datetime.min clear solution for Lightbulb Start Watching by veky - python coding challenges

Enable Javascript in your browser and then refresh this page, for a much enhanced experience.

datetime.min solution in Clear category for Lightbulb Start Watching by veky

import contextlib, datetime

def sum_light(els, start_watching=datetime.datetime.min):
    """How long the light bulb has been turned on."""
    import datetime
    result, it = datetime.timedelta(), iter(els)
    with contextlib.suppress(StopIteration):
        while ...:
            start = max(next(it), start_watching)
            end   = max(next(it), start_watching)
            result += end - start
    return result.total_seconds()

Nov. 14, 2020

Comments:

kdim on Feb. 2, 2021, 6:56 a.m.
An interesting combination, for me as a newbie. Now I will know and use it: <pre class='brush: python'>with contextlib.suppress(StopIteration): while ...: </pre>

veky on Feb. 2, 2021, 6:58 p.m.
`while ...` is just cute. :-) And the contextmanager is there only because of PEP479, which is one of rare intentional design errors in Python. :]

Ken_w on Feb. 3, 2021, 8:18 a.m.
Not quite understand how the iteration is terminated in the code. And I wonder whether `While ...:` is equivalent to `While Ture:`. Would you please explain a bit more?

veky on Feb. 3, 2021, 10:27 a.m.
It is terminated as it is almost always terminated, by raising StopIteration. :-] At least, it should be, in the world without PEP479. Here we need to hide the StopIteration (see the above comment), but still, it stops the loop from executing, since it is managed by the suppress manager. Ture is not equivalent to True (and While is not while:), but ... is. :-D

O'Reilly

0 %

CheckiO ClassRoom Don’t waste any time! Create your first class right now for free and help your students to learn programming more effectively.