Martin v. Löwis added the comment: Am 12.11.12 14:53, schrieb Tom Pohl: > What do I expect from FD (x//y): > 1. Perform a division (I don't care about the details here). > 2. Return an integer value q (even if it's stored in a float). > 3. The absolute difference between the mathematical division q'=x/y and the > returned result q is less than 1, since it's just a floor operation, right? > > 1//0.1 = 9.0 violates my personal last expectation and I guess I'm not the > only one.
However, it matches *precisely* your description of what you expect: 1. 1 divided-by 0.1 gives 9.99999999999999944488848768742176060306327615036178207623262235371852234374499248... Please understand that the correct result of 1 divided-by 0.1 is *not* 10, because 0.1 is *not* 1/10. 2. returned is then the integer 9 3. the difference is .99999999999999944488848768742176060306327615036178207623262235371852234374499248... which is indeed smaller than 1. P.S. In case you want to get a more exact result of 1 divided-by 0.1, get the digits from int(1/fractions.Fraction(0.1)*10**180) ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue16460> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
