John Salerno <[EMAIL PROTECTED]> writes: > Can someone explain to me why the expression 5 / -2 evaluates to -3, > especially considering that -2 * -3 evaluates to 6? > > I'm sure it has something to do with the negative number and the > current way that the / operator is implemented, but why doesn't it > evaluate to -2 instead?
Well, -2 * -2 is 4, which is not especially better than 6. The reason for choosing -3 instead of -2 is so that if b is positive, then a%b is non-negative even if a is negative. That is, the motivating case is (-5 % 2) which is done the same way as (5 % -2). You want (b*(a/b) + a%b)==a at all times. If (-5 / 2) = -3, then you need (-5 % 2) = -1. But if (-5 / 2) = -2, then (-5 % 2) = +1. Since a%b is positive, you can use it as a list index, etc. -- http://mail.python.org/mailman/listinfo/python-list
