On 2012-02-22, Alec Taylor <alec.tayl...@gmail.com> wrote: > Simple mathematical problem, + and - only: > >>>> 1800.00-1041.00-555.74+530.74-794.95 > -60.950000000000045 > > That's wrong.
Oh good. We haven't have this thread for several days. > Proof > http://www.wolframalpha.com/input/?i=1800.00-1041.00-555.74%2B530.74-794.95 > -60.95 aka (-(1219/20)) > > Is there a reason Python math is only approximated? http://docs.python.org/tutorial/floatingpoint.html Python uses binary floating point with a fixed size (64 bit IEEE-754 on all the platforms I've ever run across). Floating point numbers are only approximations of real numbers. For every floating point number there is a corresponding real number, but 0% of real numbers can be represented exactly by floating point numbers. > - Or is this a bug? No, it's how floating point works. If you want something else, then perhaps you should use rationals or decimals: http://docs.python.org/library/fractions.html http://docs.python.org/library/decimal.html -- Grant Edwards grant.b.edwards Yow! What I want to find at out is -- do parrots know gmail.com much about Astro-Turf? -- http://mail.python.org/mailman/listinfo/python-list