--- a/python/tests/utils.txt	Tue Aug 11 11:49:01 2015 -0400
+++ b/python/tests/utils.txt	Tue Aug 11 12:06:10 2015 -0400
@@ -50,6 +50,13 @@
 >>> mostCommon([range(2), range(4), range(2)])
 [0, 1]
 
+>>> res = sortByLength([range(3), range(4), range(1)])
+>>> [len(r) for r in res]
+[1, 3, 4]
+>>> res = sortByLength([range(3), range(4), range(1), range(5)], reverse = True)
+>>> [len(r) for r in res]
+[5, 4, 3, 1]
+
 >>> lcss = LCSS(similarityFunc = lambda x,y: abs(x-y) <= 0.1)
 >>> lcss.compute(range(5), range(5))
 5

--- a/python/utils.py	Tue Aug 11 11:49:01 2015 -0400
+++ b/python/utils.py	Tue Aug 11 12:06:10 2015 -0400
@@ -233,6 +233,19 @@
     xsorted = sorted(D.keys())
     return xsorted, [D[x] for x in xsorted]
 
+def compareLengthForSort(i, j):
+    if len(i) < len(j):
+        return -1
+    elif len(i) == len(j):
+        return 0
+    else:
+        return 1
+
+def sortByLength(instances, reverse = False):
+    '''Returns a new list with the instances sorted by length (method __len__)
+    reverse is passed to sorted'''
+    return sorted(instances, cmp = compareLengthForSort, reverse = reverse)
+
 def ceilDecimals(v, nDecimals):
     '''Rounds the number at the nth decimal
     eg 1.23 at 0 decimal is 2, at 1 decimal is 1.3'''