On Tue, May 29, 2018 at 7:07 PM, Ruifeng Guo <ruifeng....@synopsys.com> wrote: > Hello, > We encountered a bug in Python recently, we checked the behavior for Python > version 2.7.12, and 3.1.1, both version show the same behavior. Please see > below the unexpected behavior in "red text". > > Thanks, > Ruifeng Guo > > From: Brian Archer > Sent: Tuesday, May 29, 2018 5:57 PM > To: Ruifeng Guo <rf...@synopsys.com> > Subject: Python Bug > > Python 3.1.1 (r311:74480, Nov 20 2012, 09:11:57) > [GCC 4.2.2] on linux2 > Type "help", "copyright", "credits" or "license" for more information. >>>> a=1017.0 >>>> print(int(a)) > 1017 >>>> b=1000*1.017 >>>> print(b) > 1017.0 >>>> int(b) > 1016 >>>> c=1017.0 >>>> int(c) > 1017
Try this, and you'll see what the problem is: >>> repr(b) '1016.9999999999999' The value of b is not really 1017, but fractionally less as a result of floating point rounding error, because 1.017 cannot be exactly represented as a float. In Python 3.2, the str() of the float type was changed to match the repr(), so that when you use print() as above you will also get this result: >>> print(b) 1016.9999999999999 By the way, Python 3.1.1 is really old (six years!). I recommend upgrading if possible. -- https://mail.python.org/mailman/listinfo/python-list
