"normalizing" data

D Yuniskis · 2010-11-26T06:38:38+00:00

Hi,The Back Story: I have a "units calculator" that letsthe user do things like: (1 mi + 5300 ft - 7 yds + 12 in) / 20 min = 6 MPH[assuming I have done the arithmetic correctly tonight]A consequence of this ability is the user can specifythings like "4 ft 3 in" (instead of "4.25 ft").My parser doesn't enforce particular rules on how theuser specifies such values (though, obviously, the unitsmust be similar -- no adding inches to candelas!). So,something like: "3 in 7 yd 5 ft" (!) is legitimate.Issue: There are many places in the application where user*stores* such data (i.e., where it must be "recall-able").I currently do NOT "normalize" the data when re-presentingit to the user. I.e., the above example is regurgitatedas "3 in 7 yd 5 ft" and *not* as "8 yd 2 ft 3 in" (nor as"26 ft 3 in", "26.25 ft", etc.).This recognizes the fact that the user had a reason forspecifying it in a particular manner and silently convertingit to some "normalized" form would only confuse him/her.("Hmmmm... I thought I specified '3 in 7 yd 5 ft'... isthat the same as '26.25 ft'?")[the user can always have the data converted to whatever formhe wants -- including something like "mm fur in"]However, I *do* process his/input to remove "superfluous"characters -- leading trailing zeroes, extra whitespace, etc.This saves an insignificant amount of time in subsequentprocessing of the data. And, an even more insignificantamount of *space*. As such, it seems like my reasons fordoing so are not really justifiable -- why not have theuser ask for "pretty printed" data just like he would/couldask for it to have been converted to other arbitrary units??Furthermore, there can be significance to some of that stuffthat I am stripping off -- "2.000" is different from "2".Comments?Thx,--don

Nov 26, 2010 21 Replies

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D Yuniskis 15 years ago

I've actually had to lecture accountants on this issue. To them, everything is a finite, measurable quantity (e.g., "dollars and cents"). So, to them, "$1" is the same as "100 cents" (i.e., "$1.00"). When asked to audit "non-financial" data, they carry the same assumptions with them -- regardless of the units under scrutiny. :<

And, the whole precision/resolution/accuracy discussion leaves them glassy-eyed and drooling.

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Ulf Samuelsson 15 years ago

D Yuniskis skrev:

Certainly makes me happy I am using the SI system.

Best Regards Ulf Samuelsson These are my own personal opinions, which may or may not be shared by my employer Atmel Nordic AB

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