[issue10346] strange arithmetic behaviour
New submission from Alexey Radkov alexey.rad...@gmail.com: The following excerpt will show the issue: $ python Python 2.7 (r27:82500, Sep 16 2010, 18:02:00) [GCC 4.5.1 20100907 (Red Hat 4.5.1-3)] on linux2 Type help, copyright, credits or license for more information. 8 * 4 / ( 2 - 7 ) * 6 / 3 -14 Why it is evaluated to -14 ?? In floating point arithmetic it should be -12.8, in integer arithmetic i believe it should be -12 (at least bc and a small dedicated C program evaluate it to -12). Perhaps i do not understand some specific python arithmetic priority or associativity rules, anyway i cannot find a specific combinations of them to yield -14 in this expression. -- components: None messages: 120665 nosy: alexey.radkov priority: normal severity: normal status: open title: strange arithmetic behaviour type: behavior versions: Python 2.7 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10346 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10346] strange arithmetic behaviour
Mark Dickinson dicki...@gmail.com added the comment: It's not a bug: you're seeing Python's rules for integer division, which do indeed differ from those of (some) other languages when either the divisor or the dividend is negative. For integers x and y, in Python 2.x, x / y gives the floor of the exact quotient. -32 / 5 -7 32 / -5 -7 In Python 3.x, the '/' operator does 'true division', giving you (a floating-point approximation to) the true result: -32 / 5 -6.4 32 / -5 -6.4 You can also get this behaviour in Python 2.x if you start your script with 'from __future__ import division'. See the documentation at: http://docs.python.org/reference/expressions.html#binary-arithmetic-operations for more. -- nosy: +mark.dickinson resolution: - invalid status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10346 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
