This implies the if a is negative, (a%b) should also be negative.
No, python is giving you the Modulus after division (i.e. a "distance" which should be positive). If you interpret it that way everything is fine:
>>> a = -1
>>> b = 3
>>> (a/b)*b
-3
>>> (a%b)
2
>>> (a/b)*b + (a%b)
-1
Perhaps you're thinking of the Remainder?
Edit: it seems there isn't much consensus about what to do when a or b are negative. Wikipedia gives a helpful chart here how different languages choose to implement this: http://en.wikipedia.org/wiki/Modulo_operation
No, python is giving you the Modulus after division (i.e. a "distance" which should be positive). If you interpret it that way everything is fine:
Perhaps you're thinking of the Remainder?Edit: it seems there isn't much consensus about what to do when a or b are negative. Wikipedia gives a helpful chart here how different languages choose to implement this: http://en.wikipedia.org/wiki/Modulo_operation