Tim Peters <t...@python.org> added the comment:
"Multiple roundings" in the float code is a red herring - that's just implementation details trying to cheaply get the same effect as computing with infinite precision. Here with actual unbounded precision: >>> from fractions import Fraction >>> y = Fraction(0.4) >>> y Fraction(3602879701896397, 9007199254740992) >>> q = 4 / y >>> q Fraction(36028797018963968, 3602879701896397) >>> int(q) 9 >>> 4 - 9 * y Fraction(3602879701896395, 9007199254740992) >>> float(_) 0.3999999999999998 >>> So exactly the same results as divmod(4, 0.4) returned. The underlying problem here is that the infinitely precise result of 4.0 / 0.4 is NOT an integer, in turn stemming from that the float 0.4 is not four tenths. So I recommend to close this as not-a-bug, but I'm not doing that now because I want clarification on what the OP meant by saying the results differ between Pythons 2 and 3. I see no differences here between Pythons 2.7.11 and 3.7.2 on 64-bit Windows (not in 4.0 vs 0.4, or in any of the other cases the OP mentioned). ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue36028> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
