On May 29, 7:27 pm, Ahmed Abdulshafy <abdulsh...@gmail.com> wrote: > On Tuesday, May 28, 2013 3:48:17 PM UTC+2, Steven D'Aprano wrote: > > On Mon, 27 May 2013 13:11:28 -0700, Ahmed Abdulshafy wrote: > > > > That may be true for integers, but for floats, testing for equality is > > > > not always precise > > > Incorrect. Testing for equality is always precise, and exact. The problem > > > is not the *equality test*, but that you don't always have the number > > > that you think you have. The problem lies elsewhere, not equality! > > > Steven > > Well, this is taken from my python shell> > > >>> 0.33455857352426283 == 0.33455857352426282 > > True > > Anyway, man, those were not my words anyway, most programming books I've read > state so. Here's an excerpt from the Python book, I'm currently reading> > > ">>> 0.0, 5.4, -2.5, 8.9e-4 > (0.0, 5.4000000000000004, -2.5, 0.00088999999999999995) > > The inexactness is not a problem specific to Python—all programming languages > have this problem with floating-point numbers."
0.0 == 0.0 implies 5.4 == 5.4 is not a true statement is what (I think) Steven is saying. 0 (or if you prefer 0.0) is special and is treated specially. Naturally if you reach (nearabout) 0.0 by some numerical process thats another matter... -- http://mail.python.org/mailman/listinfo/python-list
