First clear solution for Broken Clock by suic - python coding challenges

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First solution in Clear category for Broken Clock by suic

from time import strftime, gmtime


def broken_clock(t0, tb, err):
    conv_dict = {"second": 1, "minute": 60, "hour": 3600,
                 "seconds": 1, "minutes": 60, "hours": 3600}
    nv, nm, _, mv, mm = err.split(" ")
    t0, tb = map(to_seconds, (t0, tb))
    m = int(mv) * conv_dict[mm]
    n = int(nv) * conv_dict[nm]
    tw = t0 + (m / (n + m)) * (tb - t0)
    return strftime("%H:%M:%S", gmtime(tw))


def to_seconds(t):
    return sum([int(v) * (60 ** (2 - int(i)))
                for i, v in enumerate(t.split(":"))])

Nov. 18, 2014

Comments:

spoty on Dec. 13, 2014, 5:53 p.m.
Very nice! Good job.

suic on Dec. 13, 2014, 6:48 p.m.
Thanks

veky on Feb. 22, 2015, 10:04 p.m.
Nice usage of time module. conv_dict could be much less repetitive if you looked up things like this: <pre class='brush: python'>m = int(mv) * conv_dict[mm.rstrip("s")] </pre> (New TransformDict might help you in Py3.5, if it makes it there.;) And of course, that code repeated twice should be factored out as a function, just like to_seconds was. Speaking about to_seconds... why didn't you use time.strptime here? It would be much more symmetric with output. And about that code... first, drop [] inside sum(). You know the story. :-) Second, why int(i)? enumerate gives you ints, of course. And third, using enumerate and then manually fitting the index it gives you, is doing it wrong. Much nicer would be `in enumerate(reversed(t.split(":")))`

suic on Feb. 22, 2015, 10:59 p.m.
Thanks. If I were review this code today, I would write at least three of your suggestions (the first would be: omit the []) :). And of course with strptime (I have no good answer, why I didn't use it that time) and your last tip it would be more elegant.

guido on March 24, 2015, 7:11 p.m.
Cool solution! Very clever use of str.split() and a strict interpretation of the input format description (it never actually says that there's exactly one space between each part of the error argument :-). Agreed with all of veki's comments, but those are really just nit-picks, and the code is just as readable as it stands. (To me, your biggest "blunder" is int(i). :-) I think my own version would have looked totally different -- I see this primarily as a parsing problem, since the formula for computing the correct time once everything is reduced to seconds is trivial. So instead of your ad-hoc parsing approach I probably would have used regular expressions -- this is still pretty ad-hoc but the formats are too simple to bother with a parsing library. My version would definitely be longer than yours, but it would be more easily extensible when the specification is changed. There would be one function to parse the HH:MM:SS input format, a second to parse the error spec (by far the most complicated part of the spec, and the reason I see this as a parsing problem), a third to produce the output string, and perhaps a fourth to compute the correct time given the inputs as seconds -- the latter mostly just to give it a name, which makes it clear to the reader what happens. Oh, and then you need a main function that ties them all together: ``` def brokenclock(t0, tb, err): t0secs = parsetime(t0) tbsecs = parsetime(tb) errsecs, deltasecs = parseerr(err) twsecs = adjustclock(t0secs, tbsecs, errsecs, deltasecs) return formattime(twsecs) ``` (I'm not too happy with those variable names, but I don't like changing the type of a variable and then assigning it back to the same variable, as you do for t0 and tb.) I guess from this you can conclude that I spend more time in a professional software development shop than in programming contests. And you would be right. :-) Keep coding, be happy!

texom512 on Aug. 13, 2015, 3:06 p.m.
It's difficult to memorize or understand the meaning of tb, nv, nm, mv, mm, m, n and tw. It's nonsense! And you can do str.split() rather str.split(' ').

suic on Aug. 13, 2015, 7:33 p.m.
I'm wondering how other people can understand it, if it's nonsense.

texom512 on Aug. 14, 2015, 8:51 a.m.
Can you explain the meaning of the names of variables?

suic on Aug. 14, 2015, 9:22 a.m.
Hi, first of all if something does not make sense for you it does not mean that it is nonsense. <hr /> Ad variables: I used the example from the description: <blockquote> "+(-)N <a href="s">second, minute, hour</a> at M <a href="s">second, minute, hour</a>" </blockquote> which is the reason for `n` and `m`. The second letter is: `v` as value and `m` as measurement (unit and `u` would be better). <hr /> <ol> <li>The goal of this mission is not to reconstruct the story from the code, so I suppose, that people have read the description, before they read my solution.</li> <li>"Clear" is a disputable concept especially here. For example: If I had given some long names to those variables (or write some comments) in a language you don't speak, it wouldn't have helped you anyway. (E. g. comment in French for someone who doesn't speak French means hardly anything.)</li> <li>Code != Novel. One can use math style variables if its appropriate.</li> <li>"Clear" != everyone can understand it.</li> </ol>

suic on Aug. 14, 2015, 1:26 p.m.
I've noticed, that you've liked my explanation... Does it still have a value of 3 thumb-downs?

texom512 on Aug. 14, 2015, 1:33 p.m.
OK only -1, because the names of variables are half the clarity of code.

Master of the Time Stone

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