On Thu, Feb 23, 2012 at 1:19 PM, Buck Golemon <b...@yelp.com> wrote: > I feel like the design of sum() is inconsistent with other language > features of python. Often python doesn't require a specific type, only > that the type implement certain methods. > > Given a class that implements __add__ why should sum() not be able to > operate on that class?
The time machine strikes again! sum() already can. You just need to specify an appropriate initial value (the empty list in this example) for the accumulator : Python 2.7.1 (r271:86832, Jul 31 2011, 19:30:53) [GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> sum([[1,2],[3,4]], []) [1, 2, 3, 4] Cheers, Chris -- http://rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
