Greg Ewing writes: > [I propose for Py3k that] builtin round() > to return an int, and have something somewhere > else, such as math.fround(), for round-to-float.
+1. The need to convert float to int is pervasive. The need to round (binary) floats to integer (or other decimal) floats is _much_ less common. Furthermore, the need for "round to nearest int" is much more common than the need for "integer floor" (although as pointed out, each could be defined in terms of the other except for certain rules for rounding exact halves). And most telling of all, if I were to stop 10 random programmers on the street, most of them not familiar with Python, and ask them to guess what the function named "round" did, I'm guessing the majority would think of float-to-int. It's a nice feature of Python that "it just works". Marc-Andre Lemburg writes: > You often have a need for controlled rounding when doing > financial calculations or [other reason snipped] Hmm. Not in the banks _I_ have worked at! We *never* use binary floating point for money. The decimal class is fairly useful in that regard. Nick Maclaren write: > Decimal doesn't even help people who care about accuracy. Not true! The float class is incapable of maintaining 700 digits of precision, but Decimal handles it just fine. (Why you would WANT more than around 53 bits of precision is a different question, but Decimal handles it.) > People who care about the accuracy of calculations prefer binary, > as it is a more accurate model. Huh? That doesn't even make sense! A model is not inherently accurate or inaccurate, it is only an accurate or inaccurate representation of some "real" system. Neither binary nor decimal is a better representation of either rational or real numbers, the first candidates for "real" system I thought of. Financial accounting rules tend to be based on paper-and-pencil calculations for which decimal is usually a far better representation. If you had said that binary floats squeeze out more digits of precision per bit of storage than decimal floats, or that binary floats are faster because they are supported by specialized hardware, then I'd go along, but they're not a "better model". -- Michael Chermside _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
