On 2015-07-03 00:52, Steven D'Aprano wrote: > x = 1 - 1/2**53 > assert x == 0.9999999999999999 > for i in range(1, 1000000): > if int(i*x) == i: > print(i); break
tkc@debian:~$ python Python 2.7.9 (default, Mar 1 2015, 12:57:24) [GCC 4.9.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> x = 1 - 1/2**53 >>> assert x == 0.9999999999999999 Traceback (most recent call last): File "<stdin>", line 1, in <module> AssertionError >>> for i in range(1, 1000000): ... if int(i*x) == i: ... print(i); break ... 1 >>> x 1 >>> ^D tkc@debian:~$ python3 Python 3.4.2 (default, Oct 8 2014, 10:45:20) [GCC 4.9.1] on linux Type "help", "copyright", "credits" or "license" for more information. >>> x = 1 - 1/2**53 >>> assert x == 0.9999999999999999 >>> for i in range(1, 1000000): ... if int(i*x) == i: ... print(i); break ... >>> ^D tkc@debian:~$ uname -a Linux bigbox 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt9-3~deb8u1 (2015-04-24) x86_64 GNU/Linux Weird that on 2.7, the assert fails. -tkc -- https://mail.python.org/mailman/listinfo/python-list
