On 10 February 2012 06:21, Ian Kelly <ian.g.ke...@gmail.com> wrote: >>>>> (3219 + 99) // 100 * 100 >> 3300 >>>>> (3289 + 99) // 100 * 100 >> 3300 >>>>> (328678 + 99) // 100 * 100 >> 328700 >>>>> (328 + 99) // 100 * 100 >> 400 >> >> Those are all rounded up to the nearest 100 correctly. > > One thing to be aware of though is that while the "round down" formula > works interchangeably for ints and floats, the "round up" formula does > not. > >>>> (3300.5 + 99) // 100 * 100 > 3300.0 >
I'm surprised I haven't seen: >>> 212 - (212 % -100) 300 Here's a function that: * rounds up and down * works for both integers and floats * is only two operations (as opposed to 3 in the solutions given above) >>> def round(n, k): ... return n - n%k ... >>> # Round down with a positive k: ... round(167, 100) 100 >>> round(-233, 100 ... ) -300 >>> # Round up with a negative k: ... round(167, -100) 200 >>> round(-233, -100) -200 >>> # Edge cases ... round(500, -100) 500 >>> round(500, 100) 500 >>> # Floats ... round(100.5, -100) 200.0 >>> round(199.5, 100) 100.0 -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
