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Calculating base difference of numbersby Anonymous Monk 
on May 30, 2008 at 19:23 UTC ( #689319=perlquestion: print w/replies, xml )  Need Help?? 
Anonymous Monk has asked for the
wisdom of the Perl Monks concerning the following question:
I'm looking at the difference between currency exchange rate updates. Take for example the price change from 1.5553 to 1.5552 In trading terms I can see this is a difference of 1 point since I have a preconceived interpretation of the numbers and how they move. Sometimes my platform gets sent updates that drop trailing 0's after a decimal point. e.g. '100.20' is shown as '100.2', likewise '100.00' is shown as '100'. So how does one work out the point movement from 0.9984 > 0.998 or 100.25 > 100.3? Other than converting the number to a string, calculating the number of decimal places (as x) in both rates and then multiplying the rate by 10^x (where x is the higher count of decimal places between two rates), minus rate 2 from rate 1 and then divide this resulting value by 10^(x1)......is there an easier way...or more specifically a better performing way (mathematical)? Thanks for any input.
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