Ok then, my mistake: I thought 'del' was deleting the object AND releasing the name for later user. Sorry!
This is what I should have tried in the first place: >>> m = [2,3,4] >>> p = ['a','b','c'] >>> l = [m,p] >>> l [[2, 3, 4], ['a', 'b', 'c']] >>> p.append('w') >>> p ['a', 'b', 'c', 'w'] >>> l [[2, 3, 4], ['a', 'b', 'c', 'w']] >>> > > What did you expect for an "updated q" anyway? > I am about to work on a graph where all vertices are objects containing labels (for computing shortest paths for example) and I plan to gradually update my labels (object's member variables). I just wanted to make sure it was possible and what was the appropriate mechanism. Thanks to all of you three for shaking my thoughts. I'll try not to ask so dumb questions again ;o) - Eric -- http://mail.python.org/mailman/listinfo/python-list