Newbie help looping/reducing code

[Cameron Laird]

In article <7x1wkl8xb7.fsf at ruckus.brouhaha.com>,
Paul Rubin  <http://phr.cx@NOSPAM.invalid> wrote:
>Lance Hoffmeyer <lance at augustmail.com> writes:
>> def even_odd_round(num):
>> 	if(round(num,2) + .5 == int(round(num,2)) + 1):
>> 		if num > .5:
>> 		     if(int(num) % 2):
>> 		     	num = round(num,2) + .1 #an odd number
>> 		     else:
>> 		     	num = round(num,2) - .1 #an even number
>> 		else:
>> 		   num = 1
>> 	rounded_num = int(round(num,0))
>> 	return rounded_num
>
>I would also rewrite this function.  It's quite hard to figure out
>what it's intended to do.  At minimum it should be carefully
			.
			.
			.
>def even_odd_round(num):
>   assert num >= 0
>
>   # separate the number's integer and fractional parts
>   intpart, fracpart = int(num), num % 1.0
>
>   # decide what to do based on the fractional part
>   if fracpart < 0.495:
>      return intpart                    # round downward
>   elif fracpart > 0.505 or intpart==0:
>      return intpart+1                  # round upward
>   else:
>      return intpart + intpart % 2      # round to even


I have even less idea than Paul what the true intent of even_odd_round()
is.  I offer, though, the general observation that it's VERY often possible
to do what people want in this sort of regard with a simple use of
formatting--something like

    "%.3f" % num

If one comes from C or Java, it can be hard to appreciate immediately how
useful this is.  It's also likely to be more robust than anything naively
written "by hand".