Prototype of datetime.timedelta.__format__() method

timedelta_format.py

import datetime
import re


class timedelta(datetime.timedelta):
    def __format__(value, format_spec):
        if not format_spec:
            return str(value)

        pattern = re.compile(r'%([WdDhHmMsSuUT%])')
        def replace(match):
            specifier = match.group(1)
            return {
                'W': str(value // datetime.timedelta(weeks=1)),
                'd': str(value.days % 7),
                'D': str(value // datetime.timedelta(days=1)),
                'h': str(value.seconds // 3600),
                'H': str(value // datetime.timedelta(hours=1)),
                'm': str((value.seconds % 3600) // 60),
                'M': str(value // datetime.timedelta(minutes=1)),
                's': str(((value.seconds % 3600) % 60)),
                'S': str(value // datetime.timedelta(seconds=1)),
                'u': str(value.microseconds),
                'U': str(value // datetime.timedelta(microseconds=1)),
                'T': str(value.total_seconds()),
                '%': '%',
            }[specifier]
        return pattern.sub(replace, format_spec)


if __name__ == '__main__':
    duration = timedelta(weeks=1, days=2, hours=3, minutes=4, seconds=5, milliseconds=6, microseconds=7)
    print(f'{duration:%W wk %d day %h hr %m min %s s %u µs}')

$ python3 ~/src/timedelta_format.py
1 wk 2 day 3 hr 4 min 5 s 6007 µs