timedelta_parser.py

import re
from datetime import timedelta

def parseTimeDelta(s):
    """Create timedelta object representing time delta
       expressed in a string.
    """
    if s is None:
        return None
    d = re.match(
            r'((?P<days>\d+)\s*(days|day|d)\s*,?)?\s*((?P<hours>\d+)\s*:\s*'
            r'(?P<minutes>\d+)\s*:\s*(?P<seconds>\d+))?\s*',
            str(s)).groupdict(0)
    return timedelta(**dict(( (key, int(value))
                              for key, value in d.items() )))

def formatTimeDelta(z, defaultValue='', formatSecs=True):
	if not z:
		return defaultValue
		
	min, sec = divmod(z.seconds, 60) 
	hrs, min = divmod(min, 60) 
	if z.days == 0:
		days = ''
	elif z.days == 1:
		days = '1 day, '
	else:
		days = '%d days, ' % z.days
	if formatSecs:
		return days + '%02d:%02d:%02d' % (hrs, min, sec)
	else:
		return days + '%02d:%02d' % (hrs, min)

if __name__ == '__main__':
	from datetime import datetime
	times = ['1d, 5:4:3',
		'64 days , 18:4:53',
		'7d',
		'14 days',
		'14:45:54',
		'1233:45:54',
		'543245:4:6',
		'1d',
	]
	now = datetime.now()
	for time in times:
		td = parseTimeDelta(time)
		td2 = parseTimeDelta(str(td))
		print td==td2
		print td
		print td2		
		print '%s + %s = %s' % (now, td, now + td)
		print '%s - %s = %s' % (now, td, now - td)
		print formatTimeDelta(td)
		print