create iter_helpers since pairwise now used multiple times

diff --git a/iter_helpers.py b/iter_helpers.py
new file mode 100644 (file)
index 0000000..a5aaab3
--- /dev/null
+++ b/iter_helpers.py
@@ -0,0 +1,15 @@
+""" Helper functions with iterators -- functional program is great!
+
+Currently, recipes from python itertools docu (:py:mod:`itertools`) that have
+been deemed useful
+
+.. codeauthor:: Christian Herdtweck, christian.herdtweck@intra2net.com
+"""
+
+from itertools import *
+
+def pairwise(iterable):
+    """ s -> (s0,s1), (s1,s2), (s2, s3), ...  """
+    a, b = tee(iterable)
+    next(b, None)
+    return zip(a, b)