Race Average

gistfile1.py

import datetime
import time
import re

def stringToTimedelta(string):
    try:
        timestring, daystring = string.lower().split(',')

        day = int(re.search(r'day (\d+)', daystring).group(1))
        t = time.strptime(timestring, '%I:%M %p')
    except (AttributeError, ValueError):
        raise ValueError('Invalid time format')
    else:
        return datetime.timedelta(days=day,
                                  hours=t.tm_hour,
                                  minutes=t.tm_min)

class RaceAverage(object):
    def __init__(self, finishes, start='8:00 AM, DAY 1'):
        self.finishTimeStrings = finishes
        self.startTimeString = start

    def _timesAsDeltas(self):
        startDelta = stringToTimedelta(self.startTimeString)
        finishDeltas = [stringToTimedelta(t)
                        for t in self.finishTimeStrings]

        return (startDelta, finishDeltas)

    # camelCase is ugly in Python
    def avgMinutes(self):
        start, deltas = self._timesAsDeltas()

        diffs = [(delta - start).total_seconds() / 60
                 for delta in deltas]

        try:
            avg = int(round(sum(diffs) / float(len(diffs))))
        except ZeroDivisionError:
            raise ValueError('There must be at least one finish time in order to get an average.')
        else:
            assert avg >= 0
            return avg

if __name__ == '__main__':
    assert stringToTimedelta('8:00 AM, DAY 1') == datetime.timedelta(days=1, hours=8, minutes=0)
    assert stringToTimedelta('2:12 PM, DAY 3') == datetime.timedelta(days=3, hours=14, minutes=12)

    assert RaceAverage(['12:00 PM, DAY 1', '12:01 PM, DAY 1']).avgMinutes() == 241
    assert RaceAverage(['12:00 AM, DAY 2']).avgMinutes() == 960
    assert RaceAverage(['02:00 PM, DAY 19', '02:00 PM, DAY 20', '01:58 PM, DAY 20']).avgMinutes() == 27239