[Tutor] formatting datetime.timedelta to "HH:MM:SS"

[eryksun]

On Wed, Dec 11, 2013 at 8:37 AM, Mark Lawrence <breamoreboy at yahoo.co.uk> wrote:
>
> print('{}:{}:{}'.format(now.hour, now.minute, now.year))
>
> Sorry I can never remember the formatting types to go between {} so look for
> them around here http://docs.python.org/3/library/string.html#formatstrings

For datetime's date, time, and datetime types, the __format__ method
passes the spec to strftime:

    >>> t = datetime.datetime(2038,1,19,3,14,7)

    >>> '{:%H:%M:%S}'.format(t)
    '03:14:07'

If the format spec is empty, it uses __str__:

    >>> format(t)
    '2038-01-19 03:14:07'

But this is unrelated to timedelta, which lacks a custom __format__.