String to Float, without introducing errors

Peter J. Holzer hjp-python at hjp.at
Sat Dec 17 16:45:12 EST 2022


On 2022-12-17 21:45:06 +0100, Paul St George wrote:
> It was the rounding rounding error that I needed to avoid (as Peter J.
> Holzer suggested). The use of decimal solved it and just in time. I
> was about to truncate the number, get each of the characters from the
> string mantissa, and then do something like this:
> 
> 64550.727
> 
> 64550 + (7 * 0.1) + (2 * 0.01) + (7 * 0.001)

That wouldn't have helped. In fact it would have made matters worse
because instead of a single rounding operation you now have nine!

        hp

-- 
   _  | Peter J. Holzer    | Story must make more sense than reality.
|_|_) |                    |
| |   | hjp at hjp.at         |    -- Charles Stross, "Creative writing
__/   | http://www.hjp.at/ |       challenge!"
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