On Sep 26, 2012, at 7:07 PM, Steven D'Aprano <steve@pearwood.info> wrote:
Pretty much *everything* about binary floats is surprising to people who expect decimal semantics. Unless we're going to make Decimal the default floating point type, and shift binary floats to a module, I don't see any way around that, and a particularly don't see any reason to single round() out as more confusing than any of the other float gotchas.
Speaking from my experience on the tutor@ and python-list@python.org mailing lists, I believe that problems with round are vanishingly rare, probably an order of magnitude fewer than "why doesn't Python add my two floats correctly?" type questions.
My experience teaching and consulting is matches your experience on tutor. I agree with your suggestion to leave round() untouched. Raymond