Python 2 - How would you round up/down to the nearest 6 minutes?

Question

There are numerous examples of people rounding to the nearest ten minutes but I can't figure out the logic behind rounding to the nearest six. I thought it would be a matter of switching a few numbers around but I can't get it to work.

The code I'm working with is located at my Github. The block I've got that isn't even close to working (won't give any output) is:

def companyTimer():
    if minutes % 6 > .5:
        companyMinutes = minutes + 1
    elif minutes % 6 < 5:
        companyMinutes = minutes - 1
    else:
        companyMinutes = minutes
    print companyMinutes

Looking at it now, I see that my logic is incorrect - even if it were working, the add and subtract 1 minute portion of the code doesn't make sense.

Anyway, I have no idea how to remedy this - could someone point me in the right direction, please?

PS - this is something I'm making for personal use at work.. not asking for help with my job but this will help me keep track of my hours at work. Don't want there to be any issues with that.

Thanks!

Answer 1

Here's a general function to round to nearest x:

def round_to_nearest(num, base):
    n = num + (base//2)
    return n - (n % base)

[round_to_nearest(i, 6) for i in range(20)]
# [0, 0, 0, 6, 6, 6, 6, 6, 6, 12, 12, 12, 12, 12, 12, 18, 18, 18, 18, 18]

Explanation:

• n % base is the remainder left over when dividing n by base. Also known as the modulo operator.
• Simply subtracting num%6 from num would give you 0 for 0-5, 6 for 6-11, and so on.
• Since we want to "round" instead of "floor", we can bias this result by adding half of the base (base//2) beforehand.

Answer 2

If you want to round to the nearest 7 minutes (e.g. round7(3.6) => 7, round7(17.4) => 14), you can make use of Python's built in round function like so:

def round7(value):
    return round(value / 7.0) * 7.0

>>> round7(17.4999)
14.0
>>> round7(17.5001)
21.0

or, a more general function:

def round_to_nearest(increment, value):
    return round(value / float(increment)) * increment

>>> round_to_nearest(7, 17.4999)
14.0
>>> round_to_nearest(6, 21.0001)
24.0