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[–] 62 points 1 year ago* (last edited 1 year ago) (9 children)

You think timezones are annoying? Try handling metrics that use imperial and metric, need to be rounded to different precisions across a large system, and are sometimes recorded in a different unit than it's viewed in. Slap some floating point error on there, and you got yourself a fun time.

I spent all day working on bug where backend was categorizing 19.9999 as falling between <20, but frontend was rounding it to 20 and categorizing it as >=20.

Edit: just to be clear, I don’t really think this is more difficult than date/time. But it does remind me a lot of solving date/time issues.

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  • [+] 7 points 1 year ago (1 child)
  • [–] 2 points 1 year ago

    I agree, storing in a consistent unit is the way. That doesn’t solve conversion/rounding issues, but it does simplify things.

    Though you can run into floating point errors when editing in one unit vs storing in another. For example, maybe the user entered 2 in unit A, then it’s converted to unit B and stored in the db. However, when it’s converted back to unit A, it’s 1.999999. Fortunately rounding fixes this. We say unit A and B get 2 decimals of precision, and 1.999999 becomes 2.00.

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  • [–] 3 points 1 year ago (2 children)

    I would say your biggest issue here is needing precise decimal point computations and using imprecise data types. Any software that requires precision in the decimals needs to use types that are made for precise decimals. No floating point error.

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  • [–] 1 point 1 year ago (1 child)

    For this specific project, I need max 2-3 decimal places of precision. So rounding really fixes all the issues. It’s more that we’re preventing the user from seeing awkward decimals. We aren’t doing rocket science. But understanding what metrics need what precision, and sometimes the same metric needs a different precision in different contexts.

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  • [–] 1 point 1 year ago

    In money you can work in cents and round fractions to whole cents in someone's favour depending on policy for example my home accounting program rounds divided amounts up in transfers to the various accounts. It's pretty good right now with a can't being such an insignificant value.

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    [–] 16 points 1 year ago

    Tom Scott's video is about to do the rounds again then

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  • [–] 7 points 1 year ago

    Reading the pytz time zone database is an insane and engaging read.

    Nobody is ever going to solve that problem.

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  • [–] 1 point 1 year ago (2 children)

    Would be better as 4,294,967,295 instead of -1.

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  • [–] 2 points 1 year ago* (1 child)

    The original post would be the result of subtracting the same date in two different time zones that are currently in different days. Whereas what you’re saying is basically just an under flow error.

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  • [–] 2 points 1 year ago (1 child)

    The switch to winter time was last sunday, it's been a fun week at work so far.

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  • [–] 5 points 1 year ago

    One of the worst things about having DST at all is that it is not standardized through world. North America has not switched yet, and people making these announcements make me think my phone is broken.

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  • 1 comment in c/programmerhumor@lemmy.ml view that post
    [–] 12 points 1 year ago

    Just wait until they have to deal with places that don't use full hours to adjust the time.

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