The problem is called Cancellation in Floating Point arithmetic. It occurs
in the subtraction between nearly equivalent operands. If the string can be
represented by a real number, here is a solution I've written for you:
function parseReal(a:String){
var b = a.split('.'), l=b[1].length, b=[Number(b[0]), Number(b[1])], c =
b[1]/Math.pow(10, l);
return b[0]>0? b[0]+c:b[0]-c;
}
var s:String = "-952.86";
var i:Number = parseReal(s);
trace(i);
trace(i - -952.86); //Output: 0
M.
On 3/8/06, Boon Chew <[EMAIL PROTECTED]> wrote:
>
> It might not look like a big deal until you are using Flash to do some
> financial app, where you obtain a number from a string variable, convert it
> to a number, divide it with something and Math.floor it, all the while
> thinking it's the same as taking a number, divide it with something and
> Math.floor it. (The diff can be as big as 1 because of Math.floor).
>
> - boon
>
> Yotam Laufer <[EMAIL PROTECTED]> wrote: -1.13686837721616e-13 is as close
> to zero as you get matey.... 13 places
> after the decimal...
>
> On 07/03/06, Boon Chew wrote:
> >
> >
> > How do you usually deal with the loss in precision (a bit oxymoron since
> > floating point can't be exactly represented) when converting a floating
> > point string to a number?
> >
> > var s:String = "952.86";
> > var i:Number = parseFloat(s);
> > trace(i);
> > trace(i - 952.86); // Not zero!
> >
> >
> > - boon
> >
> >
> >
> >
> > ---------------------------------
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> --
> Yotam Laufer | Flash Developer | mobile +44 (0) 79 205 17 212 | skype:
> ubermutt
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