Python Help

Ok /prog/, so I've been awfully busy learning python lately and I was wondering if you could help me.I've been working on my side project lately and I came across this interesting little math problem and was hoping that some skilled /prog/grammers could help me out with an elegant solution.

People can rate cheeseburgers on my website with a star rating of 0-5 stars in whole stars. Five would be mighty tasty and zero would be disgusting. I want to show the average of everyone’s ratings of a single cheeseburger to the closest half star. I have already calculated the average rating as a float (star_sum) and the total number of people that rated the particular cheeseburger (num_raters). The result would then be stored as a float in a variable named “stars.”

here is my python code:

# round to one decimal place and
# separate into whole and fractional parts
parts = str(round(star_sum/num_raters, 1)).split('.')
whole = int(parts[0])
frac = int(parts[1])
if frac < 3:
___frac = 0
elif frac > 7:
___frac = 0
___whole += 1
else:
___frac = 5
# recombine for a star rating rounded to the half
stars = float(str(whole)+’.'+str(frac))

Does anybody have a better solution for me?

I’ve updated my solution to:

stars = round(star_sum*2/num_raters)/2

I knew there was a way to do this mathematically, I just couldn’t remember how. I suppose the same trick would work for rounding to thirds, fourths, etc. Thanks so much to r, Christopher Finke, and Bob for the better approach.

lol