Mark Dickinson wrote: > On Feb 14, 11:09 pm, John Nagle <[EMAIL PROTECTED]> wrote: >> You also need to think about how conditionals interact with >> quiet NANs. Properly, comparisons like ">" have three possibilities: > > True. There was a recent change to Decimal to make comparisons (other > than !=, ==) with NaNs do the "right thing": that is, raise a Python > exception, unless the Invalid flag is not trapped, in which case they > return False (and also raise the Invalid flag). I imagine something > similar would make sense for floats. > >> True, False, and "raise". Many implementations don't do that well, >> which means that you lose trichotomy. "==" has issues; properly, >> "+INF" is not equal to itself. > > I don't understand: why would +INF not be equal to itself? Having > INF == INF be True seems like something that makes sense both > mathematically and computationally. > [...]
There are an uncountable number of infinities, all different. regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
