Figure it out yourself. clear solution for Sun Angle by veky - python coding challenges

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

Figure it out yourself. solution in Clear category for Sun Angle by veky

from datetime import datetime
from scipy.interpolate import interp1d

solutions = {'06:00': 0, '12:00': 90, '18:00': 180}
stamp = lambda time: datetime.strptime(time, '%H:%M').timestamp()
line = interp1d([*map(stamp, solutions)], [*solutions.values()])

def sun_angle(time):
    try: return line(stamp(time))[()]
    except ValueError: return "I don't see the sun!"

April 21, 2018

Comments:

s_m on May 28, 2018, 7:29 a.m.
Hi! Would you be so kind to explain what means '*' in expression <pre class='brush: python'>interp1d([*map(stamp, solutions)], [*solutions.values()]) </pre> Regards, s_m.

veky on May 28, 2018, 11:32 a.m.
The same as what it means elsewhere. `f((1,2,3))` means `f(1,2,3)` (put all elements of `(1,2,3)` as arguments of `f`), right? So `[(1,2,3)]` means `[1,2,3]` (put all elements of `(1,2,3)` into a list). It is a more intuitive spelling of `list((1,2,3))`, same as long time ago the above was a more intuitive spelling of `apply(f, (1,2,3))`. :-)

s_m on May 28, 2018, 1:01 p.m.
Thank you so much! I didn't know about it.

vlad.bezden on Sept. 26, 2018, 9:54 p.m.
Great solution!

veky on Sept. 27, 2018, 9:30 a.m.
I just encouraged Python to solve it on their own. :-)

ljwoodward on Oct. 17, 2018, 10:16 a.m.
I'm not sure in what universe this is 'clear', (this is in a section for beginners) but it certainly appears to be very clever.

veky on Oct. 17, 2018, 12:38 p.m.
And what, beginners aren't supposed to know numpy? Why exactly? :-) And more importantly, why is it allowed here?

skytomba on Dec. 28, 2018, 3:44 p.m.
I believe this will be funniest solution :)

veky on Dec. 28, 2018, 3:51 p.m.
You ain't seen nothing yet. :-]

lucas234 on March 21, 2019, 9:46 a.m.
Interesting, but I didn`t know about it clearly

petergswhite on March 21, 2019, 3:38 p.m.
It's essentially creating a straight line graph of timestamp against angle, using the 3 supplied values (6am, noon, and 6pm). Then it tries to find the y value (angle) for the supplied x value (arbitrary time). If it fails, it means that the value was outside of the bounds of the line, therefore it's a time between 6pm and 6am (can't see the sun)

Bettergears on June 12, 2019, 2:01 p.m.
This is a fantastic answer. It sets up a framework to have Python do what we are asked to do and it's fun to look at. Do I know what it means, function by function? No, but I am sure going to look it up to find out. I can intuit it sets up a range of key:value pairs and and maps an answer to the input given. And all without the messy arithmetic and flow control setup. If out of range, error control picks up the 'else'. Even better is it's potentially dynamic. If we bring in the sunset/sunrise values daily this can provide an accurate answer anytime. Nice! This is the kind of solution that, to me, defines the ideal use of computers, and less importantly what's so special about Python. This is why I want to learn to code. I want computers to do the computing, not me. It's on me to learn and search for the tools to create this kind of system, and it's on the computer do all the tedium to get an answer. That feels like the best distribution of labor: each of us doing what we're best at. Thanks for sharing this answer. I've read enough of your posts to see people throwing shade for not being a beginner answer. To be fair it is anything but. However it is valid, and there is a lot to learn by dissecting it vs. dissecting code of other beginners. It might rub some people the wrong way but I'm happy to see it.

SkyJourney on June 17, 2019, 12:52 a.m.
Looks complicated

veky on June 17, 2019, 6:21 a.m.
I hope you've read other comments. If there's anything specific you'd like to know, just ask.

JingMeng on June 21, 2019, 5:06 a.m.
I suggest this solution would serve better if the story itself gets extended/generalized/complicated (either as another story/problem, or described/defined in comment/doc string) such that modeling the problem as a interpolation process would become natural, in which case those who are not familiar with python/scipy/interpolation can learn more from that.

veky on June 21, 2019, 11 a.m.
I'm not quite sure I get you... you suggest that I change the task, so my solution becomes more natural? Well, people already tell me I have unconventional methods of solving, imagine what would happen if I did that too. :-D Besides, judging from the comments, it seems people have no problem understanding how my solution works, at least on the meta-level (it tells Python to reconstruct the solution by interpolating three given solutions). I'm not sure what would be the gain if the mission was more complicated.

bsquare on Sept. 13, 2019, 6:45 a.m.
Haha, great solutions;)

mvsrsaipavan on Nov. 28, 2019, 6:09 p.m.
man you always bring new stuff

mvsrsaipavan on Nov. 28, 2019, 6:18 p.m.
You could have explained it clearly in comments and in between u r awesome.

veky on Nov. 28, 2019, 6:59 p.m.
It's always weird when people assume their lack of understanding is universal. There is no "it". :-P But if you say what exactly you have problem with, I'll be happy to explain.

maxnrg on Dec. 10, 2019, 7:42 p.m.
overhead :)

veky on Dec. 10, 2019, 7:44 p.m.
The Sun or scipy? (+_+)

teebu on Jan. 29, 2020, 12:29 a.m.
I gotta look into scipy.

veky on Jan. 29, 2020, 4:39 a.m.
probably. But this is just an ordinary linear interpolation. 🎶

teebu on Jan. 31, 2020, 3:14 a.m.
Your timestamp was giving me problems. It created a time of year 1900, and was throwing errors. The solution I found was to add years. running on Windows 10, Python 3.8. ```stamp = lambda time: datetime.strptime('2020 '+time, '%Y %H:%M').timestamp()``` Is this a known issue? The solution I found was 6 years old. What is up with that?

veky on Feb. 4, 2020, 6:23 a.m.
First, you didn't actually give any useful information. Yes, it creates a time in 1900, but what errors was it "throwing"? Times in 1900 are perfectly legal. I don't have Windows and really don't want to buy it, but on Linux, Python3.8 processes time in 1900 just fine. Second, your solution is paradoxical, and even if it worked that way, you would have to update it every year. :-] (You yourself say that you found a 6 years old solution... I really doubt it said '2020' there.;)) It's completely obvious that the year is irrelevant for this calculation, so having to specify (and update!) it isn't really the way to write maintainable code.

teebu on Feb. 6, 2020, 6:41 p.m.
You're right about the year, not a very good solution, I suspect anything after 1970 will get the job done as it doesn't matter... The error I got with your code and years below 1970: ``` Traceback (most recent call last): File "scipyplaygroup.py", line 10, in <module> line = interp1d([*map(stamp, solutions)], [*solutions.values()]) File "scipyplaygroup.py", line 8, in <lambda> stamp = lambda time: datetime.strptime(time, '%H:%M').timestamp() OSError: [Errno 22] Invalid argument ```

veky on Feb. 6, 2020, 6:55 p.m.
I found a bug that's potentially relevant... <a href="https://bugs.python.org/issue29097,">https://bugs.python.org/issue29097,</a> but it seems it was fixed 17 months ago. Can you report your findings there? I'm quite sure it must be a bug.

Juntian_Deng on March 29, 2021, 7:32 p.m.
what does lambda mean?

veky on March 30, 2021, 10:28 a.m.
It's a way of writing expressions as functions. Same as `def` defines them as statements. <pre class='brush: python'>def stamp(time): return datetime.strptime(time, '%H:%M').timestamp() </pre>

bsquare on Feb. 4, 2024, 10:27 p.m.
Haha @veky, just got randomly on this solution again, so interesting, like always ;) And ofc, so not immediate to read ^^

veky on Feb. 5, 2024, 4:20 a.m.
Ah, scipy isn't really the most readable module written in Python, I know. :-/ But at least the idea is clear, I'd say.

Strings Theory

0 %

PyCharm The Python IDE for Professional Developers. Enjoy productive Python, web and scientific development with PyCharm. Download it now!