On Jun 29, 1:37 am, Tom Evans <tevans...@googlemail.com> wrote: > Damn, this was the bit I meant to comment upon - hard and fast rules > are dangerous. Integral types are distinctly different to floating > point types, and you should be aware of which one you are using and > why. You definitely should not be using floats when you require > integral mathematics, or reliable accounting since 1.0 is only an > approximation to 1. > > Cheers > > Tom > > >>> 1.0 * 10000000000000000000000000000 > > 9.9999999999999996e+27
Actually, 1.0 is NOT an approximation to 1. It is precisely 1. All integral values up to 2^53-1 can be represented exactly. So can many rational fractions (roughly, those in which the denominator is a power of two and the numerator and denominator don't differ by a really big ratio). The reason the above example fails isn't the 1.0, it's because the second number (10^28) is bigger than 2^53, so IT can't be represented exactly. -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
