catacomb/__init__.py: Support `len' on `_groupmap' objects.

diff --git a/catacomb/__init__.py b/catacomb/__init__.py
index 43d74d9a7bd7612d0ef1028a38b61b19d6e966ac..022c5f97119fc6e88b73a834e529a5d3dab5a14b 100644 (file)
--- a/catacomb/__init__.py
+++ b/catacomb/__init__.py
@@ -531,9 +531,12 @@ class _groupmap (object):
   def __init__(me, map, nth):
     me.map = map
     me.nth = nth
-    me.i = [None] * (max(map.values()) + 1)
+    me._n = max(map.values()) + 1
+    me.i = me._n*[None]
   def __repr__(me):
     return '{%s}' % ', '.join(['%r: %r' % (k, me[k]) for k in me])
+  def __len__(me):
+    return me._n
   def __contains__(me, k):
     return k in me.map
   def __getitem__(me, k):