How to convert standard timedelta string to timedelta object

Question

What is the simplest way to convert standard timedelta string to timedelta object?

I have printed several timedelta objects and got these strings:

'1157 days, 9:46:39'
'12:00:01.824952'
'-1 day, 23:59:31.859767'

I know I could write parser myself, but is there any simpler solution?

Answer 1

I cannot find a better way other than writing a parser myself. The code looks bulky but it is essentially parsing string into a dictionary which is useful not only to creating a timedelta object.

import re

def parse(s):
    if 'day' in s:
        m = re.match(r'(?P<days>[-\d]+) day[s]*, (?P<hours>\d+):(?P<minutes>\d+):(?P<seconds>\d[\.\d+]*)', s)
    else:
        m = re.match(r'(?P<hours>\d+):(?P<minutes>\d+):(?P<seconds>\d[\.\d+]*)', s)
    return {key: float(val) for key, val in m.groupdict().iteritems()}

Test:

from datetime import timedelta

s1 = '1157 days, 9:46:39'
s2 = '12:00:01.824952'
s3 = '-1 day, 23:59:31.859767'
t1 = parse(s1)
t2 = parse(s2)
t3 = parse(s3)

timedelta(**t1) # datetime.timedelta(1157, 35199)
timedelta(**t2) # datetime.timedelta(0, 43201, 824952)
timedelta(**t3) # datetime.timedelta(-1, 86371, 859767)

Hope this can suit your purpose.

Answer 2

This is an update of Ray's answer that works for Python 3. It will return an empty string if the regex is fed a bad string for parsing, otherwise a timedelta object is returned.

from datetime import timedelta
import re

def parse_timedelta(stamp):
    if 'day' in stamp:
        m = re.match(r'(?P<d>[-\d]+) day[s]*, (?P<h>\d+):'
                     r'(?P<m>\d+):(?P<s>\d[\.\d+]*)', stamp)
    else:
        m = re.match(r'(?P<h>\d+):(?P<m>\d+):'
                     r'(?P<s>\d[\.\d+]*)', stamp)
    if not m:
        return ''

    time_dict = {key: float(val) for key, val in m.groupdict().items()}
    if 'd' in time_dict:
        return timedelta(days=time_dict['d'], hours=time_dict['h'],
                         minutes=time_dict['m'], seconds=time_dict['s'])
    else:
        return timedelta(hours=time_dict['h'],
                         minutes=time_dict['m'], seconds=time_dict['s'])

Answer 3

If you are using Django, you could do

from django.utils.dateparse import parse_duration
parse_duration('-1 day, 23:59:31.859767')