[Python-Dev] Rational approximation methods (original) (raw)

Mark Dickinson dickinsm at gmail.com
Sun Jan 20 02:22:40 CET 2008

On Jan 19, 2008 3:06 PM, Jeffrey Yasskin <jyasskin at gmail.com> wrote:

In the Rational class that I've recently checked into Python 2.6 (http://bugs.python.org/issue1682), it might be nice to provide a method that, given a particular rational number, returns a nearby number that's nicer in some way. I know of two reasonable behaviors [...] What does the list think?

I'm having trouble imagining a real use case for either of these methods. When I'm using Rational, it's almost certainly because I want exact arithmetic; if I'm getting results with huge denominators and numerators then either that's what I really want, or I probably shouldn't have been using Rational in the first place...

The only semi-use case I see is providing some way for users to turn the float 1.1 into the rational 11/10, instead of Rational(2476979795053773L,2251799813685248L).

So I'd say leave both these methods out for now---it would be easy enough to add them later if it turns out there's a real need.

Just my 200/391 UK pennies :)

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