On 09/06/2012 08:01 PM, jimbo1qaz wrote: > Is it faster to use bitshifts or floor division? Yes, and yes. Without doing any measurement, I'd expect that in CPython, it makes negligible performance difference for ordinary ints (under 2**31, more or less). Ordinary ints can be done with single instructions, and any such instruction would be a tiny fraction of the opcode overhead.
One place were there might be a difference would be for longs. The implementation of those would have to be a loop, and eventually one might be faster than the other. At that point, maybe you'd want to measure. > And which is better, & or %? > All divisors and mods are power of 2, so are binary operations faster? And > are they considered bad style? The better way is not the faster one, but rather is the one that more clearly expresses the original problem. If the problem is a modulo one, use % (or frequently divmod). If the problem is a bit shift/masking one, then use such operators. BTW, '/' on integers is redefined for Python 3.x to give float results, and not to truncate. -- DaveA -- http://mail.python.org/mailman/listinfo/python-list
