On Jul 13, 8:36 pm, Chris Angelico <ros...@gmail.com> wrote: > On Sat, Jul 14, 2012 at 1:04 AM, Steven D'Aprano > > <steve+comp.lang.pyt...@pearwood.info> wrote: > > Actually, no. Is True less than False, or is it greater? In boolean > > algebra, the question has no answer. It is only an implementation detail > > of Python that chooses False < True. > > Maybe in boolean algebra, but in code, it's handy to have sortable > bools. In SQL, for instance, I can use a boolean in an ORDER BY, > perhaps followed by another criterion, and it's effectively sorting by > "1 if some_boolean else 0" or in C notation "some_boolean ? 0 : 1" > > ChrisA
Actually a boolean algebra is a lattice with some additional properties A lattice is a poset (partially ordered set) with suprema and infimas And so there is one natural order relation on any boolean algebra which may be defined as a ≤ b iff a ⋀ b = a tl;dr version: In a boolean algebra, False is bottom and True is top -- http://mail.python.org/mailman/listinfo/python-list
