+    [[1, 2], [3, 4], [5, 6], [7], [8], [9], [10]]
+    >>> batches(l, 8)
+    [[1, 2], [3, 4], [5], [6], [7], [8], [9], [10]]
+    >>> batches(l, 9)
+    [[1, 2], [3], [4], [5], [6], [7], [8], [9], [10]]
+    >>> batches(l, 10)
+    [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]]
+
+    If there are more batches than items, empty batches will be appended
+    to the batch list.
+
+    >>> batches(l, 11)
+    [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], []]
+    >>> batches(l, 12)
+    [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [], []]
+    """
+    div, mod= divmod(len(items), number)
+    if div > 1:
+        if mod:
+            div += 1
+        return batch_size(items, div)
+    else:
+        if not div:
+            return [[item] for item in items] + [[]] * (number - mod)
+        elif div == 1 and not mod:
+            return [[item] for item in items]
+        else:
+            # mod now tells you how many lists of 2 you can fit in
+            return ([items[i*2:(i*2)+2] for i in xrange(0, mod)] +
+                    [[item] for item in items[mod*2:]])
-- 
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