Short-circuit Logic

[rusi]

On May 29, 7:27 pm, Ahmed Abdulshafy <abdulsh... at 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...