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I am using this bankers rounding script as a document level script that I found online, Gaussian/Banker's Rounding in JavaScript · GitHub . It works well except it's rounding weird when working with numbers with 3+ decimal places. For example:
55.85 rounds to 55.8 (correct)
55.850 rounds to 55.8 (correct)
55.851 rounds to 55.9 (incorrect)
55.8501 rounds to 55.9 (Incorrect)
Here is the script:
function bankersRound(num,decimalPlaces){
var d = decimalPlaces || 0;
var m = Math.pow(10, d);
var n = +(d ? num * m : num).toFixed(8); // Avoid rounding errors
var i = Math.floor(n), f = n - i;
var e = 1e-8; // Allow for rounding errors in f
var r = (f > 0.5 - e && f < 0.5 + e) ?
((i % 2 == 0) ? i : i + 1) : Math.round(n);
return d ? r / m : r;
}
Any idea how this could be fixed?
Thanks so much
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You should ask the people who wrote this code. This is not something PDF-specific, but a generic JS code.
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Hi,
Try67 is right this is not Acrobat specific code and I think it is rounding correctly ( as per the values, i.e. 55.851 > 55.85 and therefore rounds up) but if you round in stages then I believe you would get the answers you are looking for.
using 55.851 as the starting value.
call bankersRound ( 55.851, 2) // round to one less place than it currently has
result is 55.85
call bankersRound ( 55.85, 1)
result is 55.8 ( your expected result).
this could be done in a loop
// Replace Field names as appropriate.
var curValueToRound = this.getField("Text4").value;
// just making sure we have a string
var valueAsString = "" + initialValue;
// Assuming the number only has one decimal point in it
var numOfDigitsAfterDecimal = valueAsString.split(".")[1].length
// loop until we get to the desired decimal place ( 1)
for ( i = tempValue - 1; i >= 1; i--)
{
curValueToRound = bankersRound ( curValueToRound, i);
}
this.getField("Text8").value = curValueToRound;
Regards
Malcolm
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Your understanding of Bankers' Rounding is different than mine, and presumably different than the author of the script. All the results you quote seem correct to me.
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Have you tried to respond to the source of your code.
There are a number of ways to round, Wikipedia rounding.
You need to clearly state how you expect the rounding to work and for your examples what your expected answer is.