On Tue, 19 Sep 2017 01:56:29 +0000, Stefan Ram wrote: > Steve D'Aprano <steve+pyt...@pearwood.info> writes:
>>It is true that binary floats have some unexpected properties. They >>aren't the real numbers that we learn in maths. But most people who >>have been to school have years of experience with calculators training >>them to expect computer calculations are sometimes "off". They do a >>sum and get 2.999999999 instead of 3, or perhaps 3.000000001, and >>that's just the way calculators work. > It is possible that many calculators use base 10 and therefore such > surprises might be less common than in the world of programming > languages. How relevant is the "people use calculators to do arithmetic" argument today? Okay, so I'm old and cynical, but I know [young] people who don't (can't?) calculate a gratuity without an app or a web page. FWIW, I would prefer that 1/10 be a rational because rationals are exact when the operands are. Rounding could easily fall under "In the face of ambiguity, refuse to guess." Yes, every once in a while, I get a result with lots of digits, but that's usually while I'm developing an algorithm, and then I can decide whether or not and when to coerce the result to floating point. Dan -- https://mail.python.org/mailman/listinfo/python-list
