Actually, this would be <dtml-in "_.filter(lambda x: x > 12, objectValues(['MyClass']))">. Sadly, DTML does not expose 'filter'. You can change that. The list of functions DTML exposes is in lib/python/DocumentTemplate/DT_Util.py, starting at line 214 and continuing until 310. You could easily add all of the functional programming constructs (map, apply, filter) if needed. The beauty of Open Source!
A problem for more even slightly more complicated expressions, although not this one, is that DTML's security features rely on magic variables which aren't accessible to lambda's expression. For example, <dtml-var expr="(lambda x: x.id())(this())"> fails; you have to write <dtml-var expr="(lambda x, _vars=_vars: x.id())(this())">.
Yeah, my DTML is getting pretty ugly. Another option is to use a Python Method to run filter on the list with lamba functions. -- Stephen Pitts smpitts@midsouth.rr.com webmaster - http://www.mschess.org